Author Topic: Gravitational Waves Have Been Detected At LIGO  (Read 41262 times)

Offline Johnnyhinbos

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Gravitational Waves Have Been Detected At LIGO
« on: 01/12/2016 01:43 PM »
So what does / can this mean for spaceflight?
Quote
Not for the first time, the world of physics is abuzz with rumours that gravitational waves have been detected by scientists in the US.

Lawrence Krauss, a cosmologist at Arizona State university, tweeted that he had received independent confirmation of a rumour that has been in circulation for months, adding: “Gravitational waves may have been discovered!!”

http://www.theguardian.com/science/2016/jan/12/gravitation-waves-signal-rumoured-science?CMP=twt_gu
« Last Edit: 02/13/2016 09:42 AM by input~2 »
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Offline Graham

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ESA may have a much harder time justifying LISA
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Offline RonM

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So what does / can this mean for spaceflight?

Nothing, really.

It will be a great moment for science and another conformation of General Relativity. It will advance our knowledge of the universe as gravity wave observations can begin. All of this is at the very high end of energies that has nothing to do with new propulsion or anything else that would directly apply to spaceflight. The big news would be if someone found something that didn't match predictions and would lead to new physics. New physics, especially if it enables the combination of GR and quantum theory, might lead to new technologies that apply to spaceflight.

What to look for in the next few years are the results of observations by LIGO as they start gravity wave astronomy. Also the Event Horizon Telescope project where they are trying to see via radio telescopes the environment around our galaxy's central black hole. These will be the most strenuous tests of GR yet and if there are any deviations from GR in these observations, that might lead to new physics.

http://www.eventhorizontelescope.org/

Offline Rodal

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So what does / can this mean for spaceflight?
Quote
Not for the first time, the world of physics is abuzz with rumours that gravitational waves have been detected by scientists in the US.

Lawrence Krauss, a cosmologist at Arizona State university, tweeted that he had received independent confirmation of a rumour that has been in circulation for months, adding: “Gravitational waves may have been discovered!!”

http://www.theguardian.com/science/2016/jan/12/gravitation-waves-signal-rumoured-science?CMP=twt_gu

It means nothing practical concerning space propulsion during our lifetimes, but here you have:

a patent application  http://www.google.com/patents/US20070001541

a recent paper (2012) http://www.gravwave.com/docs/DirectionsForGWPropGraWaV.pdf

authors that think that "Applications of the present analysis will lead to a unique propulsion system capable of enabling the fast exploration of the solar system, the local star system, and possibly the whole galaxy."

 ;)    ::)
« Last Edit: 01/12/2016 02:17 PM by Rodal »

Offline Star One

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ESA may have a much harder time justifying LISA

I was kind of wondering that when I posted this news in the LISA thread earlier on today?

Offline 1

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ESA may have a much harder time justifying LISA

If the rumors are true (and that's still very much an IF, we shouldn't get to excited yet) I'd hope for the opposite. If we know that there's something out there to observe, it might be a good time to push for the restoration of the original scope of the program. Be really nice if NASA got back on board, but I wouldn't hold my breath.

Offline ppnl

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ESA may have a much harder time justifying LISA

I would think it would be the justification of LISA. First of all a confirmed detection of grav-waves means that LISA should also succeed. Second they are looking at very different wave lengths and amplitudes of grav-waves so they will see very different things.

The point is not to just detect grav-waves. The point is to see stuff by them.

Offline MP99



ESA may have a much harder time justifying LISA

If the rumors are true (and that's still very much an IF, we shouldn't get to excited yet) I'd hope for the opposite. If we know that there's something out there to observe, it might be a good time to push for the restoration of the original scope of the program. Be really nice if NASA got back on board, but I wouldn't hold my breath.

By analogy, astronomers didn't stop with the first detection of radio waves. "Yup, there are radio waves out there - we can stop now."

Cheers, Martin

Offline Star One

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ESA may have a much harder time justifying LISA

If the rumors are true (and that's still very much an IF, we shouldn't get to excited yet) I'd hope for the opposite. If we know that there's something out there to observe, it might be a good time to push for the restoration of the original scope of the program. Be really nice if NASA got back on board, but I wouldn't hold my breath.

By analogy, astronomers didn't stop with the first detection of radio waves. "Yup, there are radio waves out there - we can stop now."

Cheers, Martin

I suppose the question becomes now you can detect them can you do anything with this?

Offline ugordan

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I suppose the question becomes now you can detect them can you do anything with this?

Probe physics (general relativity predictions vs. reality) at levels we were never been able to do so far, using neutron star and/or black hole collisions. It's not an understatement to say that each time we opened a new window into the cosmos, we learned something new. "Seeing" with gravitational waves likely won't be any different.

Offline RonM

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #10 on: 01/13/2016 09:03 PM »
The original topic, as specified in the title of the thread, is not new physics, so it belongs in a different section.

Well the detection of grav-waves is new and it is physics...

But it's the same old physics.

The term "new physics" means physics different from what is commonly accepted by professional physicists.  Gravitational waves are not that.

New experimental results come in all the time in physics.  That doesn't make them "new physics".

What's the point of having a section with "New Physics" in the title if we're not going to follow it?

With that kind of horribly narrow definition you place yourself even further left field than cold fusion & EM drives.

At CERN they use the same definition as ChrisWilson68.

Quote
Any difference between the measured observable and prediction could indicate new physics.

http://home.cern/about/updates/2013/08/tracking-new-physics-horse-or-zebra

That's how physicists define new physics. New observations are advances in science, but it is only a hint toward new physics if the confirmed results do not match theory. If the new observations match theory, then it is a confirmation of the theory, not new physics.

When the Michelson-Morely experiment indicated that the aether did not exist, that was an indication of new physics. Quantum Theory, Special and General Relativity were the new theories that tried to explain the new physics of their day. They have been very successful, but the search for more continues.

When gravity waves are detected by LIGO or other experiments, then we will see if they match the prediction from GR. If not, then there might be some new physics behind the results.

Offline 1

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #11 on: 01/13/2016 10:03 PM »
That's how physicists define new physics. New observations are advances in science, but it is only a hint toward new physics if the confirmed results do not match theory. If the new observations match theory, then it is a confirmation of the theory, not new physics.

When the Michelson-Morely experiment indicated that the aether did not exist, that was an indication of new physics. Quantum Theory, Special and General Relativity were the new theories that tried to explain the new physics of their day. They have been very successful, but the search for more continues.

Respectfully, as a physicist, I feel some clarification is needed here. Subsequent measurements are often advances in existing physics, but brand spankin new measurements are often considered new physics simply because they act as a forcing function on any and all other competing theories. Even GR and QM, as successful as they've proven to be, are understood to be at best incomplete; and are in need of a more generalized, unified theory. At worst, we must still accept the (very remote) possibility that they're both completely wrong. Comfirmation of gravity waves would now require the formulation of any future unified theory to support them. Else, this would not be a strict requirement. In my opinion, the first direct detection of gravity waves, much like the first direct detection of the Higgs boson, would be enough to say we've moved our knowledge into new territory.

To your example, if an aether had been detected, the Michelson-Morely experiment would still have indicated new physics as well. It would have required a new, non-local generalization of Maxwell's equations rather than a new understanding of space and time, but everyone knew something was wrong with those equations; and any result, even an 'expected' one, would lead them in a new direction.

Offline sanman

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #12 on: 01/15/2016 01:58 AM »
Perhaps the discovery of Gravity Waves will further stimulate research and development towards better means of detection. I'd read that atom lasers and atom interferometry could also conceivably be used towards detection and characterization of Gravity Waves:

http://www.scientificamerican.com/article/gravity-space-based-atom-interferometers-could-find-gravitational-waves-video/

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.110.171102

Offline RonM

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #13 on: 01/15/2016 02:06 AM »
That's how physicists define new physics. New observations are advances in science, but it is only a hint toward new physics if the confirmed results do not match theory. If the new observations match theory, then it is a confirmation of the theory, not new physics.

When the Michelson-Morely experiment indicated that the aether did not exist, that was an indication of new physics. Quantum Theory, Special and General Relativity were the new theories that tried to explain the new physics of their day. They have been very successful, but the search for more continues.

Respectfully, as a physicist, I feel some clarification is needed here. Subsequent measurements are often advances in existing physics, but brand spankin new measurements are often considered new physics simply because they act as a forcing function on any and all other competing theories. Even GR and QM, as successful as they've proven to be, are understood to be at best incomplete; and are in need of a more generalized, unified theory. At worst, we must still accept the (very remote) possibility that they're both completely wrong. Comfirmation of gravity waves would now require the formulation of any future unified theory to support them. Else, this would not be a strict requirement. In my opinion, the first direct detection of gravity waves, much like the first direct detection of the Higgs boson, would be enough to say we've moved our knowledge into new territory.

To your example, if an aether had been detected, the Michelson-Morely experiment would still have indicated new physics as well. It would have required a new, non-local generalization of Maxwell's equations rather than a new understanding of space and time, but everyone knew something was wrong with those equations; and any result, even an 'expected' one, would lead them in a new direction.

Then it looks like there isn't an agreement as to what "new physics" means. Kind of makes it a useless phrase.

Offline sanman

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #14 on: 01/15/2016 02:20 AM »
So what does / can this mean for spaceflight?
Quote
Not for the first time, the world of physics is abuzz with rumours that gravitational waves have been detected by scientists in the US.

Lawrence Krauss, a cosmologist at Arizona State university, tweeted that he had received independent confirmation of a rumour that has been in circulation for months, adding: “Gravitational waves may have been discovered!!”

http://www.theguardian.com/science/2016/jan/12/gravitation-waves-signal-rumoured-science?CMP=twt_gu

It means nothing practical concerning space propulsion during our lifetimes, but here you have:

a patent application  http://www.google.com/patents/US20070001541

a recent paper (2012) http://www.gravwave.com/docs/DirectionsForGWPropGraWaV.pdf

authors that think that "Applications of the present analysis will lead to a unique propulsion system capable of enabling the fast exploration of the solar system, the local star system, and possibly the whole galaxy."

 ;)    ::)

So presumably the OP was asking if the discovery of the existence of Gravity Waves could somehow lead us toward generating Gravity Waves ourselves, or otherwise manipulating gravity.

Isn't the Mach Effect Thruster technically supposed to be based on manipulation of inertia and in some sense, gravity?

If atomic interferometry could be used to detect and measure Gravity Waves, then couldn't it also be used to measure effects from a Mach Effect Thruster? I wonder if Paul March / Star-Drive might be able to comment on that.



Offline sanman

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #15 on: 01/17/2016 01:28 AM »
Btw, here is a presentation from NASA's Jason Hogan on the use of atom interferometry in detecting Gravity Waves:


Online Stormbringer

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #16 on: 01/17/2016 10:00 PM »
completely unrelated but totally fascinating gravity stuff:  http://www.sciencedaily.com/releases/2016/01/160108083918.htm
When antigravity is outlawed only outlaws will have antigravity.

Offline NovaSilisko

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #17 on: 01/17/2016 10:07 PM »
"If followed, this proposal could transform physics and shake up Einstein's theory of general relativity."

Well, from this line my skepticism level just smashed through the roof and kept on going. Actually, this is the new physics forum, so that's as mundane a claim as "nice weather we're having".

Offline Mulletron

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #18 on: 01/18/2016 01:51 AM »
I wonder how far this has progressed.
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Offline Star One

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #19 on: 01/18/2016 06:26 AM »

completely unrelated but totally fascinating gravity stuff:  http://www.sciencedaily.com/releases/2016/01/160108083918.htm

Colour me sceptical when we still haven't discovered what fundamentally makes up gravity.

Offline Star One

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« Last Edit: 02/05/2016 08:17 PM by Star One »

Offline birchoff

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #21 on: 02/07/2016 11:20 PM »
I wonder how far this has progressed.

Same here. If it becomes accepted that gravity waves are a physical thing. The next question becomes how do we generate them today within either existing technology or technology we already have on the drawing board but havent funded the engineering for yet.

Offline Star One

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Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #22 on: 02/08/2016 06:22 AM »
I wonder how far this has progressed.

Same here. If it becomes accepted that gravity waves are a physical thing. The next question becomes how do we generate them today within either existing technology or technology we already have on the drawing board but havent funded the engineering for yet.

I can't see how it would be possible to generate these in our foreseeable future at a level that would be useful, considering what it takes in nature to produce them.
« Last Edit: 02/08/2016 06:23 AM by Star One »

Offline Star One

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #23 on: 02/08/2016 11:05 PM »
New Scientist has been having a dig around into the background of this latest rumour and seems to feel we may have some reason to hope for a positive announcement soon.

https://www.newscientist.com/article/2076754-latest-rumour-of-gravitational-waves-is-probably-true-this-time/

Offline sanman

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #24 on: 02/09/2016 02:09 AM »
Well, we all know that New Scientist leans towards pop-sci and tends to hype news stories.

But if Gravity Waves are really a thing, then it should be possible to constructively or destructively combine many tiny such waves together in superposition, shouldn't it?

The Mach Effect apparatus of oscillating masses should be able to produce many tiny waves, and perhaps these waves or their constructive combination could be detected by atom interferometry.

It seems to me that atom interferometry is the key to better detection and analysis of gravity waves. If this budding field of science could be developed, then it would allow gravity waves and their nature to be studied in greater detail.


Online ChrisWilson68

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #25 on: 02/09/2016 02:38 AM »
Well, we all know that New Scientist leans towards pop-sci and tends to hype news stories.

But if Gravity Waves are really a thing, then it should be possible to constructively or destructively combine many tiny such waves together in superposition, shouldn't it?

That's not a "superposition" in the sense of a quantum superposition, so it's better to use a different word to avoid confusion.

Yes, it's possible, but that doesn't really help anything.  You need just as much energy to produce two waves that you combine to a particular magnitude as it would take to just create a wave of that magnitude in the first place.  There's no such thing as a free lunch.

The Mach Effect apparatus of oscillating masses should be able to produce many tiny waves, and perhaps these waves or their constructive combination could be detected by atom interferometry.

Don't bring up the Mach Effect, it has nothing to do with gravitational waves.

Oscillating masses produce tiny waves.  But they're so tiny that you can't produce a measurable gravity wave by combining them without have an impractically large number of them -- as much oscillating mass as if you just had one enormous mass you were oscillating.  Either way, the energy involved is impractical.

That's why nobody has been able to detect gravity waves until now.

Offline Robotbeat

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #26 on: 02/09/2016 02:40 AM »
I wonder how far this has progressed.

Same here. If it becomes accepted that gravity waves are a physical thing. The next question becomes how do we generate them today within either existing technology or technology we already have on the drawing board but havent funded the engineering for yet.
With enormous black holes. I'm not entirely sure this is that "new physics"-y (in the sense of upending existing physics), but if confirmed, has a good chance of a Nobel Prize anyway.
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Offline Star One

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #27 on: 02/09/2016 06:32 AM »

Well, we all know that New Scientist leans towards pop-sci and tends to hype news stories.

But if Gravity Waves are really a thing, then it should be possible to constructively or destructively combine many tiny such waves together in superposition, shouldn't it?

The Mach Effect apparatus of oscillating masses should be able to produce many tiny waves, and perhaps these waves or their constructive combination could be detected by atom interferometry.

It seems to me that atom interferometry is the key to better detection and analysis of gravity waves. If this budding field of science could be developed, then it would allow gravity waves and their nature to be studied in greater detail.

I am not sure commentary on what New Scientist does or doesn't do is warranted in this case, especially in light of the wider background on this story. I'd rather be positive that they've actually done a bit of extra legwork in this case.

Offline birchoff

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #28 on: 02/09/2016 04:41 PM »
I wonder how far this has progressed.

Same here. If it becomes accepted that gravity waves are a physical thing. The next question becomes how do we generate them today within either existing technology or technology we already have on the drawing board but havent funded the engineering for yet.

I can't see how it would be possible to generate these in our foreseeable future at a level that would be useful, considering what it takes in nature to produce them.

Dont think I am as pessimestic. "OBSERVED" Nature has not needed to do the things we want to do. Therefore I feel its safe to argue that the way nature generates G-Waves is more a side effect of other things it needed to do. Now, My next question is, How hard have we honestly looked at the possibility for generating Gravity waves. How much curiosity has been road blocked in the quest to generate them, because we didnt know if they were simply a mathematical artifact or a physical object?

In addition if g-waves are simply vibrations of space time and all mass deforms space time. Then Energy deforms space time since all mass is energy. Now that c2 part of the calculation leads to you needing alot of energy to equal the changes that asteroids, comets, planets, stars and black holes make to space time. However, energy at least in the form of EM can do something those other forms cant or at the very least havent been observed to do.  Resonate. The first question I would love to see an answer to is if there is a frequency at which EM can resonate that would amplify the small  changes to space time that it naturally makes.


Offline Star One

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Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #29 on: 02/09/2016 08:51 PM »
If this is confirmed and current testing of the technology in space goes well is there any room for the development and launch of LISA to be moved up?
« Last Edit: 02/09/2016 08:51 PM by Star One »

Offline sanman

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #30 on: 02/10/2016 12:40 AM »
That's not a "superposition" in the sense of a quantum superposition, so it's better to use a different word to avoid confusion.

"superposition" can be used to describe behavior of either waves or particles ("quantum")

https://en.wikipedia.org/wiki/Superposition_principle#Wave_superposition

Anyway, we can say "wave interference" if that sounds better.


Quote
Yes, it's possible, but that doesn't really help anything.  You need just as much energy to produce two waves that you combine to a particular magnitude as it would take to just create a wave of that magnitude in the first place.  There's no such thing as a free lunch.

Well, we manipulate EM waves for various purposes, so likewise we could theorize at how to analogously manipulate gravity waves to study how gravity waves behave.


Quote
Don't bring up the Mach Effect, it has nothing to do with gravitational waves.

Alright, "Mach Effect" is an unverified conjecture, while Gravitational Waves are classical physics predicted by General Relativity. I was simply referring to the apparatus that uses oscillating masses, and not the conjecture itself. However, as a side-note, once Gravitational Waves are fully verified as real, then it would impact the theoretical conjecture around the possible Mach Effect.


Quote
Oscillating masses produce tiny waves.  But they're so tiny that you can't produce a measurable gravity wave by combining them without have an impractically large number of them -- as much oscillating mass as if you just had one enormous mass you were oscillating.  Either way, the energy involved is impractical.

That's why nobody has been able to detect gravity waves until now.

Whether a wave is tiny depends on what means you're using to detect it - as Einstein said, everything is relative.
That's why I mentioned atom interferometry - that method is capable of much greater sensitivity than LIGO.
It's a newer method, but one which now deserves to be developed further to help shed more light on things that light doesn't do as well on through classical interferometry.

While the Gravitational Waves LIGO is purported to have detected were generated by very large astrophysical phenomena (ie. colliding black holes), LIGO is detecting the waves from those phenomena across a very large distance of many lightyears. So while a man-made experimental apparatus that oscillates some masses is far smaller than massive black holes, at least the apparatus could be operated much closer to the detector, so that the falloff from R^2 isn't happening across many lightyears of distance. Yes, size matters - but distance matters too.

But if atom interferometers could be developed further, not only could they be used to detect the Gravitional Waves generated by large astrophysical phenomena that LIGO is detecting, but their high sensitivity could be used to one day measure man-made gravitational waves (ie. like from a tabletop apparatus with oscillating masses).

Learning how to manipulate gravity by exploiting its wave nature might not necessarily be for pulling objects. Perhaps we might learn how to create and modulate gravity waves for communications purposes, for example, just as we do with EM waves.
« Last Edit: 02/10/2016 05:57 AM by sanman »

Offline ppnl

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #31 on: 02/10/2016 06:58 AM »
Detecting gravity waves may be new physics but it isn't unexpected physics. What would be surprising is if they didn't detect gravity waves. And if you are hoping for a gravity based propulsion system then it may be better to hope that gravity waves are not detected. That at least gives you a mystery that may resolve into an unexpected finding that gives you your gravity drive.

Anyway they are expected to announce on the 11th.

Offline Star One

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Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #32 on: 02/10/2016 08:06 AM »
Detecting gravity waves may be new physics but it isn't unexpected physics. What would be surprising is if they didn't detect gravity waves. And if you are hoping for a gravity based propulsion system then it may be better to hope that gravity waves are not detected. That at least gives you a mystery that may resolve into an unexpected finding that gives you your gravity drive.

Anyway they are expected to announce on the 11th.

Yes this is a big discovery, but one of the main things it does is reconfirm what a genius Einstein was, but then we already knew that.:)
« Last Edit: 02/10/2016 08:06 AM by Star One »

Offline eeergo

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #33 on: 02/10/2016 10:03 AM »
I wonder how far this has progressed.

Same here. If it becomes accepted that gravity waves are a physical thing. The next question becomes how do we generate them today within either existing technology or technology we already have on the drawing board but havent funded the engineering for yet.

I can't see how it would be possible to generate these in our foreseeable future at a level that would be useful, considering what it takes in nature to produce them.

Dont think I am as pessimestic. "OBSERVED" Nature has not needed to do the things we want to do. Therefore I feel its safe to argue that the way nature generates G-Waves is more a side effect of other things it needed to do. Now, My next question is, How hard have we honestly looked at the possibility for generating Gravity waves. How much curiosity has been road blocked in the quest to generate them, because we didnt know if they were simply a mathematical artifact or a physical object?

In addition if g-waves are simply vibrations of space time and all mass deforms space time. Then Energy deforms space time since all mass is energy. Now that c2 part of the calculation leads to you needing alot of energy to equal the changes that asteroids, comets, planets, stars and black holes make to space time. However, energy at least in the form of EM can do something those other forms cant or at the very least havent been observed to do.  Resonate. The first question I would love to see an answer to is if there is a frequency at which EM can resonate that would amplify the small  changes to space time that it naturally makes.

If we consider the rumored 36+29=62 solar mass merger to be near our detectable threshold, then 3 solar masses were emitted as gravitational waves. Even if this is conservative and surely the merger emitted something else, it's probably safe to say the order of magnitude is right. This equates an energy release on the order of 10^30 kg = 10^30 eV/c^2 = 1,000,000 YeV/c^2 = one-hundred (short-scale) septillion TeV. Nowadays, we are able to produce ~10 TeV of center-of-mass energy with protons, around a factor of 10000 more in the lab frame: 10^17 eV. So just rounding things up to the largest measured energies, let's say we can in the foreseeable future control beams of ~10^20 eV=0.1 ZeV (not really, but just for the sake of argument). Of course, you need overtones to create resonance, so this is an unrealistically optimistic number.

We are a factor of 10 quintillion (10^19) away.

The largest Q factors achieved (for systems that in principle have nothing to do with the hypothetical high energy beams above) are ~10^11, so even in the most wildly optimistic case, we'd still be incapable of resonating anything hard enough to create gravitational waves, by a factor of almost a billion. And in any scenario approachin reality, by much, much more.
-DaviD-

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #34 on: 02/10/2016 10:11 AM »
We are a factor of 10 quintillion (10^19) away.

It's probably less extreme than that once you factor in the (as yet unknown) distance losses.

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #35 on: 02/10/2016 11:31 AM »
We are a factor of 10 quintillion (10^19) away.

It's probably less extreme than that once you factor in the (as yet unknown) distance losses.

Current theories give a spacetime damping characteristic time greater than the age of the universe.
-DaviD-

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #36 on: 02/10/2016 09:20 PM »
Some details on the expected announcement tomorrow.

Quote
This year marks the 100th anniversary of the first publication of Albert Einstein’s prediction of the existence of gravitational waves. With interest in this topic piqued by the centennial, researchers from UK universities in Glasgow, Birmingham, and Cardiff will discuss their ongoing efforts to observe and measure cosmic gravitational waves for scientific research at the Science Media Centre in London starting 3pm GMT on Thursday, 11 February.
Simultaneously in the US, the National Science Foundation is gathering scientists from Caltech, MIT, and the LIGO Scientific Collaboration (LSC) at the National Press Club in Washington, DC for a status report on the effort to detect gravitational waves — or ripples in the fabric of spacetime — using the Laser Interferometer Gravitational-wave Observatory (LIGO).

http://astronomynow.com/2016/02/10/scientists-to-provide-update-on-the-search-for-gravitational-waves/

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #37 on: 02/11/2016 01:57 PM »
Announcement 10:30am ET


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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #38 on: 02/11/2016 02:22 PM »
We're live! :)
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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #39 on: 02/11/2016 02:34 PM »
We did it!! 8)
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Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #40 on: 02/11/2016 02:37 PM »
Signal detected 14 September, 2015.

The two black holes are indeed about 30 solar masses. They are about 1.3 billion light years away.
« Last Edit: 02/11/2016 03:07 PM by Star One »

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #41 on: 02/11/2016 02:42 PM »
The two black holes are indeed about 30 solar masses. They are about 1.3 billion light years away.

Well, *were*. It's now just one black hole. :)

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #42 on: 02/11/2016 02:50 PM »
This time the rumours were exactly right, except that the papers are published in PRL and ApJ instead of Nature.

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #43 on: 02/11/2016 03:04 PM »
Kip Thorne cannot wait to ride those waves orbiting one of those mergers :)
-DaviD-

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #44 on: 02/11/2016 03:07 PM »
20 ms merger. During that time, the energy output was 50 times the energy released by ALL the stars in the Universe.
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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #45 on: 02/11/2016 03:09 PM »
The signal came from the Southern sky, in the rough direction of the Magellanic clouds, the satellite galaxies of the Milky Way. At 1.3 billion light years away, however, it is very far beyond the Magellanic clouds, deep in intergalactic space somewhere.

We have only seen spacetime like the surface on a calm ocean until now, says Thorne. Now, we are seeing a storm!

The ‘storm’, meaning the collision of the black holes, lasted for just 20 milliseconds. In that brief moment, it generated 50 times the power of all the stars in the Universe put together.

It was the equivalent of taking three stars, each the size of the Sun, and annihilating them into pure energy. Wow!

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #46 on: 02/11/2016 03:12 PM »
"Einstein would be beaming today"

France Cordova
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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #47 on: 02/11/2016 03:13 PM »
(Cleaned up) signals in the LIGO teams in Louisiana (blue) and Washington (orange):

http://apod.nasa.gov/apod/ap160211.html
-DaviD-

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #48 on: 02/11/2016 03:14 PM »
Dr Ed Daw has been researching gravitational waves with LIGO since 1998. He works in the Physics at the University of Sheffield, and sends the following reaction.

Discoveries of this importance in Physics come along about every 30 years. A measure of its significance is that even the source of the wave - two black holes in close orbit, each tens of times heavier than the sun, which then collide violently, has never been observed before, and could not have been observed by any other method. This is just the beginning.

Imagine that your T.V. had only ever received one channel on which the shows were all rather similar to each other. One day a second one appeared which showed completely different programs, like nothing that had ever been broadcast on the old channel. Wouldn’t you want to switch over? By detecting this signal, LIGO has effectively tuned in to a new channel - a completely new way of observing the Universe.

Gravitational waves are so completely different from light, we’re probably only just beginning to understand how they reflect and shape our Universe. For example, a gravitational wave will propagate almost completely unaltered through entire planets, star systems, galaxies....how different is that from the radio waves that your mobile phone picks up - even getting too close to a building can disrupt those signals. Light, or more generally electromagnetic waves are so much more vulnerable to interference than gravitational waves.

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #49 on: 02/11/2016 03:21 PM »
Advanced LIGO is still expected to increase its sensitivity by a factor of 3.

It is expected this year more signals are going to be detected.
-DaviD-

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #50 on: 02/11/2016 03:26 PM »
Thorne says that we expect to see more signals from similar sources within the next year. Tweeks and improvements will advance LIGO’s sensitivity by about three times. He promises, “A huge richness of gravitational wave signals in LIGO.”

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #51 on: 02/11/2016 03:34 PM »
Signal-to-noise ratio of 24, according to the paper's abstract (which is the only thing I can access right now since APL is down :O )
-DaviD-

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #52 on: 02/11/2016 03:36 PM »
VIRGO (another detector in Italy with similar sensitivity) will join the network this year, improving the collaboration's ability to locate the sources.
« Last Edit: 02/11/2016 03:36 PM by eeergo »
-DaviD-

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #53 on: 02/11/2016 03:39 PM »
Graviton mass limit has been lowered to 10^-55 kg (!!!!), basically confirming it's massless.

Whether or not it exists, or in general how Quantum Gravity may be formulated, is still up for debate. It has just been confirmed gravitational waves propagate at the speed of light.
« Last Edit: 02/11/2016 03:41 PM by eeergo »
-DaviD-

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Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #54 on: 02/11/2016 03:52 PM »
Criticism for NASA.

Rainer Weiss laments NASA’s decision to pull of the space-based gravitational wave observatory LISA, and praises Europe’s determination to ‘go it alone’ with the eLISA mission and LISA Pathfinder. But he hopes for a new collaboration.

@DrStuClark Gravitational Waves sound like Radiohead's Planet Telex intro, from album The Bends. #spooky

https://mobile.twitter.com/ClickConsultLtd/status/697819704732291072?ref_src=twsrc%5Etfw

final question of the webcast press conference is whether LIGO has seen other signals. Gonzalez answers very carefully placing the emphasis back on the signal announced today. As she finishes one of her fellow panellists quips ‘that didn’t even sound rehearsed’.

Hmmm. What should we make of that?
« Last Edit: 02/11/2016 03:56 PM by Star One »

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #55 on: 02/11/2016 04:00 PM »

Imagine that your T.V. had only ever received one channel on which the shows were all rather similar to each other. One day a second one appeared which showed completely different programs, like nothing that had ever been broadcast on the old channel. Wouldn’t you want to switch over? By detecting this signal, LIGO has effectively tuned in to a new channel - a completely new way of observing the Universe.

Gravitational waves are so completely different from light, we’re probably only just beginning to understand how they reflect and shape our Universe. For example, a gravitational wave will propagate almost completely unaltered through entire planets, star systems, galaxies....how different is that from the radio waves that your mobile phone picks up - even getting too close to a building can disrupt those signals. Light, or more generally electromagnetic waves are so much more vulnerable to interference than gravitational waves.

I'm just going to point out that if I wanted to create the perfect SETI signal.  This would be the way to do it...

Our technology may have just reached the point where we can begin to hear constant beacons from civilizations though out the universe since the dawn of time that can both detect and generate gravitational waves.

We can take any discussion of SETI over to a SETI thread: http://forum.nasaspaceflight.com/index.php?topic=39571.msg1490597#msg1490597
« Last Edit: 02/11/2016 04:08 PM by sghill »
Bring the thunder Elon!

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #56 on: 02/11/2016 04:02 PM »

final question of the webcast press conference is whether LIGO has seen other signals. Gonzalez answers very carefully placing the emphasis back on the signal announced today. As she finishes one of her fellow panellists quips ‘that didn’t even sound rehearsed’.

Hmmm. What should we make of that?

Rumours have been about (at least) two signals and given that they were almost exactly right about the details of the first detection, I'm pretty sure they're also right about there already being another.

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #57 on: 02/11/2016 04:14 PM »
Some more details from the paper:

- Signal GW150914 was recorded on September 14, 2015 at 09:50:45 UTC, and was automatically selected as interesting 3 minutes later.

- The signal took ~7ms to arrive from Louisiana to Handford, providing the clues about its origin in the Southern sky.

- No other detector was observing at the time (VIRGO was being upgraded, GEO600 wouldn't be sensitive and anyway was not in observational mode).

- Raw signal is actually audible by human ears :) in the 35-150 Hz range, and is 8 cycles long.

- AdvLIGO's sensitivity is only in this band because of "photon shot" noise above (I suppose that means the frequency of the laser on the mirrors) and several other noises below. There are still "peaks" of noise in the window because of calibration channels and power grid noise.

- Pressure in the volumes where the beam passes is <1µPa = 10^-11 atm: practically the "atmospheric pressure" at the ISS altitude (10^-12 atm).

- Injections of fake signals for verification is done through pumping sample signals with the laser.

[more on this post http://forum.nasaspaceflight.com/index.php?topic=39297.msg1490665#msg1490665]
« Last Edit: 02/11/2016 06:07 PM by eeergo »
-DaviD-

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #58 on: 02/11/2016 04:19 PM »
What will Gravity Astronomy mainly be aimed at uncovering? Presumably, it's going to be biased towards more massive events - big stuff like black holes and galaxies colliding, or neutron stars.

Besides investigating astrophysical phenomena, how could Gravity Astronomy answer questions in fundamental physics?
« Last Edit: 02/11/2016 04:21 PM by sanman »

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Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #59 on: 02/11/2016 04:24 PM »
What will Gravity Astronomy mainly be aimed at uncovering? Presumably, it's going to be biased towards more massive events - big stuff like black holes and galaxies colliding, or neutron stars.

Besides investigating astrophysical phenomena, how could Gravity Astronomy answer questions in fundamental physics?

It can look through the barrier around the Big Bang.



Imagine that your T.V. had only ever received one channel on which the shows were all rather similar to each other. One day a second one appeared which showed completely different programs, like nothing that had ever been broadcast on the old channel. Wouldn’t you want to switch over? By detecting this signal, LIGO has effectively tuned in to a new channel - a completely new way of observing the Universe.

Gravitational waves are so completely different from light, we’re probably only just beginning to understand how they reflect and shape our Universe. For example, a gravitational wave will propagate almost completely unaltered through entire planets, star systems, galaxies....how different is that from the radio waves that your mobile phone picks up - even getting too close to a building can disrupt those signals. Light, or more generally electromagnetic waves are so much more vulnerable to interference than gravitational waves.

I'm just going to point out that if I wanted to create the perfect SETI signal.  This would be the way to do it...

Our technology may have just reached the point where we can begin to hear constant beacons from civilizations though out the universe since the dawn of time that can both detect and generate gravitational waves.

We can take any discussion of SETI over to a SETI thread: http://forum.nasaspaceflight.com/index.php?topic=39571.msg1490597#msg1490597

Time to observe Tabby's star.
« Last Edit: 02/11/2016 04:25 PM by Star One »

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #60 on: 02/11/2016 04:36 PM »
There's a very good article in Quanta:

https://www.quantamagazine.org/20160211-gravitational-waves-discovered-at-long-last/

That article actually confirms that another weaker signal was seen a few weeks later (and now I'm hearing that there's been "several" weaker signals).

Edit:

In this New York Times article Weiss confirms that there were at least four detections in the first run:

http://www.nytimes.com/2016/02/12/science/ligo-gravitational-waves-black-holes-einstein.html?_r=0

Edit 2: fixed link
« Last Edit: 02/11/2016 04:53 PM by as58 »

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« Last Edit: 02/11/2016 04:53 PM by Rocket Science »
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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #62 on: 02/11/2016 04:59 PM »
Just a note: this discovery is a resounding confirmation of EXISTING physics theories, not new physics. It's new experimental evidence of the existing theory developed by Einstein 100 years ago.


LIGO may go on to discover new physics, but so far this is a resounding (heh) confirmation of our existing theories.
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Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #63 on: 02/11/2016 05:52 PM »
There's a very good article in Quanta:

https://www.quantamagazine.org/20160211-gravitational-waves-discovered-at-long-last/

That article actually confirms that another weaker signal was seen a few weeks later (and now I'm hearing that there's been "several" weaker signals).

Edit:

In this New York Times article Weiss confirms that there were at least four detections in the first run:

http://www.nytimes.com/2016/02/12/science/ligo-gravitational-waves-black-holes-einstein.html?_r=0

Edit 2: fixed link

Binary Neutron stars? Which was the other phenomena they were looking to detect.
« Last Edit: 02/11/2016 05:53 PM by Star One »

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #64 on: 02/11/2016 06:00 PM »
Binary Neutron stars? Which was the other phenomena they were looking to detect.

Probably supernovae?

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #65 on: 02/11/2016 06:07 PM »
[continues the paper highlights from this post http://forum.nasaspaceflight.com/index.php?topic=39297.msg1490602#msg1490602]

- Spin of the primary black hole is reasonably well understood, while the second's is weakly constrained.

- 3.0±0.5 solar masses (x c^2) were released exclusively in the form of gravitational waves (which ties into the previous discussion about artificial production).

- A Kerr (rotating) black hole is the result from the merger, and the signal is consistent with expectations.

- Graviton mass constraint: m_g < 1.2·10^-22 eV/c^2 (lower than that of the photon, FWIW). Better limits were already achieved with other model dependent bounds, but not with independently-observed ones.

- This is a direct proof of the existence of dozen-solar-mass class black holes, the existence of binaries and capability of merging. This wasn't proven before.

- It is expected there is a constant gravitational wave background of orbiting binaries which permeates the Universe. A large single wave has been detected, but there is a stormy sea underneath.
-DaviD-

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #66 on: 02/11/2016 06:11 PM »
- 3.0±0.5 solar masses (x c^2) were released exclusively in the form of gravitational waves (which ties into the previous discussion about artificial production).
What would that even look like up close? What would that intensity of gravitational wave energy do to things?

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #67 on: 02/11/2016 06:11 PM »
Another in-depth, behind-the-scenes article:

http://www.newyorker.com/tech/elements/gravitational-waves-exist-heres-how-scientists-finally-found-them

Seems that many reporters have received the word in advance under embargo.

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #68 on: 02/11/2016 06:12 PM »
Argentinians not only deploy huge flags on Arianespace launches, but also huge foulards in science press conferences  ;D
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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #69 on: 02/11/2016 06:18 PM »
How do they know the distance between us and the event?

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #70 on: 02/11/2016 06:18 PM »
Will Gravitational Astronomy help us to verify Dark Matter? That's supposed to have mass, but is otherwise undetectable on the EM spectrum.
Would it be possible for Gravitational Astronomy to differentiate between Dark Matter and regular matter - perhaps by cross-referencing with classical forms of astronomical observation?
« Last Edit: 02/11/2016 06:29 PM by sanman »

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #71 on: 02/11/2016 06:19 PM »
- 3.0±0.5 solar masses (x c^2) were released exclusively in the form of gravitational waves (which ties into the previous discussion about artificial production).
What would that even look like up close? What would that intensity of gravitational wave energy do to things?

I have no idea of the subtleties (and I hope to never discover firsthand ;) ) but for sure you'd see a "stretching" of depth/height/width with the observed frequency (35-100 Hz). So stretching also my imagination, I suppose you'd see a kind of flickering of "reality" by which it would be difficult to judge distances. Time distortions would possibly average out in "human" timescales.

I don't think the amplitude of the distortions, even relatively close, would be enough to see something "by eye" though. You'd probably need to be really up close to the binary, in which case there would be plenty of other effects. Since deformed space leaves matter particles relatively unaffected, if the amplitude of the waves was big enough it would possibly rip things apart, maybe even atoms themselves.
-DaviD-

Offline Rodal

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #72 on: 02/11/2016 06:22 PM »
Argentinians not only deploy huge flags on Arianespace launches, but also huge foulards in science press conferences  ;D
And they also did better than Spain and Italy at the last World Soccer Cup  ;)

Argentina #2
Italy and Spain did not make into the round of 16
Best player: Lionel Messi

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #73 on: 02/11/2016 06:24 PM »
Quote
February 11, 2016

Dear MIT graduate,

At about 10:30 this morning in Washington, D.C., MIT, Caltech and the National Science Foundation (NSF) will make a historic announcement in physics: the first direct detection of gravitational waves, a disturbance of space-time that Albert Einstein predicted a century ago.

You can read an overview of the discovery here as well as an interview with MIT Professor Emeritus Rainer Weiss PhD '62, instigator and a leader of the Laser Interferometer Gravitational-Wave Observatory (LIGO) effort.

The beauty and power of basic science
I do not typically write to you to celebrate individual research achievements, no matter how impressive; our community produces important work all the time. But I urge you to reflect on today’s announcement because it demonstrates, on a grand scale, why and how human beings pursue deep scientific questions – and why it matters.

Today's news encompasses at least two compelling stories.

First is the one the science tells: that with his theory of general relativity, Einstein correctly predicted the behavior of gravitational waves, space-time ripples that travel to us from places in the universe where gravity is immensely strong. Those rippling messages are imperceptibly faint; until now, they had defied direct observation. Because LIGO succeeded in detecting these faint messages – from two black holes that crashed together to form a still larger one – we have remarkable evidence that the system behaves exactly as Einstein foretold.

With even the most advanced telescopes that rely on light, we could not have seen this spectacular collision, because we expect black holes to emit no light at all. With LIGO's instrumentation, however, we now have the "ears" to hear it. Equipped with this new sense, the LIGO team encountered and recorded a fundamental truth about nature that no one ever has before. And their explorations with this new tool have only just begun. This is why human beings do science!

The second story is of human achievement. It begins with Einstein: an expansive human consciousness that could form a concept so far beyond the experimental capabilities of his day that inventing the tools to prove its validity took a hundred years.

That story extends to the scientific creativity and perseverance of Rai Weiss and his collaborators. Working for decades at the edge of what was technologically possible, against the odds Rai led a global collaboration to turn a brilliant thought experiment into a triumph of scientific discovery.

Important characters in that narrative include the dozens of outside scientists and NSF administrators who, also over decades, systematically assessed the merits of this ambitious project and determined the grand investment was worth it. The most recent chapter recounts the scrupulous care the LIGO team took in presenting these findings to the physics community. Through the sacred step-by-step process of careful analysis and peer-reviewed publication, they brought us the confidence to share this news – and they opened a frontier of exploration.

At a place like MIT, where so many are engaged in solving real-world problems, we sometimes justify our nation's investment in basic science by its practical byproducts. In this case, that appears nearly irrelevant. Yet immediately useful "results" are here, too: LIGO has been a strenuous training ground for thousands of undergraduates and hundreds of PhDs – two of them now members of our faculty.

What's more, the LIGO team's technological inventiveness and creative appropriation of tools from other fields produced instrumentation of unprecedented precision. As we know so well at MIT, human beings cannot resist the lure of a new tool. LIGO technology will surely be adapted and developed, "paying off" in ways no one can yet predict. It will be fun to see where this goes.
 
*        *        *
The discovery we celebrate today embodies the paradox of fundamental science: that it is painstaking, rigorous and slow – and electrifying, revolutionary and catalytic. Without basic science, our best guess never gets any better, and "innovation" is tinkering around the edges. With the advance of basic science, society advances, too.

I am proud and grateful to belong to a community so well equipped to appreciate the beauty and meaning of this achievement – and primed to unlock its opportunities.

In wonder and admiration,

L. Rafael Reif

Offline eeergo

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #74 on: 02/11/2016 06:27 PM »
How do they know the distance between us and the event?

It is a model-dependent determination (meaning it's based on assumptions), considering the standard cosmological models (ostensibly ΛCDM refined with Planck data).

They measured the redshift (I'm not sure how, since this event was not accompanied by electromagnetic (i.e. light/X-ray/UV...) detection, so it's not obvious to me what reference they used for "redshifted gravitational waves" - maybe Jonathan can help? :) ) and, assuming this standard Universe expansion model, got a distance value that would cause that redshift. This turned out to be between 250 and 570 megaparsecs.
-DaviD-

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #75 on: 02/11/2016 06:31 PM »
How do they know the distance between us and the event?

If I understood it correctly, using the observed shape of the waveform one can infer the masses involved and then the theory also gives you the energy (or power?) radiated. Then you go back to the observed amplitude of the oscillations (a.k.a. the local "strain") and, via the inverse square law, can work out the distance. With a certain error bar, of course.
« Last Edit: 02/11/2016 06:33 PM by ugordan »

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #76 on: 02/11/2016 06:32 PM »
What would that even look like up close? What would that intensity of gravitational wave energy do to things?

Unless I messed up my back-of-the-envelope calculations, even only 1 AU from the black hole pair the strain would be at parts per billion level.

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Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #77 on: 02/11/2016 06:41 PM »
How do they know the distance between us and the event?

Isn't that what they need the third detector to come online for to help with this?
« Last Edit: 02/11/2016 06:42 PM by Star One »

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #78 on: 02/11/2016 06:42 PM »
They measured the redshift (I'm not sure how, since this event was not accompanied by electromagnetic (i.e. light/X-ray/UV...) detection, so it's not obvious to me what reference they used for "redshifted gravitational waves" - maybe Jonathan can help? :) ) and, assuming this standard Universe expansion model, got a distance value that would cause that redshift. This turned out to be between 250 and 570 megaparsecs.

Aren't these ultra-violent astrophysical events like Supernova explosions and Black Hole collisions supposed to give off gamma-ray bursts at the same time? Shouldn't they have detected an accompanying gamma-ray burst signal simultaneously in connection with the gravity waves?

Offline as58

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #79 on: 02/11/2016 06:43 PM »
How do they know the distance between us and the event?

If I understood it correctly, using the observed shape of the waveform one can infer the masses involved and then the theory also gives you the energy (or power?) radiated. Then you go back to the observed amplitude of the oscillations (a.k.a. the local "strain") and, via the inverse square law, can work out the distance. With a certain error bar, of course.

Yes, that gives the luminosity distance (for very far away objects there are several "distances"). They just convert the luminosity distance to redshift, because that's what everyone is used to in cosmology/extragalactic astronomy.

Edit: The conversion from luminosity distance to redshift does depend on the cosmological model as eeergo mentioned, but in this case the merger was close enough so that it doesn't have a large effect.
« Last Edit: 02/11/2016 06:54 PM by as58 »

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #80 on: 02/11/2016 06:44 PM »
Isn't that what they need the third detector to come online for to help with this?

They need it to better be able to triangulate the source direction in the sky. The more the better.

Offline eeergo

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #81 on: 02/11/2016 06:45 PM »
How do they know the distance between us and the event?

Isn't that what they need the third detector to come online for to help with this?

That's for directionality.
-DaviD-

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #82 on: 02/11/2016 06:45 PM »
They measured the redshift (I'm not sure how, since this event was not accompanied by electromagnetic (i.e. light/X-ray/UV...) detection, so it's not obvious to me what reference they used for "redshifted gravitational waves" - maybe Jonathan can help? :) ) and, assuming this standard Universe expansion model, got a distance value that would cause that redshift. This turned out to be between 250 and 570 megaparsecs.

Aren't these ultra-violent astrophysical events like Supernova explosions and Black Hole collisions supposed to give off gamma-ray bursts at the same time? Shouldn't they have detected an accompanying gamma-ray burst signal simultaneously in connection with the gravity waves?

Not if they're non-accreting.
-DaviD-

Offline Star One

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Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #83 on: 02/11/2016 06:53 PM »
Isn't that what they need the third detector to come online for to help with this?

They need it to better be able to triangulate the source direction in the sky. The more the better.

Judging by the article they should have five soon.

Quote
Sir Alex Ferguson
Sir Alex Ferguson –  ‏@Furious_Fergie

Just had Wayne Rooney on the phone asking if gravitational waves are like Mexican waves.

I just said aye.

https://mobile.twitter.com/Furious_Fergie/status/697866904019582979

http://xkcd.com/1642/
« Last Edit: 02/11/2016 07:00 PM by Star One »

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #84 on: 02/11/2016 06:57 PM »
What would that even look like up close? What would that intensity of gravitational wave energy do to things?

Unless I messed up my back-of-the-envelope calculations, even only 1 AU from the black hole pair the strain would be at parts per billion level.
I did some back of the envelope calculations myself that could be wrong. The energy this event unleashed was within a couple of orders of magnitude to what a supernova releases. Of course a supernova releases that energy not as gravitational waves but as thermal, electromagnetic, and neutrino radiation. This event released that much energy purely as gravitational waves. A supernova will ruin anyone's day within several dozens of light years. It is odd to think of that much energy being released and not harming anything a light year or further away let alone being inseparable.
« Last Edit: 02/11/2016 06:58 PM by notsorandom »

Offline Rocket Science

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #85 on: 02/11/2016 07:04 PM »
Einstein was right...again! ;D
"The laws of physics are unforgiving"
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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #86 on: 02/11/2016 07:21 PM »
Jaunty MIT video.


Offline eeergo

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #87 on: 02/11/2016 07:23 PM »
Actually it's more like 4 orders of magnitude... https://en.m.wikipedia.org/wiki/Orders_of_magnitude_(energy) but I agree with the idea :0
« Last Edit: 02/11/2016 07:23 PM by eeergo »
-DaviD-

Offline Kimight

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #88 on: 02/11/2016 07:58 PM »
If my understanding is correct; the energy contained in the waves can be be measured either by the frequency or amplitude of these waves. I am however quite curious as to how LIGO would fare if the waves hit the detectors at an angle of (pi/4) or (5*pi/4). Assuming of course the two detectors are at an angle of (pi/2).

My guess is that they can calculate time dilations since they know the length of the detectors and the speed of light, but wouldn't a third detector increase the ability to filter out noise with better accuracy, even better than having multiple detectors scattered around the world?
« Last Edit: 02/11/2016 08:14 PM by Kimight »

Offline notsorandom

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #89 on: 02/11/2016 08:06 PM »
Actually it's more like 4 orders of magnitude... https://en.m.wikipedia.org/wiki/Orders_of_magnitude_(energy) but I agree with the idea :0
There is a neutrino pulse in core collapse supernovas that has about 1046 Joules though some of his gets reabsorbed in the process of the collapse driving the explosion. It is crazy to think about an explosion driven by a particle that rarely interacts with anything.

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Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #90 on: 02/11/2016 09:22 PM »
Very good New Yorker article not just on the project's history, but also confirms other weaker signals are coming down the line.

http://www.newyorker.com/tech/elements/gravitational-waves-exist-heres-how-scientists-finally-found-them
« Last Edit: 02/11/2016 09:22 PM by Star One »

Offline FinalFrontier

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #91 on: 02/11/2016 10:40 PM »
Another article
http://www.sciencemag.org/news/2016/02/gravitational-waves-einstein-s-ripples-spacetime-spotted-first-time

This is so exciting. We might finally be getting closer to understanding how and what gravity actually is. If we can crack that nut it may eventually be possible for us to get to make artificial gravity a thing. That would have HUGE impacts for our entire civilization, but the biggest hurdle so far has even been understanding how gravity works and what exactly gravity is. Now we are solving that. Congratulations to the LIGO teams!
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Offline Robotbeat

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #92 on: 02/11/2016 11:41 PM »
Another article
http://www.sciencemag.org/news/2016/02/gravitational-waves-einstein-s-ripples-spacetime-spotted-first-time

This is so exciting. We might finally be getting closer to understanding how and what gravity actually is. If we can crack that nut it may eventually be possible for us to get to make artificial gravity a thing. That would have HUGE impacts for our entire civilization, but the biggest hurdle so far has even been understanding how gravity works and what exactly gravity is. Now we are solving that. Congratulations to the LIGO teams!
Currently, we are finding that the "graviton" is basically massless. This basically confirms our theories. So far, this LIGO detection is pounding more nails in the coffin of the idea of artificial gravity and other hypothetical phenomenon that require new physics. We HOPE new discoveries start to pull some of those nails out, but the recent announcement was another one pounded in.
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Offline RonM

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #93 on: 02/12/2016 01:10 AM »
Another article
http://www.sciencemag.org/news/2016/02/gravitational-waves-einstein-s-ripples-spacetime-spotted-first-time

This is so exciting. We might finally be getting closer to understanding how and what gravity actually is. If we can crack that nut it may eventually be possible for us to get to make artificial gravity a thing. That would have HUGE impacts for our entire civilization, but the biggest hurdle so far has even been understanding how gravity works and what exactly gravity is. Now we are solving that. Congratulations to the LIGO teams!
Currently, we are finding that the "graviton" is basically massless. This basically confirms our theories. So far, this LIGO detection is pounding more nails in the coffin of the idea of artificial gravity and other hypothetical phenomenon that require new physics. We HOPE new discoveries start to pull some of those nails out, but the recent announcement was another one pounded in.

Good point. Maybe more observations will find some deviation from GR, but isn't two colliding black holes as strong of a test as possible?

Congratulations LIGO teams. Another great day for science.

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #95 on: 02/12/2016 08:03 AM »

Another article
http://www.sciencemag.org/news/2016/02/gravitational-waves-einstein-s-ripples-spacetime-spotted-first-time

This is so exciting. We might finally be getting closer to understanding how and what gravity actually is. If we can crack that nut it may eventually be possible for us to get to make artificial gravity a thing. That would have HUGE impacts for our entire civilization, but the biggest hurdle so far has even been understanding how gravity works and what exactly gravity is. Now we are solving that. Congratulations to the LIGO teams!
Currently, we are finding that the "graviton" is basically massless. This basically confirms our theories. So far, this LIGO detection is pounding more nails in the coffin of the idea of artificial gravity and other hypothetical phenomenon that require new physics. We HOPE new discoveries start to pull some of those nails out, but the recent announcement was another one pounded in.

But you're rather forgetting that quantum physics also appears, through increasing experimental evidence, to do lots of things that Einstein really didn't like. I am more confident that this realm will be the one where things will get interesting.

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #97 on: 02/12/2016 09:35 AM »
Because yesterday's excitement wasn't enough... turns out the Fermi observatory **might** have detected a coincident GRB, which is unexpected for this kind of merger ! Here's the technical paper preprint:

http://gammaray.nsstc.nasa.gov/gbm/publications/preprints/gbm_ligo_preprint.pdf

PS: Swift didn't see anything but the source's favored regions from LIGO and GLAST were either obscured by the Sun or not in the instrument's FOV.
« Last Edit: 02/12/2016 10:17 AM by eeergo »
-DaviD-

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #98 on: 02/12/2016 02:47 PM »
And no coincident neutrinos were detected by either Antares (the neutrino detector, not the rocket :) ) or ICECube:

https://dcc.ligo.org/public/0123/P1500271/013/GW150914_neutrino.pdf (paper)
http://icecube.wisc.edu/news/view/398

PS: I just saw the same links posted in the "Space Science" subforum thread. I will keep these here, but if they are merged my posts are redundant since I wrote them several hours after the other guys'. Moderators please delete this and the previous post if you're merging the treads.
« Last Edit: 02/12/2016 03:17 PM by eeergo »
-DaviD-

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #99 on: 02/12/2016 03:04 PM »
How do they know the distance between us and the event?

If I understood it correctly, using the observed shape of the waveform one can infer the masses involved and then the theory also gives you the energy (or power?) radiated. Then you go back to the observed amplitude of the oscillations (a.k.a. the local "strain") and, via the inverse square law, can work out the distance. With a certain error bar, of course.

Yes, that gives the luminosity distance (for very far away objects there are several "distances"). They just convert the luminosity distance to redshift, because that's what everyone is used to in cosmology/extragalactic astronomy.

Edit: The conversion from luminosity distance to redshift does depend on the cosmological model as eeergo mentioned, but in this case the merger was close enough so that it doesn't have a large effect.

I found some more details on this in the source characterization paper: https://dcc.ligo.org/LIGO-P1500218/public/main

Quote
The observed frequency of the signal is redshifted by a factor of (1 + z),  where z is the cosmological redshift. There is no intrinsic mass or length scale in vacuum general relativity, and the dimensionless quantity that incorporates frequency is fGm/c^3. Consequently, a redshifting of frequency is indistinguishable from a rescaling of the masses by the same factor. We therefore measure redshifted masses m,  which are related to source frame masses by m= (1 + z)·m_source. However, the GW amplitude A_GW,  Eq. (2),  also scales linearly with the mass and is inversely proportional to the comoving distance in an expanding universe. This implies that A_GW ~ 1/D_L and from the GW signal alone we can directly measure the luminosity distance, but not the redshift.

The  observed time delay, and the need for the  registered signal at the two sites to be consistent in amplitude and phase, allow us to localize the source to a ring on the sky [34, 35].  Where there is no precession, changing the
viewing angle of the system simply changes the observed waveform by an overall amplitude and phase. Furthermore,
the two polarizations are the same up to overall amplitude and phase. Thus, for systems with minimal precession, the
distance, binary orientation, phase at coalescence and sky location  of  the  source  change  the  overall  amplitude  and
phase of the source in each detector, but they do not change the signal morphology.  Phase and amplitude consistency
allow us to untangle some of the geometry of the source. If the binary is precessing, the GW amplitude and phase have
a complicated dependency on the orientation of the binary, which provides additional information.
-DaviD-

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #100 on: 02/12/2016 07:08 PM »

And no coincident neutrinos were detected by either Antares (the neutrino detector, not the rocket :) ) or ICECube:

https://dcc.ligo.org/public/0123/P1500271/013/GW150914_neutrino.pdf (paper)
http://icecube.wisc.edu/news/view/398

PS: I just saw the same links posted in the "Space Science" subforum thread. I will keep these here, but if they are merged my posts are redundant since I wrote them several hours after the other guys'. Moderators please delete this and the previous post if you're merging the treads.

Just shows that GW really can detect things nothing else can.

Offline Mulletron

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #101 on: 02/13/2016 08:28 AM »
Guess the communication satellite days are numbered.
Challenge your preconceptions, or they will challenge you. - Velik

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #102 on: 02/13/2016 08:54 AM »
Guess the communication satellite days are numbered.

Not until someone invents a cheap and reliable way to create detectable gravity waves here on Earth.  ;)

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #103 on: 02/18/2016 12:24 AM »
excuse my ignorance but isn't  this a confirmation for space time warp  in macro scale(instead of micro) for which dr. white was looking for in egale works for warp drive potential

or is it different kind of warp of space time?
is it a little step forward or no relevance at all?

The metric derived by Alcubierre was mathematically motivated by cosmological inflation
so this would by much more solid  proof of concept if i understand it correctly
of course it doesn't give an answer if we could induce such a warp artificially
still dark matter /dark energy is just a hypothesis 
« Last Edit: 02/18/2016 12:32 AM by spirytus »

Offline eeergo

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #104 on: 02/18/2016 09:03 AM »
LIGO-India has received initial approval!

http://pib.nic.in/newsite/erelease.aspx?relid=136479

(I post this here since the new facility falls more under the "Advanced Physics" rather than Space Science thread)
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Online ChrisWilson68

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #105 on: 02/18/2016 10:48 AM »
Another article
http://www.sciencemag.org/news/2016/02/gravitational-waves-einstein-s-ripples-spacetime-spotted-first-time

This is so exciting. We might finally be getting closer to understanding how and what gravity actually is. If we can crack that nut it may eventually be possible for us to get to make artificial gravity a thing. That would have HUGE impacts for our entire civilization, but the biggest hurdle so far has even been understanding how gravity works and what exactly gravity is. Now we are solving that. Congratulations to the LIGO teams!
Currently, we are finding that the "graviton" is basically massless. This basically confirms our theories. So far, this LIGO detection is pounding more nails in the coffin of the idea of artificial gravity and other hypothetical phenomenon that require new physics. We HOPE new discoveries start to pull some of those nails out, but the recent announcement was another one pounded in.

But you're rather forgetting that quantum physics also appears, through increasing experimental evidence, to do lots of things that Einstein really didn't like. I am more confident that this realm will be the one where things will get interesting.

Robotbeat isn't forgetting anything.  Everyone knows that quantum physics and relativity/gravity are separate theories that describe different domains and we don't have a compelling theory to combine them.  It's irrelevant to his point.

His point is that the LIGO data simply confirms the most widely held theories, so it in of itself simply rules out some of the more esoteric theories and doesn't do much to lead us to new ground.

New experimental results that are a surprise are much more useful to get us to understand things we didn't understand before.  The LIGO results aren't a surprise.  They're the opposite.  We turned over another rock and found exactly what we expected.  We'll keep turning over rocks, looking for surprises, and the LIGO hardware might yet help us find surprises under different rocks, but so far, no surprises, and no help toward new physics.

Offline FinalFrontier

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #106 on: 02/18/2016 11:01 AM »
Another article
http://www.sciencemag.org/news/2016/02/gravitational-waves-einstein-s-ripples-spacetime-spotted-first-time

This is so exciting. We might finally be getting closer to understanding how and what gravity actually is. If we can crack that nut it may eventually be possible for us to get to make artificial gravity a thing. That would have HUGE impacts for our entire civilization, but the biggest hurdle so far has even been understanding how gravity works and what exactly gravity is. Now we are solving that. Congratulations to the LIGO teams!
Currently, we are finding that the "graviton" is basically massless. This basically confirms our theories. So far, this LIGO detection is pounding more nails in the coffin of the idea of artificial gravity and other hypothetical phenomenon that require new physics. We HOPE new discoveries start to pull some of those nails out, but the recent announcement was another one pounded in.

But you're rather forgetting that quantum physics also appears, through increasing experimental evidence, to do lots of things that Einstein really didn't like. I am more confident that this realm will be the one where things will get interesting.

Robotbeat isn't forgetting anything.  Everyone knows that quantum physics and relativity/gravity are separate theories that describe different domains and we don't have a compelling theory to combine them.  It's irrelevant to his point.

His point is that the LIGO data simply confirms the most widely held theories, so it in of itself simply rules out some of the more esoteric theories and doesn't do much to lead us to new ground.

New experimental results that are a surprise are much more useful to get us to understand things we didn't understand before.  The LIGO results aren't a surprise.  They're the opposite.  We turned over another rock and found exactly what we expected.  We'll keep turning over rocks, looking for surprises, and the LIGO hardware might yet help us find surprises under different rocks, but so far, no surprises, and no help toward new physics.
There are four natural forces in the Universe. Electromagnetic, Strong Nuclear, Weak Nuclear, and Gravitational.

Humans currently have a fairly decent mastery of the Electromagnetic force, some mastery of the strong and weak nuclear forces, though incomplete (commonplace power generating fusion reactors are still in development), and absolutely no control and limited knowledge of Gravitational.

Throughout our history we were not able to harness any of these without first gaining a more or less complete understanding of what they actually were, and how they worked in nature. To any extent, even limited use such as a nuclear weapon.

My point here was that the only shred of hope mankind will ever have of trying to master Gravity is to gain a total and full understanding of how it works in nature, and working backwards from there. That historically, is how we have gotten this far, up until now. This doesn't mean it is ultimately, or will ultimately be possible to actually gain any control over gravity under the processes by which this Universe operates, all it means is that you 100% can't without first understanding the natural force in its normal domain. THAT to me is why experiments and programs like this one, and this discovery, are so important. The more we know about the natural state the better equipped we become, if there is ever a chance of manipulating it.
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Offline Star One

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #107 on: 02/18/2016 01:15 PM »

Another article
http://www.sciencemag.org/news/2016/02/gravitational-waves-einstein-s-ripples-spacetime-spotted-first-time

This is so exciting. We might finally be getting closer to understanding how and what gravity actually is. If we can crack that nut it may eventually be possible for us to get to make artificial gravity a thing. That would have HUGE impacts for our entire civilization, but the biggest hurdle so far has even been understanding how gravity works and what exactly gravity is. Now we are solving that. Congratulations to the LIGO teams!
Currently, we are finding that the "graviton" is basically massless. This basically confirms our theories. So far, this LIGO detection is pounding more nails in the coffin of the idea of artificial gravity and other hypothetical phenomenon that require new physics. We HOPE new discoveries start to pull some of those nails out, but the recent announcement was another one pounded in.

But you're rather forgetting that quantum physics also appears, through increasing experimental evidence, to do lots of things that Einstein really didn't like. I am more confident that this realm will be the one where things will get interesting.

Robotbeat isn't forgetting anything.  Everyone knows that quantum physics and relativity/gravity are separate theories that describe different domains and we don't have a compelling theory to combine them.  It's irrelevant to his point.

His point is that the LIGO data simply confirms the most widely held theories, so it in of itself simply rules out some of the more esoteric theories and doesn't do much to lead us to new ground.

New experimental results that are a surprise are much more useful to get us to understand things we didn't understand before.  The LIGO results aren't a surprise.  They're the opposite.  We turned over another rock and found exactly what we expected.  We'll keep turning over rocks, looking for surprises, and the LIGO hardware might yet help us find surprises under different rocks, but so far, no surprises, and no help toward new physics.

I have seen a few articles since that have said this discovery opens the door to the possibility of artificial gravity down the line which is the exact opposite to his original claim.

Offline Rodal

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #108 on: 02/18/2016 01:20 PM »
More information on the very interesting and unexpected Gamma Ray Burst that the Fermi observatory detected "with a false alarm probability of 0.0022"  ( http://forum.nasaspaceflight.com/index.php?topic=39297.msg1490954#msg1490954 ), and that *may* be associated with the gravitational wave event GW150914

Quote
You could get a gamma-ray burst if the two black holes were enveloped inside a very massive star. “It’s sort of like a pregnant woman with twins in her belly,” Once the black holes merged, the star would collapse and trigger intense beams of gamma rays. For that to happen, the two black holes would have to have formed inside an extremely massive star a few hundred times heftier than the sun. As the star exhausted its nuclear fuel, its core began to collapse. Normally that would form a single black hole. But if the star were rotating very fast, centrifugal force would stretch the collapsing core, shaping it into a dumbbell. Eventually, the dumbbell would snap into two cores, each of which would continue to collapse into its own black hole. "The only way to explain the Fermi signal is to surround the black holes with a lot of dense material"

https://www.newscientist.com/article/2077783-ligos-black-holes-may-have-lived-and-died-inside-a-huge-star/


On the other hand, observations made by the European "International Gamma-Ray Astrophysics Laboratory" (INTEGRAL) cannot corroborate the Fermi observatory Gamma Ray Burst http://arxiv.org/abs/1602.04180
« Last Edit: 02/18/2016 02:21 PM by Rodal »

Offline birchoff

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #109 on: 02/18/2016 04:24 PM »
excuse my ignorance but isn't  this a confirmation for space time warp  in macro scale(instead of micro) for which dr. white was looking for in egale works for warp drive potential

or is it different kind of warp of space time?
is it a little step forward or no relevance at all?

The metric derived by Alcubierre was mathematically motivated by cosmological inflation
so this would by much more solid  proof of concept if i understand it correctly
of course it doesn't give an answer if we could induce such a warp artificially
still dark matter /dark energy is just a hypothesis

At most this shows that the idea of manipulating space/time is possible. What it doesnt prove is that it is possible to do so with the energy humanity currently has the ability to apply. It took the merger of two black holes much larger than our sun respectively to generate the detected waves.

edit:

I would also add that the interferance signal pattern could probably be used to rule out false positives in white's experiment
« Last Edit: 02/18/2016 04:35 PM by birchoff »

Offline sanman

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #110 on: 02/18/2016 06:20 PM »
This is why atom interferometry has to be further developed, because it's the ideal tool to study Gravitational Waves. After all, gravity affects matter much more obviously than it affects light, and so interferometry based on particles of matter is the ideal way to study gravity in detail, and to characterize its behavior in as much detail as possible.

Don't get me wrong - I'm not belittling the engineering marvel that is LIGO, but the Physics community can only move towards newer and better discoveries by developing newer and better instruments.

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #111 on: 02/18/2016 06:42 PM »
Didn't i read an article a while back that suggested an advanced gravity wave detector could be made to fit on a desktop?
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Offline sanman

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #112 on: 02/19/2016 03:46 AM »
Didn't i read an article a while back that suggested an advanced gravity wave detector could be made to fit on a desktop?


That would probably have to be an atom inferometer, or even a molecular interferometer. C60 fullerenes were among the first to be used to generate interference patterns - but all sorts of other heavy molecules have been used, including even DNA. Here's an interference pattern generated from molecules of phthalocyanine:



So those molecules are even heavier than individual atoms, and so their DeBroglie wavelength is even smaller, thus affording even finer, more precise interferometry. And you don't need a giant sized LIGO apparatus to do it.

It's ironic that while we can't get General Relativity and Quantum theory to connect with each other, we can experimentally apply the knowledge given by quantum theory to detect miniscule changes in spacetime through DeBroglie wavelength.


Meanwhile, the US and India are collaborating to build INDIGO, a Gravitational Wave detector that will extend the LIGO network.

http://arstechnica.com/science/2016/02/india-to-get-a-ligo-detector-that-could-be-online-before-2025/
« Last Edit: 02/19/2016 05:25 AM by sanman »

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #113 on: 02/19/2016 04:13 AM »
i just remembered or think i remembered a detail about what i was talking about. i think it involved Bose Einstein condensate or something like that. this may have been it:

https://www.newscientist.com/article/mg22129603-500-desktop-quantum-cloud-to-hunt-elusive-space-time-waves/
« Last Edit: 02/19/2016 04:15 AM by Stormbringer »
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Offline sanman

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #114 on: 02/19/2016 11:43 AM »
Given that even planets orbiting stars produce Gravitational Waves, I'm wondering whether Gravitational Astronomy might one day be able to detect them.

Offline philw1776

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #115 on: 02/22/2016 12:17 AM »
Given that even planets orbiting stars produce Gravitational Waves, I'm wondering whether Gravitational Astronomy might one day be able to detect them.

Many, many powers of ten orders of magnitude fainter than the waves barely detected by LIGO.
For example we are several orders of magnitude closer to detecting the visual electromagnetic images of such planets than their gravitational waves and are making far more rapid progress in that realm.

Conversely, just a few orders of magnitude improvements in gravitational wave detection or even less will bring us deep into uncharted territory.
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Offline Robotbeat

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #116 on: 02/23/2016 02:22 AM »

Another article
http://www.sciencemag.org/news/2016/02/gravitational-waves-einstein-s-ripples-spacetime-spotted-first-time

This is so exciting. We might finally be getting closer to understanding how and what gravity actually is. If we can crack that nut it may eventually be possible for us to get to make artificial gravity a thing. That would have HUGE impacts for our entire civilization, but the biggest hurdle so far has even been understanding how gravity works and what exactly gravity is. Now we are solving that. Congratulations to the LIGO teams!
Currently, we are finding that the "graviton" is basically massless. This basically confirms our theories. So far, this LIGO detection is pounding more nails in the coffin of the idea of artificial gravity and other hypothetical phenomenon that require new physics. We HOPE new discoveries start to pull some of those nails out, but the recent announcement was another one pounded in.

But you're rather forgetting that quantum physics also appears, through increasing experimental evidence, to do lots of things that Einstein really didn't like. I am more confident that this realm will be the one where things will get interesting.

Robotbeat isn't forgetting anything.  Everyone knows that quantum physics and relativity/gravity are separate theories that describe different domains and we don't have a compelling theory to combine them.  It's irrelevant to his point.

His point is that the LIGO data simply confirms the most widely held theories, so it in of itself simply rules out some of the more esoteric theories and doesn't do much to lead us to new ground.

New experimental results that are a surprise are much more useful to get us to understand things we didn't understand before.  The LIGO results aren't a surprise.  They're the opposite.  We turned over another rock and found exactly what we expected.  We'll keep turning over rocks, looking for surprises, and the LIGO hardware might yet help us find surprises under different rocks, but so far, no surprises, and no help toward new physics.

I have seen a few articles since that have said this discovery opens the door to the possibility of artificial gravity down the line which is the exact opposite to his original claim.
You're not trying very hard to convince me.
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Offline Star One

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #117 on: 02/23/2016 06:25 AM »


Another article
http://www.sciencemag.org/news/2016/02/gravitational-waves-einstein-s-ripples-spacetime-spotted-first-time

This is so exciting. We might finally be getting closer to understanding how and what gravity actually is. If we can crack that nut it may eventually be possible for us to get to make artificial gravity a thing. That would have HUGE impacts for our entire civilization, but the biggest hurdle so far has even been understanding how gravity works and what exactly gravity is. Now we are solving that. Congratulations to the LIGO teams!
Currently, we are finding that the "graviton" is basically massless. This basically confirms our theories. So far, this LIGO detection is pounding more nails in the coffin of the idea of artificial gravity and other hypothetical phenomenon that require new physics. We HOPE new discoveries start to pull some of those nails out, but the recent announcement was another one pounded in.

But you're rather forgetting that quantum physics also appears, through increasing experimental evidence, to do lots of things that Einstein really didn't like. I am more confident that this realm will be the one where things will get interesting.

Robotbeat isn't forgetting anything.  Everyone knows that quantum physics and relativity/gravity are separate theories that describe different domains and we don't have a compelling theory to combine them.  It's irrelevant to his point.

His point is that the LIGO data simply confirms the most widely held theories, so it in of itself simply rules out some of the more esoteric theories and doesn't do much to lead us to new ground.

New experimental results that are a surprise are much more useful to get us to understand things we didn't understand before.  The LIGO results aren't a surprise.  They're the opposite.  We turned over another rock and found exactly what we expected.  We'll keep turning over rocks, looking for surprises, and the LIGO hardware might yet help us find surprises under different rocks, but so far, no surprises, and no help toward new physics.

I have seen a few articles since that have said this discovery opens the door to the possibility of artificial gravity down the line which is the exact opposite to his original claim.
You're not trying very hard to convince me.

Tell that to the article writers.

Offline Star One

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #118 on: 02/23/2016 09:00 PM »
How gravitational wave detectors survived the Contract With America

Could a basic research project get funded now? Probably not, science advisor says.

Quote
Those were bitter political times, Lane said. After all, the Republican Congress would move to impeach Bill Clinton in a few years. But there were still Republicans and Democrats working across party lines on the appropriations process. Work was going on, staff to staff, principal to principal. Today, Lane doesn’t see that kind of cooperation, and it spells major trouble for any new programs a president might seek to fund, like construction of LIGO instruments.

“Never say never,” he said. “We should always hope, always try. I would just say the conditions are very different. Polarization is one thing. The other thing is the private sector some time ago—but even government now—is moving steadily toward short-term deliverables for everything. Expectations are not patient. If the President’s Office of Management and Budget sent this over today, I think you’d have a very hard time getting it through Congress.”

Lane is probably correct. On the very same day that physicists announced their spectacular findings in early February, the US House of Representatives passed legislation sponsored by Texas Republican Lamar Smith, HR3293, that allows the NSF to award grants only for research it can certify as being in the national interest, such as benefiting the economy or improving national defense.

“It really is an irony,” Lane said of the timing. A bitter one.

http://arstechnica.co.uk/science/2016/02/how-gravitational-wave-detectors-survived-the-contract-with-america/

Offline Orbiter

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #119 on: 02/23/2016 09:20 PM »
Quote
Lane is probably correct. On the very same day that physicists announced their spectacular findings in early February, the US House of Representatives passed legislation sponsored by Texas Republican Lamar Smith, HR3293, that allows the NSF to award grants only for research it can certify as being in the national interest, such as benefiting the economy or improving national defense.

That's depressing. :(
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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #120 on: 02/24/2016 12:44 AM »
...

New experimental results that are a surprise are much more useful to get us to understand things we didn't understand before.  The LIGO results aren't a surprise.  They're the opposite.  We turned over another rock and found exactly what we expected.  We'll keep turning over rocks, looking for surprises, and the LIGO hardware might yet help us find surprises under different rocks, but so far, no surprises, and no help toward new physics.
There are four natural forces in the Universe. Electromagnetic, Strong Nuclear, Weak Nuclear, and Gravitational.

Humans currently have a fairly decent mastery of the Electromagnetic force, some mastery of the strong and weak nuclear forces, though incomplete (commonplace power generating fusion reactors are still in development), and absolutely no control and limited knowledge of Gravitational.

Throughout our history we were not able to harness any of these without first gaining a more or less complete understanding of what they actually were, and how they worked in nature. To any extent, even limited use such as a nuclear weapon.

My point here was that the only shred of hope mankind will ever have of trying to master Gravity is to gain a total and full understanding of how it works in nature, and working backwards from there. That historically, is how we have gotten this far, up until now. This doesn't mean it is ultimately, or will ultimately be possible to actually gain any control over gravity under the processes by which this Universe operates, all it means is that you 100% can't without first understanding the natural force in its normal domain. THAT to me is why experiments and programs like this one, and this discovery, are so important. The more we know about the natural state the better equipped we become, if there is ever a chance of manipulating it.

This is an entirely inaccurate depiction of the state of science and history of scientific progress.

First, we understand gravity better than the strong or weak nuclear force. With the recent detection of gravitational waves, the last major prediction of general relativity is confirmed. Dark energy and dark matter could potentially be related to gravity, but the evidence is against that for dark matter, and we really don't know for dark energy. On the other hand, the weak and strong nuclear forces rely on our understanding of particle physics, which generally is incomplete (the standard model has 19 free parameters, not counting the fact that neutrinos shouldn't have mass but do, which adds at least 7 more.)

Using nuclear reactors is a horrible example of claiming that we have somehow understood nuclear forces, since the main challenge in fusion is slamming nuclei together hard enough to overcome the electromagnetic forces. The energy comes from binding with the strong nuclear force, but we don't need to understand the nuclear force to notice the energy released. Also, when we first invented fission bombs, we hadn't even begun to suspect the existence of quarks (first theorized in 1964), let alone the strong and weak nuclear forces.

Again for electromagnetism, the first telegraph was in 1844, but Maxwell published the first version of Maxwell's equations in 1861-1862.

While understanding gravity is useful, we don't necessarily need a full understanding of it to make use of it. (We already use gravitational assists for interplanetary missions, and GPS clocks need corrections for general relativity) Contrary to your claim, I don't know of a case where we didn't start using something before we fully understood it in any branch of science. The biggest openings we have left for truly new physics lie in particle physics, the union of General Relativity and quantum, and the few unexplained phenomena such as dark energy and dark matter.

Offline Nilof

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #121 on: 03/02/2016 09:28 PM »
Well, if we bring up the weak force, I'd argue we understand the electroweak force better than we understand gravity (indeed, this is the corner of the standard model where we can make 18 digit predictions). But the strong force, while we understand it's basic laws, is definitely very poorly understood even for very simple systems in the sense of solving it to make predictions.

In fact, we understand gravity incredibly well even at our current particle physics energy scales. Gravity is not incompatible with quantum mechanics in that sense, in fact gravity can be treated as a quantum force very effectively. The actual issue is that a direct interpretation of GR as a quantum force leads to ultraviolet divergences, i.e. there exists an energy scale (the Planck scale) far beyond our current accelerators at which the equations explicitly stop being applicable.

I will also note that this is also the case, although in a different way, for quantum electrodynamics which has a Landau pole. This is a sign that it needs to be included into electroweak theory, and in this sense gravity can be said to be understood just as well as electromagnetism was before it was integrated into electroweak theory (at the level of fundamental laws, obviously GR is harder to find solutions for). Electroweak theory also has a landau pole, which means it has to be integrated into a GUT eventually, and so on.

There isn't a lack of theories that could fully describe quantum gravity either, string theory is a very natural and beautiful self-consistent candidate.

The actual issue is not really that we lack theoretical understanding, but rather that our current approximative description of the universe is so ridiculously accurate that we're struggling to build experiments that can actually falsify it and give us pointers on which possible candidate theory is the most accurate extension.
« Last Edit: 03/03/2016 11:12 AM by Nilof »
For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v.   Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

Online Stormbringer

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #122 on: 03/03/2016 02:19 AM »
in the work of Zvi, Dixon and friends for which they won the Sakurai prize N=8 supergravity does not lead to ultraviolet divergences so far as has been calculated which may be as many as five loops so far.

http://www.preposterousuniverse.com/blog/2013/10/03/guest-post-lance-dixon-on-calculating-amplitudes/

Quote
Finally, let me mention N=8 supergravity. This theory was invented by Eugene Cremmer and Bernard Julia in the late 1970s, with other important contributions from Bernard deWit and Hermann Nicolai, Joel Scherk and others. When superstring theory had its 1984 revolution, N=8 supergravity was quickly pronounced dead — because string theory was manifestly free of all ultraviolet divergences, and how could any point-particle theory dare to make that claim? However, it never received a proper burial. At that time, it was generally thought that N=8 supergravity would diverge at three loops, but no-one could do a full calculation past one loop. With the unitarity method, we could get to two loops in 1998 (with Zvi, Dave Dunbar, Maxim Perelstein and Joel Rozowsky), to three loops in 2007 (with Zvi, David, John Joseph Carrasco, Henrik Johansson and Radu Roiban), and to four loops in 2009. We still have found no direct sign of a divergence in N=8 supergravity, although the conventional wisdom has retreated from a first divergence at three loops to a first one at seven or eight loops. Zvi, John Joseph, Henrik and Radu are pushing ahead to five loops, which will also give important indications about seven loops. A first divergence at even the seven loop order would be the smallest infinity known to man…
« Last Edit: 03/03/2016 02:28 AM by Stormbringer »
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Offline Nilof

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #123 on: 03/03/2016 09:56 AM »
in the work of Zvi, Dixon and friends for which they won the Sakurai prize N=8 supergravity does not lead to ultraviolet divergences so far as has been calculated which may be as many as five loops so far.

http://www.preposterousuniverse.com/blog/2013/10/03/guest-post-lance-dixon-on-calculating-amplitudes/

Quote
Finally, let me mention N=8 supergravity. This theory was invented by Eugene Cremmer and Bernard Julia in the late 1970s, with other important contributions from Bernard deWit and Hermann Nicolai, Joel Scherk and others. When superstring theory had its 1984 revolution, N=8 supergravity was quickly pronounced dead — because string theory was manifestly free of all ultraviolet divergences, and how could any point-particle theory dare to make that claim? However, it never received a proper burial. At that time, it was generally thought that N=8 supergravity would diverge at three loops, but no-one could do a full calculation past one loop. With the unitarity method, we could get to two loops in 1998 (with Zvi, Dave Dunbar, Maxim Perelstein and Joel Rozowsky), to three loops in 2007 (with Zvi, David, John Joseph Carrasco, Henrik Johansson and Radu Roiban), and to four loops in 2009. We still have found no direct sign of a divergence in N=8 supergravity, although the conventional wisdom has retreated from a first divergence at three loops to a first one at seven or eight loops. Zvi, John Joseph, Henrik and Radu are pushing ahead to five loops, which will also give important indications about seven loops. A first divergence at even the seven loop order would be the smallest infinity known to man…

Right, I was considering a mention of SUSY and how it makes everything so much simpler, but left it at a brief mention of string theory, which provably has no UV divergences and requires SUSY for fermions. SUSY is a very natural geometric idea which can in a way be viewed as just a stronger form of conservation of momentum (since the simplest form essentially boils down to introducing a pair of spinor charges whose anticommutator is the momentum, and positing that both charges are conserved, not just their anticommutator).

Sadly we don't yet have experimental evidence for SUSY, and it is not at all obvious that we will obtain it within our lifetimes. However its simplicity and the fact that it makes so many things simpler means that it is imho overwhelmingly likely that we will find it at some point.
For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v.   Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

Offline RonM

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #124 on: 03/03/2016 02:00 PM »
There isn't a lack of theories that could fully describe quantum gravity either, string theory is a very natural and beautiful self-consistent candidate.

The actual issue is not really that we lack theoretical understanding, but rather that our current approximative description of the universe is so ridiculously accurate that we're struggling to build experiments that can actually falsify it and give us pointers on which possible candidate theory is the most accurate extension.

Right, I was considering a mention of SUSY and how it makes everything so much simpler, but left it at a brief mention of string theory, which provably has no UV divergences and requires SUSY for fermions. SUSY is a very natural geometric idea which can in a way be viewed as just a stronger form of conservation of momentum (since the simplest form essentially boils down to introducing a pair of spinor charges whose anticommutator is the momentum, and positing that both charges are conserved, not just their anticommutator).

Sadly we don't yet have experimental evidence for SUSY, and it is not at all obvious that we will obtain it within our lifetimes. However its simplicity and the fact that it makes so many things simpler means that it is imho overwhelmingly likely that we will find it at some point.

A good summation of the state of modern physics.

Unfortunately, no matter how natural and beautifully self-consistent the math, a theory that doesn't make predictions that can be tested is more philosophy than theory. Of course, as you mentioned the problem is our current theories are too accurate. We need to find some flaws in current theory to point the way.

Perhaps continued observations by LIGO will spot a small deviation from theory. If not, we'll have to keep trying.

Offline Star One

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #125 on: 05/03/2016 08:20 PM »
PRIZE IN FUNDAMENTAL PHYSICS AWARDED FOR DETECTION OF GRAVITATIONAL WAVES 100 YEARS AFTER ALBERT EINSTEIN PREDICTED THEIR EXISTENCE

Selection Committee of previous Breakthrough Prize winners recognizes contributors to experiment recording waves from two black holes colliding over a billion light years away

$3 million prize shared between LIGO founders Ronald W. P. Drever, Kip S. Thorne and Rainer Weiss and 1012 contributors to the discovery

https://breakthroughprize.org/News/32

Offline sghill

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #126 on: 05/03/2016 08:21 PM »
PRIZE IN FUNDAMENTAL PHYSICS AWARDED FOR DETECTION OF GRAVITATIONAL WAVES 100 YEARS AFTER ALBERT EINSTEIN PREDICTED THEIR EXISTENCE

Selection Committee of previous Breakthrough Prize winners recognizes contributors to experiment recording waves from two black holes colliding over a billion light years away

$3 million prize shared between LIGO founders Ronald W. P. Drever, Kip S. Thorne and Rainer Weiss and 1012 contributors to the discovery

https://breakthroughprize.org/News/32

Mazel Tov!!!

I couldn't agree more with the award for this discovery!
« Last Edit: 05/03/2016 08:22 PM by sghill »
Bring the thunder Elon!

Offline Star One

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #127 on: 05/03/2016 08:35 PM »
I don't think it works out to much each.

Offline sghill

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #128 on: 05/03/2016 08:47 PM »
I don't think it works out to much each.

I meant the award, not the cash.  Though I guess they can all take their families to Disney with $3k.
Bring the thunder Elon!

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #129 on: 05/03/2016 09:01 PM »
From the quoted article:

Quote
The Special Breakthrough Prize can be conferred at any time in recognition of an extraordinary scientific achievement. The $3 million award will be shared between two groups of laureates: the three founders of the Laser Interferometer Gravitational-Wave Observatory (LIGO), who will each equally share $1 million; and 1012 contributors to the experiment, who will each equally share $2 million.

So the main three don't quite get the lions share, so to speak, but they do get the largest individual slices by far. I think this is a good split. It recognizing both the importance and sheer magnitude of the vision of the three founders, but also the huge amount of work and contributions done by the other 1012. Congrats to all involved.
« Last Edit: 05/03/2016 09:02 PM by 1 »

Offline Star One

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #130 on: 05/04/2016 06:26 AM »
Just a shame the Nobel prize cannot be subdivided so.

Offline Star One

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Gravitational Waves Have Been Detected At LIGO
« Reply #131 on: 05/05/2016 05:14 PM »
Colliding Black Holes May Sing Different Gravitational Songs

Quote
This simple cosmic song may not be the only music these gravitational-wave emitters are capable of producing. At the American Physical Society April Meeting, held April 16 to 19 in Salt Lake City, Niels Warburton, a postdoctoral fellow at the MIT Kavli Institute, discussed simulations showing what kind of gravitational-wave "song" should be produced by collisions involving black holes that spin faster and are significantly larger than those that have been detected by LIGO.

Quote
The two black holes that LIGO observed merged together and produced a "chirp" — that is, the frequency of the signal rose steadily, then was cut off abruptly when the two objects combined. But Warburton and his colleagues showed that fast-spinning black holes create a signal that reaches a peak frequency, and then starts to lower in frequency, before fading out.

"Instead of chirping, you get this kind of singing sound from the black hole," Warburton said. "It'll rise, it won't get cut off, it'll sing, and then it's quiet at the end."

"[It's] a completely different gravitational-wave signature … than what was detected [by LIGO]," he said. If a gravitational-wave detector picked up a signal that looked like the one the researchers' model describes, "you would know you were looking at a gargantuan system, something that is rotating extremely close to the maximum," he said.

This runs contrary to what scientists expected from a merger involving a very fast-spinning black hole, according to Jolyon Bloomfield, a lecturer at MIT, who presented research at the same press conference.

"It was certainly very unexpected to see something that didn't chirp," Bloomfield said, when asked during the press conference what he thought of the results. "Every template that we've seen so far … has had this beautiful, chirping feature, and we just assumed that [if we] make [the spin of the black hole] bigger … it chirps bigger. But this is quite interesting work that says no, the chirp actually goes away. Something else is happening here."

http://www.space.com/32723-colliding-black-holes-sing-different-songs.html
« Last Edit: 05/05/2016 05:14 PM by Star One »

Offline Star One

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #132 on: 05/06/2016 05:13 PM »
Was gravitational wave signal from a gravastar, not black holes?

Quote
“Our signal is consistent with both the formation of a black hole and a horizonless object – we just can’t tell,” says B. S. Sathyaprakash of Cardiff University, UK, who is part of the LIGO team. But if we can detect larger black holes merging, or a pair that is closer to us, it should settle the matter, he says. “That’s when we can conclusively say if the late-time signal is consistent with the merged object being a black hole or some other exotic object.”

Ultimately, the black hole explanation is likely to win out, but it is worth double-checking, says Pani. “As scientists, we try to play the devil’s advocate and not believe in paradigms without observational evidence.”

https://www.newscientist.com/article/mg23030724-100-was-gravitational-wave-signal-from-a-gravastar-not-black-holes/

Offline Rodal

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #133 on: 06/16/2016 02:20 PM »
LIGO and VIRGO announced a second observation of a gravitational-wave signal produced by the coalescence of two stellar-mass black holes.

This event was much smaller than the first detection: The first event involved black holes that were 29 and 36 times as massive as the sun, while this new collision, which took place 1.4 billion years ago, brought together black holes of 8 and 14 solar masses.  While the first detection “jumped out” from the data, the researchers say, the second one was only noticed thanks to the analysis of specially developed software.

The detection of smaller black holes makes some LIGO researchers hope that they’ll soon detect the interactions of ultra-dense neutron stars, which are even less massive and very poorly understood.

The signal, GW151226, was observed by the twin detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) on December 26, 2015 at 03:38:53 UTC. The signal was initially identified within 70 s by an online matched-filter search targeting binary coalescences.  All uncertainties define a 90% credible interval. This second gravitational-wave observation provides improved constraints on stellar populations and on deviations from general relativity.


http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.241103

https://www.washingtonpost.com/news/speaking-of-science/wp/2016/06/15/ligo-scientists-announce-their-second-detection-of-gravitational-waves/

https://www.facebook.com/apsphysics/videos/10154335027472952/
« Last Edit: 06/16/2016 02:36 PM by Rodal »

Offline philw1776

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #134 on: 06/16/2016 07:44 PM »
These lower mass BHs & collision/mergers should be more common.  Hopefully lots of detections to come when they start up again this fall with increased sensitivity.
“When it looks more like an alien dreadnought, that’s when you know you’ve won.”

Offline Eusa

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #135 on: 06/16/2016 08:34 PM »
Is the vibration after the merging meaningful?

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #136 on: 06/24/2016 04:39 PM »
sensitivity for these sorts of instrument may be about to take another quantum leap:

http://nextbigfuture.com/2016/06/russian-physicists-create-high.html

Quote
June 23, 2016

Russian physicists create a high-precision 'quantum ruler'

Physicists from the Russian Quantum Center (RQC), MIPT, the Lebedev Physical Institute, and L'Institut d'Optique (Palaiseau, France) have devised a method for creating a special quantum entangled state. This state enables producing a high-precision ruler capable of measuring large distances to an accuracy of billionths of a metre. The results of the study have been published in Nature Communications.

When antigravity is outlawed only outlaws will have antigravity.

Offline Star One

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #137 on: 06/29/2016 08:29 PM »
Event Horizon ringing damped by unstable space-time

Probing the event horizon of a black hole is not so easy.

Quote
Now that gravitational waves have been detected, theoreticians have been furiously speculating about what we might learn from our gravitational wave observatories. Now that we have a couple of observed black hole collisions under our belt, it is time to consider what we might study. There's some speculation that, depending on the sort of physics at play, the event horizon of a black hole might be studied through gravitational waves.

For this to work, the gravitational wave signal has to change depending on what type of black holes are merging. A recent paper in Physical Review Letters indicates that, unfortunately, reality will probably not cooperate.

http://arstechnica.com/science/2016/06/event-horizon-ringing-damped-by-unstable-space-time/

Offline KelvinZero

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #138 on: 07/01/2016 11:42 PM »
People ask if this could revolutionise space flight. What if it discovered something like this in our vicinity? Something we hadn't been able to see before precisely because it wasn't shooting vast amounts of dangerous radiation our way?

http://www.centauri-dreams.org/?p=25605
The "Dyson Slingshot"
Two neutron stars, each with a diameter of 20 kilometers and a mass of one solar mass — and a combined orbital period of 0.005 seconds — would provide a departure velocity of 0.27 c

This was taken from my "dark matter planet/oberth effect" thread, but this example requires neither dark matter or oberth effect, is just more powerful and less hypothetical, and someone has apparently already done the math. It might be more interesting to discuss in terms of detection. Could we have missed an object like this and could gravity waves give us a way to detect it?



Offline bolun

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Re: Rumor Claims Gravitational Waves Have Been Detected At LIGO
« Reply #139 on: 07/17/2016 08:08 PM »
Criticism for NASA.

Rainer Weiss laments NASA’s decision to pull of the space-based gravitational wave observatory LISA, and praises Europe’s determination to ‘go it alone’ with the eLISA mission and LISA Pathfinder. But he hopes for a new collaboration.

@DrStuClark Gravitational Waves sound like Radiohead's Planet Telex intro, from album The Bends. #spooky

https://mobile.twitter.com/ClickConsultLtd/status/697819704732291072?ref_src=twsrc%5Etfw

final question of the webcast press conference is whether LIGO has seen other signals. Gonzalez answers very carefully placing the emphasis back on the signal announced today. As she finishes one of her fellow panellists quips ‘that didn’t even sound rehearsed’.

Hmmm. What should we make of that?

http://english.nssc.cas.cn/ns/headline/201605/t20160518_163197.html

The 12th China-ESA Space Science Bilateral Meeting Opens in Shanghai

Quote
In addition, both parties introduced the respective gravitational wave detection plans and agreed that there is a cooperation possibility in this area.

Offline Star One

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #140 on: 07/19/2016 07:43 PM »
Quote
Scientists from Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory are using powerful X-rays to study high-performance mirror coatings that could help make the LIGO gravitational wave observatory 10 times more sensitive to cosmic events that ripple space-time.

http://media.slac.stanford.edu/news/2016/07-19-stanford-slac-xray-studies-help-make-ligo-gravitational-wave-detector-10-times-more-sensitive/

Offline Star One

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #141 on: 08/01/2016 07:13 PM »
chrislintott – Verified account ‏@chrislintott

The region of the sky within which an observed gravitational wave signal might lie is called an ‘error banana’

https://mobile.twitter.com/chrislintott/status/760143862132273153

Offline Star One

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #142 on: 10/04/2016 08:17 PM »
Nobel not just snubbing LIGO today but still snubbing Vera Rubin.

Offline 1

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #143 on: 10/05/2016 12:02 AM »
Nobel not just snubbing LIGO today but still snubbing Vera Rubin.

Nomination deadline is Feb 1, announcement was Feb 11th. Let's wait and see what 2017 brings. Rubin probably won't be likely to win until dark matter is better characterized.

In the meantime, congratulations are due to David Thouless, Duncan Haldane and Michael Kosterlitz for their well-deserved awards.

Offline Star One

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #144 on: 12/14/2016 05:47 PM »
LIGO Black Hole Echoes Hint at General Relativity Breakdown

Gravitational wave data show tentative signs of firewalls or other exotic physics

Quote
It was hailed as an elegant confirmation of Einstein’s general theory of relativity — but ironically the discovery of gravitational waves earlier this year could herald the first evidence that the theory breaks down at the edge of black holes. Physicists have analysed the publicly released data from the Laser Interferometer Gravitational-Wave Observatory (LIGO), and claim to have found “echoes” of the waves that seem to contradict general relativity’s predictions1.
The echoes could yet disappear with more data. If they persist, the finding would be extraordinary. Physicists have predicted that Einstein’s hugely successful theory could break down in extreme scenarios, such as at the centre of black holes. The echoes would indicate the even more dramatic possibility that relativity fails at the black hole’s edge, far from its core.
If the echoes go away, then general relativity will have withstood a test of its power — previously, it wasn’t clear that physicists would be able to test their non-standard predictions.
“The LIGO detections, and the prospect of many more, offer an exciting opportunity to investigate a new physical regime,” says Steve Giddings, a black-hole researcher at the University of California, Santa Barbara. The LIGO team says that it is aware of the prediction and searching its data for echoes.

https://www.scientificamerican.com/article/ligo-black-hole-echoes-hint-at-general-relativity-breakdown1/

Offline as58

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #145 on: 12/14/2016 06:30 PM »
LIGO Black Hole Echoes Hint at General Relativity Breakdown

Gravitational wave data show tentative signs of firewalls or other exotic physics

Quote
It was hailed as an elegant confirmation of Einstein’s general theory of relativity — but ironically the discovery of gravitational waves earlier this year could herald the first evidence that the theory breaks down at the edge of black holes. Physicists have analysed the publicly released data from the Laser Interferometer Gravitational-Wave Observatory (LIGO), and claim to have found “echoes” of the waves that seem to contradict general relativity’s predictions1.
The echoes could yet disappear with more data. If they persist, the finding would be extraordinary. Physicists have predicted that Einstein’s hugely successful theory could break down in extreme scenarios, such as at the centre of black holes. The echoes would indicate the even more dramatic possibility that relativity fails at the black hole’s edge, far from its core.
If the echoes go away, then general relativity will have withstood a test of its power — previously, it wasn’t clear that physicists would be able to test their non-standard predictions.
“The LIGO detections, and the prospect of many more, offer an exciting opportunity to investigate a new physical regime,” says Steve Giddings, a black-hole researcher at the University of California, Santa Barbara. The LIGO team says that it is aware of the prediction and searching its data for echoes.

https://www.scientificamerican.com/article/ligo-black-hole-echoes-hint-at-general-relativity-breakdown1/

Just a general note: this preprint has been criticised quite heavily (see for example https://telescoper.wordpress.com/2016/12/12/ligo-echoes-p-values-and-the-false-discovery-rate/). In particular,  whether there's anything that could be called even a hint. The general idea is interesting, but a lot more data is needed (and luckily, should be available in not too distant future).

Offline philw1776

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #146 on: 12/26/2016 03:48 PM »
Layman here.  I know that early 2000s LIGO was greatly upgraded and I thought I'd read that the new enhanced LIGO was supposed to detect grav wave events at 10s to a hundred or more per year.  If so...
1) Is LIGO still not operating at its touted SNR?
2) Has the sigma criteria for reporting events been raised?
3) Is it just a long time from detection, to analysis, and then publication?
4) Is there something unexpected, not understood, going on?

If not so, then point is moot.
“When it looks more like an alien dreadnought, that’s when you know you’ve won.”

Offline Star One

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #147 on: 12/26/2016 04:37 PM »
Layman here.  I know that early 2000s LIGO was greatly upgraded and I thought I'd read that the new enhanced LIGO was supposed to detect grav wave events at 10s to a hundred or more per year.  If so...
1) Is LIGO still not operating at its touted SNR?
2) Has the sigma criteria for reporting events been raised?
3) Is it just a long time from detection, to analysis, and then publication?
4) Is there something unexpected, not understood, going on?

If not so, then point is moot.

LIGO is under constant upgrade. For example its most recent run saw it running in an upgraded configuration from the one that made the first detections last year.

Offline Donosauro

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #148 on: 12/26/2016 04:46 PM »
Layman here.  I know that early 2000s LIGO was greatly upgraded and I thought I'd read that the new enhanced LIGO was supposed to detect grav wave events at 10s to a hundred or more per year.  If so...
1) Is LIGO still not operating at its touted SNR?
2) Has the sigma criteria for reporting events been raised?
3) Is it just a long time from detection, to analysis, and then publication?
4) Is there something unexpected, not understood, going on?

If not so, then point is moot.

The year-end issue of SN says, on p. 18, that the sensitivity upgrade which is expected to allow almost-daily detections, will be complete "perhaps by 2019".
« Last Edit: 12/26/2016 04:48 PM by Donosauro »

Offline Star One

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #149 on: 12/27/2016 11:56 AM »
Layman here.  I know that early 2000s LIGO was greatly upgraded and I thought I'd read that the new enhanced LIGO was supposed to detect grav wave events at 10s to a hundred or more per year.  If so...
1) Is LIGO still not operating at its touted SNR?
2) Has the sigma criteria for reporting events been raised?
3) Is it just a long time from detection, to analysis, and then publication?
4) Is there something unexpected, not understood, going on?

If not so, then point is moot.

The year-end issue of SN says, on p. 18, that the sensitivity upgrade which is expected to allow almost-daily detections, will be complete "perhaps by 2019".

SN?

Offline RonM

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #150 on: 12/27/2016 01:19 PM »
Layman here.  I know that early 2000s LIGO was greatly upgraded and I thought I'd read that the new enhanced LIGO was supposed to detect grav wave events at 10s to a hundred or more per year.  If so...
1) Is LIGO still not operating at its touted SNR?
2) Has the sigma criteria for reporting events been raised?
3) Is it just a long time from detection, to analysis, and then publication?
4) Is there something unexpected, not understood, going on?

If not so, then point is moot.

The year-end issue of SN says, on p. 18, that the sensitivity upgrade which is expected to allow almost-daily detections, will be complete "perhaps by 2019".

SN?

Science News magazine.

https://www.sciencenews.org/

Offline eeergo

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #151 on: 12/27/2016 02:30 PM »
Layman here.  I know that early 2000s LIGO was greatly upgraded and I thought I'd read that the new enhanced LIGO was supposed to detect grav wave events at 10s to a hundred or more per year.  If so...
1) Is LIGO still not operating at its touted SNR?
2) Has the sigma criteria for reporting events been raised?
3) Is it just a long time from detection, to analysis, and then publication?
4) Is there something unexpected, not understood, going on?

If not so, then point is moot.

The year-end issue of SN says, on p. 18, that the sensitivity upgrade which is expected to allow almost-daily detections, will be complete "perhaps by 2019".

This is explained in the official LIGO website: http://www.ligo.org/science/Publication-ObservingScenario/index.php

Quote
The Advanced LIGO detectors officially began their first observing run, which is called O1, on 18 September 2015. The detectors are not yet at final sensitivity, but are roughly four times more sensitive than the pre-Advanced LIGO best. It is a long and complicated process to improve our gravitational-wave detectors. Rather than wait until they are at their final sensitivity before beginning observations, we plan to carry out several observing runs along the way. This is done because we are excited to start the search for gravitational waves as soon as possible; because we want to gain experience operating our detectors in stable, undisturbed observing state, and because we want to test out our data-analysis methods. Figuring out how to extract all the information we can from our data (while checking carefully for any gravitational waves that might be present) is just as tricky as getting the instruments working in the first place. O1 is planned to last for four months, closing mid-January 2016. Then work will start on upgrading the instruments for our second observing run, which is called O2; those upgrades will be informed by what we have learned about the instruments during O1. O2 will start in 2016 and last around six months . Hopefully, around this time Advanced LIGO will be joined by Advanced Virgo. Following O2 we will upgrade again, before observing for nine months in our third observing run, which is called (you can probably guess) O3. Each upgrade should improve the sensitivities of our detectors and increase our chances of detecting gravitational waves. Eventually, if all goes according to plan, both Advanced LIGO and Advanced Virgo will be running at full sensitivity by 2021.

More details about what the short-term upgrades involve: https://www.advancedligo.mit.edu/aug_2016_news.html
« Last Edit: 12/27/2016 02:30 PM by eeergo »
-DaviD-

Offline Star One

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #152 on: 12/27/2016 04:24 PM »
Layman here.  I know that early 2000s LIGO was greatly upgraded and I thought I'd read that the new enhanced LIGO was supposed to detect grav wave events at 10s to a hundred or more per year.  If so...
1) Is LIGO still not operating at its touted SNR?
2) Has the sigma criteria for reporting events been raised?
3) Is it just a long time from detection, to analysis, and then publication?
4) Is there something unexpected, not understood, going on?

If not so, then point is moot.

The year-end issue of SN says, on p. 18, that the sensitivity upgrade which is expected to allow almost-daily detections, will be complete "perhaps by 2019".

SN?

Science News magazine.

https://www.sciencenews.org/

Thank you. SN could have just as easily referred to Spaceflight Now for example.

Offline Donosauro

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #153 on: 12/27/2016 05:29 PM »
Layman here.  I know that early 2000s LIGO was greatly upgraded and I thought I'd read that the new enhanced LIGO was supposed to detect grav wave events at 10s to a hundred or more per year.  If so...
1) Is LIGO still not operating at its touted SNR?
2) Has the sigma criteria for reporting events been raised?
3) Is it just a long time from detection, to analysis, and then publication?
4) Is there something unexpected, not understood, going on?

If not so, then point is moot.

The year-end issue of SN says, on p. 18, that the sensitivity upgrade which is expected to allow almost-daily detections, will be complete "perhaps by 2019".

SN?

Science News magazine.

https://www.sciencenews.org/

Thank you. SN could have just as easily referred to Spaceflight Now for example.

The magazine's name is SN, in characters about 1-1/2" tall on the cover. Below that, in characters perhaps 3/16" tall, is "SCIENCE NEWS MAGAZINE", a description of the magazine's nature, and its former title (or close to it; it may have just been Science News). Before that, IIRC, it was Science Newsletter. SN is its actual, correct, name, not an abbreviation by me.

But this is off topic. Let's move on.

Offline sanman

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #154 on: 12/27/2016 07:49 PM »
The detection of gravitational waves is being named the breakthrough of the year for 2016:

https://thespacereporter.com/2016/12/detection-gravitational-waves-named-breakthrough-year/

Offline Star One

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Gravitational Waves Have Been Detected At LIGO
« Reply #155 on: 01/08/2017 06:49 PM »
Looking at one of the speakers here I wonder if we might get another detection announcement.

http://europeanastrofest.com/conference/

Quote
Astronomy Now –  ‏@AstronomyNow

@skyinspector More details will be posted tomorrow. Just confirming times with speakers. Show is 2nd weekend Feb, week later than usual.

As looking at the above it will be the first anniversary of the initial announcement.
« Last Edit: 01/08/2017 06:53 PM by Star One »

Offline Star One

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Gravitational Waves Have Been Detected At LIGO
« Reply #156 on: 01/29/2017 07:23 PM »
Quote
Jeff Foust –  ‏@jeff_foust

Lisa Barsotti, MIT: detected 2 candidate events since second Advanced LIGO run started late November; analysis in progress. #apsapril

https://mobile.twitter.com/jeff_foust/status/825789056554373121
« Last Edit: 01/29/2017 07:24 PM by Star One »

Offline Star One

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #157 on: 02/07/2017 10:48 AM »
Gravitational wave detector prepares to peer into bizarre stars

Quote
LIGO’s second run began on 30 November 2016. On 28 January, the team announced that it had seen two event candidates so far, which matches the expected rate of about one per month.

If they turn out to be real events, they will probably be more gravitational waves from merging black holes. Building up our bank of data on black holes is useful for comparisons and will help test questions like how stars evolve and whether Einstein’s theory of general relativity holds true.

“The only way we’re ever going to answer them is with more detections of the same type,” says Larson.

https://www.newscientist.com/article/2120507-gravitational-wave-detector-prepares-to-peer-into-bizarre-stars/

Offline as58

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #158 on: 02/08/2017 05:10 PM »
A new article on Virgo in Nature News: http://www.nature.com/news/ligo-s-underdog-cousin-ready-to-enhance-gravitational-wave-hunt-1.21437

Inauguration will be on 20th of February, but it will take 'several more weeks' before science data is taken. Still, that should mean that Virgo and aLIGO's second science run should overlap for a couple of months. With some luck there could be a detection by all three detectors, which should allow much better constraints on location of the event.

Offline eeergo

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #159 on: 02/20/2017 04:11 PM »
aVIRGO has been inaugurated today:

http://home.infn.it/it/comunicazione/comunicati-stampa/2193-taglio-del-nastro-per-advanced-virgo (still in Italian)

Construction and commissioning are complete with this ceremony, but calibration is still up for the next few months. The project has cost 23.8 M€ spread over the last 4 years. Upgrades include modifications in the optics, with heavier and higher-performing mirrors; new and more powerful electronics, new aberration-compensating system, better seismic isolation, stray light reduction system and better vacuum.
-DaviD-

Offline eeergo

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #160 on: 02/28/2017 03:09 PM »
aVIRGO has been inaugurated today:

http://home.infn.it/it/comunicazione/comunicati-stampa/2193-taglio-del-nastro-per-advanced-virgo (still in Italian)

Construction and commissioning are complete with this ceremony, but calibration is still up for the next few months. The project has cost 23.8 M€ spread over the last 4 years. Upgrades include modifications in the optics, with heavier and higher-performing mirrors; new and more powerful electronics, new aberration-compensating system, better seismic isolation, stray light reduction system and better vacuum.

4-page interview with Giovanni Losurdo, coordinator of aVIRGO:

http://home.infn.it/newsletter-eu/pdf/NEWSLETTER_INFN_32_inglese_pag6.pdf


Extremely interesting to note that the "monolithic suspensions" (fused silica fibers where the mirrors are suspended) were in use by VIRGO before, but were damaged because of dust particles impacting them when the mirror assembly was vented to atmospheric pressure (!!!). Steel wires will be used for the commissioning and first science runs, to then re-install the silica fibers to much increase sensitivity in the low-frequency range from run 03[/size][size=78%].[/size]
« Last Edit: 02/28/2017 03:19 PM by eeergo »
-DaviD-

Offline 1

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #161 on: 03/08/2017 05:55 PM »
Now this is quite unfortunate.

Gravitational wave pioneer Ronald Drever dies

I'm attempting to see if an award may be made posthumously if the person was nominated before death, but it's not clear. If the person had already been awarded the prize, but died before reception, then they will still receive it, but prize announcements for 2017 won't be until October-ish. I do hope the committee rules on the lighter side of this gray area.  Looking for precedents at the moment

Regardless, the man saw his life's work validated in a spectacular fashion. I hope he died with a smile on his face.

 

Offline as58

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #162 on: 03/09/2017 05:23 PM »
Now this is quite unfortunate.

Gravitational wave pioneer Ronald Drever dies

I'm attempting to see if an award may be made posthumously if the person was nominated before death, but it's not clear. If the person had already been awarded the prize, but died before reception, then they will still receive it, but prize announcements for 2017 won't be until October-ish. I do hope the committee rules on the lighter side of this gray area.  Looking for precedents at the moment

Regardless, the man saw his life's work validated in a spectacular fashion. I hope he died with a smile on his face.

Unfortunately, the rules are clear. From http://www.nobelprize.org/nobel_organizations/nobelfoundation/statutes.html#par4:

Quote
Work produced by a person since deceased shall not be considered for an award. If, however, a prizewinner dies before he has received the prize, then the prize may be presented.

In 2011 they did award Ralph Steinman the Prize for Physiology or Medicine posthumously, but in that case the committee wasn't aware that he had died only four days earlier.

Offline Star One

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #163 on: 05/17/2017 07:59 PM »
Physicists use Einstein’s ‘spooky’ entanglement to invent super-sensitive gravitational wave detector

Quote
The first direct detection of gravitational waves, a phenomenon predicted by Einstein’s 1915 general theory of relativity, was reported by scientists in 2016.

Armed with this “discovery of the century”, physicists around the world have been planning new and better detectors of gravitational waves.

Physicist Professor Chunnong Zhao and his recent PhD students Haixing Miao and Yiqiu Ma are members of an international team that has created a particularly exciting new design for gravitational wave detectors.

The new design is a real breakthrough because it can measure signals below a limit that was previously believed to be an insurmountable barrier. Physicists call this limit the standard quantum limit. It is set by the quantum uncertainty principle.

The new design, published in Nature magazine this week, shows that this may not be a barrier any longer.

Using this and other new approaches may allow scientists to monitor black hole collisions and “spacequakes” across the whole of the visible universe.

https://theconversation.com/physicists-use-einsteins-spooky-entanglement-to-invent-super-sensitive-gravitational-wave-detector-77822

Offline Star One

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Gravitational Waves Have Been Detected At LIGO
« Reply #164 on: 06/01/2017 06:19 PM »
Third detection made.

Quote
First, the merger demonstrates how the binary system was spinning before the two parts merged. In these systems, in addition to orbiting one another, each black hole spins around its own axis. For astrophysicists, the question is: Are the individual black holes spinning in the same direction as they're orbiting? The gravitational wave fingerprint from this latest observation suggests that they are.
"Our new LIGO measurements favor the scenario where both black holes spin in the same sense as the orbit," said Georgia Tech's Laura Cadonati, Deputy Spokesperson of the LIGO Scientific Collaboration, at the same teleconference. "This means they take longer to merge than if the spins are non-aligned."
The black holes' spin patterns add another puzzle piece to our picture of how black holes form. "This finding lightly favors the theory that these two black holes formed separately in a dense stellar cluster, sank to the core of the cluster, and then paired up," Cadonati said, "rather than being formed together from the collapse of two already paired stars." However, Cadonati cautioned that the finding does not definitively prove which theory of black hole formation is correct. It's only a clue that will require more support.
Luckily, it looks like LIGO may be getting a lot more clues. With this signal, LIGO has found another object in the category of heavy black holes, objects with masses 25 times or more that of our sun. Given the rate at which black holes merge, LIGO may eventually be able to pick up one new black hole merger every week—or even every day. The more signals it picks up, the more we'll learn about black hole formation, as well as more details about how gravitational waves spread through space. These events could even uncover the secrets of gravitons, the theoretical particles that could be the source of gravity.

http://www.popsci.com/ligo-spots-its-third-black-hole-merger
« Last Edit: 06/01/2017 06:39 PM by Star One »

Offline MP99

Re: Gravitational Waves Have Been Detected At LIGO
« Reply #165 on: 06/02/2017 07:33 AM »
There's an inconsistency in that report.

BBC news reporting the spins may not have been aligned, which would make the rest of that article make sense.

Cheers, Martin

Offline Star One

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #166 on: 06/02/2017 09:28 AM »
There's an inconsistency in that report.

BBC news reporting the spins may not have been aligned, which would make the rest of that article make sense.

Cheers, Martin

Yes I was reading another article which contradicted the above in that aspect. So it seems an error.

Here it is from the horse's mouth so to speak.

https://www.ligo.caltech.edu/news/ligo20170601

Offline eeergo

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #167 on: 06/19/2017 05:44 AM »
And just as I'm passing AdVIRGO's area in the high-speed train, I read this nice news item:


http://ligo.org/news/index.php#triplelock


Quote
FIRST TRIPLE LOCK FOR LIGO AND VIRGO INTERFEROMETERS


17 June 2017 -- For the first time, all three second generation interferometers---LIGO Hanford, LIGO Livingston, and Virgo---are simultaneously in a locked state. (When an interferometer is "locked" it means that an optical resonance is set up in the arm cavities and is producing a stable interference pattern at the photodetector.) Virgo is joining in an engineering mode, in preparation for the full triple-observing mode planned for later this summer. Congratulations, Virgo!




PS: By the way, shouldn't this thread be moved to "Space Science" or, at least, to "Advanced Concepts"? It's really not speculative and diverges quite a lot from most of the other... creative topics in this subforum.
-DaviD-

Offline jebbo

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #168 on: 06/19/2017 08:45 AM »
I'd second that: it should be moved to, my guess would be to Space Science

Offline gongora

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #169 on: 06/20/2017 05:35 PM »
By the way, shouldn't this thread be moved to "Space Science" or, at least, to "Advanced Concepts"? It's really not speculative and diverges quite a lot from most of the other... creative topics in this subforum.

The top post in this thread would put it into the New Physics for Space Technology section, but if the thread has settled into a discussion of gravitational wave detection instead of proposed uses for spaceflight it probably belongs in Space Science.

Offline jebbo

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #170 on: 06/20/2017 08:25 PM »
ESA has selected the full LISA mission for launch in 2026.

http://www.bbc.co.uk/news/science-environment-40346410

--- Tony

Offline bolun

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #171 on: 06/20/2017 08:43 PM »

Offline jebbo

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #172 on: 06/20/2017 08:46 PM »
Oops ... somehow I got it confused with the Plato date

--- Tony 

Offline Star One

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Gravitational Waves Have Been Detected At LIGO
« Reply #173 on: 06/21/2017 07:41 PM »
Yet another poor science paper comes to the attention of the internet press. This time supposedly calling into doubt the LIGO detections.

Anyway here's the whole gruesome tale as presented by one of the LIGO team. Relevant links in the article.

http://fictionalaether.blogspot.co.uk/2017/06/the-irresistible-allure-of-controversy.html?m=1

More here from another LIGO team member.

https://www.preposterousuniverse.com/blog/2017/06/18/a-response-to-on-the-time-lags-of-the-ligo-signals-guest-post/
« Last Edit: 06/21/2017 07:46 PM by Star One »

Offline Star One

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Re: Gravitational Waves Have Been Detected At LIGO
« Reply #174 on: 07/02/2017 07:48 PM »

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