Author Topic: Boyajians Star Updates And Discussion  (Read 11849 times)

Offline Star One

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Boyajians Star Updates And Discussion
« on: 11/25/2016 11:40 PM »
Is currently being observed by the Allen Telescope Array.

http://setiquest.info

Only reached a pretty common on 2.
« Last Edit: 11/26/2016 10:21 AM by Star One »

Offline Req

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Re: Boyajians Star Updates And Discussion
« Reply #1 on: 11/26/2016 06:46 PM »
I suppose if we're going to be arbitrary about naming this star, I hereby declare it Req's star!  Thread #3(or is it 4) incoming!

Edit so that this post isn't pure snark, for searches:

KIC 8462852
KIC8462852
Tabby's Star
Tabbys Star
« Last Edit: 11/27/2016 01:02 AM by Req »

Offline as58

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Re: Boyajians Star Updates And Discussion
« Reply #2 on: 11/26/2016 07:00 PM »
The main problem with the previous thread is that it seems to be undergoing an extreme dimming event so that it's not even observable any more.

Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #3 on: 11/26/2016 07:27 PM »
I suppose if we're going to be arbitrary about naming this star, I hereby declare it Req's star!  Thread #3(or is it 4) incoming!

This name has been applied to be its official name I believe.

Offline Johnnyhinbos

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Re: Boyajians Star Updates And Discussion
« Reply #4 on: 11/26/2016 10:21 PM »
The main problem with the previous thread is that it seems to be undergoing an extreme dimming event so that it's not even observable any more.
Lol - I see what you did there...
John Hanzl. Author, action / adventure www.johnhanzl.com

Offline Star One

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Boyajians Star Updates And Discussion
« Reply #5 on: 11/28/2016 07:13 PM »
Not strictly related but can anyone explain the significance of this new Tweet by Jason Wright?

Quote
Jason Wright –  ‏@Astro_Wright

@EricMamajek Now that we have a TGAS distance & space motion, is it weird that TYC 8830-410-1 has a big IR excess?
http://adsabs.harvard.edu/abs/2016ApJS..225...15C

This is the only reference I can find and it's a little old.

http://adsabs.harvard.edu/abs/2015sofi.prop..130S
« Last Edit: 11/28/2016 07:17 PM by Star One »

Offline Alpha_Centauri

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Re: Boyajians Star Updates And Discussion
« Reply #6 on: 11/28/2016 10:47 PM »
Well this is just a guess but; often when you are talking about a star's position and motion through the galaxy you are using it as a proxy for age.  I would assume what he's alluding to is the space motion implies it comes from an old population, one which shouldn't be undergoing a LHB to keep the dust hot.
« Last Edit: 11/30/2016 08:34 AM by Alpha_Centauri »

Offline Stan-1967

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Re: Boyajians Star Updates And Discussion
« Reply #7 on: 11/28/2016 10:50 PM »
Not strictly related but can anyone explain the significance of this new Tweet by Jason Wright?

Quote
Jason Wright –  ‏@Astro_Wright

@EricMamajek Now that we have a TGAS distance & space motion, is it weird that TYC 8830-410-1 has a big IR excess?
http://adsabs.harvard.edu/abs/2016ApJS..225...15C

This is the only reference I can find and it's a little old.

http://adsabs.harvard.edu/abs/2015sofi.prop..130S

Eric Mamajek is an expert on circumstellar disks and planetary formation.  I don't know if he has commented on Tabby's star anywhere.  The tweet looks like it was an "inside" message from Wright, who is looking for mechanisms to explain the lack of IR excess around Tabby's star, to an expert who has contributed to the knowledge base of transient warm disks around stars like TYC 8830-410-1.

Is Wright looking for confirmation or issuing a challenge?   I don't know.  Lately he seems to favor the ISM as the reason for dimming of Tabby's star, but that still leaves the problem of IR excess.   Maybe Wright is postulating that depending on the clumpiness of the ISM, and the proper motion of Tabby's star relative the the motion if the ISM, you could get IR excess only when a big dimming event is happening.   Then it is gone after the event, and any dust farther out of the system is cold, and would not produce the IR flux missing at Tabby's star?  Eric Mamajek is the type of expert that may have something to say about that.

Offline Star One

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Boyajians Star Updates And Discussion
« Reply #8 on: 11/28/2016 10:52 PM »
Well this is just a guess but; often when you are talking about a star's position and motion through the galaxy you are using it as a proxy for age.  I would assume what he's alluding to is the space motion implies it comes from an old population, one which shouldn't be undergoing an LHB to keep the dust hot.

People keep wanting alien megastructures well if it was one of them it could be giving off a huge excess of IR. It does throw you into that territory if you get something like this around an older star.

I did wonder if he was alluding to its age so thanks for the thoughts on that.

He's has had a reply now.

Quote
Eric Mamajek –  ‏@EricMamajek

@Astro_Wright @steinly0 I'll be visiting your dept Wed am - can chat then on this object
« Last Edit: 11/28/2016 10:57 PM by Star One »

Offline Star One

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Boyajians Star Updates And Discussion
« Reply #9 on: 11/28/2016 11:01 PM »
By the way there's a new paper on the star that is the topic of this thread.

A physically inspired model of Dip d792 and d1519 of the Kepler light curve seen at KIC8462852

Quote
The star KIC 8462852 shows a very unusual and hard to comprehend light curve. The dip d7922 absorbs 16% of the starlight. The light curve is unusually smooth but the very steep edges make it hard to find a simple natural explanation by covering due to comets or other well-known planetary objects. We describe a mathematical approximation to the light curve, which is motivated by a physically meaningful event of a large stellar beam which generates an orbiting cloud. The data might fit to the science fiction idea of star lifting, a mining technology that could extract star matter. We extend the model to d1519 and d1568 using multiple beams and get an encouraging result that fits essential parts of the dips but misses other parts of the measured flux. We recommend further exploration of this concept with refined models.

https://arxiv.org/abs/1611.08368

I believe this is going up for peer review as well.

There is also this Where's The Flux update.

http://www.wherestheflux.com/single-post/2016/11/28/October-science-update-Part-II

One thing to note is it's going to be observed by Swift.
« Last Edit: 11/28/2016 11:07 PM by Star One »

Offline Stan-1967

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Re: Boyajians Star Updates And Discussion
« Reply #10 on: 11/29/2016 01:19 AM »
From the paper by Eduard Heindl at:
https://arxiv.org/abs/1611.08368
Quote
3. The Model

The main aim of this paper is a physical model for the flux variation of the dip at day 792.
The model is based on the idea, that a stream of matter leaves the star into space similar as
observed in solar flares. The difference is, the stream of matter is quite high and lifts the
matter into a stable orbit. It is not the aim of this paper to speculate for the mechanic of this
event in detail.

Bold & underline is my addition.

The beam model was briefly discussed in the "WTF" thread.  The fit of the model to the data is interesting.   The paper would have done itself a favor if it ended after section 5.    The last 2 pages does exactly what it said was not the aim, which was to bring in the ETI hypothesis as the explanation for the mechanics of the dimming.

It would be interesting to see how the paper gets reviewed if all reference to star lifting was scrubbed.  It have the feeling it would be like the EM Drive threads where current work on EM drives show some resultant force without any basis in physics as is currently understood to offer an explanation of how it works.

I think the paper may also suffer from some language barriers.  The proposal of a lifted beam ( or CME) with a trail of "smoke" makes no sense.   What becomes of a CME when it condenses, or is no longer ejected plasma?

Offline Star One

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Boyajians Star Updates And Discussion
« Reply #11 on: 11/29/2016 05:54 AM »
From the paper by Eduard Heindl at:
https://arxiv.org/abs/1611.08368
Quote
3. The Model

The main aim of this paper is a physical model for the flux variation of the dip at day 792.
The model is based on the idea, that a stream of matter leaves the star into space similar as
observed in solar flares. The difference is, the stream of matter is quite high and lifts the
matter into a stable orbit. It is not the aim of this paper to speculate for the mechanic of this
event in detail.

Bold & underline is my addition.

The beam model was briefly discussed in the "WTF" thread.  The fit of the model to the data is interesting.   The paper would have done itself a favor if it ended after section 5.    The last 2 pages does exactly what it said was not the aim, which was to bring in the ETI hypothesis as the explanation for the mechanics of the dimming.

It would be interesting to see how the paper gets reviewed if all reference to star lifting was scrubbed.  It have the feeling it would be like the EM Drive threads where current work on EM drives show some resultant force without any basis in physics as is currently understood to offer an explanation of how it works.

I think the paper may also suffer from some language barriers.  The proposal of a lifted beam ( or CME) with a trail of "smoke" makes no sense.   What becomes of a CME when it condenses, or is no longer ejected plasma?

Why would the author delete such sections when it's clear that's one of the topics he wants to discuss.

Just because you may happen to not to agree with this hypothesis does not mean that such a debate should be stifled.
« Last Edit: 11/29/2016 05:56 AM by Star One »

Offline Stan-1967

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Re: Boyajians Star Updates And Discussion
« Reply #12 on: 11/29/2016 06:34 AM »

Why would the author delete such sections when it's clear that's one of the topics he wants to discuss.

Just because you may happen to not to agree with this hypothesis does not mean that such a debate should be stifled.

The author, Mr. Heindl, said that "It is not the aim of this paper to speculate for the mechanic of this
event in detail",...
and he then went about doing just that by including all the speculation on starlifting by ETI's. 

I'm OK with speculation on starlifting,  I don't want to stifle anything,  however his paper forfeits congruity by saying one thing and then doing another.  I think the paper may be more interesting if he would have focused on demonstrating the strong fit of modeling a "beam" of matter extended from the stars surface as the mechanism of the dimming, and leave out all ETI speculation.  The paper will likely be dismissed by serious academics for including these claims that would better off bifurcated & discussed separate from the ETI hypothesis.

It is logically more palatable to just make supportable proposals as to what the source of the dimming might be, when the more controversial argument is the cause. (i.e ETI's) 

The same goes for J. Wrights proposal for ISM/bok globules.   The body of knowledge regarding the internal structure of bok globules or other ISM is pretty sparse.   However each proposal has to first demonstrate it can "model" the dimming, and then subsequent predictions for future observations can test the hypothesis.




Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #13 on: 11/29/2016 06:46 AM »

Why would the author delete such sections when it's clear that's one of the topics he wants to discuss.

Just because you may happen to not to agree with this hypothesis does not mean that such a debate should be stifled.

The author, Mr. Heindl, said that "It is not the aim of this paper to speculate for the mechanic of this
event in detail",...
and he then went about doing just that by including all the speculation on starlifting by ETI's. 

I'm OK with speculation on starlifting,  I don't want to stifle anything,  however his paper forfeits congruity by saying one thing and then doing another.  I think the paper may be more interesting if he would have focused on demonstrating the strong fit of modeling a "beam" of matter extended from the stars surface as the mechanism of the dimming, and leave out all ETI speculation.  The paper will likely be dismissed by serious academics for including these claims that would better off bifurcated & discussed separate from the ETI hypothesis.

It is logically more palatable to just make supportable proposals as to what the source of the dimming might be, when the more controversial argument is the cause. (i.e ETI's) 

The same goes for J. Wrights proposal for ISM/bok globules.   The body of knowledge regarding the internal structure of bok globules or other ISM is pretty sparse.   However each proposal has to first demonstrate it can "model" the dimming, and then subsequent predictions for future observations can test the hypothesis.

Again you have not answered the point why shouldn't they at least discuss these matters other to confirm to some kind of institutional bias.

Offline Stan-1967

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Re: Boyajians Star Updates And Discussion
« Reply #14 on: 11/29/2016 02:31 PM »

Again you have not answered the point why shouldn't they at least discuss these matters other to confirm to some kind of institutional bias.
I gave 4 reasons why the paper would have been better off by omitting ETI speculation. 

If one submits a paper on the arvix server and invites review and criticism, it might be a better approach to stick to your best argument.   Confronting the institutional bias against ETI's is not likely helpful in getting the main argument heard & reviewed with any respect.


Offline TakeOff

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Re: Boyajians Star Updates And Discussion
« Reply #15 on: 11/29/2016 07:46 PM »
There used to be a long thread here about the WTF star. But that seems to suddenly have dipped down by 100% without any kind of explanation. Maybe there's a filter here?

In that thread I were convinced that this kind of dimmings where astrophysical and had nothing to do with human actions or software bugs on Earth. But this sudden total disappearance of one specific thread here kind of confounds me. Was it maybe a binary neutron star merger that caused it? Is there any secondary observation to confirm it?
« Last Edit: 11/29/2016 07:49 PM by TakeOff »

Offline as58

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Re: Boyajians Star Updates And Discussion
« Reply #16 on: 11/29/2016 07:55 PM »
I believe human actions or software bugs on Earth are good candidates for this second kind of dimming. But in common with the stellar brightness fluctuations, the phenomenon seems to be impossible to predict in advance.
« Last Edit: 11/29/2016 08:02 PM by as58 »

Offline Star One

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Boyajians Star Updates And Discussion
« Reply #17 on: 12/03/2016 09:52 PM »
Same old, same old.

A not unexpected null result.

Quote
RADIO SETI OBSERVATIONS OF THE ANOMALOUS STAR KIC 8462852
G. R. Harp1, Jon Richards1, Seth Shostak1, J. C. Tarter1, Douglas A. Vakoch1,2, and Chris Munson1
Published 2016 July 13 • 2016. The American Astronomical Society. All rights reserved.
The Astrophysical Journal, Volume 825, Number 2

http://iopscience.iop.org/article/10.3847/0004-637X/825/2/155
« Last Edit: 12/03/2016 09:52 PM by Star One »

Offline Stan-1967

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Re: Boyajians Star Updates And Discussion
« Reply #18 on: 12/04/2016 09:19 PM »
I understand it is necessary to put limits on the speculation regarding advanced civlizations around Tabby's star, but I do kind of lament the uselessness of the effort, as well as how it will likely be misused by skeptics to say that the Allen array looked for a signal and didn't detect anything, therefore the ETI hypothesis is disproven.

From the article:

Quote
These limits correspond to isotropic radio transmitter powers of (4–7) 1015 W and 1019 W for the narrowband and moderate band observations. These can be compared with Earth's strongest transmitters, including the Arecibo Observatory's planetary radar (2 1013 W EIRP). Clearly, the energy demands for a detectable signal from KIC 8462852 are far higher than this terrestrial example (largely as a consequence of the distance of this star). On the other hand, these energy requirements could be very substantially reduced if the emissions were beamed in our direction.

So the observation rules out transmissions that greater than a petawatt or exawatt scale isotropic source.   There is no way to make any assessment of the ETI hypothesis from the observation, as a nullification or in support.  It just "is what it is".   

I just hope the next dimming event is caught by multiple ground and space based observatories.   

Offline Johnnyhinbos

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Re: Boyajians Star Updates And Discussion
« Reply #19 on: 12/04/2016 09:24 PM »
We're talking about events that happened 1,400 years ago, is this correct?
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Offline M.E.T.

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Re: Boyajians Star Updates And Discussion
« Reply #20 on: 12/04/2016 10:10 PM »
We're talking about events that happened 1,400 years ago, is this correct?

That is correct.

Offline Johnnyhinbos

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Re: Boyajians Star Updates And Discussion
« Reply #21 on: 12/05/2016 01:30 AM »
So if there was a Dyson sphere being constructed some 1,400 years ago, wouldn't there be some much greater probability of seeing such a thing in our neighborhood some 1,400 years later?

(Queue the Fermi paradox comment...)

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Offline rocx

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Re: Boyajians Star Updates And Discussion
« Reply #22 on: 12/05/2016 07:03 AM »
So if there was a Dyson sphere being constructed some 1,400 years ago, wouldn't there be some much greater probability of seeing such a thing in our neighborhood some 1,400 years later?

(Queue the Fermi paradox comment...)

No, because travel to our neighbourhood would necessarily take longer than 1400 years.
Any day with a rocket landing is a fantastic day.

Offline LouScheffer

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Re: Boyajians Star Updates And Discussion
« Reply #23 on: 12/05/2016 02:53 PM »
[...] I do kind of lament the uselessness of the effort [...]

From the article:
Quote
These limits correspond to isotropic radio transmitter powers of (4–7) 1015 W and 1019 W for the narrowband and moderate band observations. These can be compared with Earth's strongest transmitters, including the Arecibo Observatory's planetary radar (2 1013 W EIRP). Clearly, the energy demands for a detectable signal from KIC 8462852 are far higher than this terrestrial example (largely as a consequence of the distance of this star). On the other hand, these energy requirements could be very substantially reduced if the emissions were beamed in our direction.
So the observation rules out transmissions that greater than a petawatt or exawatt scale isotropic source.   There is no way to make any assessment of the ETI hypothesis from the observation, as a nullification or in support.  It just "is what it is".   
The key here is the very substantially reduced in the abstract.  If they know we are here, and might be listening, then the power requirements can be quite modest.  In fact. 1 watt (not a typo) would suffice.  They need to cover a disc of about 1 AU centered around our star.  That's a radius of 1.5e11 meters, or an area of about 7e22 m^2.  1 watt produces 1.3e-23 w/m^2, an intensity we can detect narrowband.  (To see this is indeed plausible, note that we can detect the carriers from spacecraft at Mars even when the are using their omni-directional antennas and just a few watts.  That's a similar intensity).

Now this would require a very big (by Earth standards) transmitting antenna (to make a 10^11 m spot from 10^19 meters away takes an antenna about 10^8 wavelengths across, or 3000 km at a 3 cm wavelength).   But there are other compromises, such as 10 kw from a 30 km size antenna, or 1 MW from a 3 km antenna (that's just a factor 6 bigger than Earth technology).  And if the antenna was a phased array, not a dish, they could send signals to all potential recipients in a half sphere simultaneously, so they do not have to be targetting just us.

Anyone who might send us a signal probably already knows there is a life-bearing planet in our system, since we are (on a historical scale) close to this technology already.  So assuming they wanted to send a signal, they could target just those, for a modest investment in power and technology.   So it's not useless to look.
 



Offline notsorandom

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Re: Boyajians Star Updates And Discussion
« Reply #24 on: 12/05/2016 03:28 PM »
Sending a signal over a thousand light years means figuring out where the target will be over a thousand years from now. Even a small fraction of a meter per second unaccounted for in the prediction of the star's motion over a thousand year can throw the beam wildly off target.

Offline LouScheffer

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Re: Boyajians Star Updates And Discussion
« Reply #25 on: 12/05/2016 04:10 PM »
Sending a signal over a thousand light years means figuring out where the target will be over a thousand years from now. Even a small fraction of a meter per second unaccounted for in the prediction of the star's motion over a thousand year can throw the beam wildly off target.
As above, they need an angular accuracy of about 1 part in 10^8, projected 1400 years out (actually about twice that, since the observer sees where they were 1400 years ago, and needs to predict where they will be 1400 years from now).  Gaia, in orbit now, is measuring positions to about 1 part in 10^10.  So if the mission lasts 30 years (or better yet, 2 Gaia-like missions 100 or more  years apart), your aiming data should be more than good enough.  So aiming is likely not the limiting factor.

Offline JasonAW3

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Re: Boyajians Star Updates And Discussion
« Reply #26 on: 12/05/2016 04:57 PM »

      I hate to bring this up, but if one is expecting possible communications from a nonterrestrial source, such as Tabby's Star, has anyone considered the possibility of modulated X-rays?

      NASA is currently studying this as a potential alternative to both RF and lasers.  Apparently, not only is there far less signal diffusion from an X-ray laser, rather than an optical laser, but due to the wavelength, far more data can be encoded into such a beam, and transmitted with far less signal loss from both distance and potential obscuring gas clouds.

      There's always been the speculation that if there is sapient life, other than ourselves, in space, that they might use something other than radio waves to communicate over vast distances.
My God!  It's full of universes!

Offline notsorandom

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Re: Boyajians Star Updates And Discussion
« Reply #27 on: 12/05/2016 06:47 PM »
Sending a signal over a thousand light years means figuring out where the target will be over a thousand years from now. Even a small fraction of a meter per second unaccounted for in the prediction of the star's motion over a thousand year can throw the beam wildly off target.
As above, they need an angular accuracy of about 1 part in 10^8, projected 1400 years out (actually about twice that, since the observer sees where they were 1400 years ago, and needs to predict where they will be 1400 years from now).  Gaia, in orbit now, is measuring positions to about 1 part in 10^10.  So if the mission lasts 30 years (or better yet, 2 Gaia-like missions 100 or more  years apart), your aiming data should be more than good enough.  So aiming is likely not the limiting factor.
How predictable are stellar motions throughout the galaxy over that timeframe? Over a long enough timeline small but unaccounted for perturbations make all orbits somewhat unpredictable.

Offline as58

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Re: Boyajians Star Updates And Discussion
« Reply #28 on: 12/05/2016 07:23 PM »
How predictable are stellar motions throughout the galaxy over that timeframe? Over a long enough timeline small but unaccounted for perturbations make all orbits somewhat unpredictable.

Even a few thousand years is a very short time when you are considering motion of stars in the Milky Way. I haven't done any calculations to back it up, but it seems to me that if you had the technology to build a sender with good enough directionality to make the proper motion of stars worth considering, you would also have the technology to measure the proper motion to high enough precision.

Offline Vultur

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Re: Boyajians Star Updates And Discussion
« Reply #29 on: 12/10/2016 01:58 AM »
A hypothetical civilization capable of building structures large enough to cause the Boyajian's star dimming events certainly could beam signals to us.

But we're really not that close, and there seem to be a lot of planets in the galaxy.

Any signal that we could receive now would have been sent 1400 years ago... and their information on Earth would be how it looked 2800 years ago, in the time of Homer in Greece and the Zhou Dynasty in China. So no radio signals from Earth, no evidence of industrial pollution in spectroscopy of Earth's atmosphere, no night side lights (even if they had super-interferometry telescopes good enough to see those).

So why would they pick Earth to send signals to? What would make them think there'd be a civilization here able to receive it?

Offline Johnnyhinbos

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Boyajians Star Updates And Discussion
« Reply #30 on: 12/10/2016 07:13 AM »
To get to the point of my earlier comment - that we are looking at a star 1,400 years in the past - and it is a bit nuanced, but in a nutshell - if a civilization had survived to the point of maturity to be able to build a Dyson sphere (aka a Type II civilization on the Kardashev scale) some 1,400 years ago, then in our existence, 1,400 years later, the galaxy should be filled with intelligent radiation. Since it's not then it's doubtful that said civilization ever got to such a point in the first place.

Numerically speaking, think of the Carter catastrophe, and apply it to the Fermi paradox.

Therefore, sadly, I highly doubt the dimming events are caused by another civilization.
« Last Edit: 12/10/2016 07:18 AM by Johnnyhinbos »
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Offline JH

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Re: Boyajians Star Updates And Discussion
« Reply #31 on: 12/10/2016 07:53 AM »
Your conclusion suffers from the same problem as all applications of the German tank problem to civilizational survival: rigid application of statistics with incomplete knowledge of constraints. How do you know that the aliens in question aren't just homebodies?

To be clear, I think a natural explanation for the dimmings of Boyajian's star is much more likely than aliens.

- typo
« Last Edit: 12/10/2016 07:54 AM by JH »

Offline LouScheffer

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Re: Boyajians Star Updates And Discussion
« Reply #32 on: 12/10/2016 06:36 PM »
A hypothetical civilization capable of building structures large enough to cause the Boyajian's star dimming events certainly could beam signals to us.

But we're really not that close, and there seem to be a lot of planets in the galaxy.

Any signal that we could receive now would have been sent 1400 years ago... and their information on Earth would be how it looked 2800 years ago, in the time of Homer in Greece and the Zhou Dynasty in China. So no radio signals from Earth, no evidence of industrial pollution in spectroscopy of Earth's atmosphere, no night side lights (even if they had super-interferometry telescopes good enough to see those).

So why would they pick Earth to send signals to? What would make them think there'd be a civilization here able to receive it?
In this situation, one possibility is that Earth gets no special treatment - they send signals in the direction of all life-bearing planets they know about.  If they can build Dyson spheres, they probably know the Earth exists, and has at least a good chance of having life.  They would know, for example, that oxygen and methane co-exist in our atmosphere.  Since these react on a short time scale, that means there is an active source of each.  I don't think we know of any non-life explanation for this.

The technology to send signals to multiple planets simultaneously is straightforward using phased array antennas.  Using existing Earth technology, we could send signals that we ourselves could detect to all the planets we have discovered so far, if we wanted to (See Appendix B of the book "SETI 2020" for several ways this might be done.)   Aliens presumably know of more planets, but can build larger sending arrays to compensate.  The power requirements are modest since the beams are highly directional.

The main advantage of this strategy is that communication does not depend on long lifetimes for technical civilizations.  If they wait until they see we have technology, then even if they reply right away, then we won't know of them for at least 2800 years after technology development.  If they signal in advance, we could find it after only a few decades of technology, and might even reply.  Depending on what we chose to send, they could find out quite a bit about us even if the lifetime of our civilization is short.



Offline M.E.T.

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Re: Boyajians Star Updates And Discussion
« Reply #33 on: 12/10/2016 07:14 PM »
A hypothetical civilization capable of building structures large enough to cause the Boyajian's star dimming events certainly could beam signals to us.

But we're really not that close, and there seem to be a lot of planets in the galaxy.

Any signal that we could receive now would have been sent 1400 years ago... and their information on Earth would be how it looked 2800 years ago, in the time of Homer in Greece and the Zhou Dynasty in China. So no radio signals from Earth, no evidence of industrial pollution in spectroscopy of Earth's atmosphere, no night side lights (even if they had super-interferometry telescopes good enough to see those).

So why would they pick Earth to send signals to? What would make them think there'd be a civilization here able to receive it?
In this situation, one possibility is that Earth gets no special treatment - they send signals in the direction of all life-bearing planets they know about.  If they can build Dyson spheres, they probably know the Earth exists, and has at least a good chance of having life.  They would know, for example, that oxygen and methane co-exist in our atmosphere.  Since these react on a short time scale, that means there is an active source of each.  I don't think we know of any non-life explanation for this.

The technology to send signals to multiple planets simultaneously is straightforward using phased array antennas.  Using existing Earth technology, we could send signals that we ourselves could detect to all the planets we have discovered so far, if we wanted to (See Appendix B of the book "SETI 2020" for several ways this might be done.)   Aliens presumably know of more planets, but can build larger sending arrays to compensate.  The power requirements are modest since the beams are highly directional.

The main advantage of this strategy is that communication does not depend on long lifetimes for technical civilizations.  If they wait until they see we have technology, then even if they reply right away, then we won't know of them for at least 2800 years after technology development.  If they signal in advance, we could find it after only a few decades of technology, and might even reply.  Depending on what we chose to send, they could find out quite a bit about us even if the lifetime of our civilization is short.

This of course leaves out the "why" question. As in why they would want to send all these signals out. Maybe they're as smart as Stephen Hawking, and realise that it is kind of a dangerous thing to do. Rather finish your "Death Star' device as much as possible before announcing your existence to the Universe.

Offline LouScheffer

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Re: Boyajians Star Updates And Discussion
« Reply #34 on: 12/10/2016 07:58 PM »

This of course leaves out the "why" question.
They *why* part is really hard.  Imagine asking someone who lived 2800 years ago why we do all the various stuff we do today.  And that's the same civilization, on the same planet, with the same biology.  Add in different planet, different civilization, different biology, and potentially millions of years of development, and every conclusion needs to be treated as a guess.
Quote
Maybe they're as smart as Stephen Hawking, and realise that it is kind of a dangerous thing to do. Rather finish your "Death Star' device as much as possible before announcing your existence to the Universe.
Alternatively, it's perhaps more likely that anyone who is capable of coming here and beating us up, already knows (or will know, subject to the speed of light) about us whether we signal or not.  In that case it's better to make friends, see if they have any suggestions, and spread what we know.

Any conclusion that depends on the motivation of aliens is in very murky territory.

Offline Star One

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Boyajians Star Updates And Discussion
« Reply #35 on: 12/10/2016 10:20 PM »
I was reading a little while back that there may have been indications of planets orbiting this star but nothing terribly definitive as they probably aren't transiting from our prospective. There apparently was an indication of a brown dwarf.
« Last Edit: 12/10/2016 10:21 PM by Star One »

Online hop

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Re: Boyajians Star Updates And Discussion
« Reply #36 on: 12/11/2016 06:15 AM »
I was reading a little while back that there may have been indications of planets orbiting this star but nothing terribly definitive as they probably aren't transiting from our prospective. There apparently was an indication of a brown dwarf.
Source? I haven't seen anything like that, and it should be big news if there is any serious evidence. Not clear what kind of evidence that could be based on either, I guess a BD or giant planet could be picked up in radial velocity.

Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #37 on: 12/11/2016 08:25 AM »
I was reading a little while back that there may have been indications of planets orbiting this star but nothing terribly definitive as they probably aren't transiting from our prospective. There apparently was an indication of a brown dwarf.
Source? I haven't seen anything like that, and it should be big news if there is any serious evidence. Not clear what kind of evidence that could be based on either, I guess a BD or giant planet could be picked up in radial velocity.

Mods on the relevant Reddit who I believe some of which are professional astronomers.

https://m.reddit.com/r/KIC8462852/comments/5he29u/orbiting_planets_around_kic8462852/

Online hop

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Re: Boyajians Star Updates And Discussion
« Reply #38 on: 12/11/2016 08:43 AM »
Mods on the relevant Reddit who I believe some of which are professional astronomers.

https://m.reddit.com/r/KIC8462852/comments/5he29u/orbiting_planets_around_kic8462852/
Thanks. I suspect that that
Quote
There probably are planets, but they aren't transiting (no surprise), and they are too small or too inclined to make a dent in the radial velocity measurements we have to date
is just meant in the general sense that most stars have planets, so this one probably does too.

Quote
There is a dwarf possibly in the system.
presumably refers to the previously identified M dwarf, which may or may not be associated.

Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #39 on: 12/11/2016 02:24 PM »
Mods on the relevant Reddit who I believe some of which are professional astronomers.

https://m.reddit.com/r/KIC8462852/comments/5he29u/orbiting_planets_around_kic8462852/
Thanks. I suspect that that
Quote
There probably are planets, but they aren't transiting (no surprise), and they are too small or too inclined to make a dent in the radial velocity measurements we have to date
is just meant in the general sense that most stars have planets, so this one probably does too.

Quote
There is a dwarf possibly in the system.
presumably refers to the previously identified M dwarf, which may or may not be associated.

Will Gaia observations be able to confirm if it is associated or not?

Offline as58

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Re: Boyajians Star Updates And Discussion
« Reply #40 on: 12/11/2016 02:49 PM »
I think the (possible) companion star is a bit too faint for Gaia.

Offline Star One

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Offline jebbo

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Re: Boyajians Star Updates And Discussion
« Reply #42 on: 12/13/2016 10:37 AM »
I think the (possible) companion star is a bit too faint for Gaia.

Very likely, which is a shame: we'd be much more likely to be able to see the orbital motion on the M companion than on the A3V primary (if they're bound) ...

--- Tony

Offline as58

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Re: Boyajians Star Updates And Discussion
« Reply #43 on: 12/13/2016 10:58 AM »
I think the (possible) companion star is a bit too faint for Gaia.

Very likely, which is a shame: we'd be much more likely to be able to see the orbital motion on the M companion than on the A3V primary (if they're bound) ...

--- Tony

A3V?

Offline jgoldader

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Re: Boyajians Star Updates And Discussion
« Reply #44 on: 12/13/2016 12:14 PM »
I think the (possible) companion star is a bit too faint for Gaia.

Very likely, which is a shame: we'd be much more likely to be able to see the orbital motion on the M companion than on the A3V primary (if they're bound) ...

--- Tony

A3V?

Spectral type A3, luminosity class 5 (main sequence dwarf).  The Sun is G2V.  The spectral type sequence reflects temperature, and goes (from hottest to coldest) OBAFGKM (I am not including the brown dwarfs).  Each spectral type goes from subtype 0 to 9 (e.g., G0 is warmer than G1, etc., then G9, then K0).  Luminosity classes go from I to V, in order of decreasing luminosity.  It depends on the temperature and radius of the star.  Supergiants are the class I, dwarfs (normal core hydrogen burning stars) are V.

How we ended up with those letters (OBAFGKM) is a fascinating story, but way beyond the scope of this post!
Recovering astronomer

Offline as58

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Re: Boyajians Star Updates And Discussion
« Reply #45 on: 12/13/2016 12:49 PM »

Spectral type A3, luminosity class 5 (main sequence dwarf).  The Sun is G2V.  The spectral type sequence reflects temperature, and goes (from hottest to coldest) OBAFGKM (I am not including the brown dwarfs).  Each spectral type goes from subtype 0 to 9 (e.g., G0 is warmer than G1, etc., then G9, then K0).  Luminosity classes go from I to V, in order of decreasing luminosity.  It depends on the temperature and radius of the star.  Supergiants are the class I, dwarfs (normal core hydrogen burning stars) are V.

How we ended up with those letters (OBAFGKM) is a fascinating story, but way beyond the scope of this post!

I meant that I didn't think the primary is an A star and now that I've checked, it seems to be F3V.

Not that there's anything wrong with your explanation ;)

Offline jgoldader

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Re: Boyajians Star Updates And Discussion
« Reply #46 on: 12/13/2016 01:49 PM »


I meant that I didn't think the primary is an A star and now that I've checked, it seems to be F3V.


Yer right, I didn't catch that.  D'oh.

Nothing to see here everyone, carry on, carry on.
Recovering astronomer

Offline Star One

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Boyajians Star Updates And Discussion
« Reply #47 on: 12/19/2016 08:07 PM »
Short documentary about this subject.

« Last Edit: 12/19/2016 08:08 PM by Star One »

Offline Mongo62

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Re: Boyajians Star Updates And Discussion
« Reply #48 on: 12/20/2016 01:03 AM »
Mysterious eclipses in the light-curve of KIC8462852: a possible explanation

ABSTRACT:

Apart from thousands of 'regular' exoplanet candidates, Kepler satellite has discovered a few stars exhibiting peculiar eclipse-like events. They are most probably caused by disintegrating bodies transiting in front of the star. However, the nature of the bodies and obscuration events, such as those observed in KIC8462852, remain mysterious. Swarm of comets or artificial alien mega-structures have been proposed as an explanation for the latter object.

We explore the possibility that such eclipses are caused by the dust clouds associated with massive parent bodies orbiting the host star.

We assume a massive object and a simple model of the dust cloud surrounding the object. Then, we use the numerical integration to simulate the evolution of the cloud, its parent body, and resulting light-curves as they orbit and transit the star.

It is found that it is possible to reproduce the basic features in the light-curve of KIC8462852 with only four objects enshrouded in dust clouds. The fact that they are all on similar orbits and that such models require only a handful of free parameters provide additional support for this hypothesis.

This model provides an alternative to the comet scenario. With such physical models at hand, at present, there is no need to invoke alien mega-structures into the explanation of these light-curves.

7. Conclusions

Our main findings and arguments are briefly summarized below.

1. It was demonstrated that it is possible to explain the complex morphology of the Kepler light-curve of KIC8462852 with a very simple model. Only four massive objects, each surrounded by a dust cloud can account for most of the observed features. The objects are apparently of a common origin i.e. a result of a break-up process of a single progenitor.

2. Most of the features may be represented by a simple, initially spherical dust cloud. Such clouds in eccentric orbits are observed to naturally vertically shrink and develop a leading tail as they approach periastron. The feature at 1 540 days seems to be special since it is best reproduced by an initially ring-like structure.

3. This scenario of 4 massive objects is further supported by the following arguments: the smooth shape of the 800 day feature which is difficult to assemble from a number of smaller objects such as comets; a tendency towards shallower ingress and steeper egress of the 800 day feature which is just the opposite of what is expected for the less massive objects such as comets; the 1 520 and 1 570-day features also show a gradual increase in strengths of individual ’sub-features’ and fast recovery what resembles the 800 day feature; the symmetric ’ring-like’ structure of the 1 540-day feature which would presume a non-negligible gravity of the object; the very existence of another symmetric structure at 1 210 days which is very similar to the above mentioned feature and which is difficult to understand within comet scenario or other models; the clustering of the obscuration features into 4 main events which naturally leads to the association with four objects; as well as by the fact that our solution indicates that all four bodies are on very similar eccentric orbits. Apart from that all best fits were for the P-R drag parameter β = 0.629 what indicates that also the dust particles may be similar in size and chemical composition.

4. It is not claimed that we found the only/best solution within this concept of 4 massive bodies. We rather state that we found a possible solution.

5. Iron or carbon grains smaller than about 0.1 micron experience a very strong radiative push which quickly disconnects them from the parent body and places them on hyperbolic orbits. Thus it is unlikely that such grains contribute significantly to the observed features.

6. Grains larger than about 100 microns experience small radiative accelerations and may remain bound to the massive object. Their opacity is small so they are not likely to contribute significantly to the obscuration events. However, they may act as a reservoir and produce smaller dust grains via collisions.

7. It is argued that 0.3−10 micron size dust grains are the best candidates to explain the obscuration events. Smaller grains, unless they were being replenished, would be easily expelled from the system while larger grains would have a relatively small opacity.

8. It was shown that the mutual interaction between the massive objects and their dust clouds within few astronomical units from the periastron can be neglected and that they can be treated independently of each other in this region.

9. If the two massive objects follow each other on identical eccentric orbits with a short enough time lag, a strong interaction between them and their dust clouds may happen at larger distances from the star which might disperse the clouds but, at the same time, also expose sub-surface volatile material, trigger outbursts and produce debris.
« Last Edit: 12/20/2016 01:04 AM by Mongo62 »

Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #49 on: 12/20/2016 07:37 PM »
Viewpoint: New Clues as to Why Boyajian’s Star is Dimming

A statistical analysis links a star’s mysterious brightness fluctuations to internal nonequilibrium phenomena, rather than structures orbiting around the star.

http://physics.aps.org/articles/v9/150

Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #50 on: 12/21/2016 08:48 PM »

Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #51 on: 12/22/2016 07:12 PM »
Quote
Jason Wright ‏@Astro_Wright
Inaugural K-band #BreakthroughListen observations underway at 22 GHz at @GrnBnkTelescope. Target:@tsboyajian's Star. #SETI
Moist Chure
3h
Moist Chure ‏@MoistChure
@Astro_Wright @GrnBnkTelescope @tsboyajian How long till SETI analyzes the data?
Jason Wright
3h
Jason Wright ‏@Astro_Wright
@MoistChure @GrnBnkTelescope @tsboyajian First we have to get it to PSU, then I have to learn the software. Timescale is weeks to months.
Jason Wright
Jason Wright –  ‏@Astro_Wright

@MoistChure @GrnBnkTelescope @tsboyajian Timescale to publication much longer. Unless we see something obvious; then maybe not so long :)

Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #52 on: 12/30/2016 02:07 PM »
Quote
Hello Backers,

Edit: Over the past week, a few papers were published on WTF. Jason Wright blogged about the first two, you can view that discussion here (including links to the original papers). The third paper has only been 'submitted' to the journal, meaning that it has not gone through the peer review process necessary for publication. We will discuss the contents on this once it has been accepted. Be sure to visit the sub-reddit (which now has over 4,000 subscribers) if you want to discuss more with the community. Updates to the Observations

As discussed in the last report, we have modified our observing strategies to optimize data quality. This was a concern because the image was saturating because the defocus command not properly executing. When this happened, the scatter increased in the light curve, an effect we want to minimize. To remedy this, we have now selected settings that will work whether the defocus command executes or not. Just after this change in the schedule request we were reviewing the data and saw something.

We saw the data points trending downwards - like the start of a dip. But this trend was not downwards enough to be a sure thing (it was too soon), especially if we considered the measurement errors (which is a must!). Furthermore, we only saw the downwards trend in one of the three filters at only at one of the observatory sites (what is plotted in the figure above). OK, so nothing significant, right? Right? Well, we weren't so confident about whether or not it was real because we couldn't explain what was causing the trend we observed. And if we couldn't explain the data, we couldn't let our guard down. So here we are frantically checking the LCO scheduler to see when new data was expected to be taken. If the dip trend continued at the same rate, it was the next observations that would confirm it.

At the same time we are asking ourselves hundreds of questions. Why would a trend like this appear only in one filter at one observing site? Was is astrophysical or instrumental? Did a thin layer of clouds roll in that affected the conditions? Did the image get contaminated by scattered moonlight? Did we just not understand our errors well enough? Is there some unknown source of correlated noise in the data?

And then Tyler triumphantly announced - this comparison star is BAD! It was one of the comparison stars that we have been using all along. But after the configuration change to address saturation, the conditions were just barely right (or wrong) enough to affect the one star enough to make it look like there was a dip in the data. Removing the bad comparison star fixed everything, and the data now lines up with the rest of the curve to reveal nothing but a flatline. I guess that is good. For now. We remain patient. This highlights the odd nature of astronomy (and science as a whole), occasionally things just don't work right even though they should.

On the management side of things, we are now set up with a new computer which we have named Toph. Tyler chose this name because we wanted a theme which is expandable if we ever need future computers and the computer generally won't have a monitor attached. Toph is from Avatar: The Last Airbender and is a blind, but fierce fighter. Blind, no monitor. Look, we're scientists first and good at naming things somewhere further down the list.

This is where all the data will be stored locally. Each image is about 7 megabytes in size, but throughout this campaign we will take thousands (possibly over ten thousand images). At the moment we almost have 20 GB of images! From these images we will have Toph automatically extract and produce the light curves and then email them to us and send alerts if a dipping event occurs. This is largely possible with the photometry code developed by Rachel Street and the other astronomers at LCO.

Happy holidays to you all,

~the entire WTF team Thank you once again for your support!

https://www.reddit.com/r/KIC8462852/comments/5kq58q/latest_kickstarter_post_wtf_star/

Offline jebbo

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Re: Boyajians Star Updates And Discussion
« Reply #53 on: 01/04/2017 08:38 AM »
I meant that I didn't think the primary is an A star and now that I've checked, it seems to be F3V.

Not that there's anything wrong with your explanation ;)

Doh!  Why I wrote "A" eludes me ... I know it's an F.  Senility can't be ruled out :-)

--- Tony

Offline jebbo

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Re: Boyajians Star Updates And Discussion
« Reply #54 on: 01/04/2017 08:41 AM »
Another theory:

Quote
Secular Dimming of KIC 8462852 Following its Consumption of a Planet

Quote
The Kepler-field star KIC 8462852, an otherwise apparently ordinary F3 main-sequence star, showed several highly unusual dimming events of variable depth and duration. Adding to the mystery was the discovery that KIC 8462852 faded by 14% from 1890 to 1989, as well as by another 3% over the 4 year Kepler mission. Following an initial suggestion by Wright & Sigurdsson, we propose that the secular dimming behavior is the result of the inspiral of a planetary body or bodies into KIC 8462852, which took place ~10 to 1e4 years ago (depending on the planet mass). Gravitational energy released as the body inspirals into the outer layers of the star caused a temporary and unobserved brightening, from which the stellar flux is now returning to the quiescent state. The transient dimming events could then be due to obscuration by planetary debris from an earlier partial disruption of the same inspiraling bodies, or due to evaporation and out-gassing from a tidally detached moon system. Alternatively, the dimming events could arise from a large number of bodies comet- or planetesimal-mass bodies placed onto high eccentricity orbits by the same mechanism (e.g. Lidov-Kozai oscillations due to the outer M-dwarf companion) responsible for driving the more massive planets into KIC 8462852. The required high occurrence rate of KIC 8462852-like systems which have undergone recent major planet inspiral event(s) is the greatest challenge to the model, placing large lower limits on the mass of planetary systems surrounding F stars and/or requiring an unlikely probability to catch KIC 8462852 in its current state.

https://arxiv.org/abs/1612.07332

--- Tony

Offline Star One

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Boyajians Star Updates And Discussion
« Reply #55 on: 01/04/2017 10:21 AM »
Thing is we can keep coming up with theories on this forever but only more data is going to resolve it. So let's hope we see another dip this year or something comes out of Jason Wright's et al observing campaign.
« Last Edit: 01/04/2017 10:22 AM by Star One »

Online savuporo

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Re: Boyajians Star Updates And Discussion
« Reply #56 on: 01/04/2017 12:37 PM »
Thing is we can keep coming up with theories on this forever but only more data is going to resolve it. ..
Not really. More data is going to refine the hypothesis, not resolve anything definitely
Orion - the first and only manned not-too-deep-space craft

Online hop

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Re: Boyajians Star Updates And Discussion
« Reply #57 on: 01/05/2017 03:01 AM »
Wright's commentary on the "swallowed a planet" paper posted above http://sites.psu.edu/astrowright/2017/01/03/metzger-shen-and-stone/

It still has some loose ends, but ends up with higher marks than he gave the idea in his paper:
Quote
I’m glad to see this scenario fleshed out so well. I suspect that there are ways to save the model by finding ways to make sort of event occur more frequently—perhaps by making the merging/dips more frequent by getting a chain of material from a single massive object—so I’m optimistic there’s more to this.  I’d say this paper has moved the “post-merger return to normal” scenario from “unclear” plausibility to something like “less plausable,” or even higher.

Offline TakeOff

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Re: Boyajians Star Updates And Discussion
« Reply #58 on: 01/13/2017 07:22 PM »
Yeah, like a planet, swallowed or crushed or whatever, covers 22% of the star's light. A star 50% larger than the Sun. Very desperate. (Please accept that it is a peryton until confirmed by a second observatory)
« Last Edit: 01/13/2017 07:24 PM by TakeOff »

Online hop

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Re: Boyajians Star Updates And Discussion
« Reply #59 on: 01/13/2017 08:55 PM »
Yeah, like a planet, swallowed or crushed or whatever, covers 22% of the star's light.
You should probably read the paper (or at least Wright's blog post) because that's not the mechanism proposed.

edit:
And FWIW, a disrupted planet would have no trouble blocking ~22% of the stars output, the problem is doing it without infra red excess.
« Last Edit: 01/14/2017 04:35 PM by hop »

Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #60 on: 01/13/2017 10:25 PM »
Yeah, like a planet, swallowed or crushed or whatever, covers 22% of the star's light.
You should probably read the paper (or at least Wright's blog post) because that's not the mechanism proposed.

edit:
And FWIW, a disrupted planet would have not trouble blocking ~22% of the stars output, the problem is doing it without infra red excess.

That's why a lot of these so called explanations look bogus.

Offline TakeOff

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Re: Boyajians Star Updates And Discussion
« Reply #61 on: 01/14/2017 12:53 PM »
Yeah, like a planet, swallowed or crushed or whatever, covers 22% of the star's light.
You should probably read the paper (or at least Wright's blog post) because that's not the mechanism proposed.

edit:
And FWIW, a disrupted planet would have not trouble blocking ~22% of the stars output, the problem is doing it without infra red excess.
The star's rotation period is about 21 hours. But somehow a planet spiraled into it and caused it to dim it by tens of percent EXACTLY every two Earth years? This is so very desperate that it is nothing but riding on the media hype by now. And we are only beginning to see Big Data coming. Soon anyone can data mine anything they have beforehand concluded that they will find. It will typically be that which is most hypable in social media. I'm glad I'm born with a BS-detector to filter this garbage!


Kepler was made to make a STATISTICAL survey of the occurrence of exoplanets. But this poor Tabby's star is now the victim of very elaborate individual interpretations from very questionable and unconfirmed data. It is taking way more attention than it deserves. It's another canali on Mars. It will backfire.
« Last Edit: 01/14/2017 01:02 PM by TakeOff »

Offline jebbo

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Re: Boyajians Star Updates And Discussion
« Reply #62 on: 01/15/2017 02:42 PM »
The star's rotation period is about 21 hours. But somehow a planet spiraled into it and caused it to dim it by tens of percent EXACTLY every two Earth years?.

What are you talking about? The star does not dim every two years ... the dips are unpredictable with no repeat frequency.

--- Tony

Offline TakeOff

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Re: Boyajians Star Updates And Discussion
« Reply #63 on: 01/15/2017 06:05 PM »
The star's rotation period is about 21 hours. But somehow a planet spiraled into it and caused it to dim it by tens of percent EXACTLY every two Earth years?.

What are you talking about? The star does not dim every two years ... the dips are unpredictable with no repeat frequency.

--- Tony

There was two Earth years between the day 792 dimming and the final set of dimmings starting day 1519. And two years earlier there was a 1% or so dimming. The malfunction was triggered regularly and caused a greater anomaly each time.

Online hop

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Re: Boyajians Star Updates And Discussion
« Reply #64 on: 01/15/2017 08:54 PM »
What are you talking about? The star does not dim every two years ... the dips are unpredictable with no repeat frequency.
The problems with Takeoff's theories were explained in excruciating detail in the previous thread, but the only effect appears to have been the thread getting deleted :-\ This is rather unfortunate since it had links to most of the papers about this star and some serious discussion.

Offline Stan-1967

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Re: Boyajians Star Updates And Discussion
« Reply #65 on: 01/15/2017 09:14 PM »
Yeah, like a planet, swallowed or crushed or whatever, covers 22% of the star's light.
You should probably read the paper (or at least Wright's blog post) because that's not the mechanism proposed.

edit:
And FWIW, a disrupted planet would have not trouble blocking ~22% of the stars output, the problem is doing it without infra red excess.

That's why a lot of these so called explanations look bogus.

Yes, some of the posited explanations seem like a contrived "end state" that can be shown to somewhat model the flux dips.  However when you have to run the condition backwards in time they have difficulty creating the circumstances for the proposed event to happen, much less match observations & make testable predictions regarding future observations.

Offline as58

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Re: Boyajians Star Updates And Discussion
« Reply #66 on: 01/15/2017 09:20 PM »
There was two Earth years between the day 792 dimming and the final set of dimmings starting day 1519. And two years earlier there was a 1% or so dimming. The malfunction was triggered regularly and caused a greater anomaly each time.

Can you describe what kind of malfunction could cause all this and why it would be triggered regularly? I sure can't.

Offline Alpha_Centauri

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Re: Boyajians Star Updates And Discussion
« Reply #67 on: 01/15/2017 10:08 PM »
The star's rotation period is about 21 hours. But somehow a planet spiraled into it and caused it to dim it by tens of percent EXACTLY every two Earth years?.

What are you talking about? The star does not dim every two years ... the dips are unpredictable with no repeat frequency.

--- Tony

There was two Earth years between the day 792 dimming and the final set of dimmings starting day 1519. And two years earlier there was a 1% or so dimming. The malfunction was triggered regularly and caused a greater anomaly each time.

Well clearly the difference between 1519 and 792 is not exactly two Earth years.  And the 1% dip is not another two years previous, only 652 days.

But this is irrelevant.  Kepler is on an Earth-trailing heliocentric orbit that is longer than an Earth year.  What significance is an Earth year?
« Last Edit: 01/16/2017 12:05 AM by Alpha_Centauri »

Online savuporo

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Re: Boyajians Star Updates And Discussion
« Reply #68 on: 01/15/2017 10:13 PM »
Can you describe what kind of malfunction could cause all this and why it would be triggered regularly? I sure can't.
F-22 squadron crossing international date line comes to mind. Superficial parallel though
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Online hop

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Re: Boyajians Star Updates And Discussion
« Reply #69 on: 01/15/2017 11:48 PM »
F-22 squadron crossing international date line comes to mind. Superficial parallel though
Would be quite a trick for a bug like that to affect one star out of ~150K.

On top of that:
1) The dimming is visible in the raw data
2) The effect was seen on more than one sensor module, but only for the one star
3) There's no obvious reason for calendar years to be relevant to the on-board processing that produces the raw data. Unlike an F-22, which has to interface extensively with human date standards, one would expect Kepler flight software to operate on some simpler system
4) As Alpha_Centauri points out, the contention that the dips are exactly 2 years apart is dubious. The 1519 and 792 dates aren't exactly 2 years apart, and they represent the deepest part of the dip, not the start of the events. The gradual start of the dimmings makes a precise start time difficult to identify.
5) The people who operate the instrument found the dimming to be consistent with real astrophysical dimming. Common defects like cosmic ray hits or changes in individual pixel sensitivity would be very obvious in the data
6) The apparent long term dimming seen by Schaefer suggests this star is undergoing some weird astrophysical behavior, and analysis of Kepler full frame engineering data by Montet & Simon appear to show a similar long term trend, once again only affecting this particular star

Again, this was almost all covered in the previous thread. It's really hard to make the case for hardware or software defects alone being responsible for the observations. That said, the raw data and instrument descriptions are all publicly available, so anyone who wants to seriously make the case should be able to do so.
« Last Edit: 01/16/2017 03:07 AM by hop »

Online savuporo

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Re: Boyajians Star Updates And Discussion
« Reply #70 on: 01/16/2017 12:19 AM »
I've read the thread, and not trying to make the case for software or hardware bugs. All I'm saying, weird stuff has been seen before

http://catb.org/esr/jargon/html/magic-story.html

Edit: and the most credible way to rule out mysterious instrument error from observation is to use another instrument.
« Last Edit: 01/16/2017 12:40 AM by savuporo »
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Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #71 on: 01/16/2017 05:54 AM »
I've read the thread, and not trying to make the case for software or hardware bugs. All I'm saying, weird stuff has been seen before

http://catb.org/esr/jargon/html/magic-story.html

Edit: and the most credible way to rule out mysterious instrument error from observation is to use another instrument.

Which is what they are currently doing following their successful crowdfunding campaign,

Offline jebbo

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Re: Boyajians Star Updates And Discussion
« Reply #72 on: 01/16/2017 08:39 AM »
Again, this was almost all covered in the previous thread. It's really hard to make the case for hardware or software defects alone being responsible for the observations. That said, the raw data and instrument descriptions are all publicly available, so anyone who wants to seriously make the case should be able to do so.

Indeed.  We (mostly others :-) ) spent a lot of time in the discovery paper eliminating all sorts of possible problems (including a few not mentioned here). And I've not heard anything serious questioning the astrophysical nature of the events since ...

I'm rather hoping the LCOGT campaign sees a dip and that we can bring some big instruments to bear on this weird star.

--- Tony

Offline TakeOff

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Re: Boyajians Star Updates And Discussion
« Reply #73 on: 01/16/2017 03:14 PM »
What level of dimming can the telescopes now (since the Autumn of 2015, I suppose) observing this star detect? Except for the 3 deepest dips, I looks to me one would need better than 1% sensitivity to capture the last 60 days or so long pattern at the end of Kepler.

How large are the uncertainty bands for the light curve?

Except for the big dips, the sudden step down drop by ½% on day 1559 is odd. How fast did that happen, within how many minutes? And between days 1581 to 1587 the light curve suddenly has its most stable period in the entire time series. Could these be data artifacts, for example simply that the telescope did not gather any data for this star during those 6 days?

(Don't worry, since it is such a touchy issue here, for some reason, I won't bring up the hypothesis that it is a telescope problem here again, and I don't have much more to say about it anyway).
« Last Edit: 01/16/2017 03:15 PM by TakeOff »

Offline Ben the Space Brit

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Re: Boyajians Star Updates And Discussion
« Reply #74 on: 01/16/2017 03:34 PM »
At the risk of being a devil's advocate, we should avoid assuming that something falling into what seems to be a neat pattern to us is indubitably a sign of intelligence. For example, given a universe of arbitrarily large size it is actually more unlikely that there would not be at least one occasion where two completely natural phenomena take place essentially 2 yrE apart.

There is no particular compelling reason why any intelligently-generated event would fit into a multiple of some Earth-specific time-frame. Indeed, it would be more likely for any signal to be based on universal time constants such as the emission frequency of ionised hydrogen.
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Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #75 on: 01/16/2017 05:54 PM »
At the risk of being a devil's advocate, we should avoid assuming that something falling into what seems to be a neat pattern to us is indubitably a sign of intelligence. For example, given a universe of arbitrarily large size it is actually more unlikely that there would not be at least one occasion where two completely natural phenomena take place essentially 2 yrE apart.

There is no particular compelling reason why any intelligently-generated event would fit into a multiple of some Earth-specific time-frame. Indeed, it would be more likely for any signal to be based on universal time constants such as the emission frequency of ionised hydrogen.

But again you're thinking like a human being, there is nothing to say that any ETI would have remotely the same frames of reference.

Offline Vultur

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Re: Boyajians Star Updates And Discussion
« Reply #76 on: 01/19/2017 12:49 AM »
At the risk of being a devil's advocate, we should avoid assuming that something falling into what seems to be a neat pattern to us is indubitably a sign of intelligence.

I don't think anyone (any of the scientists, anyway) is saying that it's "indubitably" a sign of intelligence. But it's a natural thought when something is encountered that doesn't fit any known natural phenomenon, and all the proposed natural explanations seem to be more than a bit of a stretch.

OTOH, the problem with any ETI hypothesis is that there's no real "bounds" since we have no way to predict what an arbitrarily advanced civilization could or would do.

EDIT: And I think that this 'lack of constraints' is the real problem not its extraordinary or 'sensational' nature. I don't see any real reason to think that solar system scale engineering is 'less likely' or 'more extraordinary' than any undemonstrated astrophysical process, as we have no way to judge its likelihood.
« Last Edit: 01/19/2017 12:52 AM by Vultur »

Offline jebbo

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Re: Boyajians Star Updates And Discussion
« Reply #77 on: 01/20/2017 08:13 AM »
I don't think anyone (any of the scientists, anyway) is saying that it's "indubitably" a sign of intelligence.

Almost everyone is, first and foremost, considering astrophysical explanations. Though intelligent origins can't be ruled out, there is no reason to prefer them as an explanation, and such an explanation would require extraordinary evidence (which we don't have).

--- Tony

Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #78 on: 01/20/2017 03:49 PM »
I don't think anyone (any of the scientists, anyway) is saying that it's "indubitably" a sign of intelligence.

Almost everyone is, first and foremost, considering astrophysical explanations. Though intelligent origins can't be ruled out, there is no reason to prefer them as an explanation, and such an explanation would require extraordinary evidence (which we don't have).

--- Tony

See this is something of a moving the goal posts statement as to why does intelligence in particular need extraordinary evidence compared to other explanations. Surely any explanation should be judged on a level playing field, not that one has to reach a higher bar anything else.

Offline notsorandom

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Re: Boyajians Star Updates And Discussion
« Reply #79 on: 01/20/2017 04:44 PM »
Extraordinary evidence is simply evidence that can only be interpreted as being cause by ETI.

Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #80 on: 01/20/2017 04:53 PM »
Extraordinary evidence is simply evidence that can only be interpreted as being cause by ETI.

But I have the suspicion some people at least use this so they can move the goal posts so it makes proving the theory virtually impossible.

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« Last Edit: 01/20/2017 05:13 PM by Star One »

Offline Robotbeat

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Re: Boyajians Star Updates And Discussion
« Reply #82 on: 01/20/2017 06:57 PM »
For the same reason we require extraordinary evidence that some phenomenon on Earth is caused by little elf people and not some more mundane physical explanation.
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Offline Star One

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Boyajians Star Updates And Discussion
« Reply #83 on: 01/20/2017 07:02 PM »
For the same reason we require extraordinary evidence that some phenomenon on Earth is caused by little elf people and not some more mundane physical explanation.

That's an extremely poor comparison being as little elf people definitely don't exist but intelligent aliens possible do. And seemingly typically of the narrow thinking some take on this.
« Last Edit: 01/20/2017 07:03 PM by Star One »

Offline matthewkantar

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Re: Boyajians Star Updates And Discussion
« Reply #84 on: 01/20/2017 07:25 PM »
little elf people definitely don't exist

Prove it.

Matthew

Offline KelvinZero

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Re: Boyajians Star Updates And Discussion
« Reply #85 on: 01/20/2017 07:43 PM »
That's an extremely poor comparison being as little elf people definitely don't exist but intelligent aliens possible do. And seemingly typically of the narrow thinking some take on this.
They not only could exist, they could also be aliens :-)

For me, the important part of the debate is simply that no amount of eliminating other explanations goes to proving aliens. There will always be infinite more possible explanations we haven't thought to eliminate.

Eliminating any one of these other explanations does make aliens more likely, sure, but what makes it not help as a proof is that it tells us nothing about how likely it actually is. There can't be a formula that says the probability was 0.00996, and after eliminating one thing we thought of, the chance is now 0.00997.

I think to prove aliens you have think of tests for particular types of aliens we can describe and then seeing if it passes those tests. Note that failing these tests also does nothing to disprove aliens. It could be another sort of alien we have not thought of yet. But continually passing those tests would not only become a proof of aliens, it would define the term.

Off the top of my head things that would be evidence for aliens.
* Evidence of the same phenomena spreading to neighbouring stars.
* Evidence in the spectra that suggests the dips are caused by something blocking the light that is highly abnormal chemically. Perhaps we can detect crystal or polymer, or just concentrations of certain elements that are highly unexpected from natural explanations
* Evidence of communication, obviously.
* Evidence that matches specific theories of how star-lifting or other mega engineering feats might be achieved. Just 'dips in the light that might be from something blocking it' is by itself very little.

Again, not finding these things does not quantifiably disprove aliens. Finding them would begin to build up the case for aliens though.

Offline redliox

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Re: Boyajians Star Updates And Discussion
« Reply #86 on: 01/21/2017 12:06 AM »
Off the top of my head things that would be evidence for aliens.
* Evidence of the same phenomena spreading to neighbouring stars.
* Evidence in the spectra that suggests the dips are caused by something blocking the light that is highly abnormal chemically. Perhaps we can detect crystal or polymer, or just concentrations of certain elements that are highly unexpected from natural explanations
* Evidence of communication, obviously.
* Evidence that matches specific theories of how star-lifting or other mega engineering feats might be achieved. Just 'dips in the light that might be from something blocking it' is by itself very little.

Regarding checking neighboring stars, I'd call it 50/50.  A civilization capable of transforming their solar system into a Dyson Sphere or Ring World will both be capable of tremendous things and have a great need for resources, but interstellar travel may be hard even for them.  The physics of either warp drive or creating a wormhole already seem to imply crazy amounts of energy even a Type 2 Kardashev scale civilization may find wasteful.

All the same, comparing the system to its immediate neighbors is wise, especially if the phenomenon isn't limited to one system but is natural.  At the least we need a better look at Tabby's Star with larger telescopes.
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Offline KelvinZero

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Re: Boyajians Star Updates And Discussion
« Reply #87 on: 01/21/2017 03:34 AM »
A civilization capable of transforming their solar system into a Dyson Sphere or Ring World will both be capable of tremendous things and have a great need for resources, but interstellar travel may be hard even for them.
That is right. Failure to find these things is not the same as disproving aliens. It is finding things like this that would begin to build a case for a certain plausible type of alien. A "proof", if it were to come, would also give us a model of what these aliens are.

Real proof could tell us incredible things. For example suppose we find that really peculiar chemical spectra. In trying to figure out a model of alien that would use that, we might figure out why we would use it, and peek millions of years ahead in our own evolution. If pondering this material leads us to develop a perfect superconductor for example then that is very good evidence for intelligence there.. as it changes us here.

Proof will come simultaneously with constraining our model of our aliens to a specific thing. "Disproof", or the closest thing to it, would only come from finding a perfectly good mundane explanation that matched all our current evidence and continued to match new predictions based on that model.

Offline LouScheffer

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Re: Boyajians Star Updates And Discussion
« Reply #88 on: 01/21/2017 04:31 PM »
Proof will come simultaneously with constraining our model of our aliens to a specific thing. "Disproof", or the closest thing to it, would only come from finding a perfectly good mundane explanation that matched all our current evidence and continued to match new predictions based on that model.
Disproof is even harder than proof.  You can imagine a pretty solid proof, such as a coherent radio signal counting out digits of PI. 

But it's hard to imagine a convincing disproof.  No amount of mundane explanations can do this, for if aliens don't want to be seen, they may arrange their affairs to look natural.  After all, camouflage is common on Earth, in biology, military, and aesthetic applications (think of cell phone towers designed to look like trees).   So a natural explanation can only suggest, but not prove, that aliens are not responsible.

The difficulty of disproof is shown by psychology experiments where they start by showing a magic trick.  Some of the audience think it's really magic, and others think it's a trick.   Then they have the magician show exactly how the trick is done, and ask the audience again.  Still not all are convinced - maybe *this time* was done by a trick, but it could be that the last time *really was* magic.  It's philosophically possible...


Online hop

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Re: Boyajians Star Updates And Discussion
« Reply #89 on: 01/22/2017 06:55 AM »
But it's hard to imagine a convincing disproof.  No amount of mundane explanations can do this, for if aliens don't want to be seen, they may arrange their affairs to look natural.  After all, camouflage is common on Earth, in biology, military, and aesthetic applications (think of cell phone towers designed to look like trees).   So a natural explanation can only suggest, but not prove, that aliens are not responsible.
I would argue you can get close enough for all practical purposes. Pulsars looked like a relatively good candidate for an alien signal when they were discovered, but given what we know now, it's very clear they are natural.  It's not hard to imagine additional observations leading us to a similarly compelling, self consistent explanation for Boyajian's star.

Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #90 on: 01/22/2017 08:22 AM »
But it's hard to imagine a convincing disproof.  No amount of mundane explanations can do this, for if aliens don't want to be seen, they may arrange their affairs to look natural.  After all, camouflage is common on Earth, in biology, military, and aesthetic applications (think of cell phone towers designed to look like trees).   So a natural explanation can only suggest, but not prove, that aliens are not responsible.
I would argue you can get close enough for all practical purposes. Pulsars looked like a relatively good candidate for an alien signal when they were discovered, but given what we know now, it's very clear they are natural.  It's not hard to imagine additional observations leading us to a similarly compelling, self consistent explanation for Boyajian's star.

I think you're going to be disappointed if you think it's going to be that easy to solve this Star.

Offline gospacex

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Re: Boyajians Star Updates And Discussion
« Reply #91 on: 01/22/2017 12:51 PM »
A civilization capable of transforming their solar system into a Dyson Sphere or Ring World will both be capable of tremendous things and have a great need for resources, but interstellar travel may be hard even for them.

Disagree. For a civilization which can do such megascale engineering, interstellar flight is nearly trivial: just build a ship big enough so that for the crew, it is no longer a vehicle they use to move from place to place, it's the place where they live. Then travel time is not a problem any more.

IOW: "spaceship Earth". (Of course, it probably can be much smaller. ~100 km asteroid-sized spacecraft/space-city should do).

Offline Orbiter

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Re: Boyajians Star Updates And Discussion
« Reply #92 on: 01/22/2017 12:54 PM »
Off the top of my head things that would be evidence for aliens.
* Evidence of the same phenomena spreading to neighbouring stars.
* Evidence in the spectra that suggests the dips are caused by something blocking the light that is highly abnormal chemically. Perhaps we can detect crystal or polymer, or just concentrations of certain elements that are highly unexpected from natural explanations
* Evidence of communication, obviously.
* Evidence that matches specific theories of how star-lifting or other mega engineering feats might be achieved. Just 'dips in the light that might be from something blocking it' is by itself very little.

I've got one to add: direct imaging of the system. If there's really a Sol sized artificial alien megastructure orbiting this star no doubt future telescopes could resolve them (maybe as soon as JWST).
« Last Edit: 01/22/2017 12:55 PM by Orbiter »
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Offline as58

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Re: Boyajians Star Updates And Discussion
« Reply #93 on: 01/22/2017 02:09 PM »
I've got one to add: direct imaging of the system. If there's really a Sol sized artificial alien megastructure orbiting this star no doubt future telescopes could resolve them (maybe as soon as JWST).

Direct imaging is still quite far from being able to do such things. JWST doesn't even come close to having enough resolution to resolve such things at ~500 pc.

Offline TakeOff

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Re: Boyajians Star Updates And Discussion
« Reply #94 on: 01/22/2017 03:35 PM »
A civilization capable of transforming their solar system into a Dyson Sphere or Ring World will both be capable of tremendous things and have a great need for resources, but interstellar travel may be hard even for them.

Disagree. For a civilization which can do such megascale engineering, interstellar flight is nearly trivial: just build a ship big enough so that for the crew, it is no longer a vehicle they use to move from place to place, it's the place where they live. Then travel time is not a problem any more.

IOW: "spaceship Earth". (Of course, it probably can be much smaller. ~100 km asteroid-sized spacecraft/space-city should do).
Or they never die, either naturally or by technology. Then spending 100 million years in a tin can to get to Andromeda is nothing. It is pointless to speculate, based on one unstable light curve in one telescope. It is Disneyfication of "aliens". (But I think it is telling that this speculation occurs in connection to this "light curve of hope" for the SETI seekers.)

Offline Patchouli

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Re: Boyajians Star Updates And Discussion
« Reply #95 on: 01/22/2017 07:30 PM »


Disagree. For a civilization which can do such megascale engineering, interstellar flight is nearly trivial: just build a ship big enough so that for the crew, it is no longer a vehicle they use to move from place to place, it's the place where they live. Then travel time is not a problem any more.

IOW: "spaceship Earth". (Of course, it probably can be much smaller. ~100 km asteroid-sized spacecraft/space-city should do).

Traveling to the nearest stars likely would be old hat for such a civilization.
Heck they may have even mastered relativistic ships or even some form of FTL travel.
« Last Edit: 01/22/2017 07:56 PM by Patchouli »

Offline as58

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Re: Boyajians Star Updates And Discussion
« Reply #96 on: 01/22/2017 11:08 PM »
Could we please not turn this thread into scifi speculation about alien societies.

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Re: Boyajians Star Updates And Discussion
« Reply #97 on: 01/23/2017 06:39 AM »
I think you're going to be disappointed if you think it's going to be that easy to solve this Star.
I didn't mean to imply that I expect it be easy, only that it's an outcome that doesn't require any great leap of imagination: New dips detected, big telescopes pointed at it, results clearly point to some specific natural phenomena. There's a pretty long history of astronomical mysteries turning into a clear, consistent picture once some key piece of data falls into place.

Of course, there's plenty of other possible outcomes, but the point is that there are some which would effectively remove aliens from reasonable consideration.

Offline Star One

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Boyajians Star Updates And Discussion
« Reply #98 on: 01/23/2017 06:51 AM »
I think you're going to be disappointed if you think it's going to be that easy to solve this Star.
I didn't mean to imply that I expect it be easy, only that it's an outcome that doesn't require any great leap of imagination: New dips detected, big telescopes pointed at it, results clearly point to some specific natural phenomena. There's a pretty long history of astronomical mysteries turning into a clear, consistent picture once some key piece of data falls into place.

Of course, there's plenty of other possible outcomes, but the point is that there are some which would effectively remove aliens from reasonable consideration.

But why even try and corral an explanation down one route at this stage? After all in his last paper on the subject Jason Wright still offered a variety of possible explanations.
« Last Edit: 01/23/2017 06:53 AM by Star One »

Offline gospacex

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Re: Boyajians Star Updates And Discussion
« Reply #99 on: 01/23/2017 12:45 PM »


Disagree. For a civilization which can do such megascale engineering, interstellar flight is nearly trivial: just build a ship big enough so that for the crew, it is no longer a vehicle they use to move from place to place, it's the place where they live. Then travel time is not a problem any more.

IOW: "spaceship Earth". (Of course, it probably can be much smaller. ~100 km asteroid-sized spacecraft/space-city should do).

Traveling to the nearest stars likely would be old hat for such a civilization.
Heck they may have even mastered relativistic ships or even some form of FTL travel.

That assumes that there IS a way to move FTL. It may be so that laws of physics simply don't allow it.

Offline Johnnyhinbos

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Re: Boyajians Star Updates And Discussion
« Reply #100 on: 01/23/2017 01:47 PM »
I'll add again that we're looking at 1,400 years in the past. Who knows, even if there's a Dyson sphere out there, it could be a smoldering ruin by now. Or perhaps the next thing we see is an occlusion of a near star in line but only a 100 light years from us - or perhaps we see a new star 10 light years from us and it's blue shifted, as in something's headed our way...
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Offline Ben the Space Brit

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Re: Boyajians Star Updates And Discussion
« Reply #101 on: 01/23/2017 02:12 PM »
That assumes that there IS a way to move FTL. It may be so that laws of physics simply don't allow it.

I don't know how current this is but I did see on one text book that the famous Feynman diagram suggests that travelling FTL is as easy as travelling STL; the thing forbidden by orthodox solutions of General Relativity is crossing the v=c barrier in either direction.
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Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #102 on: 03/05/2017 08:30 PM »
Technical overview.

The strange star discovered by Planet Hunters

http://physicstoday.scitation.org/doi/10.1063/PT.3.3504

Offline M.E.T.

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Re: Boyajians Star Updates And Discussion
« Reply #103 on: 03/16/2017 06:11 PM »
So if I recall correctly, the next big dip is expected to recur around April/May 2017, is that correct? And if it does recur, would that go some way in reducing the number of options for a potential solution to the mystery?

For example, if it does recur as predicted, am I right in saying that this would pretty much dismiss the idea that the blockage was caused by something in the interstellar medium? Because surely nothing in the interstellar medium would be rotating around the star in this manner? Instead some interstellar dust cloud would drift randomly, with a non-reptitive dimming pattern, right?

Also, my understanding is that with the number of telescopes now focused on this star, the next dimming event will be better analysed, with additional data gathering capabilities, allowing us to better understand the shape and substance of the intervening object?

In short, my understanding is that the mere fact that the dimming pattern repeats itself in April/May will tell us a whole lot, and then the data gathered from this dimming event (if it occurs) will provide further answers on top of that.

Am I correct?
« Last Edit: 03/16/2017 06:12 PM by M.E.T. »

Offline gospacex

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Re: Boyajians Star Updates And Discussion
« Reply #104 on: 03/16/2017 06:24 PM »
That's possible. New data usually gives some new ideas.

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Re: Boyajians Star Updates And Discussion
« Reply #105 on: 03/16/2017 06:29 PM »
That's possible. New data usually gives some new ideas.

My point is that there is rather a lot riding on this dimming event actually occuring as predicted. If it doesn't it would pretty much be a death blow to the idea of a locally orbiting object, and significantly strengthen the idea of a blockage in the interstellar medium instead.

So it is much more significant than just an opportunity to gather more data to form some new ideas.
« Last Edit: 03/16/2017 06:33 PM by M.E.T. »

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Re: Boyajians Star Updates And Discussion
« Reply #106 on: 03/16/2017 07:23 PM »
So if I recall correctly, the next big dip is expected to recur around April/May 2017, is that correct?
IMHO "expected" is probably too strong a word. The case for the events being periodic is not very compelling.

Dr Boyajian's email newsletter to backers on Feb 22 addressed this:
Quote
The big dip "birthday" was Feb 21, 2017.  This date was calculated from the time difference the deepest dips in Kepler data occurred: dip on day 1519 minus dip on day 792 equals a "period" of 727 days. We then use 1519 (+ 727 + 727) to predict this event happening on Feb 21, 2017. Note: the dips on day 792 and 1519 look nothing like each other, they only have similar depths. 

Just wanted to send a short note to say that observations on Feb 21 and Feb 22 show no variation in the star's brightness.

This information, while not as exciting as detecting a dip, is still useful. It does not rule out the presence of any object in orbit, just any object with an orbital period of 727 days. In fact, if an object was on a 727 day orbital period, it would have meant that we would have seen a large dip in the start of the Kepler mission, and we did not.

Looking ahead, the dip at day 1519 was accompanied by dozens of other dips spanning at least 100 days, we may still see the star dip in the coming months and we are keeping a close eye on it.

Back to your post:
Quote
For example, if it does recur as predicted, am I right in saying that this would pretty much dismiss the idea that the blockage was caused by something in the interstellar medium?
It would probably disfavor it, but not clear it would rule it out. There are plenty of astrophysical processes which produce things that are repetitive at various scales, so if you accept filaments in the interstellar medium as a plausible cause, having them repeat is not a huge stretch. As Dr Boyajian notes, the existing data doesn't really favor a really strictly periodic signal. A repetitive structure generating a quasi-periodic signal might be a better fit (to be clear, this is my interpretation, not from Dr Boyajian)

Quote
Also, my understanding is that with the number of telescopes now focused on this star, the next dimming event will be better analysed, with additional data gathering capabilities, allowing us to better understand the shape and substance of the intervening object?
The main thing is that with monitoring, more instruments can be brought to bear if a new dimming is detected. Getting spectra during a dip should narrow things down a lot, or even resolve the mystery completely.
« Last Edit: 03/16/2017 07:24 PM by hop »

Offline M.E.T.

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Re: Boyajians Star Updates And Discussion
« Reply #107 on: 03/16/2017 07:31 PM »
So if I recall correctly, the next big dip is expected to recur around April/May 2017, is that correct?
IMHO "expected" is probably too strong a word. The case for the events being periodic is not very compelling.

Dr Boyajian's email newsletter to backers on Feb 22 addressed this:
Quote
The big dip "birthday" was Feb 21, 2017.  This date was calculated from the time difference the deepest dips in Kepler data occurred: dip on day 1519 minus dip on day 792 equals a "period" of 727 days. We then use 1519 (+ 727 + 727) to predict this event happening on Feb 21, 2017. Note: the dips on day 792 and 1519 look nothing like each other, they only have similar depths. 

Just wanted to send a short note to say that observations on Feb 21 and Feb 22 show no variation in the star's brightness.

This information, while not as exciting as detecting a dip, is still useful. It does not rule out the presence of any object in orbit, just any object with an orbital period of 727 days. In fact, if an object was on a 727 day orbital period, it would have meant that we would have seen a large dip in the start of the Kepler mission, and we did not.

Looking ahead, the dip at day 1519 was accompanied by dozens of other dips spanning at least 100 days, we may still see the star dip in the coming months and we are keeping a close eye on it.

Back to your post:
Quote
For example, if it does recur as predicted, am I right in saying that this would pretty much dismiss the idea that the blockage was caused by something in the interstellar medium?
It would probably disfavor it, but not clear it would rule it out. There are plenty of astrophysical processes which produce things that are repetitive at various scales, so if you accept filaments in the interstellar medium as a plausible cause, having them repeat is not a huge stretch. As Dr Boyajian notes, the existing data doesn't really favor a really strictly periodic signal. A repetitive structure generating a quasi-periodic signal might be a better fit (to be clear, this is my interpretation, not from Dr Boyajian)

Quote
Also, my understanding is that with the number of telescopes now focused on this star, the next dimming event will be better analysed, with additional data gathering capabilities, allowing us to better understand the shape and substance of the intervening object?
The main thing is that with monitoring, more instruments can be brought to bear if a new dimming is detected. Getting spectra during a dip should narrow things down a lot, or even resolve the mystery completely.

Thank you. That clarifies a lot for me. I'm not sure where I got the April/May dip expectation from then. And if the dips are in fact not strictly repetitive, what type of orbiting body could produce such a pattern? Something that changes orbital speed? Or perhaps multiple overlapping objects that only align occasionally?

Anyway, it would be rather disappointing if no dips occur ever again. The whole thing would then just fizzle out and remain a mystery, similar to the SETI "WOW" signal some decades ago.

Online hop

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Re: Boyajians Star Updates And Discussion
« Reply #108 on: 03/16/2017 08:20 PM »
Thank you. That clarifies a lot for me. I'm not sure where I got the April/May dip expectation from then.
Dr. Boyajian gives a ~100 day window starting at the end of February, so April/May could have come from someone picking the midpoint or end instead. Again, the "period" is pretty fuzzy, because the episodes of dips last varying amounts of time and the boundaries aren't well defined.
Quote
And if the dips are in fact not strictly repetitive, what type of orbiting body could produce such a pattern? Something that changes orbital speed?
The existing data already rules out single or small numbers of solid objects with a very high degree of confidence.

The original comet swarm hypothesis might be able to do it: We might only see the activity when a particularly large one disintegrates, or they might be on a much longer orbit with the ~700 day interval produced by spacing between bodies sharing the orbit e.g. due to break up on a previous orbit.

The "alien megastructure" idea can do it, because aliens can do whatever they want... or less glibly, it assumes vast swarms of objects possibly under active control, so getting periodic but variable groupings is not a stretch.

None of this is particularly satisfactory, but it's not completely unphysical ;)

Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #109 on: 03/20/2017 07:34 PM »
K2 finds 23 more stars with unusual dips in their light curves.

Quote
The primary Kepler mission provided light curves for over 100,000 stars, and its continuation K2 is observing another 20,000 stars every three months. As we enter an era where these enormous photometric data sets become commonplace — Gaia will obtain photometry for millions of stars, and LSST billions — it’s crucial that we understand the different categories of variability observed in these stars.

The authors find three different types of light curves among their 23 unusual stars. Scallop-shell curves (top) show many undulations; persistent flux-dip class curves (middle) have discrete triangularly shaped flux dips; transient, narrow dip class curves (bottom) have only one dip that is variable in depth. The authors speculate a common cause for the scallop-shell and persistent flux-dip stars, and a different cause for the transient flux-dip stars. [Stauffer et al. 2017]
After filtering out the stars with planets, those in binary systems, those with circumstellar disks, and those with starspots, a number of oddities remain: a menagerie of stars with periodic variability that can’t be accounted for in these categories. Some of these stars are now famous (for instance, Boyajian’s star); some are lesser known. But by continuing to build up this sample of stars with unusual light curves, we have a better chance of understanding the sources of variability.

http://aasnova.org/2017/03/17/more-unusual-light-curves-from-kepler

Offline Ben the Space Brit

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Re: Boyajians Star Updates And Discussion
« Reply #110 on: 03/21/2017 12:34 PM »
If these other objects turn out to have the same family of spectral type, similar light curves and the same overall behaviour, I desperately hope that the IAU calls them 'Tabby-class Variables'.
« Last Edit: 03/21/2017 12:35 PM by Ben the Space Brit »
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Offline jebbo

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Re: Boyajians Star Updates And Discussion
« Reply #111 on: 03/22/2017 08:41 AM »
Unlikely, the group of 23 stars are all very very young and the dips are consistent with still-forming systems.
Tabby's star is respectably middle aged and these causes are pretty much ruled out.

But a nice thought :-)

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Offline Proponent

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Re: Boyajians Star Updates And Discussion
« Reply #112 on: 03/22/2017 10:10 AM »
For the same reason we require extraordinary evidence that some phenomenon on Earth is caused by little elf people and not some more mundane physical explanation.

That's an extremely poor comparison being as little elf people definitely don't exist but intelligent aliens possible do. And seemingly typically of the narrow thinking some take on this.

ISTM it's ultimately an application of Occam's Razor.  An explanation involving intelligence introduces a huge number of degrees of freedom and limits predictive power.

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Re: Boyajians Star Updates And Discussion
« Reply #113 on: 03/22/2017 10:29 AM »
For the same reason we require extraordinary evidence that some phenomenon on Earth is caused by little elf people and not some more mundane physical explanation.

That's an extremely poor comparison being as little elf people definitely don't exist but intelligent aliens possible do. And seemingly typically of the narrow thinking some take on this.

ISTM it's ultimately an application of Occam's Razor.  An explanation involving intelligence introduces a huge number of degrees of freedom and limits predictive power.

That's an ineffective argument against it though as it saying because this is hard to predict then it cannot be the answer.

Offline Proponent

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Re: Boyajians Star Updates And Discussion
« Reply #114 on: 03/22/2017 10:57 AM »
I'm not saying the difficulty in predicting the phenomenon in the first place is the problem, I'm saying that it's difficult to make testable predictions on the basis of an explanation involving intelligent life, because if a prediction doesn't pan out, you can probably say, "Oh well, I guess they made a different decision than the one I expected."  There are too many degrees of freedom.

To put it another way, given a large number of free variables, I can fit just about any model to any set of observations.  So, the fact that I've managed to fit a very complicated model to the observations give me very little confidence in the model.  Life, especially intelligent life, involves a very large number of degrees of freedom, so we should be very skeptical of the likelihood of an explanation involving intelligent life, unless the data are truly overwhelming.

In the context of the scientific method, simpler theories and those with greater predictive are to be preferred.  One reason for preferring predictive power is that it makes theories more testable, and testability is central to the scientific method.

A more practical reason for a scientist to prefer natural explanations is that explanations involving extraterrestrial life have poor track records:

* The canals of Mars;
* The vegetation hypothesis for the seasonal changes in Mars' coloration;
* The suggestion that Mars' moons were artificial, because the large decay rates of their orbits (which were inaccurately determined) implied very low densities;
* The LGM hypothesis for pulsars; and
* The suggestion that quasars were the exhaust plumes of starship engines (the lack of blue-shifted quasars be explained by the paucity of UV observations at the time).

(Can anybody think of any more examples?)

Explanations involving life are emotionally appealing, and there's nothing wrong with discussing them.  But I think we need guard against that appeal clouding our judgments as to their likelihoods.
« Last Edit: 03/22/2017 02:40 PM by Proponent »

Offline Star One

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Boyajians Star Updates And Discussion
« Reply #115 on: 03/22/2017 03:07 PM »
I'm not saying the difficulty in predicting the phenomenon in the first place is the problem, I'm saying that it's difficult to make testable predictions on the basis of an explanation involving intelligent life, because if a prediction doesn't pan out, you can probably say, "Oh well, I guess they made a different decision than the one I expected."  There are too many degrees of freedom.

To put it another way, given a large number of free variables, I can fit just about any model to any set of observations.  So, the fact that I've managed to fit a very complicated model to the observations give me very little confidence in the model.  Life, especially intelligent life, involves a very large number of degrees of freedom, so we should be very skeptical of the likelihood of an explanation involving intelligent life, unless the data are truly overwhelming.

In the context of the scientific method, simpler theories and those with greater predictive are to be preferred.  One reason for preferring predictive power is that it makes theories more testable, and testability is central to the scientific method.

A more practical reason for a scientist to prefer natural explanations is that explanations involving extraterrestrial life have poor track records:

* The canals of Mars;
* The vegetation hypothesis for the seasonal changes in Mars' coloration;
* The suggestion that Mars' moons were artificial, because the large decay rates of their orbits (which were inaccurately determined) implied very low densities;
* The LGM hypothesis for pulsars; and
* The suggestion that quasars were the exhaust plumes of starship engines (the lack of blue-shifted quasars be explained by the paucity of UV observations at the time).

(Can anybody think of any more examples?)

Explanations involving life are emotionally appealing, and there's nothing wrong with discussing them.  But I think we need guard against that appeal clouding our judgments as to their likelihoods.

But then that still is ineffective argument because that then creates an inherent bias towards natural explanations. An effective argument should have no bias at all in the scientific method. There was an interesting discussion recently that scientific papers that came in from SETI were seemingly being rejected more often from publication and the argument put forward by some to explain this was there is an inherent bias by editors to anything that might include any kind of discussion of ETI.
« Last Edit: 03/22/2017 03:11 PM by Star One »

Offline JasonAW3

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Re: Boyajians Star Updates And Discussion
« Reply #116 on: 03/22/2017 07:55 PM »
Odd thought here;

      Is it possible that what we are seeing with the dips in luminosity are from multiple clouds of debris, in different orbits and with different orbital inclinations?

      In other words; is it possible that the big dip we saw the last time was a coincidental alignment of multiple debris clouds in different orbits, that just happened to align together between us and Boyajian's star?  This would explain a semi-periodic nature of the various dips we are seeing.

      But it does pose another interesting question;  If the dips are caused by multiple debris clouds in different orbits, what caused the debris clouds to form in the first place?
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Re: Boyajians Star Updates And Discussion
« Reply #117 on: 03/22/2017 09:40 PM »
There was an interesting discussion recently that scientific papers that came in from SETI were seemingly being rejected more often from publication and the argument put forward by some to explain this was there is an inherent bias by editors to anything that might include any kind of discussion of ETI.

Too many kooks have spoiled the broth!

Offline Proponent

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Re: Boyajians Star Updates And Discussion
« Reply #118 on: 03/23/2017 09:23 AM »
But then that still is ineffective argument because that then creates an inherent bias towards natural explanations. An effective argument should have no bias at all in the scientific method. There was an interesting discussion recently that scientific papers that came in from SETI were seemingly being rejected more often from publication and the argument put forward by some to explain this was there is an inherent bias by editors to anything that might include any kind of discussion of ETI.

If you follow the scientific paradigm, the repeating cycle of hypothesis and test, it is rational to prefer simple explanations.  To put it in more colloquial terms, extraordinary claims require extraordinary evidence.

Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #119 on: 03/23/2017 09:24 AM »
But then that still is ineffective argument because that then creates an inherent bias towards natural explanations. An effective argument should have no bias at all in the scientific method. There was an interesting discussion recently that scientific papers that came in from SETI were seemingly being rejected more often from publication and the argument put forward by some to explain this was there is an inherent bias by editors to anything that might include any kind of discussion of ETI.

If you follow the scientific paradigm, the repeating cycle of hypothesis and test, it is rational to prefer simple explanations.  To put it in more colloquial terms, extraordinary claims require extraordinary evidence.

Which again is just a form of moving the goalposts.

Offline ChrisWilson68

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Re: Boyajians Star Updates And Discussion
« Reply #120 on: 03/23/2017 09:43 AM »
But then that still is ineffective argument because that then creates an inherent bias towards natural explanations. An effective argument should have no bias at all in the scientific method. There was an interesting discussion recently that scientific papers that came in from SETI were seemingly being rejected more often from publication and the argument put forward by some to explain this was there is an inherent bias by editors to anything that might include any kind of discussion of ETI.

If you follow the scientific paradigm, the repeating cycle of hypothesis and test, it is rational to prefer simple explanations.  To put it in more colloquial terms, extraordinary claims require extraordinary evidence.

No.  You are equating two very different things.  Extraordinary claims requiring extraordinary evidence is about a claim for something that violates a principle for which there is a large amount of good evidence.  It is not about whether a given theory is simple or complex.

It is not logical to prefer a simple mechanism over a complex mechanism for a physical phenomenon.  What is logical is to prefer a theory that has a lot of evidence over one that has little evidence.

In the case of Tabby's Star, there is no good evidence against the idea of alien megastructures around this world, and no good evidence for any particular theory, so the "extraordinary claims require extraordinary evidence" rule does not apply.


Offline gospacex

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Re: Boyajians Star Updates And Discussion
« Reply #121 on: 03/23/2017 10:22 AM »
No.  You are equating two very different things.  Extraordinary claims requiring extraordinary evidence is about a claim for something that violates a principle for which there is a large amount of good evidence.

Wrong.
I'll give an example.

If I'd claim that I have a house, people wouldn't have serious reasons to not believe me, and "ordinary" evidence of it, such as a few photos of me and the house, would do.

If I'd claim that I have a house with a garage with a functioning gravitic interstellar starship inside, a few photos of me with that "starship" would not convince anyone.
« Last Edit: 03/23/2017 10:22 AM by gospacex »

Offline ChrisWilson68

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Re: Boyajians Star Updates And Discussion
« Reply #122 on: 03/23/2017 10:32 AM »
No.  You are equating two very different things.  Extraordinary claims requiring extraordinary evidence is about a claim for something that violates a principle for which there is a large amount of good evidence.

Wrong.
I'll give an example.

If I'd claim that I have a house, people wouldn't have serious reasons to not believe me, and "ordinary" evidence of it, such as a few photos of me and the house, would do.

If I'd claim that I have a house with a garage with a functioning gravitic interstellar starship inside, a few photos of me with that "starship" would not convince anyone.

Your so-called example doesn't help your case at all, because it's not remotely similar.

In your example, there's no data that is unexplained and in need of a theory to explain it.  On the contrary, there is plenty of evidence that it would be unlikely for humans to have interstellar sharships in their garage, and plenty of evidence that people often lie.  So, the lie is the far more likely explanation, because it's what's supported by the evidence.

There's no evidence either way for what is causing the observed light curve at Taby's Star, and no evidence against the idea that alien intelligence is present in the solar systems of some stars.

Offline gospacex

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Re: Boyajians Star Updates And Discussion
« Reply #123 on: 03/23/2017 10:39 AM »
No.  You are equating two very different things.  Extraordinary claims requiring extraordinary evidence is about a claim for something that violates a principle for which there is a large amount of good evidence.

Wrong.
I'll give an example.

If I'd claim that I have a house, people wouldn't have serious reasons to not believe me, and "ordinary" evidence of it, such as a few photos of me and the house, would do.

If I'd claim that I have a house with a garage with a functioning gravitic interstellar starship inside, a few photos of me with that "starship" would not convince anyone.

Your so-called example doesn't help your case at all, because it's not remotely similar.

In your example, there's no data that is unexplained and in need of a theory to explain it.  On the contrary, there is plenty of evidence that it would be unlikely for humans to have interstellar sharships in their garage, and plenty of evidence that people often lie.  So, the lie is the far more likely explanation, because it's what's supported by the evidence.

There's no evidence either way for what is causing the observed light curve at Taby's Star, and no evidence against the idea that alien intelligence is present in the solar systems of some stars.

I can easily use your argument against "alien structure" claim:

"There is plenty of evidence that it would be unlikely for any alien artificial structures to be seen anywhere, and plenty of evidence that variable star types are abundant."

Specifically, by now there are some 50 different types of variable stars known. Considering that they were identified during only some 150 years, it means on average a new variable star type is identified every 3 years.
« Last Edit: 03/23/2017 10:39 AM by gospacex »

Offline Star One

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Boyajians Star Updates And Discussion
« Reply #124 on: 03/23/2017 12:33 PM »
No.  You are equating two very different things.  Extraordinary claims requiring extraordinary evidence is about a claim for something that violates a principle for which there is a large amount of good evidence.

Wrong.
I'll give an example.

If I'd claim that I have a house, people wouldn't have serious reasons to not believe me, and "ordinary" evidence of it, such as a few photos of me and the house, would do.

If I'd claim that I have a house with a garage with a functioning gravitic interstellar starship inside, a few photos of me with that "starship" would not convince anyone.

Your so-called example doesn't help your case at all, because it's not remotely similar.

In your example, there's no data that is unexplained and in need of a theory to explain it.  On the contrary, there is plenty of evidence that it would be unlikely for humans to have interstellar sharships in their garage, and plenty of evidence that people often lie.  So, the lie is the far more likely explanation, because it's what's supported by the evidence.

There's no evidence either way for what is causing the observed light curve at Taby's Star, and no evidence against the idea that alien intelligence is present in the solar systems of some stars.

I can easily use your argument against "alien structure" claim:

"There is plenty of evidence that it would be unlikely for any alien artificial structures to be seen anywhere, and plenty of evidence that variable star types are abundant."

Specifically, by now there are some 50 different types of variable stars known. Considering that they were identified during only some 150 years, it means on average a new variable star type is identified every 3 years.

There are too many unknown variables at this stage. How would we know what aliens do or don't do. It's just as likely that it is a limit of our current observational  technology as to why we haven't detected ETIs as anything else. It's like in the fifties where all the moons of Jupiter were assumed to be lifeless chunks of rock it wasn't until our technology improved we discovered they weren't.

Your argument just flags up a temporal arrogance over our current level of understanding and technology.
« Last Edit: 03/23/2017 07:09 PM by Star One »

Offline notsorandom

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Re: Boyajians Star Updates And Discussion
« Reply #125 on: 03/23/2017 01:10 PM »
In the case of Tabby's Star, there is no good evidence against the idea of alien megastructures around this world, and no good evidence for any particular theory, so the "extraordinary claims require extraordinary evidence" rule does not apply.
There is good evidence against the alien megastructures hypothesis, the lack of IR excess. Energy collectors blocking that much light would reradiate an amount of IR detectable by WISE and other telescopes yet we don't seen that IR. The classic Dyson Swarm doesn't fit the already observed data. For the aliens to still be a hypothesis they need to have either built a thin disk of collectors exactly edge on to us, be directing the energy into a beam to power a light sail or something like that, or have figured out a way to break thermodynamics.

As more observations are made the ETI hypothesis may get further constrained and thus require the aliens to be doing doing weirder and more exotic things to still be able to fit with the data. The objection that people have with aliens as an explanation is that aliens can be hypothesized do arbitrarily weird and exotic things. At what point do we say we are expecting the aliens to be doing too much to take that hypothesis out of contention?

Offline Proponent

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Re: Boyajians Star Updates And Discussion
« Reply #126 on: 03/23/2017 03:14 PM »
It is not logical to prefer a simple mechanism over a complex mechanism for a physical phenomenon.  What is logical is to prefer a theory that has a lot of evidence over one that has little evidence.

Given a two data points, would you fit a straight line to them or a parabola, cubic or higher-order polynomial?  They will all fit the data perfectly.

Offline llanitedave

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Re: Boyajians Star Updates And Discussion
« Reply #127 on: 03/23/2017 03:33 PM »
It is not logical to prefer a simple mechanism over a complex mechanism for a physical phenomenon.  What is logical is to prefer a theory that has a lot of evidence over one that has little evidence.

Given a two data points, would you fit a straight line to them or a parabola, cubic or higher-order polynomial?  They will all fit the data perfectly.


Exactly.  It is always preferable to choose the simpler solution over the complex one, with the caveat that the simpler solution also accommodates all observed data.
"I've just abducted an alien -- now what?"

Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #128 on: 03/23/2017 07:12 PM »
In the case of Tabby's Star, there is no good evidence against the idea of alien megastructures around this world, and no good evidence for any particular theory, so the "extraordinary claims require extraordinary evidence" rule does not apply.
There is good evidence against the alien megastructures hypothesis, the lack of IR excess. Energy collectors blocking that much light would reradiate an amount of IR detectable by WISE and other telescopes yet we don't seen that IR. The classic Dyson Swarm doesn't fit the already observed data. For the aliens to still be a hypothesis they need to have either built a thin disk of collectors exactly edge on to us, be directing the energy into a beam to power a light sail or something like that, or have figured out a way to break thermodynamics.

As more observations are made the ETI hypothesis may get further constrained and thus require the aliens to be doing doing weirder and more exotic things to still be able to fit with the data. The objection that people have with aliens as an explanation is that aliens can be hypothesized do arbitrarily weird and exotic things. At what point do we say we are expecting the aliens to be doing too much to take that hypothesis out of contention?

Its entirely possible that to our limited knowledge they maybe doing weird and exotic things. Would you expect ants to understand what we are doing?

Offline Phil Stooke

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Re: Boyajians Star Updates And Discussion
« Reply #129 on: 03/23/2017 07:22 PM »
"Would you expect ants to understand what we are doing?"

Well, no... but as a well-educated academic ant I wouldn't rely on 'magic human' to explain everything I didn't yet understand.  Aliens are always going to be a possibility, but it's not a good idea to rely on them as an explanation for anything.  More likely, we just haven't figured out the non-alien explanation... yet.

Offline gospacex

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Re: Boyajians Star Updates And Discussion
« Reply #130 on: 03/23/2017 11:39 PM »
No.  You are equating two very different things.  Extraordinary claims requiring extraordinary evidence is about a claim for something that violates a principle for which there is a large amount of good evidence.

Wrong.
I'll give an example.

If I'd claim that I have a house, people wouldn't have serious reasons to not believe me, and "ordinary" evidence of it, such as a few photos of me and the house, would do.

If I'd claim that I have a house with a garage with a functioning gravitic interstellar starship inside, a few photos of me with that "starship" would not convince anyone.

Your so-called example doesn't help your case at all, because it's not remotely similar.

In your example, there's no data that is unexplained and in need of a theory to explain it.  On the contrary, there is plenty of evidence that it would be unlikely for humans to have interstellar sharships in their garage, and plenty of evidence that people often lie.  So, the lie is the far more likely explanation, because it's what's supported by the evidence.

There's no evidence either way for what is causing the observed light curve at Taby's Star, and no evidence against the idea that alien intelligence is present in the solar systems of some stars.

I can easily use your argument against "alien structure" claim:

"There is plenty of evidence that it would be unlikely for any alien artificial structures to be seen anywhere, and plenty of evidence that variable star types are abundant."

Specifically, by now there are some 50 different types of variable stars known. Considering that they were identified during only some 150 years, it means on average a new variable star type is identified every 3 years.

There are too many unknown variables at this stage. How would we know what aliens do or don't do. It's just as likely that it is a limit of our current observational  technology as to why we haven't detected ETIs as anything else. It's like in the fifties where all the moons of Jupiter were assumed to be lifeless chunks of rock it wasn't until our technology improved we discovered they weren't.

Your argument just flags up a temporal arrogance over our current level of understanding and technology.

You completely misunderstood my argument.
I gave a real-world example why extraordinary claim ("I have a starship") requires extraordinary evidence to be accepted, whereas a mundane one ("I have a house") does not.
I did not say anything at all about our understanding of possible aliens.
I'm saying that "it's aliens!" is an extraordinary claim.
« Last Edit: 03/23/2017 11:39 PM by gospacex »