Author Topic: New Physics are Needed to Explain the Accelerating Universe  (Read 6551 times)

Offline SteveKelsey

https://phys.org/news/2017-03-expansion-universe-dark-energy.html
Interesting results if any other researchers could confirm, but it sounds like they made a mistake somewhere. Dark matter is additional mass, and therefore more reason that everything in the universe should be more attracted to each other, which is the exact opposite of what is needed to explain the universe having accelerating expansion. I only read the news article and not the original, so may be something important got lost in between.

Yes I agree it needs replication in order to be taken seriously but I am intrigued by the central proposition that if you include the effect of structure on the calculations within the simulation you automatically get a result similar to what we observe without the arbitrary need for Dark Energy, which is not an observed phenomena but, like Inflation, a hypothesis that fits what we observe. Structure is an emergent property of matter and energy and does not require invention. I must admit I was surprised that structure has not been taken into account previously, I appreciate this may be due to a lack of computing power before, but it does seem like a fundamental property which must have a large impact if omitted.

As for the effect of Dark Matter on the Hubble Constant I don't think this has been summarised that well in the précis but as I don't have the math I can't take it much further.

My naive outtake is that both Dark Matter, which is a variable that has to be set subjectively in every case, and Dark Energy, which is not falsifiable, are approximations to solutions that will be revealed in time. I am not expecting any engineering opportunities to arise from them sadly.
« Last Edit: 10/27/2018 12:35 pm by SteveKelsey »
2001 is running a little late, but we are getting there.

Offline as58

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Re: New Physics are Needed to Explain the Accelerating Universe
« Reply #21 on: 10/27/2018 02:40 pm »
https://phys.org/news/2017-03-expansion-universe-dark-energy.html
Interesting results if any other researchers could confirm, but it sounds like they made a mistake somewhere. Dark matter is additional mass, and therefore more reason that everything in the universe should be more attracted to each other, which is the exact opposite of what is needed to explain the universe having accelerating expansion. I only read the news article and not the original, so may be something important got lost in between.

The paper is about cosmological backreaction, i.e. the effect of inhomogeneity on expansion. It has been argued that such inhomogeneity can lead to apparent accelerating expansion without any dark energy. It's a very difficult question (one needs to deal with the full non-linear GR) and still actively debated.

Offline meberbs

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Re: New Physics are Needed to Explain the Accelerating Universe
« Reply #22 on: 10/27/2018 10:59 pm »
https://phys.org/news/2017-03-expansion-universe-dark-energy.html
Interesting results if any other researchers could confirm, but it sounds like they made a mistake somewhere. Dark matter is additional mass, and therefore more reason that everything in the universe should be more attracted to each other, which is the exact opposite of what is needed to explain the universe having accelerating expansion. I only read the news article and not the original, so may be something important got lost in between.

The paper is about cosmological backreaction, i.e. the effect of inhomogeneity on expansion. It has been argued that such inhomogeneity can lead to apparent accelerating expansion without any dark energy. It's a very difficult question (one needs to deal with the full non-linear GR) and still actively debated.
Thanks for the additional info, with that and a bit more research on my end, it seems like it could be a solution, but there is a lot more work that would need to be done to be confident it covers everything, and even more work to show that it should be the new standard. I'll wait for the people who devote their lives to this to work it out.

Offline Propylox

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Re: New Physics are Needed to Explain the Accelerating Universe
« Reply #23 on: 10/28/2018 01:47 am »
What you have described is how Doppler radar works, an application of the Doppler effect, not the Doppler effect itself. Absorption and emission are not required. The Doppler effect is the change in frequency of a wave in relation to an observer moving relative to the wave source. Cosmological redshift looks like the Doppler effect, but it's not. It's due to the expansion of space, not the motion of an individual body.
The "Doppler Effect", as you've described, is an observation with causes as diverse as the waves. The Doppler Effect with electromagnetic waves is a result of a receiver not being calibrated. Once calibrated, Doppler Radar is possibly by measuring the frequency change of re-emitted energy (there's no such thing as reflecting as a change in energy will always occur). Eliminating re-emittance is the basis of stealth. With photons, re-emittance is required for any frequency change to occur -or- your device hasn't been calibrated and is giving false readings.

No re-emission is needed for there to be a Doppler shift. Paint an object black and you can still measure the effect as the difference between the energy and momentum from the frame of the source to the energy and momentum imparted to the receiver in its own frame.
How the heck does "painting something black", assuming it will then absorb all light, become a means to measure a photonic Doppler Effect? And if it "can still be measured", assuming with radar, what was the point of painting it. What are you inferring or attempting to talk about?

..
Somebody here .(I'm too polite to say who) is posting the most ridiculous load of scientific crap since the last Flat Earth Society meeting.
I'll say it, its meberbs. I got lost trying to follow his last post of circular, yet contrary and largely indecipherable attempted rebuttal. Yep, it's "qualitative nonsense" word-soup playing as insight just like the term "Dark Energy", but without whimsy to his fancy.

  ------------------------
1) As this thread suggests "New Physics" to explain all conventional theories to date being incapable of describing the Universe, I would suggest correcting the use of existing theories rather than make up fantastic energies or matter to fill the void of ignorance. All science starts with "I don't know", but if that is replaced with mythical, unmeasurable "things" - it's not really science.

2) I would suggest avoiding the crutch of theoretical mathematics. Math is a language with rules. But one can just as easily assemble a meaningless word-soup (as mentioned above) as assemble a meaningless equation of jibberish. This disparity between reality and mathematics doesn't just occur in astronomy, but also subatomic particle physics (often ridiculously renamed "Quantum") and complex systems like fluid dynamics.

I leave some recent wisdom;
     "There are many equations because there are many phenomena. They are an attempt to describe mathematically the physical phenomena so that you can solve these problems. Words alone won't solve the problem. .. If you don't use the right model, the rest becomes an exercise in futility. It may be a model that's self-consistent but has no reality," he said. "Of course, the only way you can validate a model is to run experiments and even then, you're introducing another reality into the picture which is the experiment... We use both math and physics in engineering, but within limitations. In physics, we don't always understand what's going on," he said. "That's the case here as well. There are pieces of principles that haven't been resolved. The mathematics are very exact but we tend to shade the equations in terms of what we can solve, rather than what it should be. .."
     Quotes by University of Illinois Professor Harry Hilton and his work on aerodynamic modelling.
Oct 23, cut to avoid link - ht tp://ww w.spacedaily.com/re ports/Me rging_mathematical_and_physical_models_toward_building_a_more_perfect_flying_vehicle_999.html
« Last Edit: 10/28/2018 01:51 am by Propylox »

Online ChrisWilson68

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Re: New Physics are Needed to Explain the Accelerating Universe
« Reply #24 on: 10/28/2018 02:12 am »
Somebody here .(I'm too polite to say who) is posting the most ridiculous load of scientific crap since the last Flat Earth Society meeting.
I'll say it, its meberbs.

Incorrect.

meberbs has a very good understanding of physics and is known around here for very good posts on the topic.

The Doppler Effect with electromagnetic waves is a result of a receiver not being calibrated.

Incorrect.

This is one of many, many things you've said in this thread that are so completely wrong that most people on this forum will just give up on you and not even try to help you understand where you are wrong.

I admire meberbs for trying to help you understand what you're getting wrong.  I wish you were more respectful of that.

Offline meberbs

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Re: New Physics are Needed to Explain the Accelerating Universe
« Reply #25 on: 10/28/2018 06:35 am »
What you have described is how Doppler radar works, an application of the Doppler effect, not the Doppler effect itself. Absorption and emission are not required. The Doppler effect is the change in frequency of a wave in relation to an observer moving relative to the wave source. Cosmological redshift looks like the Doppler effect, but it's not. It's due to the expansion of space, not the motion of an individual body.
The "Doppler Effect", as you've described, is an observation with causes as diverse as the waves. The Doppler Effect with electromagnetic waves is a result of a receiver not being calibrated. Once calibrated, Doppler Radar is possibly by measuring the frequency change of re-emitted energy (there's no such thing as reflecting as a change in energy will always occur). Eliminating re-emittance is the basis of stealth. With photons, re-emittance is required for any frequency change to occur -or- your device hasn't been calibrated and is giving false readings.
What you are saying here has no relation to reality. There is a difference between absorption and re-emission (such as what happens in fluorescence, or emission of black body radiation (also 2 different things)) and reflected light. Go look up those terms online if you don't know what they mean.

You apparently haven't bothered to even read the Wikipedia page on the Doppler effect I linked before, which clearly shows it applies outside the context of radar, and it typically refers to a transmitter and receiver moving at different velocities relative to each other, with no need for any signal returning to the original transmitter to be discussed.

No re-emission is needed for there to be a Doppler shift. Paint an object black and you can still measure the effect as the difference between the energy and momentum from the frame of the source to the energy and momentum imparted to the receiver in its own frame.
How the heck does "painting something black", assuming it will then absorb all light, become a means to measure a photonic Doppler Effect? And if it "can still be measured", assuming with radar, what was the point of painting it. What are you inferring or attempting to talk about?
Radar has nothing to do with what I said. You measure the effect, because you are holding the piece of material and you can measure how much energy it received from the incident radiation and how much momentum was transferred to it. This is the basis of how cameras (or your eyes) work. If a camera is moving towards a light source outputting a fixed frequency, it will detect higher frequency light. If it is moving away it detects lower frequency light. No discussion of radar, or re-emission, or reflection is required.  (And you know the frequency of the emitted light in the rest frame of the source, because you use something well known and fundamental, such as the emission spectra of specific elements.)

1) As this thread suggests "New Physics" to explain all conventional theories to date being incapable of describing the Universe, I would suggest correcting the use of existing theories rather than make up fantastic energies or matter to fill the void of ignorance. All science starts with "I don't know", but if that is replaced with mythical, unmeasurable "things" - it's not really science.
You should correct your own understanding of physics before you try and claim that you understand astronomy better than the people who have devoted their lives to it. Attaching a label to an area of physics that is a "known unknown" is simply a tool to facilitate discussion. Your continued attempts to make fun of scientists are still inappropriate, especially since it is for wanting to not have to say the mouthful "that thing where the universe has accelerating expansion and we aren't sure why" thirty times per conversation. Scientists have given it a name to facilitate discussion, and quantified the correction factor needed to make existing theories match the data. There is nothing mythical about it, the data they measure is real, and it is no secret that the reason for the discrepancy between unmodified theory and measured data is not understood.

2) I would suggest avoiding the crutch of theoretical mathematics. Math is a language with rules. But one can just as easily assemble a meaningless word-soup (as mentioned above) as assemble a meaningless equation of jibberish.
What you appear to be saying here is that you don't understand math and won't be bothered to try. Math as a language is a whole lot more rigorous than English, and if you know what you are doing can be used to prove things and communicate with others. If you form gibberish in it, there is also a way to show that it is gibberish.

This disparity between reality and mathematics doesn't just occur in astronomy, but also subatomic particle physics (often ridiculously renamed "Quantum") and complex systems like fluid dynamics.
Quantum has a specific meaning, which relates to the quanitzation of physical properties at the level of subatomic particles. Since this is the usually the most important feature of the behavior of particles at the subatomic level, I fail to see how it is "ridiculous" to name the field after the category of effects that dominate it.

I have no idea what your issue is with fluid mechanics, as fluid mechanics equations work despite the complexity (the equations contain the complexity as well, which does make them usually unsolvable in simple closed forms), but you have drifted completely off topic here anyway.

Offline colbourne

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Offline Nomadd

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Re: New Physics are Needed to Explain the Accelerating Universe
« Reply #27 on: 11/07/2018 08:32 am »
Somebody here .(I'm too polite to say who) is posting the most ridiculous load of scientific crap since the last Flat Earth Society meeting.
I'll say it, its meberbs.

Incorrect.

meberbs has a very good understanding of physics and is known around here for very good posts on the topic.

The Doppler Effect with electromagnetic waves is a result of a receiver not being calibrated.

Incorrect.

This is one of many, many things you've said in this thread that are so completely wrong that most people on this forum will just give up on you and not even try to help you understand where you are wrong.

I admire meberbs for trying to help you understand what you're getting wrong.  I wish you were more respectful of that.

Just saw this.
 You better believe incorrect. I respect few people more than meberbs when it comes to understanding and explaining physics.
Those who danced were thought to be quite insane by those who couldn't hear the music.

Offline JohnFornaro

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Re: New Physics are Needed to Explain the Accelerating Universe
« Reply #28 on: 11/15/2018 01:00 pm »
Just saw this.
 You better believe incorrect. I respect few people more than meberbs when it comes to understanding and explaining physics.

Hah!  I saw the comment "Spacetime flows toward mass" from a few days ago, and got a chuckle.  I would have made a correction, but I was too late!  Meberbs explanations are very helpful.
Sometimes I just flat out don't get it.

Offline Star One

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Re: New Physics are Needed to Explain the Accelerating Universe
« Reply #29 on: 11/17/2018 07:42 pm »
China Plans to Build a Particle Collider Five Times More Powerful Than the LHC

Quote
For about a decade, the biggest machine on the planet has been the Large Hadron Collider (LHC), situated on the border between Switzerland and France. The main body of the collider is a giant ring over five miles in diameter and the entire facility employs thousands of people. But according to a new announcement from China’s Institute of High Energy Physics, it might not be the world’s largest machine for long.

The Chinese institute announced plans to build its own particle accelerator over the next decade, and it’s designed to surpass the LHC in every way. According to the report authored by the institute, the upcoming collider will be over five times more powerful and over 20 miles in diameter.

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