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Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Bogie_smiles on 21/07/2017 16:01:40

Title: Is there cyclic cosmology hidden in LIGO noise?
Post by: Bogie_smiles on 21/07/2017 16:01:40

(https://www.thenakedscientists.com/forum/gallery/43933_21_07_17_5_29_17.jpeg)

http://physicsworld.com/cws/article/news/2017/jul/20/roger-penrose-asks-if-a-cyclic-cosmology-is-lurking-in-ligo-noise (http://physicsworld.com/cws/article/news/2017/jul/20/roger-penrose-asks-if-a-cyclic-cosmology-is-lurking-in-ligo-noise)

Roger Penrose asks if a cyclic cosmology is lurking in LIGO noise?


Cosmological noise: signals from both LIGO detectors (http://images.iop.org/objects/phw/news/21/7/36/2017-07-20-flash-2.jpg)
Correlated noise in the two LIGO gravitational-wave detectors may provide evidence that the universe is governed by conformal cyclic cosmology (CCC). That is the claim of Roger Penrose (https://www.maths.ox.ac.uk/people/roger.penrose) of the University of Oxford, who is proposing that the apparent noise is actually a real signal of gravitational waves generated by the decay of hypothetical dark-matter particles predicted by CCC.


Last month, physicists at the Niels Bohr Institute pointed out (http://physicsworld.com/cws/article/news/2017/jun/19/flash-physics-ligo-gravitational-waves-are-not-noise-stretching-relaxes-white-blood-cells-india-joins-esrf) that some of the noise in the two LIGO detectors appears to be correlated – with a delay that corresponds to the time it takes for a gravitational wave to travel the more than 3000 km between the instruments.


Writing in a preprint on arXiv, Penrose argues that a significant amount of this noise could be a signal of astrophysical or cosmological origin – and specifically CCC.

Infinite aeons

First proposed over a decade ago by Penrose, CCC assumes that the universe consists of a succession of aeons. Each aeon begins with a big bang and proceeds into an unending future in which the universe expands at an accelerating rate. As this expansion becomes infinitely large, Penrose argues that it can be transformed back into the next big bang.


He says that a "reasonably robust implication of CCC" is that dark matter consists of particles called erebons – the name deriving from the Greek god of darkness Erebos. As dark matter goes, erebons are extremely heavy and have masses of about 10[size=0pt]–5[/size] g. This is roughly the Planck mass and on a par with a grain of sand and about 22 orders of magnitude heavier than a proton.

Near-instantaneous impulses

Penrose says that when an erebon decays, it deposits all its energy into a gravitational wave. While such waves have frequencies well above the detection capabilities of LIGO, their arrival at the detectors would be recorded as near-instantaneous impulses that could be mistaken for noise.About the authorHamish Johnston (hamish.johnston@iop.org) is editor of physicsworld.com
Title: Re: Is there cyclic cosmology hidden in LIGO noise?
Post by: evan_au on 22/07/2017 03:03:21
If you were measuring correlation between the two LIGO detectors, you wouldn't do it in a time segment where a black hole collision was detected - because there is a correlated signal there from a "point source" in the sky.

I think that this correlation is very hard to achieve with just 2 detectors, because the noise bursts would be coming from all directions in the sky, and you get a very poor indication of direction when you have just 2 detectors. So you have to look for any events within ±10ms (the detectors are 3000km apart); this is likely to produce a lot of "false positives".

However, with another 2 gravitational wave detectors planned to come online in the next couple of years, it may well be possible to detect gravitational wave impulses coming from different directions in the sky. The extra detectors then allow you to eliminate coincidences from 19ms of this 20ms window.

Some researchers are trying to build gravitational wave detectors with a higher frequency response than LIGO, and these should also be useful for detecting fast events.

Detection of high-frequency gravitational wave impulses from across the sky may point to annihilation of new types of particle (or even "starquakes" on neutron stars), but it does not directly prove the ultimate fate of the universe.
Title: Re: Is there cyclic cosmology hidden in LIGO noise?
Post by: Bogie_smiles on 22/07/2017 15:44:52
That is all true and well said. In regard to Penrose, he has been a mainstay in the field of cosmology, and his CCC model has some interesting logic; I say that from a layman perspective. Lee Smolin said some kind words about him, “Simply put, there is no one who has contributed more to our understanding and use of the general theory of relativity, save Einstein himself, than Roger Penrose”.

I'll say the following here in this forum about CCC, and I will add some of my own ideas about his cosmology out in the "new theories" arena:

Penrose spent a lot of time on the details and the mathematics, and his writing includes a lot on conformal space, diagrams, mapping, rescaling; pretty much beyond my so called “pay grade”, but interesting to peruse. He mentions certain peculiarities like the notion that length becomes path-dependent, and that there is no absolute scaling for time or space measures.

In a typical twins experiment using two clocks and a rocket, one twin stays home, and the other travels at relativistic velocities, relative to that home rest position, and returns home some time later. He will return to see his stay-at-home twin not only appears to have aged much more than he did during the duration of the journey, but also that the clocks on Earth measure the passing of time at a different rate from those on his rocket ship. This is the effect of the conformal rescaling, as I understand it.

I can’t help but think that this conformal rescaling is what he is proposing in the end phase of his version of cyclic cosmology. CCC predicts a high entropy expanded phase in the cyclic universe, like that of the Big Rip cosmology, but with a twist. The twist is a new lease on “life”, so to speak, a new potential, associated with the end phase of an entire universe that has reached some limit in the advance of entropy. This is my take, and not to be considered a good representation, but it is as if the cold, dead universe is equated to one universal wave function, and the cyclic Big Bang that follows is the collapse of that wave function.


Title: Re: Is there cyclic cosmology hidden in LIGO noise?
Post by: evan_au on 23/07/2017 11:17:22
Quote from: Penrose
Near-instantaneous impulses
Wondering about this further....

My primitive understanding of gravitational waves is that they twist spacetime as they are passing through, and then untwist it back to the original geometry after they have passed.

This suggests that gravitational waves do not impart an impulse to the hanging mirrors (which would show up as a change in length after the gravitational wave has passed), but would return the mirror to their previous separation.

The current LIGO detectors have a bandwidth of about 1kHz, so this suggests that gravitational impulses much less than 0.5ms should not be detectable unless they caused some overload and nonlinear distortion in the measurement circuits and filters.
See: https://en.wikipedia.org/wiki/LIGO#A.2B

It would be good for the LIGO team to characterize the behavior of their detectors when presented with a high-amplitude impulse of short duration, to see if there are detectable distortion and noise at the output. The two LIGO detectors have a common design, and would produce a similar signature under overload conditions. But it is likely that gravitational wave detectors from an independent design team would have significantly different overload behavior than LIGO, making correlation less obvious.

In any case, I look forward to more rigorous tests when there are additional gravitational wave detectors.
Title: Re: Is there cyclic cosmology hidden in LIGO noise?
Post by: Bogie_smiles on 02/08/2017 14:17:42
https://arxiv.org/pdf/1707.04169.pdf (https://arxiv.org/pdf/1707.04169.pdf)


In regard to the detection by LIGO of past cyclic action consistent with predictions of Conformal Cyclic Cosmology (CCC), the long wavelength image of such impulses would be beyond the ability of LIGO to detect. It seems that the wave action of two in-swirling converging black holes tests the limits of detection on the long end of the spectrum.


However, I interpret Penrose’s point in characterizing the “noise” as near-instantaneous impulses of the decay of very massive dark matter particles may be the thinking that even very long wavelength impulses, much longer than the in swirling action of converging black holes, would have peaks or valleys that could be detected as “noise”, like a single frame of a motion picture that randomly coincides with the capability of the measuring instrument.


I’m not a CCC advocate, but I can see how the “father” of CCC would be alert to such possibilities.