New view on gravity does not rely on the presence of dark matter

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RocksEverywhere

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New view on gravity does not rely on the presence of dark matter
« on: November 09, 2016, 02:04:24 AM »
https://arxiv.org/abs/1611.02269

Pretty interesting stuff. I must say that a part of it goes over my head, but this could turn out to be pretty revolutionary. It's awaiting peer review in the mean time however, let's see how that turns out.

Thoughts?
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Bullwinkle

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Re: New view on gravity does not rely on the presence of dark matter
« Reply #1 on: November 09, 2016, 03:00:20 AM »
You put no effort into your post.
I feel no need to click the link to discover what you found on the internet.

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RocksEverywhere

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Re: New view on gravity does not rely on the presence of dark matter
« Reply #2 on: November 09, 2016, 03:21:16 AM »
You put no effort into your post.
I feel no need to click the link to discover what you found on the internet.
Thank you for your feedback.
AMA: https://www.theflatearthsociety.org/forum/index.php?topic=68045.0

Just because you don't understand something, doesn't mean it's not real.

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Bullwinkle

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Re: New view on gravity does not rely on the presence of dark matter
« Reply #3 on: November 09, 2016, 03:36:46 AM »
You aren't even going to bother giving a hint as to what is behind the link?

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RocksEverywhere

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Re: New view on gravity does not rely on the presence of dark matter
« Reply #4 on: November 09, 2016, 03:44:54 AM »
It is the abstract and full text pdf of a recently submitted article that is awaiting peer review. It is not my aim to "lure" you to click the link. More like, I came across something interesting, and I figured some people here may find it interesting enough to check it out.

Anyway, here's the abstract.

Quote
Recent theoretical progress indicates that spacetime and gravity emerge together from the entanglement structure of an underlying microscopic theory. These ideas are best understood in Anti-de Sitter space, where they rely on the area law for entanglement entropy. The extension to de Sitter space requires taking into account the entropy and temperature associated with the cosmological horizon. Using insights from string theory, black hole physics and quantum information theory we argue that the positive dark energy leads to a thermal volume law contribution to the entropy that overtakes the area law precisely at the cosmological horizon. Due to the competition between area and volume law entanglement the microscopic de Sitter states do not thermalise at sub-Hubble scales: they exhibit memory effects in the form of an entropy displacement caused by matter. The emergent laws of gravity contain an additional `dark' gravitational force describing the `elastic' response due to the entropy displacement. We derive an estimate of the strength of this extra force in terms of the baryonic mass, Newton's constant and the Hubble acceleration scale a_0 =cH_0, and provide evidence for the fact that this additional `dark gravity~force' explains the observed phenomena in galaxies and clusters currently attributed to dark matter.
AMA: https://www.theflatearthsociety.org/forum/index.php?topic=68045.0

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Master_Evar

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Re: New view on gravity does not rely on the presence of dark matter
« Reply #5 on: November 09, 2016, 04:08:43 AM »
Sadly I have little to no knowledge beforehand of some of the things discussed, but as they put it themselves:
Quote
The observed phenomena that are currently attributed to dark matter are the
conesquence of the emergent nature of gravity and are caused by an elastic response
due to the volume law contribution to the entanglement entropy in our universe.
As I understand it, an intrinsic property of space-time that has something to do with "entanglement entropy"  and it's volume law overcomes the area law of an expanding gravitational field at some distance, which means that the gravitational field strength after a certain distance will not drop off as much but remain quite strong.

Taken from Discussion and Outlook of the thesis:
Quote
The real reason why most physicists believe in the existence of particle dark matter is not the observations, but because there was no theoretical evidence nor a conceptual argument for the breakdown of these laws at the scales where the new phenomena are being observed. It has been the aim of this paper to provide a theoretical and conceptual basis for the claim that this situation changes when one regards gravity as an emergent phenomena. We have shown that the emergent laws of gravity, when one takes into account the volume law contribution to the entropy, start to deviate from the familiar gravitational laws precisely in those situations where the observations tell us they do. We have only made use of the natural constants of nature, and provided reasonably straightforward arguments and calculations to derive the scales and the behavior of the observed phenomena. Especially the natural appearance of the acceleration scale a0 should in our view be seen as a particularly convincing aspect of our approach. In our view this undercuts the common assumption that the laws of gravity should stay as they are, and hence it removes the rationale of the dark matter hypothesis. Once there is a conceptual reason for a new phase of the gravitational force, which is governed by different laws, and this is combined with a confirmation of its quantitative behavior, the weight of the evidence tips in the other direction. Admittedly, the observed scaling relations have played a role in developing the theoretical description, and motivated our hypothesis that the entropy of de Sitter space is distributed over de bulk of spacetime. But the theoretical arguments that support this hypothesis together with the successful derivation of the observed scaling relations are in our view sufficient proof of hypothesis.

Our main conclusion therefore is:
The observed phenomena that are currently attributed to dark matter are the
conesquence of the emergent nature of gravity and are caused by an elastic response
due to the volume law contribution to the entanglement entropy in our universe.


In order to explain the observed phenomena we did not postulate the existence of a dark matter particle, nor did we modify the gravitational laws in an ad hoc way. Instead we have to tried to understand their origin and their mutual relation by taking seriously the theoretical indications coming from string theory and black hole physics that spacetime and gravity are emergent. We believe this approach and the results we obtained tell us that the phenomena associated with dark matter are an unavoidable and logical consequence of the emergent nature of space time itself. The net effect should be that in our conventional framework one has to add a dark component to the stress energy tensor, which behaves very much like the cold dark matter needed to explain structure formation, but which in its true origin is an intrinsic property of spacetime rather than being caused by some unknown particle. Indeed, we have argued that the observed dark matter phenomena are a remnant, a memory effect, of the emergence of spacetime together with the ordinary matter in it. In particular, we have made clear why the apparent dark matter behaves exactly in the right way to explain the phenomenological success of modified Newtonian dynamics, as well as its failures, without the introduction of any freely adjustable parameters. We have found that in many, but not all, aspects the apparent dark matter behaves similar to as one would expect from particle dark matter. In particular, the excess gravity and the gravitational potential wells that play a role in these scenarios also appear in our description.
Bolded some of the interesting parts, italic-ed their stated conclusion.
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markjo

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Re: New view on gravity does not rely on the presence of dark matter
« Reply #6 on: November 09, 2016, 06:19:34 AM »
You aren't even going to bother giving a hint as to what is behind the link?
I think that the hint was in the thread title: "New view on gravity does not rely on the presence of dark matter"
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