Talk:Entropic gravity/Archive 1

Archive 1

NY Times article

http://www.nytimes.com/2010/07/13/science/13gravity.html —Preceding unsigned comment added by 71.251.222.38 (talk) 11:33, 13 July 2010 (UTC)

Sounds biased

"Also, a specific microscopic model has been proposed that indeed leads to entropic gravity emerging" The 'indeed' bothers me. 68.225.192.99 (talk) 09:30, 9 August 2010 (UTC)

Attention needed on Informal Explanation

I'm turning the "attention needed" parameter on in the infobox, as I believe this article needs attention from the WP:Physics community. Specifically, the "Informal Explanation" section, fairly recently added, needs attention from an expert. At the moment, it's definitely grammatically flawed, isn't written in proper MoS style, and doesn't actually do a great job of explaining the concept any more "simply" than the intro at the top. I'm happy to do edits on the section to improve the grammar and readability, but I don't want to do so if the underlying quality of the explanation isn't worth the effort. I'm vaguely familiar with the holographic principle, but not in any great detail--I stopped physics in the middle of undergraduate QM (with the exception of some "pop" books on the subject and reading here on WP)--so I'd love for an expert to take a look first and cleanup the physics before I cleanup the writing. Thanks for your help!Qwyrxian (talk) 11:52, 25 August 2010 (UTC)

sorry i'm not a native English writer, i did my best to explain this theory, there are a lot of references on the internet; most however are quite complex, i tried to write it down as simple as possible, without formula's or complex terms. Maybe i could have written it more detailed (more about the blackhole information surface) but then it would become also more complex to understand. If some expert on this field is going to rewrite this part, please let it be readable for people without such expert knowledge, explaining this complex theory in simple was my main goal, it took me quite a while to conclude the theory in simple from various sources. —Preceding unsigned comment added by 82.217.115.160 (talk) 09:59, 30 August 2010 (UTC)

Entropic gravity

I'm wondering if this page should be moved to "Entropic gravity" -- that seems to be the name coming into usage for this theory. Also, this page really needs the attention of an expert right now. Danski14^(talk) 22:40, 5 September 2010 (UTC)

That actually makes a lot of sense. I'll put a formal move proposal on the article. Qwyrxian (talk) 00:45, 6 September 2010 (UTC)

I went ahead and moved it. It can always be moved somewhere else if necessary. Danski14^(talk) 21:00, 6 September 2010 (UTC)

Logical Arguments and Critiques

Articles describing early theoretical work should be accompanied by a section outlining critiques and factual or logical arguments. —Preceding unsigned comment added by 76.204.18.32 (talk) 19:25, 22 September 2010 (UTC)

Per WP:V, we should include whatever reliable sources say. If you know of reliable sources that critique the theory of Entropic gravity, and those critiques have enough weight, then please do add them to the article. Qwyrxian (talk) 02:23, 23 September 2010 (UTC)

Preprint

If there was a preprint of the paper on January 6 2010, when will be the official publication? Xenan (talk) 20:59, 17 September 2010 (UTC)

If the referees ask questions that take a lot of work to respond to, 6-12 months from initial submission to official acceptance is reasonably common. It could also be possible that the referees pointed out problems that are impossible to correct, without essentially writing a new paper. If Verlinde does not tell us (in the Comments: field at http://arXiv.org/abs/1001.0785), then the outside world can only speculate. The version on arXiv is still at v1 - if Verlinde has received referees' comments and updated his paper, then he has also chosen not to make the updated version public. Boud (talk) 08:57, 1 October 2010 (UTC)

More on the Informal Explanation

I tried to improve at least the wording on the informal explanation, but it's still not very good. Is this kind of thing normal in other complex scientific articles? While I was writing it, it "felt" bad, like I was doing OR instead of relying on what reliable sources have said. I'm now tempted to agree with deleting the section, unless we can find an "informal explanation" somewhere else and then summarize it. Is there a "Holographic Theory for Dummies" book? Is there anyone else who thinks it should be kept? If not, I'm willing to just take it all out, despite my earlier objections. Qwyrxian (talk) 01:16, 12 October 2010 (UTC)

Yes this kind of thing is done, e.g. Introduction to general relativity. That section's tone is better and all it needs now is some refs to back up the claims, so I will change the tag. Devourer09 (t·c) 15:52, 12 October 2010 (UTC)

Amsterdam, june 10, 2011 In 2003 Vasily Yanchilin published his book The quantum Theory of Gravitation. He sees gravity as a pure quantum-mechanic phenomen: "Suppose a tiny particle is at x=10 while a mass is at x=0; there exists a probability that in a while the particle appears at x=9. There exists also a probability of the reverse transition. At x=9 the uncertainty (Heisenberg) is a bit smaller than at x=10. Therefore the probability of the particle's transitions is netto in the direction of the mass". (In the book also a picture is presented, I changed some words for this text without illustration). The founding hypothesis is that mass reduces uncertainty. This is worked out in the book by using potential of mass. When Verlinde says " Gravity is a consequence of information associated with the position of material bodies" does he give then more information than Yanchilin? Verlinde still believes in black holes and the dogma of constant speed of electro-magnetic waves in vacuum. Einstein took only constant speed as a temporary hypothesis when there was no quantummechanics yet and thought it could not be quite independent of all other things (therefore must vary somehow). Look at the words electro/magnetic/waves, which indicate from themselves already some relation. Newton and einstein only gave quantitative description of gravity. Vasily Yanchilin is the first to explain qualitatively and such in harmony with quantummechanics.

He derives a new formula from the principle of least action for the square of an interval with as first part 1/(1 + 2GM/rc(quadrat and with index o)) while in the old general theory of relativity this is (1 - 2GM/rc(quadrat)). In the new theory black holes, inflation, the cosmological constant, negative energy and accellerated expansion of the universe have no place anymore. Speed of light depends on the potential of the total mass of the universe and becomes zero at the edge of it. The special theory of gravity stays valid if understood thus that observers do not notice difference in speed of light. Because that depends on the potential of the total mass of the universe and is the same in all directions at a certain spot and a certain time.

Presently Yanchilin is looking for a publisher as he wrote a book on supposed black holes. His previous book deserves to be read by all students. P.e. he gives new solution regarding the red shift of sunlight, which according to the einsteiners is caused by slower second and by overcoming gravitational attraction. While not the sum of both is measured! Jitso Keizer — Preceding unsigned comment added by 130.37.91.199 (talk) 12:06, 10 June 2011 (UTC)

"Einstein took only constant speed as a temporary hypothesis". For Einstein the observer independence of the speed of light wasn't a hypothesis but an experimentally observed physical reality (and we haven't found a counterexample in nature in the past 100 years, either). Indeed, effects that would effectively break Lorentz invariance, would do away with both special and general relativity completely. But until such physical phenomena have been identified by experimentalists, both theories are alive and well.

There are enough strongly gravitating compact objects known to astronomers that one can argue that black holes, or at least black hole like objects have been confirmed observationally. Dynamics of matter in general relativity has been studied with high precision in the weak and the strong field limit and no deviation from general relativity has been found, so far. Any model that argues that black holes can not exist, therefor needs to find very good explanations for the nature of these observed compact objects. That is a very hard problem and I doubt Yanchilin has the necessary framework to solve it.

And since theory can only exist on top of experimental data, at this moment GR holds up just fine. I have no idea how Yanchilin uses the uncertainty principle, but it is probably not in the way you are portraying it, which is incorrect, as the uncertainty of momentum measurements is not tied to an absolute coordinate but to the uncertainty of the position measurement (and those are AVERAGES over many actual measurements, i.e. mathematical quantities in the observer's bookkeeping and not actual physical quantities that are being assigned objective physical meaning in the system at any given time). The potential in which the particle moves is, in the case of very precise position measurements, completely irrelevant, as the momentum uncertainty goes towards infinity, which essentially means that the particle under measurement will not be bound any longer to the (finite) potential of the mass at x=0 but will basically bounce off the measuring device with high energy. The majority of the kinetic energy of the final particle state does not come from the quantum dynamics of the particle itself, but from the measuring device. To measure very small scales, one needs to build an accelerator. In case of LHC that's millions of Joules of electrical energy that get imparted on the particles in the beam. Without the energy of those power plants powering the accelerator, the precision position measurement in the collision would simply not be possible.

Just a few thoughts by an experimentalist. — Preceding unsigned comment added by 76.126.52.72 (talk) 05:38, 7 February 2013 (UTC)

September 2011 Update

I have just made some edits to the article reflecting the fact that this proposal seems to be completely ruled out by experiment. From what I can tell, the arguments, especially the ones based on neutron interference experiments, seem completely robust. I dont see any way of escaping them, but feel free to discuss if anyone has an argument to the contrary. Isocliff (talk) 21:06, 18 September 2011 (UTC)

The neutron interference only proves that cold neutrons obey the Schroedinger equation, despite the Schroedinger equation being completely wrong on the actual physics that is going on. We already know that gravity is not a Newtonian force. Gravity is not a force, at all, and never has been (not even in Newton's time!). Objects under the influence of gravity alone, are in free fall, and they experience absolutely no forces, whatsoever. F=m*a does not work for gravity, because there is no measurable force F that leads to an acceleration a of the mass m. Instead, the mass m seems to accelerate without any actual forces acting on it, at all. The kinds of gravitational forces we are talking about in Newtonian theory are the negatives of the forces that it would take to keep a test mass from moving in the "gravitational potential" of other bodies. Those "holding forces" are real, physical forces. They can be measured with a force gauge. They are the forces civil engineers are dealing with when they are building bridges. The negative of these forces, however, can not be measured with force gauges. They are a MODEL of the force that gravity would have to exert on test masses to accelerate them the way we see them accelerate. But while we can write the mathematical description of those forces down (by simply changing the sign of the measurable holding forces), we can not measure them with force gauges. Therefor, they are not physical forces, at all.

The correct description for all of that is general relativity, which changes the geometry of space-time. Since Schroedinger's original equation is not capable of describing quantum-mechanics in curved space-time, it is not a useful equation to describe the physics of single particle systems under the influence of gravity.

The only "mystery" then is to why the Schroedinger equation even works in this case, since it uses a concept of gravity that is completely false. Kobakhidze's criticism fails to analyze the problem in a theory that is actually suited to make a connection between gravity and quantum phenomena. The neutron interference in a gravity "field", of course, is real. Neutrons do have their wave function modified by the non-flat geometry of the space in which they move and this leads to interference terms which seem to be equivalent to a "gravitational potential". That the wave function doesn't experience any decoherence, is, of course, trivial. Free falling bodies are not accelerated in their local reference frame, therefor, they do not experience any Unruh-radiation and there is no stochastic local field to decohere the wave-function.

Now, if one were to repeat the analysis in a framework that might work, e.g. by replacing the Schroedinger equation with the equivalent path integral for a non-relativistic action of a free particle in a coordinate system with the proper curvature, one could probably hope to recover the observed interference effects, while at the same time working with a mathematical model of quantum mechanics that also properly reflects that actual physics of gravity. I wouldn't expect to find anything to rule out entropic gravity that way, though, since it correctly derives the correct curvature and it starts from scratch with the assumption that free-falling objects do not experience any stochastic backgrounds.

Now, the very opposite is also true, though. If gravity is, indeed, an emergent phenomenon, which comes with an Unruh-like temperature field for accelerated observers, then it would be the very act of holding something in a gravity field that would cause an effective acceleration in the rest frame of the particle... which is indeed the very "acceleration" that makes it experience a holding force! And in this case it would be quantum systems that are being held in a trap (rather than the ones that are evolving in free fall), that would be subject to a de-coherence phenomenon. In Earth's gravitational potential, the effective temperature of that stochastic field would be on the order of 1e-19K... far smaller than any realistic cryogenic temperature achievable to date, and therefor the decoherence is not measurable with trivial quantum interference experiments. And that makes me believe that, at least the Kobakhidze approach to falsifying entropic gravity not only fails, but that it does so by falling on its face completely because it mistakes Newtonian gravity for something that it wasn't even for Newton.

Having said that, it has been pointed out that entropic gravity works very poorly for technical reasons in the Newtonian case... but THAT is a correct line of argument against it. Experimental falsification, at this time, is not. — Preceding unsigned comment added by StillFascinated (talk • contribs) 05:22, 10 February 2013 (UTC)

I'm no expert but...

Can we have at least some attmept at an explanation for the idea behind this theory? I find it difficult to see how gravity could arise thermodynamically. For example, gravity tends to destabilise density perturbations in the universe as denser regions of the interstellar medium collapse into compact objects like starts, planets and black holes. Entropy, on the other hand, tends to equilibrate density perturbations in order to achieve a system with the largest number of microstates. — Preceding unsigned comment added by 92.27.55.215 (talk) 20:46, 18 May 2012 (UTC)

You can find a very fine explanation for entropic forces in Verlinde's paper. That thermodynamics strives to create equilibria is logically not contradictory to the existence of large scale effects that look like they are based on classical forces. Acoustic waves in gases are a well known example of a thermodynamic system that has many aspects of a classical Newtonian system, like elastic waves in a perfectly elastic solid. Thermal equilibrium also doesn't mean that only a single, uniform phase can exist. Every solid coexists in equilibrium with its liquid and gaseous forms at any given temperature and pressure. These equilibria can be almost completely on the side of one phase, or another, but at triple points even macroscopic quantities of three phases can exist. It takes external supply of thermal energy to change the ratio of these phases. And the universe, as of today, is still very far away from its thermal equilibrium, which means that thermodynamics can produce very strong local non-equilibria with greatly decreased entropy, at the cost of an entropy increase for the whole system. As far as gravity is concerned, the entropically preferred state in a closed universe (with perfectly reflective walls) would be that all matter is condensed into black holes. Because of the expansion of the universe and black hole evaporation, the real equilibrium state will be an ever inflating cosmic event horizon filled with an ever colder photon gas. — Preceding unsigned comment added by StillFascinated (talk • contribs) 02:04, 6 February 2013 (UTC)

StillFascinated, it sounds like you know this area, and we're happy to have you participate! You seem to have put all your opinions on the article page without references. Remember that you're not writing a journal article or commenting on a blog, but writing an encyclopedia entry. Could you add more references? Sanpitch (talk) 20:58, 11 February 2013 (UTC)

Sanpitch... unfortunately, you are right! I did add my personal comments about Kobakhidze's criticism of entropic gravity into the main text. It should be removed. But then, probably so should the references to Kobakhidze's articles, since they do not represent the highest quality of criticism against Entropic Gravity. I can't find much material that will actually take the Kobakhidze argument apart. Neither can I find many serious citations to it that analyze it in detail. My feeling is that the community doesn't take him seriously enough to even write a detailed rebuttal that one could refer to in an encyclopedic article. In my personal opinion Kobakhidze keeps talking pure nonsense in this case. I have no opinion about the rest of his work, but I think he really got on the wrong horse with this one and he shouldn't be included in citations of criticism of entropic gravity any more than the many blogs about entropic gravity that make similarly ridiculous arguments. But then, I didn't want to go as far as to actually remove the references to these papers, and that's why I tried to put them in context. But that's not how Wikipedia works or should work.

What would you suggest?

Would you prefer removing the Kobakhidze references and go with Matt Visser's formal arguments against entropic forces as a general framework in classical mechanics, instead? To me Visser's reasoning presents a very, very strong formal argument against the universality of the concept. It is much more powerful than criticizing a concept like entropic gravity, that is not-even-physics-yet (and may never be), with catastrophically wrong physics (by pretending that the Schroedinger equation can serve as a probe to post-GR gravity).

I am currently reading a paper by Tower Wang (arXiv:1211.5722), which seems to suggest that, if entropic gravity works, at all, it only works for a very limited scenario, which happens to be pretty much exactly general relativity and little else. The conclusions from that could be that either the universe really didn't give itself much of a choice when it expressed space-time as an emergent phenomenon, or that entropic gravity is simply a poorly reasoned logical artifact that has been derived mostly from results that are strongly tied to general relativity, in the first place. In the latter case, of course, it is not so much an insight into new physics as it is a case of a complex, but ultimately circular argument. I was hoping to understand the Wang argument a little better first, and then to maybe find a third paper that could shed even more light on these formal limitations of Verlinde's idea. The additional advantage is that both Visser and Wang stake out the territory that they manage to exclude entropic gravity from quite well. What remains after that seems like a rather small sliver of ground.

The alternative is to leave the references to all these criticisms in, but to remove the obvious objections that any physicist should have about "experimental arguments against entropic gravity". To be honest, that would leave me with a pretty bad taste with regards to the quality of selected materials, which was the main reason why I got involved in editing this Wikipedia article, to begin with.

All thoughts on the matter are welcome! — Preceding unsigned comment added by StillFascinated (talk • contribs) 06:32, 12 February 2013 (UTC)

StillFascinated, thanks for the great reply. I think the article would be much improved if you would rewrite the entire "Criticism and experimental tests" section of the article. If you think that references to Kobakhidze should be removed, I'm ok with that. The main thing is that the article should not be so technical that only you or Edward Witten can read it :-). I suggest keeping the section to just a couple of paragraphs, that as much as possible you 'Wikify' the article, and that you include references. If you really want to get into technical detail about all the arguments for and against entropic gravity, I suggest that you create a separate wikipedia article (I personally would love to read this article, BTW). Sanpitch (talk) 19:06, 12 February 2013 (UTC)

Sanpitch. Thanks for your feedback! I think that removing the Kobakhidze references and replacing them with the technically much better arguments mentioned would greatly improve the quality of the article. I think your suggestion to separate the article into a basic overview of a more detailed discussion is a very good idea. Let's try with shortening the criticism section, first.

Funny you mentioned Witten... I was looking for some quotes from him that could indicate his thoughts about emergent spacetime and entropic gravity, but I couldn't find any. It would be very interesting to have an idea what he thinks about it.

Re-wrote Criticism Section

After detailed discussion with Sanpitch, I completely rewrote the criticism section. Arguments against entropic gravity that claim that one can experimentally falsify it are very hard to motivate since entropic gravity, as a handwaving argument, essentially just re-interprets general relativity (and in approximation Newtonian gravity). Since GR does not violate any of the precision tests that it has been subjected to, it is not clear why entropic gravity should, as it leads to the same conclusion, that Einstein's equations are the macroscopic equations of motion of space-time. The main paper that makes such a claim (based on an obscure analysis of neutron interference experiments in a framework that is not suitable to include post-Newtian models of gravity) has, in my opinion, extremely serious flaws and should't be cited.

There are, however, some fairly straight forward formal arguments that limit the scope of entropic gravity quite severely. Matt Visser's paper shows that Verlinde's hand waving argument for the derivation of Newtonian gravity as an entropic force only works under very limited assumptions. His more detailed analysis mostly eliminates entropic forces as sources of conservative forces in the setting of classical mechanics and is suggestive that Verlinde's initial handwaving argument is too naive, by far.

That, all by itself, is not a particularly large hurdle for entropic gravity as a possible explanation of gravity, since Newtonian gravity, (i.e. the notion that gravity can be understood as a potential), had always been merely shoehorned into classical mechanics. In a sense the naive treatment of Newtonian gravity by Verlinde himself seems to give credence to his own opinion that we need to learn to deal with gravity in a different way and listen much more carefully to what we already know about its detailed nature as a phenomenon that is deeply tied into space and time itself.

In the wake of Verlinde's paper multiple authors have made additional derivations of modified versions of general relativity. In response, Tower Wang has analyzed a wide class of such models for consistency with energy-momentum tensor conservation and the ability to derive a homogeneous and isotropic solution for the global universe from them. He concluded that the local conservation and the global homogeneity/isotropy demands put very strong limits on the types of models that can be derived from an entropic gravity formalism. This, again, is a double edged result for entropic gravity. On one hand, it strongly favors general relativity as a very special theory that can not be easily modified without serious consequences. On the other hand, it also limits entropic gravity to a narrow subset of physically possible models of gravity.

It remains to be seen if future work can narrow these results down further to either a unique theory of space-time (which may very well turn out to be GR), or, if entropic gravity will, eventually, be completely eliminated on formal grounds.StillFascinated (talk) 06:40, 16 February 2013 (UTC)

StillFascinated, I hope you'll forgive me for moving your description of your big edit to this new section. Typically one does not reply to comments that are so old as those above (2.5 years).

As to the content of your edits, I think the new content is a big improvement. The main thing that I suggest you do now is to make links in your text to other articles in Wikipedia. For example, links to Einstein's equations, Matt Visser, Jacobsen, and Padmanabhan all likely have wikipedia entries that can be linked to. I'd also love to make the section shorter if at all possible. Thanks again! Sanpitch (talk) 07:36, 16 February 2013 (UTC)

Sanpitch, I am perfectly fine with the move. I will gladly add links to other Wikipedia articles and I will shorten the section as much as I can. Please give me a few days to make the changes. — Preceding unsigned comment added by StillFascinated (talk • contribs) 20:48, 16 February 2013 (UTC)

March 2016

Article is biased by criticism without adequate opposite point of view. Also it is low quality overall. I don't have time do rewrite it, but I will add some response to criticism to balance a little. wp:npov

If you are completely unfamiliar with the topic please don't edit with 'common sense approach'. --Asterixf2 (talk) 18:48, 10 March 2016 (UTC)

the main content is missing

My personal judgment of 1001.0785v1 from a quick look is that Verlinde doesn't clearly state what space-time or alternative to space-time he starts off with. If space-time is emergent, then it has to be emergent from something. It would be OK to start off with just an abstract set, but things have to be defined clearly if this is to be more than just an heuristic essay. You cannot assume what you are trying to derive. Anyway, this is just my personal judgment and irrelevant for the article itself (unless i publish it somewhere in a reliable source :P).

For crying out loud. Of course it's emergent. What are you suggesting? That it's a fundamental and axiomatic material thing?178.255.168.77 (talk) 21:12, 4 May 2016 (UTC)

What's more important is that most of the material should be shifted from the top down to some sections below which try to present the topic. The lead section (introduction) should then be just a condensed version of the actual content. Shifting material down the page is easy. Writing a short, NPOV summary is more difficult - which is why i'm leaving someone else to do it :P. Boud (talk) 09:04, 1 October 2010 (UTC)

The main content is not missing. The main content was there first. Someone then added an "informal summary" which you took to be the body of the article. 84.13.66.108 (talk) 09:55, 1 October 2010 (UTC)

In his paper Verlinde very clearly states that many microscopic details of the space-time do not matter while he also clearly states what the necessary ingredients for his "derivation" of gravity as an emergent force are. One of them is that it obeys a holographic principle in the very way he used it in his paper. This, of course, excludes a great many microscopic models (although I don't believe that it necessitates some form of string model - but that is a religious belief of mine). So if nature can be shown not to obey the kind of holographic principle used in the paper, this particular "derivation" of gravity as an emergent force would be either completely wrong or, at the very least, would have to be generalized to a scenario without this kind of holography, which still produces the same or, at least, very similar results.

Verlinde, by the way, explains in his paper very clearly what he believes to have accomplished and what he doesn't. He points out that one of the great weaknesses of Newtonian gravity (that it introduces a force at a distance without any microscopic mechanism to explain it), already bothered Newton and Hooke and that this flaw never went away, only that we have gotten used to seeing it, naively, as a virtue. The appeal of his suggestion is that, by reversing centuries of logical reasoning, while using the very same, and experimentally extremely well supported empirical relations, one can make a logical case for gravity indeed being an emergent phenomenon, one with a microscopic explanation founded in statistical mechanics, rather than quantum physics.

The logic of his paper follows along the lines of many important fundamental papers, Einstein's papers on special relativity included, which, instead of postulating new physics, cleverly re-interpret well established physics in such a way that rapid progress can be made by others who follow up on logical consequences rooted in the re-interpretation. Naive attacks on this argument are therefor as unlikely to succeed as naive attacks on special relativity, since Verlinde's paper merely re-interprets standard physics and does not claim to produce any new phenomena. The real questions it poses lies in the assumption that nature obeys a holographic principle that can be applied in the straight forward, even hand-waving, way as the paper does. Until experimental evidence is found to the contrary, however, theoretical attacks that apply a different interpretation of a, necessarily different, holographic principle, are, despite the best technical efforts of their authors, not logical repudiation of Verlinde's article, they will merely pit one theoretical pet model of holography against another.

And if one had to chose one "winner", it would have to be the paper which predicts the correct physics. Therefor, in the contest of Verlinde against, say, Kobakhidze, Verlinde's argument is the clear winner, as it "predicts" the correct physics, while Kobakhidze's does not. Kobakhidze's claim that his derivation proves Verlinde's interpretation wrong and eliminates emergent gravity is therefor fundamentally flawed in its logic. Instead, he merely manages to show that his interpretation of Verlinde's assumptions about the mathematical consequences of holography are flat out wrong. From a phenomenological angle there is nothing wrong with emergent gravity, in any case. Just as other stochastic forces on atoms, be that random electromagnetic fields or weak collisions, do not collapse electron orbitals and do not destroy line spectra in atomic physics, there is absolutely no reason to assume that extremely weak fluctuations of a very weak gravitational field can do much harm to the stability of quantum phenomena such as neutron wave functions. Only after an experiment has seen modifications to the dynamics of quantum systems that are clearly caused by gravity can we hope to decide if nature has implemented a (very quirky) form of quantum gravity, or chosen to implement a rather straight forward form of thermodynamic gravity. My money, given the evidence, is on the second one. — Preceding unsigned comment added by StillFascinated (talk • contribs) 01:02, 6 February 2013 (UTC)

Question

So if between elements occasionally information is lost from the collection, is that 'entropic gravity'? Or are we talking about something else? 178.255.168.77 (talk) 21:22, 4 May 2016 (UTC) PS is there a better way of editing this stuff than in a text editor and with these stupid tildes and wotnot?

Emergent gravity 2016

Should we mention Verlindes 2016 formulation as "Emergent gravity". Seems to improve and explains MOND. New Scientist reports on an experimental test of EG and says it passes without resorting to free parameters. EG: Emergent Gravity and the Dark Universe Verlinde 2016, Brouwers test : First test of Verlinde's theory of Emergent Gravity using Weak Gravitational Lensing measurements Brouwer 2016, NS news item : First test of rival to Einstein’s gravity kills off dark matter. Whereas MOND explains galactic rotations, EG seems to also explain galactic clusters that MOND had problems with (and provides an explanation/mechanism for MOND). - Rod57 (talk) 10:27, 9 January 2017 (UTC)