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Emergent Gravity Disproved
kdawson writes "A paper up on the ArXiv claims to disprove the gravity-from-entropy theory of Erik Verlinde, which we discussed soon after he introduced the idea in a symposium late in 2009. Archil Kobakhidze says that experiments measuring the effect of gravity on quantum particles (neutrons in this case) match results expected from classical Newtonian gravity, not Verlindian entropic gravity. Here is Kobakhidze's paper (PDF)."
In his Giant Star novels, if I recall correctly. The great breakthrough in physics by the aliens was the understanding that gravity was a consequence of particles decaying rather than through the standard Einstein model. Kind of puts a torpedo through that aspect of the books.
Kdawson, could you please try to have the first clue about something that you submit? This is a non-peer-reviewed article, fresh on the arXiv. It's a followup to an earlier article which was widely criticized within the community as being full of holes, and the arguments in this article are very very weak. At best it's an argument against entropic gravity, but it is a LONG way from a proof that entropic gravity is wrong.
The way that neutron states are treated here is questionable - see http://arxiv.org/abs/1104.4650 for a summary of what's wrong with them.
Disclaimer: I am a gravitational theorist. I think gravity ISN'T entropic. However this paper is nowhere near sufficient to show that. I'd wait a LOT longer for the dust to settle on this one before making a strong statement one way or the other.
This is a non-peer-reviewed article
I was under the impression that a peer-reviewed article was more likely to be paywalled and thus inaccessible to those Slashdot readers who had already graduated.
...in very simple words:
Exciting headlines get page hits.
A statement like "some data gathered might suggest gravity isn't entropic" will get very few page hits, and hence generate very little ad revenue.
A completely wrong but much more interesting statement like "Emergent Gravity Disproved" will get more hits, and hence more money.
So, Kdawson has every incentive to state the title wrongly, whether he understands it or not.
Complain all you want, the nature of the beast does not change.
Lubo Motl has some additional, supportive, thoughts on his blog:
Once more: gravity is not an entropic force
Seriously, I read about this three days ago.
Would you have bumped the departure of Steve Jobs in favor of this story? If not, which story would you have chosen to bump? Think of Slashdot on weekends as a weekly publication that has articles of lower urgency.
I thought that we decided to go with intelligent falling?
FRA: STFU GTFO
Considering the bunk and completely unproved concepts that physics is using currently ie. Dark Matter, Dark Energy, String Theory, Supersymmetry and the Higgs Boson. Even IF there is a Higgs particle, the Higgs does NOT explain gravity. Emergent Gravity is a VERY compelling concept. It could also explains Mass, Inertia AND the 2nd law of thermodynamics.
Currently it is obvious that physics has been stuck in a rut for decades. The discovery of virtual particles has yet to be fully incorporated into other theoretical aspects of physics. It is my understanding, that these virtual particles are the 'Ether' that Einstein had mentioned before he resorted to the cosmological constant.
In my opinion, these chaotic particles have an effect,Entropy. Areas with less virtual particles, like the occlusion between two near objects, experience a negative pressure, which we call gravity. Gravity is emergent from Entropy. Entropy is emergent from Virtual Particles.
Of course, this is pure conjecture. But I would love to hear other peoples opinions...
Translation: I'm a fucking moron who doesn't understand things, but loves to insist my ignorance is in fact someone else's problem, so I have no problem spouting pure idiotic bullshit, and through a combination of low IQ and high hubris factor, throw my retarded thoughts out there as if they weren't the mumblings of a halfwit.
The world's burning. Moped Jesus spotted on I50. Details at 11.
I don't know what you consider as "making practical sense", but a theory which mathematically works (and GR doesn't work "at times", it works everywhere where we can test it) is considered correct.
If gravity would need atmospheric pressure, there would have been major problems for the moon landing teams, as there's no atmosphere there. Also, you would have a hard time to explain how the sun attracts the planets. The only fluid in the solar system is the solar wind, and that goes away from the sun.
I think your proposal is disproved by the planets orbiting the sun, by the moon orbiting the earth, as well as by the moon landings (both manned and unmanned) and several interplanetary missions.
Also nobody has shown the speed of light not be limited (if you think of the Nimtz experiments, that one is just a misinterpretation of the experimental results).
The Tao of math: The numbers you can count are not the real numbers.
To be fair, the article only addresses one formulation of emergent gravity from a single hypothesis. To say the whole idea of emergent gravity is wrong is a little disingenuous. My pet theory (hey, a boy needs a hobby) is that gravity is emergent from a universe where the physics, the actual computation, has to be done to make anything happen. Apple falls to the ground? The universe has to perform the calculations to make it happen. If there's a processor limit then it would manifest as the speed of light, and if the calculations involving regions of space with mass ("particles") take a little more calculating then that section of space will be retarded in a timelike direction, ie GR. There's a whole host of emergent gravity or emergent relativity possibilities, and to my mind at least it's a very elegant way to get around some of the big fundamental problems, like why gravity doesn't seem to behave like the other forces, or why the speed of light even exists.
Please consider this account deleted, I just can't be bothered with the spam anymore.
At first pass I read the headline as "Emergency Gravity Disallowed".
My thought was, "Wow, this Hurricane Irene hysteria has really gotten out of hand. People are even afraid the gravity's going to get knocked out."
dragonhawk@iname.microsoft.com
I do not like Microsoft. Remove them from my email address.
-You're flying!
-How?
-Gentoo!
Escher was the first MC and Giger invented the HR department.
Hi cj,
I think think the idea's got legs.
You can see some of my thoughts on this via the comments by Marble on someone else's blog.. (You'll have to scroll down / ctrl-f for gravity).
I gave up arguing not because he convinced me otherwise - but lets just say he has a greater belief in the infallibilty of published science that I (or history I believe) can afford to give it.
Cheers, Marble.
"Gravitational lensing" is a known, 100% solid, FACT. Doesn't matter how much you dislike the idea, world+dog has seen it's effects in action, here on planet earth.
Nice. What keeps the atmosphere (the source of that pressure) grounded, then? Why don't high-altitude (edge-of-space) pilots go floating off? Why don't non-magnetic objects in vacuum start floating? How about the planets themselves, in a nice orbit?
Incidentally, I have a pretty low concentration of magnetic material in my body, and atmospheric pressure is lower the higher you go, so, much like swimming under water, that should mean we FLOAT to the top, not get held-down by it.
The only sense your idea makes is if you redefine your "electromagnetic forces" to something identical to gravity.
Don't take it too hard, kid. We were all angsty teenagers who thought we were smarter than the rest of the world, and developed plenty of misconceptions due to a poor education system and whatnot, which take many years to completely shake off and replace with knowledge.
Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
I can do without the condescension. And it seems that type of arrogance to state that gravity is 100% fact, is merely your own assertion based on what we are taught in schools as fact, though it is only a theory still. Albeit one that is sufficient mathematically for most of our money grubbing endeavors. You're knee-jerk reaction to assume I only meant magnetism is not my fault. However, based on just that alone, electromagnetism is how much stronger than the supposed force of gravity? So even a little bit of iron in the blood would be sufficient, though what I said what electromagnetism, not magnetism. l8r, cj
The funny thing about science is that you can do experiments to see who's right. You don't have to endlessly debate stuff.
GP states many experimental observations that directly contradict your hypotheses. Now you can whine about condescension, or man up and rethink them.
I suffer from attention surplus disorder.
You've made a complete and total fool out of yourself by spouting off baseless nonsense that flies in the face of observed facts. Condescension is the best you can possibly hope for.
GRAVITATIONAL LENSING. Doesn't have a damn thing to do with what school you went to. You can grab a telescope and go observe it, in action, RIGHT NOW. At least go look it up.
Also, talking about dogma from what is "taught in schools" just proves you're a school-aged kid. An overwhelming majority of people here have continued their education independently after leaving school, and long-since dumped any dogma that school has imposed. See the discussions on global warming, dark matter, etc., which haven't much made it into school books yet.
Try not to go to far over the edge with your pet theories and disdain of the world. If you also continue learning after you leave school, you'll find that, while your teachers may be idiots who can't intelligently defend or debate the information you've being told, out in the real world there are a large number of very smart people developing all these theories, considering all conceivable alternatives, trying to disprove them all, and more.
Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant