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The End Of Gravity As a Fundamental Force

kdawson posted more than 4 years ago | from the mccavity's-not-there dept.

Science 650

An anonymous reader writes "At a symposium at the Dutch Spinoza-instituut on 8 December, 2009, string theorist Erik Verlinde introduced a theory that derives Newton's classical mechanics. In his theory, gravity exists because of a difference in concentration of information in the empty space between two masses and its surroundings. He does not consider gravity as fundamental, but as an emergent phenomenon that arises from a deeper microscopic reality. A relativistic extension of his argument leads directly to Einstein's equations." Here are two blog entries discussing Verlinde's proposal in somewhat more accessible terms.
Update: 01/12 04:48 GMT by KD : Dr. Verlinde has put up a blog post explaining in simpler terms the logic of the gravity from entropy paper. He introduces it with: "Because the logic of the paper is being misrepresented in some reports, I add here some clarifications."

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650 comments

Just because the math works doesn't mean it's true (5, Insightful)

XanC (644172) | more than 4 years ago | (#30716674)

But it sure sounds promising.

Re:Just because the math works doesn't mean it's t (4, Insightful)

Profane MuthaFucka (574406) | more than 4 years ago | (#30716700)

And even if it's not true, if the math works, it still might be useful. Newton's and Einstein's theories aren't strictly "true" but they are incredibly useful despite that.

Re:Just because the math works doesn't mean it's t (3, Insightful)

v1 (525388) | more than 4 years ago | (#30716722)

That's one funny thing about math, "close doesn't count", until you get to a certain advanced point. Then we say "this works for all but a few special cases... close enough."

Re:Just because the math works doesn't mean it's t (4, Insightful)

negRo_slim (636783) | more than 4 years ago | (#30717028)

The one funny thing about the way the majority of people use math, "close does count", until you get to a certain advanced point. Then we say "this works for all but a few special cases... close enough"

Obviously Newtonian gravity is much more understandable to your average person than say general relativity and also offers a good aproximation of expected behaviors of the physical world.

Re:Just because the math works doesn't mean it's t (4, Interesting)

node 3 (115640) | more than 4 years ago | (#30717244)

That's one funny thing about math, "close doesn't count", until you get to a certain advanced point.

I didn't realize irrational numbers, a huge portion of the rational numbers, and trigonometry, were considered advanced.

But this really isn't about the *math* being close, but not exact, it's about the math being close to *reality*, but not exact. Again, however, this is not advanced. Even grade school science is close but not exact. What's the temperature outside? How many inches of water did it rain last night? What's the circumference of the Earth? And Newtonian physics (which is also not advanced) is close, but not exact. Even at the slow speeds and low gravities of our mundane lives. Special and General Relativity have the honor *not* of being exact, but merely of being closer to exact than anything else so far.

The only common types of math where "close doesn't count" are basic arithmetic (excepting fractions) and pure algebraic manipulation.

In your high school physics class, do you *really* think you were exact when you used 186,000 mi/s or 300,000 km/s for the speed of light? Or in grade school, that the Earth rotates in exactly 24 hours (as measured from solar zenith to solar zenith)?

Or even before that, when you bought one candy bar at 3 for a dollar, and you got 66 cents in change?

Precision and accuracy are two terms you should have been made aware of by high school science, and rounding errors by middle school math.

Re:Just because the math works doesn't mean it's t (4, Interesting)

Anonymous Coward | more than 4 years ago | (#30716774)

Well, it does make a jump from a fundamental force we can't seem to detect into a latent, emergent phenomenon which we, er, also can't detect the source of.

So it transfers one critical unknown into a less important, impossible to verify unknown. Then it links up with Relativity somehow. Not exactly a "theory of everything".

Re:Just because the math works doesn't mean it's t (2, Informative)

MightyMartian (840721) | more than 4 years ago | (#30716814)

Indeed. Until there is some confirmation of string theory, it, and anything extrapolated from it, while interesting in an academic sense, is ultimately meaningless in an empirical sense.

Re:Just because the math works doesn't mean it's t (3, Interesting)

Rockoon (1252108) | more than 4 years ago | (#30717156)

There is a difference between assigning names to things and understanding them. While we have loads of empirical stuff to back up our theories, not a single one of those theories is grounded in actual understanding. This is true for string theory, for the theory of relativity, for quantum electrodynamics, and on and on.

Even the simple things that you take for granted, such as Inertia, is not understood. Nobody can explain why there is Inertia, or what mechanisms makes it a requirement.

What is important is that we can model things. If two such models fit observations, then there is no reason to dismiss one of them (such as string theory) out of hand. In the end, neither model is truth. Model's can't explain "why."

Re:Just because the math works doesn't mean it's t (1)

Myopic (18616) | more than 4 years ago | (#30717090)

Have we conclusively shown that relativity isn't quite exactly right? Or do you just mean that relativity hasn't been rectified with quantum mechanics?

Re:Just because the math works doesn't mean it's t (3, Insightful)

JaWiB (963739) | more than 4 years ago | (#30717122)

My understanding of an "entropic force" is that it can be described in terms of fundamental forces. The pressure in an ideal gas, for instance, can be derived by looking at the impulse created by a single molecule, and then extending that to a collection of N molecules. This guy seems to be saying that gravity is an entropic force and therefore NOT a fundamental force, but it seems to me that entropic forces are just an abstraction that allows us to ignore the underlying fundamental forces. Of course, I didn't read the whole article, but what I read was poorly written and that doesn't inspire a lot of confidence. Maybe I'll take another look if it gets published.

If the math works, then it approximates reality (4, Insightful)

AliasMarlowe (1042386) | more than 4 years ago | (#30716926)

If the math works, then "shut up and calculate" (ascribed to both Dirac and Feynman regarding quantum mechanics). Non-mathematical forms of understanding may follow, eventually, perhaps even including opinions on "truth". If the math does not work, the hypothesis will be quickly abandoned or revised.

Re:If the math works, then it approximates reality (2, Insightful)

qazsedcft (911254) | more than 4 years ago | (#30717180)

If the math works, then "shut up and calculate"

Sorry, but experiments trump math.

Re:Just because the math works doesn't mean it's t (4, Funny)

phantomfive (622387) | more than 4 years ago | (#30716942)

Indeed. The truth is, it is all a dream. My dream, in fact. It all emanates from me, I designed it all based on what you know as mathematical principles.

That assertion can also never be proved wrong, and it is mathematically sound.

Re:Just because the math works doesn't mean it's t (3, Insightful)

mad_minstrel (943049) | more than 4 years ago | (#30717016)

A theory is as good as its predictive power. If it predicts reality better than the previous one, who cares if it's "true", whatever that may mean.

Re:Just because the math works doesn't mean it's t (0)

Anonymous Coward | more than 4 years ago | (#30717194)

They say explaining ability of a theory is more important than predicting. Otherwise religion would be the best theory - everything will happen exactly as the god wants. As soon as you start asking what exactly he wants under given circumstances you start asking for explanations.

European Achievements in Science and Technology (-1, Offtopic)

Anonymous Coward | more than 4 years ago | (#30717052)

This amazing achievement in deriving the laws of classical physics from string theory is more evidence that Europeans are highly capable at scientific investigation and technological breakthroughs. Europeans dominate the winners of the Nobel prize in physics and chemistry. Germans (including Germans of Jewish ancestry) co-invented calculus (with an Brit), invented rocket technology, invented the jet aircraft, discovered the theory of relativity, etc.

The Japanese have also made astounding breakthroughs in technology. The Japanese invented the blue LED, invented most of the technology in the modern LCD display, developed numerous drugs (approved by the FDA for sale in the USA) treating chronic conditions, etc.

The notable exception to this smorgasbord of achievement is Africans and Americans of African ancestry. Africans do poorly in comprehending advanced mathematics, which is prerequisite to the work that leads to amazing achievements in science and technology.

Is the lack of African achievement in science and technology due to the fact that African IQ is about 15 points lower than Japanese IQ?

Re:European Achievements in Science and Technology (1)

postbigbang (761081) | more than 4 years ago | (#30717136)

Odd how you need to inject this racist conjecture into the thread. Feeling insecure? Ashamed that we all have genes that likely come from Africa, but you're ashamed of that small penis? Tsk tsk.

Re:European Achievements in Science and Technology (1)

Ethanol-fueled (1125189) | more than 4 years ago | (#30717306)

Agreed. Being a brainiac means nothing to a sexually-frustrated troll if he's unable to reproduce because he can't thrust deep enough.

Evolution has not yet caught up to higher-level intelligence. That's why, even though I am a mixed non-African, I manage to get laid -- I beat my chest and don't wear deodorant. My superior genes allow me to produce pheromones which make women flush and juice-up on the spot.

My legacy will live on, his will not. All because real men don't yap like chihuahuas, they just grunt here and there. Jealous, racist trolls just don't get it. There is a foolproof method to attracting women:

Speak slowly, in a deep voice, using as few words as possible.

Re:European Achievements in Science and Technology (1)

mister_playboy (1474163) | more than 4 years ago | (#30717314)

GP is just a copypasta troll with the beginning modified to fit this article.

Nothing interesting.

Re:European Achievements in Science and Technology (1)

Chrisje (471362) | more than 4 years ago | (#30717300)

And here I was thinking they closed Rasbiologiska Institutet around 1958... Oh. Wait. ;-)

Re:Just because the math works doesn't mean it's t (5, Interesting)

Zarf (5735) | more than 4 years ago | (#30717116)

I do like the idea of not needing an explanatory tool like "Dark Energy" ... that has always bothered me. Far more than "Dark Matter".

Stop posting articles from arXiv! (5, Insightful)

Interoperable (1651953) | more than 4 years ago | (#30716738)

I couldn't begin to assess how plausible this theory is; neither could most of the people on Slashdot. However, I do know the arXiv is not a peer-reviewed journal, which mean that we can't even rely on the peer-review system to gain information on how sound the underlying research is. Many excellent publications appear on arXiv before being published in excellent journals, but some fairly questionable research ends up there as well.

Rather than post completely uninformed comments on the subject, leave that to people in the field.

Re:Stop posting articles from arXiv! (5, Insightful)

drakaan (688386) | more than 4 years ago | (#30716804)

...but since the articles are publicly available, doesn't that mean that they can be more widely reviewed than traditional peer-reviewed papers?

It didn't sound like it was research, but rather mathematical theory based on looking at existing principles from a different direction. If there is enough underlying research in newtonian physics and general relativity, then wouldn't that same research also apply here?

Granted, I'm no mathematician, but it just seems a bit cliquish to say "don't pay attention to this" because of where the first publication is happening.

Re:Stop posting articles from arXiv! (0)

Anonymous Coward | more than 4 years ago | (#30716946)

the issue is that in a traditional peer-reviewed journal, a specialist in the field would look at the paper and make comments (even 10 pages of comments for a 15 page paper is possible); thus what the reader sees is actually the result of the author's work + author's responses to the many critiques of a specialist. you cannot expect that kind of dedication from arXiv (although it is read by specialists, not each paper receives the complete and undivided attention of a specialist who would like all the kinks to be worked out).

Re:Stop posting articles from arXiv! (0)

Anonymous Coward | more than 4 years ago | (#30717032)

I think the point is more that it is not news until a few other experts have reviewed it and written about it. It's fine if they write blog articles referencing arXiv, but assertions from a single source are considered more or less meaningless in science.

Re:Stop posting articles from arXiv! (0)

apoc.famine (621563) | more than 4 years ago | (#30717066)

It's not. Peer reviewed means that some of your peers reviewed it before it was published. That is, it's passed a bare minimum of screening to make sure it's at least semi-legitimate. This journal might take a well written article from me on the subject. I'm nowhere near a legitimate researcher in this area.
 
Peer Review is the ability to throw out the completely bogus articles before eyeballs land on them. Technically, could more eyes read this? Sure. Realistically will they? Probably not.
 
The people who would be interested will turn to the peer reviewed journals first, because they weed out a lot of the cruft. If an article makes it there, it's at least got a minimum QA attached to it.
 
It's on par with National Enquirer type newspapers vs normal newspapers. Sure, the NE types may get a story semi-correct before anyone else does. But the signal to noise is so low, it's not worth going to if you want real news.

Re:Stop posting articles from arXiv! (3, Insightful)

Myopic (18616) | more than 4 years ago | (#30717150)

Hmmm, I don't think "peer review" can be satisfied by "amateur review". Amateurs can sometimes make some interesting contributions, but not usually.

Re:Stop posting articles from arXiv! (-1, Offtopic)

Anonymous Coward | more than 4 years ago | (#30716858)

Mod parent up, absolutely correct.

A fundamental theory of this sort MUST be peer reviewed before it's even worth discussing - lay evaluation is the same as no evaluation in such a specialized topic.

Re:Stop posting articles from arXiv! (3, Insightful)

Anonymous Coward | more than 4 years ago | (#30716972)

If you've spent any time in academia, you'd know that peer review is a cruel joke.

It's more politics than science. It doesn't matter which country you're in, nor which college, university or lab you're affiliated with. It's all about making sure your paper says the right things to support the fucks (your "peers") who have managed to trick various corporate and government officials into giving them the large grants, especially when their research is total crap. Otherwise, you're ostracized.

After years of seeing the high-quality research of others basically shut out by the peer review process, I said "Fuck It" to academia and returned to industry. While there is lots of bullshit in industry, at least it is more of a true meritocracy than academia is.

Re:Stop posting articles from arXiv! (0)

Anonymous Coward | more than 4 years ago | (#30717308)

It's more politics than science. It doesn't matter which country you're in, nor which college, university or lab you're affiliated with. It's all about making sure your paper says the right things to support the fucks (your "peers") who have managed to trick various corporate and government officials into giving them the large grants, especially when their research is total crap.

Let me guess... you're a climate change denialist? Because this is exactly the same excuse they use to disparage the research they don't like.

Re:Stop posting articles from arXiv! (1)

abigor (540274) | more than 4 years ago | (#30717342)

Don't be bitter just because your more level-headed peers rejected your kooky theories.

Re:Stop posting articles from arXiv! (4, Insightful)

Kjella (173770) | more than 4 years ago | (#30717012)

Rather than post completely uninformed comments on the subject, leave that to people in the field.

Awwww, don't we get to do anything? We have such expertize in giving completely uninformed comments, who else has such refined skill at not RTFA, probably not even the summary and yet comment as if it was the topic of our PhD thesis in a field we know nothing about? That sort of thing only comes through years of practice and non-studying. No I think we'll leave them to do the informed comments, for the truly abhorrent comments devoid of all facts, correctness and sanity they should leave it to professionals.

Re:Stop posting articles from arXiv! (1)

Just Some Guy (3352) | more than 4 years ago | (#30717318)

Don't install things from SourceForge! Many excellent applications appear on SourceForge before being published to the Debian repositories, but some fairly questionable projects end up there as well.

Summary of comments (5, Funny)

Daniel Dvorkin (106857) | more than 4 years ago | (#30716750)

At least half the comments on this story will boil down to one or more of the following:

  • String theory is bunk. I know this because I heard someone call it "string theology" once and I thought that was clever.
  • This idea is bunk because I think it contradicts something I vaguely remember from the Physics 101 course I took as a requirement for my CS degree ten years ago.
  • Modern physics is bunk because nothing can move in spacetime [rebelscience.org]. Visit my blog to learn the truth!
  • Everyone knows the unifying force that holds the universe together is not gravity, but electricity. [the-electr...verse.info] We have books [holoscience.com], too!
  • Ivory-tower egghead academics want to keep all their science locked away behind paywalls! How are we supposed to evaluate this if we can't read the paper [arxiv.org]?!?
  • Modern science is bunk. These stupid liberal academics should just read the Bible.
  • YOU ARE EDUCATED STUPID! [timecube.com]

There. That should save everyone some time.

Re:Summary of comments (5, Insightful)

Tablizer (95088) | more than 4 years ago | (#30716788)

There. That should save everyone some time.

You assume the destination is more important than the journey, young Grasshopper.
     

Re:Summary of comments (1, Funny)

tepples (727027) | more than 4 years ago | (#30716812)

YOU ARE EDUCATED STUPID!

No, PlayStation fans are educated stupid. Wii come from the GameCube [fateback.com]. Animal Crossing is 24 simultaneous days in one.

Re:Summary of comments (3, Funny)

JamesP (688957) | more than 4 years ago | (#30717010)

In addition:

Someone is going to say "this violates conservation of energy/conservation of entropy/ blah" (even if it doesn't) and dismiss it. Also ignoring the fact that most new theories does violate something at the time of its discovery at some point

Another person is going to complain that this theory is crap but their favorite 'new thory' is the one, like, I dunno, "it's turtles all the way down" and this respects conservation of charge.

A "christian scientist" (LOL) is going to spin this as proof of Jesus or something.

Re:Summary of comments (1)

fm6 (162816) | more than 4 years ago | (#30717128)

That comes under the second bullet. Very important to use Occam's Razor, even when making fun of scientific ignoramuses. Especially then!

Re:Summary of comments (1)

VJ42 (860241) | more than 4 years ago | (#30717042)

You forgot "the universe is just a figment of my imagination"...
Which it is: given that the volume of the universe is infinite there must be an infinite number of worlds. But not all of them are populated; therefore only a finite number are. Any finite number divided by infinity is zero, therefore the average population of the Universe is zero, and so the total population must be zero. So anyone I meet must be a product of my deranged imagination.

Thank to Douglas Adams insight for the above.

Re:Summary of comments (0)

Anonymous Coward | more than 4 years ago | (#30717200)

Everyone knows the unifying force that holds the universe together is not gravity, but the Force

Fixed that for ya.

Re:Summary of comments (1)

astar (203020) | more than 4 years ago | (#30717220)

Ha Ha, try this

looks to me like holographic theory is pretty much a causality model. there are hundreds of those and they have a hard time integrating into TOES. I figure causality at this point is mainly a philosophical inquiry. for instance, it looks to me that the dominate physics causality model goes something like: "Now" is a thin shell advancing in time and it contains all the causes for the next "Now". If you are a reductionist, this probably sounds fine, but if you are not, it is pretty silly.

way cool (4, Interesting)

drDugan (219551) | more than 4 years ago | (#30716754)

FTA:"Starting from first principles, using only space independent concepts like
energy, entropy and temperature, it is shown that Newtons laws appear naturally and
practically unavoidably. Gravity is explained as an entropic force caused by a change
in the amount of information associated with the positions of bodies of matter. "

and "... the holographic hypothesis provides
a natural mechanism for gravity to emerge. It allows direct contact interactions
between degrees of freedom associated with one material body and another, since all
bodies inside a volume can be mapped on the same holographic screen."

If this is proven correct - that gravity and inertia are emergent from information entropy
and statistics, it would be very, very exciting if for no other reason than it would be yet
another support (probably the strongest yet) for the holographic universe description /
the 'reduced dimensionality' description. This could also resolve some of the impossibly
inconsistent problems in physics integrating gravity with microscopic forces and spooky
effects like action at a distance.

So far all we've had to support a holographic universe is black hole physics and string
theory conjectures.

It's mind warping to imagine that the whole of our existence necessarily depends
on encodings that are 2-dimensional in nature. If this is the case, what a world
it would be. Philosophers and religious folk will argue over what that might mean.

Re:way cool (0)

Anonymous Coward | more than 4 years ago | (#30716830)

Philosophers and religious folk will argue over what that might mean.

You mean like how our universe is nothing more than a hologram on someone elses Credit Card? Me thinks that goes against entropy...

I'm nuts nuts nuts!! No, wait. Your nuts! Oh well, were all nuts!

Re:way cool (2, Insightful)

richdun (672214) | more than 4 years ago | (#30717008)

Philosophers and religious folk will argue over what that might mean.

And while they are all deciding whether God/god/Xenu programmed the universe via voice command or a PADD, I'll be working to convince the Creator that I am self-aware, thus securing a free warp-capable shuttlecraft!

On a more serious note, as is always the case, this "new" line of thought seems to be a better description of something we observe, yet still constrained by our ability to model and describe things. As IANATP (I am not a theoretical physicist, more the applied kind), what does this potentially bring us, other than that better description? You know us engineers will be snickering until you show us something we can do or make shiny with this.

Re:way cool (0)

Anonymous Coward | more than 4 years ago | (#30717198)

sorry to disappoint, but the article starts out assuming the holographic prinipal. this leads to gravity and inertia emerging.

Re:way cool (0)

Anonymous Coward | more than 4 years ago | (#30717250)

This would put new meaning to the old saying, "Beauty is skin deep"! In fact, it's only a surface and has no depth.

Re:way cool (0)

Anonymous Coward | more than 4 years ago | (#30717312)

Well, one would also have to check that statistics involved wasn't a modified form of the original theory.

There are a lot of reworkings of basic theories that seem to work only because assume the basic theories in a way that is hidden.

Physics is hard...

Textbooks (4, Funny)

marciot (598356) | more than 4 years ago | (#30716760)

Damn it. I knew I should have sold back my college Physics textbooks when I had the chance...

Re:Textbooks (0)

Anonymous Coward | more than 4 years ago | (#30716878)

But now they're valuable collectors items!

I usually don't rant... (0, Troll)

Max Romantschuk (132276) | more than 4 years ago | (#30716766)

But 'here is two', um, seriously? English is my third language and I've yet to have problems with using is for singular and are for plural.

On a sidenote, it's interesting how tiny a force gravity ultimately is... The gravity effect of the whole...friggin...planet on your body can be countered with the atomic bonds in a comparatively meager rope. Fascinating really.

Descriptive analysis of "here is two" (2, Interesting)

tepples (727027) | more than 4 years ago | (#30716872)

But 'here is two', um, seriously? English is my third language and I've yet to have problems with using is for singular and are for plural.

The traditional analysis supporting "here are two" treats the sentence as having been inverted into verb-subject order, an unusual order for English. Dialects admitting "here is two", on the other hand, treat "here" as a singular subject referring to "the set presented here", in the same sense that "everyone" is singular, and "two" becomes the complement.

Testable, currently unseen predictions. (0, Troll)

Vellmont (569020) | more than 4 years ago | (#30716768)

I see a lot of explanations and mathematics, but I don't see anything in the way of testable predictions.

Scanning through the paper the word prediction occurs twice. Here's both of them:

Does this view of gravity lead to predictions? The statistical average should give
the usual laws, hence one has to study the fluctuations in the gravitational force. Their
size depends on the effective temperature, which may not be universal and depends on
the effective value of . An interesting thought is that fluctuations may turn out to
be more pronounced for weak gravitational fields between small bodies of matter. But
clearly, we need a better understanding of the theory to turn this in to a prediction.

Wake me when the guy comes up with at least one, and it's testable.

Re:Testable, currently unseen predictions. (2, Interesting)

Anonymous Coward | more than 4 years ago | (#30717096)

Clearly, the author is aware that a good theory is testable, as that paragraph admits that it's not at that stage right now. That doesn't mean it's meaningless, as most any idea starts out pretty vague.

Golden ratio (1, Redundant)

ylikone (589264) | more than 4 years ago | (#30716782)

I have a gut feeling that golden ratio will fit into all this somewhere.

Re:Golden ratio (4, Funny)

AliasMarlowe (1042386) | more than 4 years ago | (#30716964)

I have a gut feeling that golden ratio will fit into all this somewhere.

Provided the golden ratio is exactly 42.

Not at an all an expert but... (3, Interesting)

JoshuaZ (1134087) | more than 4 years ago | (#30716798)

From http://www.scientificblogging.com/hammock_physicist/holographic_hot_horizons [scientificblogging.com] the first of the two blog entries:

The value for G comes out correctly if you enter for Abit the value corresponding to a Planck area. However, the Planck area (G/c3) is defined in terms of Newton's gravitational constant G. Have we not introduced a circular reasoning here? I am actually not sure.

This does seem like an issue. However, it looks like you can do this with G as a variable. The upshot then is not that you get the right value for G at the end but that you get Newton's inverse square law (up to a scalar) which by itself would be really impressive even if one can't a priori get the value of G.

Obligatory disclaimer: I'm a math grad student not a physicist so I could be completely wrong here.

Re:Not at an all an expert but... (0)

Anonymous Coward | more than 4 years ago | (#30716966)

I'm not a mathematician or a physicist, but I always thought that physics was the mathematical explaination of the universe. Surely they can't be that different?

Re:Not at an all an expert but... (1)

JoshuaZ (1134087) | more than 4 years ago | (#30717000)

Yes, but math is much broader than physics. So much of the math that is needed for physicists isn't necessarily stuff most mathematicians will know well. So for example, my area is number theory/algebra. There isn't much overlap between that and the stuff being talked about here.

Re:Not at an all an expert but... (0)

Anonymous Coward | more than 4 years ago | (#30716990)

Generally relationships are more interesting than constants, so I think you're on the right track. Upper-division Physics rarely deals with anything numerically because we all recognize that the laws are more important than their specific applications.

Re:Not at an all an expert but... (1)

shadowofwind (1209890) | more than 4 years ago | (#30717140)

Taking a wild, poorly informed guess....Maybe if you were to assume a different value for G and follow through all the implications, you would wind up with essentially the same universe but with different units. So it would be arbitrary, and in theory you could get rid of the G entirely and just use the plank area everywhere.

Re:Not at an all an expert but... (4, Insightful)

TeknoHog (164938) | more than 4 years ago | (#30717176)

The upshot then is not that you get the right value for G at the end but that you get Newton's inverse square law (up to a scalar) which by itself would be really impressive even if one can't a priori get the value of G.

The inverse square relation comes easily from the fact of 3 spatial dimensions. The gravitational flux from a mass is spread out over a surface of a sphere, whose area is proportional to the square of the radius. It is a perfect analogy of electric fields.

It is possible to derive the same form in many different ways. It is a nice exercise to play with alternative theories of gravity, and see how they are similar or different. However, general relativity has a crucial deviation from the inverse square law, which results in the anomalous orbit of Mercury, for example. This does not mean GR is the final correct answer, of course.

Gravity, do we understand it yet? (1)

starbugs (1670420) | more than 4 years ago | (#30716824)

An atom around a massive object is a raindrop to space, but a perfect sphere to itself.
That's what I got to when I was 15.
I wish I knew the math to make more of it, but it seems that this article is heading in that direction.

Maybe someday.

Nice use of entropy BTW.

Re:Gravity, do we understand it yet? (1)

bloobloo (957543) | more than 4 years ago | (#30716950)

Raindrops are spheres too. They aren't actually "raindrop" shaped.

Re:Gravity, do we understand it yet? (1)

apoc.famine (621563) | more than 4 years ago | (#30717108)

Nope. I just finished an Atmospheric Physics class. They generally come down flattening into a plate, and deforming into a cup due to air resistance. Like this [livescience.com].

Re:Gravity, do we understand it yet? (1)

Lakitu (136170) | more than 4 years ago | (#30717278)

on that note, they are actually "raindrop" shaped if they land on, say, a window, and begin to slide down it slowly. Sometimes.

I hereby change the name from raindrops to raindroppeds.

Another idea (0)

Anonymous Coward | more than 4 years ago | (#30716826)

I've read ideas that gravity isn't an attraction between two masses, but a force radiating from all the suns/stars in space, so, the space inbetween two objects acts as a vacuum, and things fall toward each other because of an external push.

Awesome conversation starter! (4, Funny)

uradu (10768) | more than 4 years ago | (#30716838)

"He does not consider gravity as fundamental, but as an emergent phenomenon that arises from a deeper microscropic reality."

If that doesn't make you the life of the party in one fell swoop, NOTHING ever will.

Re:Awesome conversation starter! (0)

Anonymous Coward | more than 4 years ago | (#30716980)

Didn't Sheldon say that on an episode last season?

Re:Awesome conversation starter! (4, Funny)

grcumb (781340) | more than 4 years ago | (#30716988)

"He does not consider gravity as fundamental, but as an emergent phenomenon that arises from a deeper microscropic reality."

If that doesn't make you the life of the party in one fell swoop, NOTHING ever will.

No kidding. Chicks really dig my emergent phenomenon.

Re:Awesome conversation starter! (0)

Anonymous Coward | more than 4 years ago | (#30717146)

That is HEAVY, dig?

Getting paranoia to a new level (4, Funny)

gmuslera (3436) | more than 4 years ago | (#30716920)

Like when you study information theory because don't like physics, and the basis of physic world, like gravitation, turns to be information theory.

Good books to get familiar with all this stuff (0)

Anonymous Coward | more than 4 years ago | (#30716922)

Black holes entropy, urundu effect, holographic principle, dark matter, dark energy ....
Q few years back I could understand quite a good amount of hot new physic's concepts thanks to a book about string theory, from newton to einstein's relativity, calabi yau spaces, but I am completely lost in all those new theories. I got some math and physics background, but all this is just too far away from what I can understand.

Are there any good and simple books explaining most of all those astrophysics and quantum concepts ?
I mean something that presents clearly with a lot of analogies all those cutting edge works in physics so I don't miss the point when a good article like this one pops up ?

Stéphane

Comments from Lubos Motl (5, Informative)

Sara Chan (138144) | more than 4 years ago | (#30716960)

Lubos Motl [wikipedia.org] (string theorist, formerly at Harvard), has recently blogged about this: http://motls.blogspot.com/2010/01/gravity-as-holographic-entropic-force.html [blogspot.com]. His conclusion is "I remain undecided".

Re:Comments from Lubos Motl (0)

Anonymous Coward | more than 4 years ago | (#30717104)

Coming from Lubos, that's a hell of a compliment.

Re:Comments from Lubos Motl (3, Funny)

WilyCoder (736280) | more than 4 years ago | (#30717158)

He's 'undecided' because he hasn't been observed yet.

Thanks, I'll be here all week...

My crazy idea about gravity. (2, Interesting)

DigiShaman (671371) | more than 4 years ago | (#30716970)

I had this crazy idea about gravity. I've always though gravity was a "push" rather then a "pull". The way I see it, matter (quarks and other subatomic particles) doesn't occupy space/time, but rather displaces it. Meanwhile, space/time is trying displace the void that is matter. It's sort of like having a sheet of rubber and then creating a small pin prick in it. If I try hard enough, I could push my finger through it, but the rubber will try and displace that bigger hole I'm creating.

Which leads me to a system of proportional displacement. If the distance of space/time is greater on the outside vs between two objects, they get "pushed" toward each other. However, if the distance of space/time between two objects becomes great enough, they pulled apart. Kind of like how galaxies coalesce stars, but galaxies them selves are so far away from each other, the entire universe gets expanded as we speak.

Anyways, just may crazy messed up idea. No proof what-so-ever to back it up. Granted, I'm not ignorant to the real math a science we know today. After all, the written laws of physics is what gets us to the moon and mars. :)

Re:My crazy idea about gravity. (2, Funny)

Chees0rz (1194661) | more than 4 years ago | (#30717130)

Anyways, just may crazy messed up idea. No proof what-so-ever to back it up. Granted, I'm not ignorant to the real math a science we know today. After all, the written laws of physics is what gets us to the moon and mars. :)

Reminds me of a previous girlfriend who had a theory on tickling. She theorized there were little bubbles (coined 'tickle bubbles') under our skin that popped when we touched them, resulting in a tickling sensation.

Fuck hundreds of years of anatomy and biology.

Re:My crazy idea about gravity. (1)

Jorl17 (1716772) | more than 4 years ago | (#30717168)

Even if that is completely wrong, it is appealing -- I too, as an idiot, have thought about it.

Here is two (0, Troll)

SgtKeeling (717065) | more than 4 years ago | (#30716994)

Here is two blog entries discussing Verlinde's theory in somewhat more accessible terms.

Perhaps this should be, "Here are two..." ?

I'm sorry to interrupt here.... (0)

Anonymous Coward | more than 4 years ago | (#30716998)

but I was the anonymous coward that submitted this. I've been lurking here for a dozen years or more and....I couldn't be more happy.

I'm having a complete nerdgasm.

What is "information"? (In that context.) (1, Interesting)

Hurricane78 (562437) | more than 4 years ago | (#30717044)

In his theory, gravity exists because of a difference in concentration of information in the empty space between two masses and its surroundings.

One of those words is not like the others. The word “information” does not fit in there. I can’t put it into words, but I can show you what I mean:

Bad:

In his theory, gravity exists because of a difference in concentration of thetans in the empty space between two masses and its surroundings.
In his theory, gravity exists because of a difference in concentration of hope in the empty space between two masses and its surroundings.
In his theory, gravity exists because of a difference in concentration of imagination in the empty space between two masses and its surroundings.

Good:

In his theory, gravity exists because of a difference in concentration of gluons in the empty space between two masses and its surroundings.
In his theory, gravity exists because of a difference in concentration of $particleToBeFoundByLHC in the empty space between two masses and its surroundings.
In his theory, gravity exists because of a difference in concentration of neutrinos in the empty space between two masses and its surroundings.

(Not saying that’s right. Just saying this would be an argument that one could build something around. As opposed to the bad examples.)

Re:What is "information"? (In that context.) (5, Interesting)

FooAtWFU (699187) | more than 4 years ago | (#30717330)

Dude! Information is a perfectly useful theoretical property in theoretical physics, directly related to entropy. Observe, for instance, all the cool stuff Stephen Hawking has done is related to black hole entropy in some manner or another. (Black holes have to have entropy, otherwise you could violate the second law of thermodynamics by tossing stuff into them.... but if they have entropy, they should emit radiation.... hey, guys, look, a way for black holes to emit radiation and evaporate!!)

As Jacob Bekenstein put it, the trend in physics is to "regard the physical world as made of information, with energy and matter as incidentals." (Bekenstein came up with the Bekenstein bound, a fundamental limit on the amount of information/entropy which can be contained within a space. If you could come up with a system with more entropy in a given space, then you might be able to violate the Second Law of Thermodynamics by tossing it into a black hole.)

In his theory, gravity exists because of a difference in concentration of information in the empty space between two masses and its surroundings.
In his theory, gravity exists because of a difference in concentration of entropy in the empty space between two masses and its surroundings.
Same darned thing.

Put theory to test in real world (4, Funny)

noidentity (188756) | more than 4 years ago | (#30717068)

In his theory, gravity exists because of a difference in concentration of information in the empty space between two masses and its surroundings.

I think we could put this to the test in the real world. We could gather various entities, some of which are known to have a very low concentration of information, like marketing people and bureaucrats, and see whether they cause a local reduction in gravity.

Obligatory HGGTG (1)

mfnickster (182520) | more than 4 years ago | (#30717080)

"Hotblack Desiato's chief research accountant has recently been appointed Professor of Neomathematics at the University of Maximegalon, in recognition of both his General and his Special Theories of Disaster Area Tax Returns, in which he proves that the whole fabric of the space-time continuum is not merely curved, it is in fact totally bent."

Reminds me some of the way the 'Casimir' force (1)

shadowofwind (1209890) | more than 4 years ago | (#30717222)

emerges naturally from a few very simple assumptions about light and vacuum.

Though I hate the tag Casimir force, since its just a bulk Van der Waals or London's force, not some spooky new energy source.

Even further off topic....People speak of vacuum energy, quantum foam, virtual photons and whatnot, but nobody calls it the ether anymore. Of course earlier pre-relativistic concepts of the ether were flawed, and overturned by observation and better theories. But it still seems to me that what is now called 'vacuum' could be called ether, and that the word ether would be more appropriate in some regards. Maybe someone better qualified would like to comment on this.

Crap.. (1)

JustShootMe (122551) | more than 4 years ago | (#30717226)

Now all the new-agers will jump on this and we'll never hear the end of it.

"But space is a hologram! Scientists said so!"

It very well may be, but new agers tend to jump on the most specious of claims and parrot them as fact...

(Thing is, I actually agree with the new-agers on some things, but I'm not going to try to prove it scientifically, I wonder if it's even possible!)

Piffel, dribbeling idiotic crapola! (-1, Troll)

Paracelcus (151056) | more than 4 years ago | (#30717302)

"He does not consider gravity as fundamental, but as an emergent phenomenon that arises from a deeper microscropic reality."

Wadda buncha dumbass shit, this dipfuck really needs to shuddup and sit down!

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