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New Theory of Gravity Decouples Space & Time
eldavojohn writes "Petr Horava, a physicist at the University of California in Berkeley, has a new theory about gravity and spacetime. At high energies, it actually snips any ties between space and time, yet at low energies devolves to equivalence with the theory of General Relativity, which binds them together. The theory is gaining popularity with physicists because it fits some observations better than Einstein's or Newton's solutions. It better predicts the movement of the planets (in an idealized case) and has a potential to create the illusion of dark matter. Another physicist calculated that under Horava Gravity, our universe would experience not a Big Bang but a Big Bounce — and the new theory reproduces the ripples from such an event in a way that matches measurements of the cosmic microwave background."
You mean the space-time continuum doesn't exist? Star Trek is wrong?
Every few years, there is yet another theory that claims to be better suited for our models than Einstein's. Then they realize they overlooked something and find Einstein's idea fit better than ever.
"When life gives you lemons, don't make lemonade. Make life take the lemons back!" -- Cave Johnson
this article was covered by SciAm too. I think that this is a first step in the right direction as far as innovation in the theory. i read that some of the theory used math from helium super-fluids.
It needs to be rigorously tested, and with the LHC seeming to be working, we will be able to start.
and he should be punished.
Special relativity, of course, forbids sending information faster than light. A theory supplanting the space-time unification of General Relativity would also supplant special relativity, and hence might not have that limitation. Here's an inteersting tidbit from the article: "Gia Dvali, a quantum gravity expert at CERN, remains cautious. A few years ago he tried a similar trick, breaking apart space and time in an attempt to explain dark energy. But he abandoned his model because it allowed information to be communicated faster than the speed of light."
I'd call that a feature, not a bug!
http://www.geoffreylandis.com
Horavec's formulation works for certain (perfectly spherical) cases of the stress-energy tensor, not in other cases. In fact it produces some wildly inaccurate results in more realistic cases. Nor is he the first to try this kind of thing. Still, it sounds interesting and further refinements could produce a fully consistent theory which can match observation. When and if that happens then it will be a really major advance. It certainly seems like we're edging closer to something.
"Malo periculosam, libertatem quam quietam servitutem." -- Jefferson
Does this theory suck or is there some pull to it? It just seems so weighty to me.
Help save the critically endangered Blue Iguana
They are all scrambling for new theories on how to get research money now that string theory is loosing momentum. What Brian Greene has been up to lately?
... in a presentation from the 30th Workshop on Gravitation and Numerical Relativity at Jungwon University. It's a PDF version of a PowerPoint deck, so it's not exactly easy to read.
So does this compete with string theory or have a chance modifying it to an eventual theory of everything?
http://arxiv.org/abs/0901.3775 PS Slashdot has the slowest comment preview of any website I know.
it fits some observations better than Einstein's or Newton's solutions. It better predicts the movement of the planets (in an idealized case)
Oh. In an idealized case. Imaginary physics. Of course, in the actual case, it does not (it requires patching to allow for non-spherical planets).
At any rate, there are at present no known relativistic measurements that are not consistent with General Relativity, so I am not clear where the "better than" comes from.
And, from the standpoint of a General Relativist, the stubborn desire of the particle physicists to have a flat spacetime at high enough energies, no matter what, seems, well, quaint.
I don't know, let's hope that someone has the time to shed some light on this matter...
Firehed - Unfortunately, thanks to medical breakthroughs, common sense is not as common as it once was.
Behold, science.
The catch is, eventually one will more closely match the observed universe than General Reletivity , and explain things that are out of the scope of Einstein's theories or more accurately explain in-scope things.
Or do you believe we are at the pinnacle of the field, and can achieve no more?
There fixed that for you.
Quantum Gravity at a Lifshitz Point
Just because communication at FTL speeds doesn't fit the model as we can understand it doesnt mean that it doesn't or cannot occur. We should stop dismissing ideas of science simply because they don't fit with what we believe should happen. It is entirely plausible that there are things that happen in the universe that we cannot yet mathematically explain - but because we cannot fully mathematically explain them they should not be dismissed.
"i lost my dignity on a slippery wiener"
1. Gravity is still spooky action at a distance with no causal mechanism defined.
2. I don't think time, as in "time lines" or some kind of unidirectional movement through a medium exists. Now exists, hypostatized out of a past (which stops existing when it stops being now) and which in turn hypostatizes the future (which does not exist.)
3. Electromagnetism is the dominant force in the heavens as it is on Earth.
4. Stars are organisms and they reproduce through fission.
5. Galaxies are powered by vast electric circuits; beads on a string.
When a true genius appears, you can know him by this sign: that all the dunces are in a confederacy against him.
Sounds to me like this is just an hypothesis as there doesn't appear to much experimental evidence supporting it. This is an extraordinary claim and so need extraordinary proof.
And, the interchanging of hypothesis and theory by scientific magazines is a bad thing. If scientists, science fans, and science writers do not use the words correctly how are we to defend the difference when creationists come around misusing the words?
There is no "-1 offended" or "-1 you don't agree with me" mod options for a reason.
Yet, who is Petr Hoava? He maintains a Web page that offers the following biography.
"Petr Horava received his Ph.D. in 1991 at the Institute of Physics of the Czech Academy of Sciences in Prague. He was awarded the Robert McCormick Research Fellowship at the Enrico Fermi Institute at the University of Chicago, worked as a Research Associate at Princeton University, and won a Sherman Fairchild Senior Research Fellowship at Caltech, before joining the New High Energy Theory Center at Rutgers University in 2000 as an Associate Professor. In 1997, he was awarded the Junior Prize of the Czech Learned Society, and in 1999 he appeared on the list of top three scientists of the Czech Republic of the 90's. He joined the Physics Department at UC Berkeley in 2001."
The liberation of Eastern Europe in 1989 has unleashed an intellectual force that will advance human knowledge by leaps and bounds. 2009 is the 20th anniversary of that liberation.
Buddha bless the Eastern Europeans.
Sounds like this guy's saying "Let us assume the speed of light is not necessarily the fastest anything can travel. If we assume this, then..."
The reason for Einstein's initial assumption is that we have never to date observed anything which has moved faster than light. Then again, would we know such a thing if we observed it, and have we actively looked for such a thing? If so, how have we looked?
If it means that we can travel through space at FTL speeds, I'll buy it. Heck. I'll take two, but if I do, you have to let me be Worf.
It took me long enough to get my head around the intertwining of space and time in relativity. Now you're telling me that they might also be decoupled in special circumstances.
Ow! My brain hurts.
Einstein's theory led to the atomic bomb. The most tangible output from any subsequent theory is "Stargate:Atlantis" at best. I doubt we'll have a satisfactory understanding of space, time, or gravity in my lifetime, and I'm not closing in on social security anytime soon.
From the linked article, it seems the theory both predicts the heat death of the universe (continued accelerated expansion) and that our universe started from a "Big Crunch" scenario (gravity had pulled everything back again). This seems quite strange (although of course nature can be quite strange at times). Anyone know this theory any better and can provide some enlightenment?
So that's why Gravity's facebook relationship status switched to available. I bet the SNF totally makes a play.
So let's say our universe is expanding (doesn't matter if it's this theory or mainstream Big Bang). We already know there's volume beyond the visible edges of our universe. What if there's another universe expanding towards us, accelerating into heat death, and then its edges hit our own? Wouldn't that Big Smack be a Big Crunch? And thus another universe is born?
Here's to hot beer, cold women, and Glaswegian kisses for all.
In one day, and they are both in California. I am stuck here in New Jersey. New Jersey is Hell. When people die, they don't go under the ground, they just pop up somewhere in Newark. See, us citizens of New Jersey are immortal because if we are killed, we just pop up back again in New Jersey. Its just really hard to navigate around Newark, so that's why you don't see us again..................
i am so very tired....
Might this new theory explain how the speed of spooky action at a distance is possible (below)?
It must have been something you assimilated. . . .
"Others have made even bolder claims for Hoava gravity, especially when it comes to explaining cosmic conundrums such as the singularity of the big bang, where the laws of physics break down".
I wish people would quit saying this. The laws of physics don't break down, just our understanding of them. Physics knows perfectly well what its up to.
It's Horava (r with "v" above), not Horava! Fix the spelling and your unicode "support" (rendering me unable to even report the error properly)! It will soon be 2010, wake up!
I refuse to read TFA. After all, the first thing I learned about gravity was that if I don't know anything about it, it can't effect me! Thank you, professor Coyote.
My hypothesis about gravity:
Everything is growing. We can't see anything growing, because our rulers and tapemesures and everything is growing. That's gravity: Just the growing earth pushing against your growing feet. Gravity at a distance is just objects growing towards each others (the void doesn't grow). Come to think of it. It's probably a bad hypothesis. It couldn't explain a slingshot effect, could it? Nevermind.
Some of my favourite people are from th US; Vonnegut, Chomsky, Bill Hicks.
But does it also predict that time is an illusion, lunch-time doubly so? If not then there is still room for a more refined theory.
Gia Dvali, a quantum gravity expert at CERN, remains cautious. A few years ago he tried a similar trick, breaking apart space and time in an attempt to explain dark energy. But he abandoned his model because it allowed information to be communicated faster than the speed of light.
How do we know for sure that it's impossible? How can we test against it to conclude it's definitely an impossibility? We surely haven't found any way to achieve that, but given that all theories are still in the balance, how do we know for sure there's no way we possibly could?
This being said, nice to see a theory that's more intuitive than usual, that attempts to explain dark matter and dark energy by revising how things work rather than claiming there's a bunch of invisible mysterious things at work, and that does so without adding a bucketload of new unperceptible dimensions and weird vibrating strings that no one can prove. Ah, and give an alternative to the ailing theory of Big Bang.
And nice to see that it took SciAm's commenters less time than Slashdot users to make the discussion drift into some crap about religion. Maybe we're not that bad after all.
You just got troll'd!
This can't possibly be correct. Don't you remember? The science is already settled! Whew - boy, glad that's over (hand wiping)!
Einstein was an Eastern European. As were most of the other scientists coming up with what Einstein brought together in Relativity. Soviet physicists were mostly Eastern European, and came up with quite a lot of advances in physics.
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make install -not war
Not only should it be cold obvious that time is merely an illusion for a conscious being with the trait of memory and only applicable as a mathematical derivative but that we only have 3 dimensions in the same sense which could be seen as a single dimension in which we exist. I'm not a published theoretical physicist nor am I claiming that his theories are accurate but it's a step in the right direction, less abstract, more concrete. On another note I don't know what I'm writing, had a couple too many shots of... something.
http://mndl.hu/works/fractalcow
Schroedinger's Brexit: The UK is both in and out of the EU at the same time!
As far as I know, there is currently no basis for assuming that it is relativity that is wrong (or that is the only one wrong).
My personal theory is in line with Have Brain Will Rent (just below), that relativity and quantum mean completely different things by "time". But that's just a guess.
I'm a promoter of the Big Ooze theory, myself. Sort of like leakage from an omnipotent being's a$$
In physics the term theory is generally used for a mathematical framework--derived from a small set of basic postulates (usually symmetries--like equality of locations in space or in time, or identity of electrons, etc.)--which is capable of producing experimental predictions for a given category of physical systems. A good example is classical electromagnetism, which encompasses results derived from gauge symmetry (sometimes called gauge invariance) in a form of a few equations called Maxwell's equations. Note that the specific theoretical aspects of classical electromagnetic theory, which have been consistently and successfully replicated for well over a century, are termed "laws of electromagnetism", reflecting that they are today taken for granted. Within electromagnetic theory generally, there are numerous hypotheses about how electromagnetism applies to specific situations. Many of these hypotheses are already considered to be adequately tested, with new ones always in the making and perhaps untested.
“A universe filled with matter will contract down to a small—but finite—size and then bounce out again, giving us the expanding cosmos we see today,” he says. Brandenberger’s calculations show that ripples produced by the bounce match those already detected by satellites measuring the cosmic microwave background, and he is now looking for signatures that could distinguish the bounce from the big bang scenario.
Maybe I'm just missing something obvious, but my understanding is that current measurements/observations point to an ever expanding universe, that is doomed to end via heat death. This statement would seem to wildly contradict this.
The Big Bounce has been previously documented here: http://www.bigtitpatrol.com/
The linking of space and time was complete silly nonsense. In my opinion the simple paradoxes presented by his theory alone prove it wrong. Altering time makes great fiction, but terrible science. At least this is a step in the right direction.
(If at first you don't succeed, do it different next time!)
Just because determining whether a program will ever stop doesn't fit the model as we can understand it doesn't mean that it doesn't or cannot occur. We should stop dismissing ideas of computer science simply because they don't fit with what we believe should happen. It is entirely plausible that you can solve the halting problem but cannot mathematically explain how - but because we cannot fully explain how it should not be dismissed.
n/t
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
If it matches previously observed phenomena, which the summary says it does, then it is supported by those observations and can be considered a theory. To replace existing theory it would also need to produce new hypotheses and answer them better than existing theory.
Build a man a fire, he's warm for one night. Set him on fire, and he's warm for the rest of his life.
Faith is belief in something for which there is no proof or even strong evidence. Faith is generally applied only to spirituality, and it should be so according to the definition. For example, I don't need faith to believe that the Yankees won the World Series this year - there IS evidence for that. I do believe that they won BECAUSE of the evidence.
You do NOT need faith to believe that the universe is anything. Ordered, structured, causal, etc. A good scientist believes these things because there is evidence of order, causality, etc.
To not have faith is to not believe in something for which there is no evidence.
One does not need faith to look forward to the future doing something chaotic because of the belief (through prior observation) that those kind of things (earth turning into a carnivore butterfly) just does not happen.
Science and faith are NOT intrinsically linked. Science and belief ARE. Science and faith are two completely separate things.
No one is questioning the intelligence of the soviets or eastern europeans. The problem was that when they did science, they did it in an inverted way. For example, in Soviet Russia, the particles accelerated you.
Every belief system will have some unfounded axioms. There are no exceptions.
However, religious belief systems include a lot more such axioms than scientific belief systems. Having faith that the universe was created is one thing. Having faith that said creator inspired the writing of a specific book, handed down specific moral teachings, directly caused specific historical events, and wants you to take specific actions, is quite another.
Maybe this new theory will Embrace, Extend and Extinguish General Relativity.
New theory my ass. Separation of time and space was the norm before Einstein came and confused the whole thing. Maybe it's a relatively new theory?
It sounds like you're claiming that Kuhn didn't believe that a new paradigm offers more accurate results than the last, which he almost certainly didn't.
If he said something controversial along those lines, he might have meant that our perceptions don't actually reflect reality as it really is, so as we are trying to mold science into our reality, we aren't necessarily molding it into a model of actual reality.
Sokal may have been correct that Kuhn didn't make the distinction, but that doesn't mean Kuhn didn't have a valid concern that our scientific reality is socially-constructed. Again, I don't know if Kuhn actually believed this, I'm just guessing based on my reading of Kuhn that he wouldn't have said something as controversial as what you've implied.
Kuhn did not deny that sciences progresses, however he did subtlety deny that we are progressing toward anything - such as closer approximations to the truth or objective reality.
Read Weinberg criticisms here
http://www.cs.utexas.edu/users/vl/notes/weinberg.html
I'm not a scientics but if I recall correctly gravity propogates at the speed of light? Which isn't spooky. Einsteins "Spooky Action at a distance" quote is referring to something different in quantum mechanics.
http://www4.ncsu.edu/unity/lockers/users/f/felder/public/kenny/papers/bell.html
Remember the saying that science proceeds by successive approximation to the truth.
I notice these guys have "live support" from their page. It's not that much effort for us to waste a lot of their time, and make it impossible for them to tell the difference between us and the real queries.
Einstein was an Eastern European. As were most of the other scientists coming up with what Einstein brought together in Relativity. Soviet physicists were mostly Eastern European, and came up with quite a lot of advances in physics.
No he wasn't - Western Germany/Italy/Switzerland are hardly 'Eastern Europe'. Nor were the others: Poincaré (France), Planck (Germany), Bohr (Denmark), Lorenz (Netherlands), Schwarzschild (Germany), Lemaitre (Belgium)... (Not that Eastern Europeans weren't well represented in sciences, they just have very little to do with the early history of relativity.)
From the description in TFA I think a very useful illustration of the concepts of the 3 to 1 space enfolding and the decoupling of space and time as equivalent in relativistic terms can be seen in "A Brief History Of Time". Hawking describes his alternative to a big bang singularity, showing that near the event, time and space would fold into each other, rounding off the point of the light cone. The illustrations use a single space dimension line to represent all 3. Here the picture can simply be taken as more accurate than that schematic had intended to portray. In ABHoT time and space lose their right angle relationship, a function of relativity. Here, they lose their relativistic relationship at high energies (a singularity should probably count), become decoupled in their original sense, and take on a different relationship. Taken together, if the 3 space dimensions enfold into 1, and the 3-in-1 folds over (decouples from the right angle) and approaches the time line, you have 3 space lines approaching parallel with the one time line. From TFA: "within this regime, space stretches only a third as quickly as time." Restated, three space dimensions together would stretch at the same rate (under these conditions) as the one time dimension.
Of course that may just be my tendency towards visual cognition trying to fit things together. Therefore, the question: can anybody suggest a 'for dummies' version? Something that describes the math rather than requiring one to follow the mathematical development? Pictures would be helpful.
"I may be synthetic, but I'm not stupid." -- Bishop 341-B
Einstein certainly was not an eastern European. He was born in Württemberg in southern Germany, and that is central Europe geographically by any measure, and part of western Europe in geopolitical sense.
Eastern Europe usually means countries of the former Soviet block, like Poland, Check Republic, Slovakia, Hungary, Bulgaria, former Yugoslavia (even though technically not part of the block), Romania, Baltic states etc.
As the island of our knowledge grows, so does the shore of our ignorance.
The universe is a giant plutonium atom. Archimedes told me so.
Shoes for Industry. Shoes for the Dead.
Einstein was an Eastern European.
Errm, what?
Lars T.
To the guy who modded me down from perfect to terrible Karma - Apple haters still suck
Those vowels got a rough deal.
"Now, why God suddenly gave up on defeating the Roman occupiers, I leave to your imagination."
Yes, damn those Roman occupiers that still oppress the Israelites to this day... oh wait...
Besides, the points of the message Jesus brought, which wasn't about defeating whatever flavour of regime that was oppressing the Hebrews at that time, can be summarized with tolerance, love, and forgiveness. Those are messages apparently lost in your blind cynicism.
"Of course, this is the same dude who considers shrimp an abomination, and thinks you can cure leprosy by killing a bird on an altar."
You're confusing old testament survivalism law (Leviticus) with Jesus's teachings (New Testament), which mention little about law and nothing about shrimp, sacrifices, or survivalism.
Don't make claims about people in the Bible without reading the Bible. It'll just make you look like a misguided fool to those who have.
TFA says that the dark matter is coming from interactions between gravitons and normal matter. However this http://www.nasa.gov/home/hqnews/2006/aug/HQ_06297_CHANDRA_Dark_Matter.html
clearly shows that dark matter is separate from normal matter.
I've never heard Germany referred to as Eastern Europe before...and the previous post clearly was referring to former Soviet-influenced states, which arguably could include East Germany, which didn't exist when Einstein was born or lived there (besides he was born in what would become West Germany).
So I really don't see how you could claim Einstein to be Eastern European.
Is there any freakin link to the paper?
Only his tendency toward a dazed stupor prevented him from screaming aloud.
Time doesnt "exist", its an abstract concept that humans use to represent how stuff changes.
Nobody can change time (or anything else that doesnt exist), but we can change the stuff that time measures.
Make an analogy to a car, velocity is similarly an abstract concept, its a measure of how far stuff moves within a certain time, for simplicity we talk about changing the velocity of our car, but really we are changing the cars location within a certain time.
By what reason do physicists claim time exists ?
I just finished reading this article: http://arxiv.org/abs/0905.2579v2 "Strong coupling in Horava gravity" And in one short sentence, there is a lot of problems with theory, and as a theorist, I don't think it's a viable one!
Observation of wavefunction collapse can lead to the impression that measurements performed on one system instantaneously influence other systems entangled with the measured system, even when far apart. Yet another interpretation of this phenomenon is that quantum entanglement does not necessarily enable the transmission of classical information faster than the speed of light because a classical information channel is required to complete the process
This is just above in the same link what you cited.
OK if it bounced, where did it bounce from?
Interesting article to say the least! I've never 'liked' dark matter or dark energy but there wasn't much else to hang your hat on when it came to some observations in the real world and the mathematical models to explain them. I hope this proves out in the end because I think it will be a whole lot easier to prove then trying to prove dark matter. Sorry dark matter researchers, but don't loose hope, after all it's still a theory and I'm sure the underground research will yield some interesting results.
Think of how stupid the average person is, and realize half of them are stupider than that.
I've heard this argument between the two testaments before, and it's bullshit. For instance, when engaging in animal sacrifices, the good lord instructs that you must make heave offerings forever (LV 10:15). I know of no Jews or Christians currently engaged in this practice. It also gives instructions for the worth of slaves, and demands that anyone who says Jehovah be stoned to death.
At what precise moment did these concepts become immoral, or did they at all? Jesus said, "until heaven and earth disappear, not the smallest letter, not the least stroke of a pen, will by any means disappear from the Law until everything is accomplished." So, why aren't we stoning blasphemers on every corner? Because we're more moral and more civilized than the bronze age goat herders of the ancient Levant.
There's that word again... "heavy". Why are things so heavy in the future? Is there a problem with the earth's gravitational pull?
I thought we were calling it the Horrendous Space Kablooie now?
From the particles frame of reference, it did.
So sad, but true.. .it's like Purgatory 2.0 :)
This is the first time I've laughed out loud at that joke.
"Horava’s graviton fluctuates as it interacts with normal matter, making gravity pull a bit more strongly than expected in general relativity."
Now that's what sounds promising. Dark matter always seemed like an ad hoc explanaition. How would you (try to) falsify that dark matter exist under the current theories that are predicting it?
testing 1 2 3
I read this article several times looking for at least one sentence that made sense and didn't find one.
General rule of physics, if you can't explain your theory, then it's wrong. Because there isn't one.
Big Bounce? WHAT THE FUCK. I could get a better creation theory by going to church.
first herd of the big band theory.
Is the first herd the trumpets? Would the second herd be the trombones? Sousa, is that you?
Lose essential liberties to get temporary safety = get only hassles and security theater.