New Theory of Gravity Decouples Space & Time 575
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."
Re:Not again (Score:5, Insightful)
Behold, science.
The catch is, eventually one will be right, 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?
It is also not a complete and consistent theory (Score:5, Insightful)
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.
Re:And FTL, too (Score:5, Insightful)
Whether it's a feature or a bug depends on whether it reflects reality.
It's strange to me that Dvali would abandon his model for allowing FTL propagation of information unless he experimentally checked the conditions in question to see if information really could propagate FTL in those cases. I have to assume he did not - lacking clarification on the matter I'm left to assume that the conditions were not something simple he could test no a whim.
Without the experimental results, it's meaningless to call such an artifact in the model "good" or "bad".
Re:Not again (Score:5, Insightful)
Yeah: http://yfrog.com/b9sciencevsfaithbigp [yfrog.com]
This sentiment is rather old, I'm sure before and when Einstein came about, people were saying the same thing about Newtonian physics. Skepticism about new theories are fine, but I'm sure the science will come to a point where we do discover something better than Einstein's formulas in some areas.
BTW, my physics is really rusty, doesn't one of Einstein's equations devolve into a newtonian equation at slow speed? Which just shows that things are truly built on top of one another.
Just Because... (Score:2, Insightful)
Re:Not again (Score:5, Insightful)
This is healthy. Science can only progress if we accept that thinking outside the box is admissable. If the idea works ehen it will be testable.
Ow! (Score:4, Insightful)
Ow! My brain hurts.
Re:Not again (Score:5, Insightful)
BTW, my physics is really rusty, doesn't one of Einstein's equations devolve into a newtonian equation at slow speed?
Wouldn't be correct if it didn't. Newton wasn't *wrong*, he just didn't specify the parts he couldn't see. Same with Einstein, same with this.
Re:Theory or Hypothesis? (Score:3, Insightful)
The theory of special relativity and of general relativity existed before there was any experimental proof.
I think when you are dealing with theoretical physics, if you can get a mathematical model to "work," then it is a theory. Like String Theory.
Re:Not again (Score:3, Insightful)
The catch is, eventually one will be right,
This is, perhaps, a minor quibble with wording. (Depending on what you meant.) But no, neither is likely to be right. One will be shown to be wrong before the other, however. Or, if you prefer, one will probably be more accurate.
Re:Not again (Score:2, Insightful)
This process is science at its best. Problem doesn't fit solution, so find new problem without bending and complicating either... It's happened before, and will happen again (until we know everything, in which case what's the point?)...
Re:Not again (Score:3, Insightful)
The problem with faith is when it becomes blind faith. Some people think what they've found is the be all end all and refuse to search anymore. It's not specific to the religious either. If you notice, there are "science" folk in here mocking this new theory because it contradicts the old one. Think about this next time you want to take a swing at someone who holds faith.
Re:Not again (Score:1, Insightful)
Re:Not again (Score:2, Insightful)
Actually, it's quite simple: The old theory correctly describes the old experiments. If the new theory is to be right, it must also correctly describe the old experiments, therefore under those conditions it must not differ from the old theory any more than the measurement errors.
Re:Much more mathematical detail... (Score:5, Insightful)
Re:Not again (Score:2, Insightful)
Re:Not again (Score:3, Insightful)
The difference between science and faith is whether the statement could possibly be disproved. If it can, it's science. If it can't, it's faith.
That's a tiny difference in length of description. But the difference between what can be disproved and what can't is a very big difference. While faith statements could be the most important if true, like a diety, afterlife, consequences of pure morals, without proof or disproof those statements are the most unreliable to be true.
Re:Just wondering out loud... (Score:1, Insightful)
I'm sorry, but this is factually inaccurate and gets modded up and that may piss of your random anonymous coward. Einstein never assumed "nothing can go faster than light". His assumptions were
(1) The laws of physics are the same for all observers moving at a constant speed in a straight light ('inertial observers').
(2) All observers measure the same speed of light.
You can if you want regard (2) as redundant since electromagnetism implies that the speed of light is independent of the observer but both
postulates are traditionally made for emphasis.
From that you can _derive_ that no massive particle will ever reach the speed of light and that massless particles (e.g. photons) must necessarily
move at that speed. The reason for Einstein's assumption was certainly not that nothing had been observed going faster than the speed of light.
He made the assumption because it is an extremely reasonable assumption to make (and indeed in this respect) and because if you abandon this
assumption you must abandon electromagnetism entirely. Electromagnetism at that point had been extensively verified experimentally.
Re:And FTL, too (Score:3, Insightful)
I think you have the tail wagging the dog there. Whether there is an efficient way to solve NP problems is an open question. Why would the fact that a physical phenomenon would lead to such a solution method make that phenomenon invalid?
In any case, experimental evidence doesn't show us that things are impossible; it shows agreement (or disagreement) with theories (models of the world), and those models may imply that something is impossible. The GR model says that FTL information propagation is impossible, and as we've never observed information propagating FTL we're ok with that, at least for now.
Re:And FTL, too (Score:3, Insightful)
Whether it's a feature or a bug depends on whether it reflects reality.
Clearly with FTL travel it cannot reflect reality, so it must be false.
Re:Not again (Score:4, Insightful)
Re:Not again (Score:3, Insightful)
Yes, with science there is a certain amount of established expectation based on observation. Do something, see what happens, expect it to behave the same way in an identical situation. If it doesn't behave the same way, figure out what's not identical about the situation. I don't think it's right to call this faith, or if you want to, it's important to suggest the only REAL faith is "expecting what you've already observed will continue to be true". There are still tests that can be tried and repeated, there are generally equations that can be applied to the results.
Religious faith, on the other hand, deals with having insight into the unknowable. As such there aren't any tests, any results, no expectation of repetition, no equations.
Religious faith may be rewarding for many people in many ways (hey, it seems pretty popular), but it doesn't pay to confuse it with the scientific process. Those two different uses of the word faith are so divergent, it's probably better just not to use them.
Re:Not again (Score:4, Insightful)
All faith is blind.
'Faith - Belief that does not rest on logical proof or material evidence.'
And just because some may swing one way or the other within either group doesn't show anything. At its root religions are unchanging, or at least the Judeo-Christian ones are meant to be. At sciences base we strive for changing, evolving viewpoints.
No, that is a stupid terrible meme. First off the axioms of science are things like 'a + b = b + a', compared to there is a God and history as described in a multiple 1000page book. Not the % of which is axiom, In fact the whole christian belief system IS a huge axiom, individuals get to add theories on top that's all.
As well, science is made of 'best guesses so far'. That 'so far' stipulation means you don't actually have faith in anything merely knowledge of a best guess. Scientists/Philosophers haven't proven with any great certainty that we can know anything so all we CAN do is make guesses. The only absolute proofs we make do use givens, so we can prove things withing certain constructs. Like, we can PROVE things in math, but it is an artificial device. That isn't the same as universal truths. All we get there are good guesses.
Do we act on those guesses? Certainly, much like you'd call a friend's cell before his house. You don't KNOW he is there, simply that is the best educated guess you can make at the moment. The idea that people EVER need to make a leap of faith is total BS.
Re:Not again (Score:5, Insightful)
Re:Not again (Score:5, Insightful)
Not so. You cannot prove that repeatedly making a measurement in the past is any indication that it will hold in the future. Pointing out that it's worked before is just begging the question, and therefore reproducing the results doesn't help, for it does not mean you'll reproduce the results *again*.
You *must* presuppose that the future is relevantly like the past for empiricism to have any meaning in any context; it's pretty much an irreducible problem.
With that said, such "faith" is, I would argue, essentially to daily living and doesn't really deserve to be categorized as "faith" except in the most pedantic of senses. Without acting under this presupposition, you cannot learn. Anything. I suspect that biologically this presupposition cannot be unlearned since it appears to be intrinsic to learning even in some of the stupider members of the animal kingdom.
Re:Not again (Score:3, Insightful)
The problem with faith is when it becomes blind faith.
No, the problem with faith is that it is always blind. Faith is a strong belief in the absence of evidence, but without evidence, you are utterly and completely blind.
Faith will always be there for the things we do not have the tools to understand.
There are better words for the things we do not have the tools to understand. "Ignorance" is a pretty good one, for instance.
If you notice, there are "science" folk in here mocking this new theory because it contradicts the old one. Think about this next time you want to take a swing at someone who holds faith.
Criticizing new theories is part of what "science folk" do, you know.
Re:Not again (Score:1, Insightful)
Re:And FTL, too (Score:3, Insightful)
I don't see how that's necessarily true. Special Relativity is based on two postulates:
1. The Principle of Relativity: The laws of physics are the same in all inertial reference frames.
2. The Law of Propagation of Light: The speed of light is a specific constant value independent of the motion of its source (and this is a "law" for purposes of postulate #1 above).
These two postulates allow you to derive the conclusion that if you send a signal from Event A to Event B such that the signal travels faster than light in one inertial reference frame, then the events are said to be "spatially separated" (as opposed to "temporally separated"). With such events, the temporal ordering is ambiguous, and different inertial reference frames will disagree as to which event occurred first, with neither being more "right" than the other. In other words, there will exist inertial reference frames in which Event B occurred before Event A, and therefore in which the signal traveled backwards in time.
The falsity of this conclusion would imply the falsity of one of those two postulates, both of which are well confirmed experimentally.
Rather than viewing this as overturning Einstein (Score:3, Insightful)
Remember the saying that science proceeds by successive approximation to the truth.
Re:Not again (Score:5, Insightful)
"You cannot prove that repeatedly making a measurement in the past is any indication that it will hold in the future."
Flip side, you can't prove that it won't hold true in the future either. In essence, your argument is a case of argumentum ad ignorantiam.
The bottom line is that you're engaging in fancy footwork trying to get to him to use the word "faith", in which case you then have a basis for moving on to a discussion of "true faith", a belief in God or some such. Faith is belief without proof.
But... if you have proof then you don't need faith. Past personal observation, history, science, math, and orbital mechanics all say that the sun will come up tomorrow. Faith is not needed.
Re:Not again (Score:1, Insightful)
You don't need faith; just natural selection. The sort of measurements that happen to be repeatable are the ones that generally allow organisms to survive when they rely on those measurements. There is no guarantee that they are the right, best, or smart measurements, but they are good enough. You might argue that on a metaphysical level there is no reason for natural selection to work either, but that simply contradicts our own experience. Ultimately if natural selection stopped working, so would our experience of the world because we would likely die. The anthropic principle basically implies that humans (as we understand them) are only going to exist in universes that have repeatable measurements, and therefore that our own trust in repeatable science is justified. Any other situation would not lead to beings that we would identify as human like ourselves, and assuming they existed, they would have to practice a very different form of science.
Re:Not again (Score:2, Insightful)
There are actually only to possibilities. Either the things continue to work the same way they did before, or they don't. If they do, then acting on the assumption that they do is clearly the right choice. If they don't, then we have no idea what to do; whatever we do could be right or wrong. Therefore the rational behaviour is to assume that the rules continue to work.
Re:Not again (Score:4, Insightful)
Re:And FTL, too (Score:3, Insightful)
If you could slow down time enough and watch that laser pointers light, the light from it would likely be bending as you moved it from friend A to friend B as a function of the time it took you to move it. At all points, the laser would never go faster than light, although from your location, point C, it might seem to, but both friend A and friend B would experience the event at the speed of light and not faster. When you flick your wrist from friend A to friend B, the moment you finally point at friend B, the laser light would, in current time, still be shining farther down the wall, racing to catch up and focus on friend B, but only as fast as the speed of light.
The more I think about it, the more like a lighthouse, or neutron star, your example is, and obviously neither is producing light at FTL speeds regardless of how many observers in various locations.
Re:Not again (Score:5, Insightful)
Belief without evidence is called blind faith, science rests on the faith that the universe is ultimately predictable and will continue to exist even if we don't (in other words it believes that the proverbial tree in a forest does indeed make a noise).
There is no way to "prove" that the universe behaves like this but rational people take it as an indisputable fact because the evidence of ones own perceptions is very difficult to ignore particularly when they match the perceptions of other humans. So yes, science is based on faith as is all knowledge that goes further than "I think therfore I am".
"The bottom line is that you're engaging in fancy footwork trying to get to him to use the word "faith"
No he is not, the "bottom line" is that basic scientific philosophy confuses the hell out of people who subscribe to the popular but incorrect notion that science is in the bussiness of "proof". We wouldn't even be having this discussion if epistemology [wikipedia.org] was taught in modern high schools.
Re:Not again (Score:2, Insightful)
Or do you believe we are at the pinnacle of the field, and can achieve no more?
Depends on the funding.
Re:Not again (Score:3, Insightful)
That's not what the OP was arguing either. He was saying that you must have some form of faith to even accept your reality as stable such that you can observe with the scientific method to make your conclusions in the first place.
It's simply difficult to have a motivation to find a formula representing a natural system if you have no faith that there is even order in the first place.
That doesn't mean that it cannot be derived without faith, but simply that human nature, for the most part, would not allow it. After all, we are animals, not computers, and are preconditioned to seek for some goal with that goal in mind, not stumble blindly through logical conclusions until we find useful knowledge.
Re:Not again (Score:5, Insightful)
Can you send me an example where Jesus accurately predicts known experimental results?
(I'm not sure if your stay on rejection was genuine or troll-bait, but it's caught momentum and I thought I'd provide an honest response rather than leave the question hanging.)
There's the golden rule, for starters. He didn't invent it, but he was instrumental in the widespread use of its positive statement ("Do unto others as you would have them do unto you" as opposed to "Do not to your neighbor what you would take ill from him"). And the result of following that rule, the rule of initiating kindness, you are statistically more likely to be treated kindly in return. Common sense and anecdotal evidence bear this out as well.
Then there's a bunch of other stuff he said, including things about the Kingdom of Heaven being here and now, forgiveness, faith, and love, that has unfortunately been so steadily downplayed and cloaked in tradition and dogma that it gets lost in the "war" to "win souls" for God. I think the historical Jesus would get along just fine with good-hearted atheists, Muslims, Hindus, Krishnas, Christians, Buddhists, and followers of most any other creed that you can imagine--and he probably had more in common with the Buddhists than we tend to think. He might not agree with all of the beliefs in those various systems, but he was more interested in disciples, people who would emulate his way of living, than converts to his religion, which didn't even exist during his lifetime. In other words, I think he'd be an excellent person to discuss philosophy and religion with, and he'd probably be the first to quell any budding flame wars.
This is of course only my understanding of Jesus. I've put a lot of thought and a decent amount of study into it, so I have a nuanced view not shared by most Christians, but I prefer to simply act in a manner I think he would approve of than to talk about it. It's more challenging and more effective to act, and I lack the agenda to convert people so dislike being perceived as having it. It is still disheartening to see his teachings rejected out-of-hand because of the centuries of stupid, un-Christlike actions of his followers, not to mention the (in my opinion) corruption of his words within the Bible. I hope to change that by trying to live up to the way I think he did. Even if most people who learn from me never find out my source, it is a good way to live.
Re:Not again (Score:3, Insightful)
"Science complements the gambler's fallacy with the same flaw but the opposite conclusion--that the 4 is more probable because of the sequence."
And you're arguing by analogy, another fallacy.
Speaking in those terms, and to use my example: the sun may rise tomorrow, or it may not. But thousands of years of observation, coupled with the scientific inference and deduction of natural laws, all tell us the mechanics of just what it means for the sun to "rise" tomorrow, and that it's not a simple 50/50 proposition.
Or to use your example, four straight 4's may be a statistical fluke... or one might begin to use that statistical anomaly to make some deduction as to the nature of the dice themselves (loaded). Accumulate enough observations, and you might decide that it's in your best interests to do go play dice with someone else, "probabilities" be damned.
"Even if you could assert something definitive from the repetition of events..."
If you truly believe that, then I invite you to step off the top of the nearest ten-story roof. Under your assertion, repetition and past experience will not necessarily hold true, and you'll float there and win your argument. From my perspective, however, if you do so then I'll need to make a call to 911 so they can scrape the pieces off the sidewalk.
So... unless you're willing to put your money where your mouth is, I suggest you go back to counting the number of angels that can dance on the head of a pin.
Re:Not again (Score:3, Insightful)
You seem to have failed entirely to answer the question that you quoted. The "known experimental results" was in the context of a debate about physics, and yet you've just inserted a huge bunch of unrelated waffle about how nice Jesus was, and how much he worked hard to make everyone happy. I certainly would have let that pass if you had the decency to be correct, but sadly where you have wandered from theology through the social sciences to the far extremes of testable science you have erred.
When you say that the golden rule is "statistically more likely", based on "common sense" and "anecdotal evidence" you really are reaching. A simpler (and more scientific) way of analysing it would be in terms of game theory. Let's consider a world where everyone follows this advice: if I decide to act like a complete tool then nobody is going to change their behaviour towards me, so I can get all of the advantages without suffering any of the consequences. By symmetry this argument applies to anyone else. So everybody derives an advantage by switching away from the golden rule. Hence it is a weak equilibrium strongly dominated by (almost) any other strategy.
More complete work has been published on the game theoretic analysis of truth-telling/lying and altruism. So your imaginary friend not only lacks accurate predictions of known experimental results, but when you try and twist his alleged words into such proofs you run up into the problem that he was wrong. Perhaps more critical thought is required?