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Testing Relativity
MGDruss writes "NASA are proposing an empirical measurement on the ISS which would test general relativity to a precision within the bounds of superstring (and other) theories to predict deviation." We mentioned the Cassini experiment last year.
What ever happened to the concept that the simplest explaination is probably the best?
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This is probably going to be marked flamebait or offtopic but this experiment could have been unmanned. If anyone claims this is a good reason to have a manned space station, I defy them to specify how having humans aboard is needed in this case.
Now geology, that's a different story.
Blaze a trail to the New World
The article implies that Einstein's relativity is incorrect, in the opinions of most scientists. I'm no physicist, but I would say that most scientists are trying to build onto Einstein's relativity and show that it agrees with Quantum Mechanics: Therefore, they think it is correct.
Simon's Rock College
That is often true but... what is that simplest solution? People compare string/M-Theory to how the geocentric view of the universe was justified. People had supposed a heliocentric view of the world, but people believed that there were epicycles and such instead of that.
Where is the simpler solution here? General Relativity and Quantum Mechanics are NOT compatible in many cases (for example extremely small but extremely heavy objects like black holes cause things like infinite probabilities which does NOT make sense). We have no simpler solution. String theory is about all we have now.
Is it no surprise then that the EU wants to cancel the ISS? Even with the faults the station has, it's still the best way to conduct low gravity experiments. It's intolerable that the Europeans want it over and done with.
If you read the article, you will see this is not a "low gravity experiment". They are placing an interferometer aboard the ISS, above atmospheric distortion. An unmanned rocket would probably do the job more cheaply. But, as long as governemnts are already wasting billions of dollars sending people up to the ISS, we might as well give the interferometer to them and tell them to turn it on, thus sparing a separate rocket launch.
This still doesn't mean the ISS is anything other than a giant orbiting multibillion dollar turkey.
The dude who invented this principle phrased it this way (translated from the Latin): "Entities should not be multiplied more than necessary." But what entities are "necessary"? To Ockham, God was a necessary entity, yet you hear Ockham's Razor used to deny the existence of God.
Bottom line: OR is a highly subjective tool that should be applied with great care. And even then, it can mislead you -- the simplest plausible theory can still be wrong, due to evidence you haven't seen. OR is a strategy for coming up with good theories, not a law of nature!
String theory, man... I'm taking a class on it this year as it pertains to astronomy and wow... it's good stuff. Plus, the whole part where general relativity breaks down is the black hole -- string theory and quantum gravity, however, fill in those gaps quite nicely, and I've seen the math that leads me to believe it's going to come out in favor of string theory.
IAALS.
lol, not what I meant. Testing the theory we are not :). Finding out what people's gut tells them based on what they know, we are. The science will always win the debate because it never lies. Now, scientists on the other hand do.
You're right, I wouldn't steal a car. But if it were possible, I sure as hell would download one!
Read the whole thread.
What you're talking about are exceptions which use different warp scales, entirely different methods of traveling through space, supernatural beings, or in some cases alternate realities created by supernatural beings. All of which is perfectly explained and believable. The only one that isn't is Voy: Threshold. It's the biggest stain on Trek since TOS: Miri.
You're right, I wouldn't steal a car. But if it were possible, I sure as hell would download one!
String theory predicts deviations from General Relativity at very high energies and very small distances. I would be very surprised to read of a string theory model -- or class of models -- that predicted solar system scale effects in their basic framework. The importance of string theory effects is suppressed by a huge factor depending on the local energy density in the experiment you are testing. The string energy scale is so far away that it would be a great coincidence if it just barely showed up in the solar system but did not, e.g. rip it all apart. Sort of like crashing your car through the window of a bookstore and having the resultant mess just precisely turn one page of one book.
This is not a bad experiment to do, because there are theories -- mostly cosmological ones -- that predict differences in gravity that would show up in this theory, but they are definitely non-standard modifications to particular theories. I have done work on these kinds of theories, and let me tell you, it is a certain amount of work to actually generate theories that even care about such low energies and large distances that you can test them even with an "ultimate" measurement.
I am disappointed by the rather slipshod understanding of science and the issues that this article represents. "Evicting Einstein" is a sensationalistic headline, and it's just not true -- as anyone will tell you, Newton was not "impeached." A much better angle that this article could have taken was that of exploration of gravity, as opposed to "putting the chalk scribblers in place."
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James P. Hogan believes that special relativity is wrong. I don't care what he believes about it. But my enjoyment of fiction is severely hampered when he begins having fictional characters take the soapbox and deliver lectures that I disagree with.
On his claims that SR has not been verified, I've followed detailed discussion of the issue before on sci.physics, and the sad reality is that SR has been tested to incredible accuracy. In fact it has been tested to such accuracy that deviations to it have been detected. For a commercial example, GPS did not work correctly until they added a general relativistic correction term to the clocks to account for the fact that, being farther from the Earth, they suffered less of a dilation from the Earth's gravity field.
I have yet to see any proponent of throwing out special relativity manage to explain that level of accuracy, or come up with a decent alternative to general relativity for GPS systems.
Einstein wrote it. I beleive it. You should too. No need to test it.
Oh wait, I've confused Science with religion, again.
I know you're joking, but you bring up an interesting point: experiments like this are an excellent example of the difference between science and religion, and a refutation of those who argue that science is a religion. Einstein is (rightly) revered, a figure whose importance to physics is equivalent to the status of, if not Jesus or Mohammed, at least a Christian Apostle or a major prophet in Judaism or Islam. So what are the physicists doing? They're not praying to his ghost; they're saying, "He was a really smart guy who was right about a lot of things, but we're pretty sure he was wrong about a lot of things too, and we're going to find out exactly how he was wrong and by how much." Bravo, sez I.
The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
Heh. The reason (1) is the "orthodox line" is because (2) is ruled out by stellar aberration. Michelson-Morley says that if the ether exists, it must be dragged along with the earth. Stellar aberration says that if the ether exists, it must be stationary.
I imagine that this is the cause of NASA's perplexing refusal to take up Mr. Hogan's proposal.
The "Evicting Einstein" title of the article is misleading. IMHO, the Theory of Relativity cannot be proven incorrect...it can only be proven *incomplete*. Far too much evidence/data exists to prove the interaction of light and gravity and space-time as predicted by the GTR.
Sure, it can be proven incorrect. They key idea behind general relativity is the relativity principle, and that may simply turn out to be false.
The fact that GR makes numerically good predictions is nice, but there are plenty of other theories that make numerically identical predictions but do not postulate a relativity principle.
Even if the Quantum theory is proven correct, the Theory of Relativity will live on as an effect of the quantum theory - since it explains the effects of Quantum behavior on the macro-level...
Not every theory that makes good numerical predictions turns out to be a reasonable special case of a more general theory. Epicycles were pretty good, but Newtonian mechanics basically made them obsolete; they have no meaning anymore even as a special case. Likewise, general relativity may just turn out to be based on bogus core assumptions, and it just doesn't matter how good its numerical predictions are then.
This is either a flippant answer or a very good one. I'm guessing the latter.
Our 'gut' tells us that things will behave the way they always have seemed to behave, and to our perception that's Newtonian mechanics.
First of all, I suggest you do go to the trouble to read the article. It is interesting and, amazingly enough, it answers your question. We know that GR doesn't work for really tiny things. We know that it works for really big things. We want to know more about how it works in the in-between area. Therefore we are doing this experiment.
You are implying that theories are either right or wrong and if they are wrong they are not right at all. For starters, this is wrong. Just because you know something is not totally right, doesn't help you know what way to go to fix it. Think of it like this: your computer is broken. Any of the following could be the cause:
1. The CRT in your monitor stopped working.
2. Your hard drive won't spin up.
3. The RAM fell out.
4. The BIOS doesn't work.
5. The CPU died on you.
6. You have a non-system disk inserted.
7. There's a blackout.
We are in effect testing the pieces one at a time here rather than going to the store and buying a new black-box computer.
Scott
As a reader of The Elegant Universe by Brain Greene (highly recommended!). I must put my money on Super String Theory. After reading that book, and sorta getting my head around it, I must say that it will probably be the winner. However, I am not well versed in other theories so I can't really give an educated guess... Nevertheless, the beauty of if M-Theory, (grr keep interchanging all the theories names) really makes you want to believe it.
But! we must realize that our views of the universe constantly changes! And so tomorrow some physicist who locked him/herself in a room for 10 years will come up with a brand knew way to look at the universe and it will be ever more elegant than the previous.
The thing that troubles me about String theory, M-Theory or whatever you want to call it is the fact that everything is built on super complicated math (hence the super in super string theory ^^) with very little experiemental observations. It's interesting, but it's all theoritical! Then again, those crazy physicists/mathematicians who know these theories well will show how the math really does connect with the real world.
But anyways, my money is on String theory!
I believe neither will win in the long run. Its like back in the Sir Issac Newtons's age. Everyone thought its the truth while it wasn't. In a few centruies, or decades, a new theory will develope as technology advancement which allow more accurate calculations. The brand new theory will then, like Relatively overthrown Newtons' Law of Gravity, prove some point that neither theory cannot. This will happen again, and again. "The abolsute truth can never be found because all truth presee mankind are perseptive."
Bullshit.
Actually, Occam's Razor is not "the simpler theory is usually the right one," it is "create no unnecessary hypotheses." That may sound the same, but it's not. For example, many religions posit a soul or other non-corporeal entity that persists after the death of the body. Modern science doesn't claim to have a firm grip on sentience and awareness, but it appears to be a highly complex system of nervous reactions. (I imagine most of the Slashdot crowd knows that a complex system of conditionals, like a computer, can seem very life-like.) The point is, the mechanistic understanding of awareness explains it without recourse to a soul. Consider the natural chemicals in our bodies that contribute to mood, or artificial chemicals (like drugs or alcohol) that can alter one's personality, or even cases of trauma to the head, and "soul" is left as nothing but a non-explanation -- an unnecessary hypothesis.
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Another non-explanation is the idea that "warped space" explains gravity. All it does is push the explanation back one step from "what is gravity?" to "why do masses warp space?" So which is the correct theory? I don't think there is one, and our ideas or "understanding" of the universe will continue to evolve with everything else around us. The Pythagoreans believed that math was truth, and that reality was merely an imperfect shadow of the real world hidden beyond the veil of our senses. Well, this isn't the Matrix, an no amount of passion for "perfect" answers (like "elegant" equations or crystal spheres in the sky) will make it so.
You want an alternative theory? Give Tom Van Flandern's Meta Model a try. It may be no better than the orthodoxy of Einsteinian Relativity and quantum mechanics, but at least it won't resort to mathematical trickery and the comforting reassurance of what we'd LIKE to believe. A good introductory article may be found at:
http://metaresearch.org/cosmology/physicshasits
The only way to test this empirically would be to sit on an incoming muon and observe whether the laboratory clocks (at rest in the field) also slow down (as the observer-referred SRT holds) or speed up (as a field-referred theory would predict). This has never been done. (A whole literature exists on all this, but I don't think that here would be the place to elaborate further.)
This has been done, many times. Parent post is a crackpot.
It's not a question of "String theory vs. Relativity". String theory is -designed- to postdict (opposite of predict) relativity and quantum physics as limiting cases.
In the same way relativity postdicts Newton's theory of gravity, or how quantum mechanics gives classical mech as a limiting case.
So the alternatives here are really:
Relativity is disproved but not String theory
Relativity -and- String theory are disproved
Or the most likely outcome:
a result which is inconclusive and doesn't disprove either theory.
> You can only disprove a theory. And the easier a theory is to disprove, the better the theory.
Yes, another one of those "facts" that physicists know. Why bother looking into those lesser sciences (statistics, philosophy, mathematics, cognitive science, psychology, etc.), where people actually have some understanding of what theories are and how they get proven or disproven? Oh, no, "we are physicists, we don't need to understand these things, we know what we are doing". Sure.
You cannot prove a physical theory, ever. You can only test it and fail to disprove it. In statistics we call this "failure to reject the null hypothesis". When you perform an experiment you do not say "this data proves our theory", you say "this data agrees with our theory".
Do you have better ideas? I've had enough training in statistics, philosophy and mathematics to know that they don't.
You haven't thought that through. I said that we assume that there are some form of "additional measurements" possible (this doesn't necessarily require any kind of fundamentally new physical interaction). GR would keep its structure for the kinds of measurements we have tested in on, but it would get some additional structure (different from GR) for the new kinds of measurements.
You have just completely changed your argument. You said "mathematically identical" before. Now you are saying that the two theories will differ on a new domain of measurement which is obvious because GR is a low energy, classical theory and is going to be the classical limit, hbar->0, of some quantum gravity.
GR uses a lot of math, but that doesn't make it a "very mathematical theory". Euclidean geometry is a very mathematical theory, GR is still just a mess. Maybe mathematicians will eventually succeed in cleaning it up enough and connecting the dots, but that's probably still a long ways off.
You are so full of shit.
Einstein's GR is one single equation. Compare to Newtonian mechanics where you have Newton's second law for the dynamics and some Field equations for the sources.
Einstein's GR was the first Yang Mills theory, with the group structure of diffeomorphisms.
Einstein's GR is expressed in a coordinate free, purely geometric, language. For example, conservation of energy is derived from the geometric fact that a boundary of a boundary is zero.
I claim that Einstein's GR is the most mathematical of any physical theory that has ever existed. If GR isn't mathy then no physical theory is!
And I think physicists need a little more taste and they need to look a little more outside their very limited horizons. If they did, perhaps physics wouldn't be the mess that it is today and has been for more than a century.
There is no mess to clean up. GR is the most elegant physical theory. If GR is messy, it is only because Riemmanian Geometry and Differential Geometry are messy.
And I think physicists need a little more taste and they need to look a little more outside their very limited horizons. If they did, perhaps physics wouldn't be the mess that it is today and has been for more than a century.
You are more full of shit than I ever thought was possible. You must really get a kick out of trolling on Slashdot.
Let's see, what did the physicists do last century?
Semiconductors -> Transistor -> the mother fucking Computer
Quantum Mechanics -> Quantum Field Theory -> the most accurate physical predictions EVER
A Usenet Troll Triumphs on Slashdot