Einstein's Theory Passes Strict New Test 243
FiReaNGeL writes with an excerpt from a story at e! Science News: "Taking advantage of a unique cosmic configuration, astronomers have measured an effect predicted by Albert Einstein's theory of General Relativity in the extremely strong gravity of a pair of superdense neutron stars. Essentially, the famed physicist's 93-year-old theory passed yet another test. Scientists at McGill University used the National Science Foundation's Robert C. Byrd Green Bank Telescope (GBT) to do a four-year study of a double-star system unlike any other known in the Universe. The system is a pair of neutron stars, both of which are seen as pulsars that emit lighthouse-like beams of radio waves."
And that, boys and girls, (Score:5, Insightful)
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What use is this study if his theories don't agree with themselves? Call me when they find crucial discrepancies, not similarities.
Re:And that, boys and girls, (Score:5, Informative)
You do realize that is what they're doing, right? They're looking out into the Universe for ways to test the theory against real live data.
Re:And that, boys and girls, (Score:5, Funny)
I think what he's saying is that since these scientists's job to to disprove relativity, or kill cancer, or cure AIDS, and they failed at their job, then they should not get their paycheck next month.
Seems perfectly logical to me.
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It only makes sense if you have absolutely no idea how science works.
Re:And that, boys and girls, (Score:5, Funny)
Yes, this upholds the theory that pink unicorns, which are known to exist, are invisible, otherwise this experiment would have revealed them. Further proof of the existence of invisible pink unicorns!!!
Here's an experiment you can do yourself. Find a dark room, such as a bathroom stuck between two other rooms and therefore windowless. Close the door and keep the light off. Reach out your hand. Do you feel anything? Holy Crap, you just found an OMGPONIES! Turn the light on, quick! Did you see the OMGPONIES!? No, you didn't. Further proof that OMGPONIES!s, known to exist, hate artificial lighting, and run very fast. Isn't that amazing?
Re:And that, boys and girls, (Score:5, Funny)
Be careful my friend! You won't survive many unlit areas because you confusing fluffy pink unicorns with grues.
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Yeah. Although it is sort of depressing that we can't find the flaws in the theory; I mean, no theory is supposed to last forever - they're always stop-gaps until flaws are identified and we need to find a new one. Where's the fun in a theory that's always right?
I'm know it won't last forever, but with every new experiment there's always the hope that maybe this one will finally reveal a flaw to work on.
Re:And that, boys and girls, (Score:5, Insightful)
It's the value of good old fashioned visual thinking and geometry actually, einstein's theories were so powerful correct BECAUSE he was an excellent visual thinker and thought in terms of geometry. Geometry is highly under-rated in mathematics and physics in my opinion.
Re:And that, boys and girls, (Score:5, Interesting)
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It's not just about what is taught it's about how one thinks about problems:
Even more vivid was Albert Einstein's explanation how human reasoning includes visual thinking.
"The words or the language, as they are written or spoken, do not seem to play any role in my mechanism of thought. The psychical entities which seem to serve as elements in thought are certain signs and more or less clear images which can be 'voluntarily' reproduced and combined .... this combinatory play seems to be the essential feature
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Having studied all of these fields, I can safely say that the average undergraduate curriculum or textbox in any of
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Actually, it seems that Einstein worked out the equations and most of the geometrical analogies came later, from other people. Einstein at first thought it was unnecessary complication.
this is getting boring (Score:2)
We already know that there is something wrong with it on the quantum end of the scale. When are we going to get some tests which prove it wrong in a way that will help us refine it? Doesn't anyone have any tests they can do that will give us that information?
Re:this is getting boring (Score:4, Interesting)
Why prove it wrong? Perhaps its not possible to rectify the way matter curves spacetime at the quantum level, perhaps Einstein doesn't need to ever be proved wrong for the description of the entire universe to be expanded upon. Perhaps there's nothing wrong at the quantum end of the scale, its just asking the wrong question.
not so fast (Score:2)
Re:Can't be right (Score:5, Insightful)
I hate it when people discuss science in this banal way. It is as if they think that the physical theories are what cause nature to act (the Laws of Nature). This is wrong. These physical theories only describe how nature appears to act. Quantum mechanics is a classic example. Look at all the different formulations that describe how the state vector or wave function or whatever you want to call it acts (Heisenberg's, Schrödinger's, Dirac's, Feynman's, etc.). They are all good theories because they explain the experimental evidence, they are simple, and they can predict things. Take a look at the so-called wave-particle duality. A photon, for example, doesn't act as a wave or as a particle. It acts as a photon (paraphrasing Feynman). We only describe it as acting as a wave or a particle.
The truth about science is that it may very well not be possible to understand why the Universe acts as it does. It may not even be possible to understand the most basic laws governing it. But we can certainly study and try to understand its behavior where we can observe it. General relativity does that well, and quantum mechanics does that well. Calling one right and the other wrong sort of loses its meaning in this context when both theories describe their data exceptionally well for the ranges that they observe. Neither of them proposes to govern nature, nor should we ever expect that of a physical theory.
Re:Can't be right (Score:5, Interesting)
Feynman's take was that light is *always* particles. He was unequivocal about that.
Re:Can't be right (Score:4, Informative)
Ok, but to clarify for some readers, "particle" does not mean corpuscular like a tennis ball, which is why the term "particle" tends to be a little misleading. In fact, it is why any "it's like a " phrase tends to fail, and why it was such a shock to discover indeterminable states to begin with. Quantum theory rests on the (unsurprising) revelation that at small scales, things are not as we have always visualized in the large, solid man-world. I don't think anyone other than Bohr was comfortable at the time with *any* explanation of some of these phenomena, even with models that were so fucking accurate.
And light does travel in wave form. Pics from a slashdot story very short while ago:
http://technology.newscientist.com/article/dn14172-fastestever-flashgun-captures-image-of-light-wave.html?DCMP=ILC-hmts&nsref=news1_head_dn14172 [newscientist.com]
But it is easier to think of the quantized light in terms of... quanta! New particles, now with many new features and a money back guarantee!
Happy Independence Day!
Re:Can't be right (Score:4, Informative)
Re:Can't be right (Score:5, Insightful)
You are exactly right, but to paraphrase:
"All models are wrong, but some are useful." [wikiquote.org]
Re:Can't be right (Score:4, Interesting)
yes, but the hard problems, like interstellar travel, will best be solved by a theory which holds up at all levels, quantum, micro, macro, and cosmological.
Re:Can't be right (Score:4, Informative)
Not sure if you're talking about superluminal travel or subluminal travel.
Theory already allows slower than light travel. You're spaceship would have to be big. VERY big. But if we really wanted to we could probably send mankind to the nearest stars with current technology.
But superluminal travel is a different kettle of fish. There are only two possible universes, one where there's an upper limit in the speed of information and another where there is no upper limit. The two universes have very different characteristics and our universe appears to be the smaller. It's hard to think of a way where you can transmit matter without also allowing information transfer.
Of course, even today faster than light travel is possible by current theory - but only by points A and B separating faster than light, not by allowing points A and B to communicate faster than light. Effectively this means that the speed of light is only constant locally. Maybe it would be possible to reverse the expansion and shrink the universe so that although the speed of light would still be an upper limit, communication between A and B could occur in less time than light could make the journey in a flat universe.
But I'd wager that faster than light travel in the special relativity sense is, and always will be, impossible.
Tim.
Re:Can't be right (Score:5, Insightful)
Except that isn't possible, because theories that hold up well at describing things like gravity on a large scale break down horribly at the quantum level. Even basic interactions between particles cannot be described in the sense of, say, a truck hitting a telephone pole.
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And chimpanzees don't get termites, spit-covered sticks do.
Technology is as much a part of humanity as wings are of birds.
Re:Can't be right (Score:5, Insightful)
You are aware that "impossible" means "cannot be done" and not just "we can't do it right now", right?
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A statistician said that. You know what they say about statistics, right?
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Re:Can't be right (Score:5, Insightful)
Calling one right and the other wrong sort of loses its meaning in this context
I agree. Once again science... REAL science, is never about "right" or "wrong". It's about "can I use what you just told me in a predictable manner?". If it's BS and it doesn't work, then leave me alone I have stuff to do. :)
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There's lots of right and wrong in science. Just not applied to entire theories. Well, right never applies to a whole theory. Wrong does.
General relativity gave the right (ie observed) answer in this case. That doesn't make general relativity right. But if GR had given the wrong answer, in a test in a domain that it claims to describe accurately, then we'd know that GR is in fact wrong. That is opposed to GR not making proper predictions in the quantum realm, where it is known not to work properly, wh
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REAL science, is never about "right" or "wrong". It's about "can I use what you just told me in a predictable manner?". If it's BS and it doesn't work, then leave me alone I have stuff to do.
What you're describing sounds more like engineering than science, you know. As an engineer, I don't care too much about why nature acts the way it does - as long as I can find a usable method to get things working the way I need them to work. I take the pragmatic approach, because I have a real-life goal.
Science, on the other hand, is not per se concerned about "using what you just told me", it's about discovering the whys and hows. Mathematics is "REAL science", as you put it, and they are most definitely
Pulsars (Score:2, Funny)
An overview presentation of the capabilities of Pulsars has been uploaded to Youtube [youtube.com].
And yet... (Score:4, Funny)
Re:And yet... (Score:5, Funny)
Einstein has yet to prove why hot dogs and hot dog buns come in inequal quantities.
I guess relativity explains that again. It depends on your country. In my country, you get 8 buns in a package and 8 sausages in a package. However my country is probably closer to the equator than yours, therefore our frame of reference is a lot faster than yours. Therefore the parity increases as a function of velocity. I would probably have to weight the buns and sausages to figure out any discrepancies in mass, but presumably the optimum is reached asymptotically when approaching the speed of light.
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When it comes to hot dogs and buns it's not the mass that counts, but the volume.
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But why are you eating hot dogs, when real men eat bratwurst? Now those typically come 5 or 6 on a foam tray, and I have yet to see the bun counterpart.
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1. You run out of buns, but still have hot dogs.
2. Buy more buns to eat the leftover hot dogs. Have buns leftover.
3. Buy more hot dogs to use the leftover buns. Have hot dogs left over.
4. Goto 2
5. Profit!
It's a shame really (Score:2, Interesting)
Makes things like this sit in the same bucket as one of my drunken musings. "I have a theory that.... in..... etc". There should be a state of a theory where they can say "Well, we can't yet prove all of it, but we have managed to prove x amount, or in x years of testing, it has yet to be unproven".
Maybe term it Conjecture [thefreedictionary.com]? It's the fitting word to use.
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That's exactly how "theory" is used in science. It doesn't carry that connotation of "this is just some stuff I'm guessing at" that it does in colloquial use. This is why creationists always talk about how "evolution is just a theory" when in fact, that indicates it's well-accepted among scientists.
Laws and Theories (Score:5, Informative)
Consider, as examples, Newton's laws of motion, or the laws of thermodynamics. Newton's theory of motion is deduced from his laws; the conventional theory of thermodynamics, likewise.
I say this because there are plenty of non-scientists who deliberately attempt to exploit confusion induced by popular use of the terms "law" and "theory" so as to imply that scientific theories, notably the theory of evolution, are held tentatively.
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I think that, most of the time anyway, "law" as used in science has an even more specific meaning: a "law" is a relation (often an equation) between two or more variables. For instance, Boyle's Law [wikipedia.org] states "for a fixed amount of gas kept at a fixed temperature, pressure and volume are inversely proportional". This is, strictly speaking, not true of reality. It describes an ideal gas with completely elastic collisions, a property that no real gas has. But it's close enough to true with real gases that it
Re:It's a shame really (Score:5, Informative)
Some time ago, I took a "History of Science" course. My memory is fuzzy around the dates, but originally, anything in science was granted the term "law". IIRC, "Caloric Theory" which was superseded by the theory of heat and thermodynamics was originally called a "law".
Around the 1700's, it was decided to call all new science a "Theory". In deference to previous conventions, the things still held over previously known as laws retained the name. Hence the apparent difference between the two terms.
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Makes things like this sit in the same bucket as one of my drunken musings. "I have a theory that.... in..... etc".
Not really the same. Theories have been tested and are supported by facts. A drunken musing, valid scientific starting point though that may be, is merely a hypothesis which then must be tested. If it survives the test, it then becomes a theory. And if it survives the test of time, it may become a "Law". There are very few scientific "laws", however. The gas laws are pretty much the only ones
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A theory never becomes a law, because they are entirely distinct. A law is a description, i.e. "what", whereas a theory is an attempt at an explanation, i.e. "how".
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There are very few scientific "laws", however. The gas laws are pretty much the only ones I can think of off the top of my head.
Newton's Laws, the Laws of Thermodynamics and Hooke's Law are three more (assuming you weren't thinking of thermodynamics when you said "gas laws", in which case I'll throw in Boyle's Law too).
hypothesis - 1 of 4 scientific terms (Score:5, Informative)
The word you are searching for is hypothesis.
There are 4 terms that need to be understood in the realm of science - hypothesis, theory, law & fact. They are all separate & distinct, except for the only progression that occurs - hypothesis => theory.
A fact is what has been carefully observed.
A law describes that observation.
A hypothesis is a proposal intended to explain that observation.
A theory seeks to explain that observation & has been confirmed by considerable evidence and has endured all attempts to disprove it.
example:
Fact
Objects fall at the same rate regardless of mass.
Law
http://www.glenbrook.k12.il.us/GBSSCI/PHYS/Class/circles/u6l3c1.gif [k12.il.us]
Hypothesis => Theory
Mass causes a curvature of spacetime which creates the effect of gravity.
Re:hypothesis - 1 of 4 scientific terms (Score:5, Informative)
An observation is some type of measurement. We could call this a fact if we like, but observation is better because is acknowledges the role of the observer in a way that "fact" does not.
A law is some invariance across multiple observations. See, for instance, Kepler's laws. (They do not, as the parent says, "describe" observations, but rather they postulate invariant aspects of planetary motion)
A hypothesis is a testable prediction based on naturalistic explanation of lawful behavior, typically of smaller scope than a theory and untested or weakly tested. Theories can also lead to hypotheses, through logical implication (ie, "my theory predicts that X, therefore I hypothesize X will occur in this experiment")
A theory is a unified, parsimonious, testable, naturalistic explanation for entire sets of laws. For instance, Newton's theory of mechanics explained all of Kepler's laws of planetary motion, and lawful behavior on earth as well.
Observation: These objects that I have dropped all appear to fall at the same rate regardless of mass, within measurement error
Law: All objects fall at the same rate regardless of mass
Hypothesis and theory Newton's theory of mechanics, or Einstein's theory of relativity
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Mod parent up. He is more correct than the grandparent.
Hypotheses do not necessarily lead to theories. This very article is an excellent example. General relativity is a theory. Using the theory, various physicists formulated a hypothesis, that massive bodies in orbit around each other should behave in such and such a way. These astronomers then made an observation, which supported the hypothesis.
Things can also work the other way. You make some observations, then formulate a hypothesis based on them.
Re: (Score:3, Insightful)
>>>>Fact: Objects fall at the same rate regardless of mass.
>>How exactly is this a fact? At best it's a generalization based on facts involving specific objects. It sounds more like a law.
Moreover, it's wrong. Heavier objects will fall slightly faster since they pull the earth up towards them as they fall.
It's a great example of how we can think we know something that's "proven" by science, but yet still have the ignorant people (that think a hammer falls faster than a feather in a vacuum)
Re: (Score:3, Interesting)
Since the hammer and the feather are classically dropped right next to each other, let's say a foot apart, the vector of the movement of the Earth will point mostly toward the hammer (depending on the ratio of mass) meaning it will still hit first even if they're dropped simultaneously.
>>Also your answer assumes a frame of reference fixed to the earth
Well, the problem posed is, "Which hits the ground first?" or, alternatively, "Which falls faster?" and in both cases, the answer is the hammer.
>>i
i always thought of the verbiage (Score:2)
as a sort of intellectual modesty, a reverence for the pursuit of science and the natural world
of course, this modesty doesn't translate well into a religious culture of simpletons who only talk in arrogant absolute laws on topics, like human sexuality, or crime and punishment, that are inherently subtle and complex. such that all these scientific "theories" to them can't possibly ring true, as flimsy and modestly phrased as they are. what they need is some cruel visage of a god to threaten fire and brimsto
Re:It's a shame really (Score:4, Insightful)
You can't prove things in physics.
No, really.
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How does that jibe with the incompleteness theorem?
For any consistent formal, recursively enumerable theory that proves basic arithmetical truths, an arithmetical statement that is true, but not provable in the theory, can be constructed.
If there will always be unprovable truths, is science always doomed to fall short of a complete answer?
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You can't prove anything in any science.
You can only prove things in mathematics and other logical systems, where you decided what assumptions were going to define the system in the first place.
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I believe "conjecture" ... also has a well-established meaning in mathematics...
The established meaning in mathematics is "something I believe is true but am unable to prove because, uh... umm... I have to go pick up my dry cleaning before they close. Maybe you can find a grad student to do it."
Einstein: Really Smart (Score:5, Interesting)
Usually pop culture gets these people's character pretty wrong. Elvis, for example, is "the King", when he was just a singing truck driver.
But Einstein they got pretty right. Sure, he didn't know everything, was smart really only within his very narrow discipline of mathematical theoretical physics. Einstein himself used to say "I really only ever had 4 good ideas, and 2 were wrong". But the couple he was right about, he was really right.
And with the wild hair, the pacifism, the "same suit every day so I don't have to waste time thinking about it", and the snappy short equations that explain everything, he's probably the coolest smart guy since they all used to wear togas and live on wine and souvlaki on the beach.
Re:Einstein: Really Smart (Score:5, Interesting)
Einstein dabbled a bit outside theoretical physics. For example he had a patent [wikipedia.org] for a refrigerator design.
Re:Einstein: Really Smart (Score:4, Informative)
Heres a couple of others:
Electrochemistry: http://alford.bios.uic.edu/teaching/Nernst.html [uic.edu]
Fluid Dynamics: http://mse-092697c.princeton.edu/lecture1001/page3.htm [princeton.edu]
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Einstein was a patent clerk, so he probably just slipped a patent or two in there when his boss wasn't looking.
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So Leo would have starved to death, whi
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He's tied for the coolest.
Feynman played bongo drums in a Samba (dance kind, not the file system kind) troupe, and hung around strip clubs.
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Well, I said Einstein was the coolest since the toga wearing beach partiers. Feynman might have been the coolest since Einstein, or since the togas. Einstein married his cousin, Feynman married the love of his life but partied with strippers (and CalTech coeds) after his wife died young. Your call.
But then, Feynman was so cool that when he met Einstein as their careers overlapped briefly, Feynman was appropriately tonguetied.
Relativity vs QM in a nutshell.
I honestly hope history proves him wrong here. (Score:2)
Otherwise, we will never leave our solar system.
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So far, Einstein has been right about everything, except that quantum mechanics is wrong.
Strict new test? Psh! (Score:5, Funny)
If they want to REALLY test a theory, they should just post it on slashdot. You know, because mass opinion is what really matters, regardless as to what's right and wrong.
Re:Strict new test? Psh! (Score:5, Funny)
If they want to REALLY test a theory, they should just post it on slashdot.
No, silly, that's just how you test the server.
Anything... (Score:2)
For years testing a theory... (Score:2, Funny)
Ironic, ain't it?
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> ... and still they are gonna go without any real proof that the LHC won't kill us, and
> turn it on.
Just as I have no proof that folding up my eyeglasses and stuffing them into a paper-towel tube won't create planet-eating stranglets. After all, it's never been done before and the physics that predicts the result is just theory. ...Well, I did it. Are we still here?
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The proof that the LHC won't kill us all is roughly equivalent to the proof that you turning on your microwave won't kill us all.
Time slowing down??? (Score:2)
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I'm pretty sure time dilation in pulsars has been observed.
Model Worshipers (Score:5, Insightful)
Re:For us plebs... (Score:5, Informative)
1. GE says two objects can cause a wobble in each other's axes due to gravity
2. Measurement of this wobble wasn't possible earlier
3. With this star system, since they are massive and pulsate, and that they are aligned in a manner that makes a measurement possible, astronomers took the plunge
4. Prof...proved.
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what is the mechanics that cause gravity to produce wobble?
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Since no one answered with anything intelligent:
I don't know. I suspect it involves frame dragging though, since the article mentions rotation. A massive rotating body with drag spacetime around with it to some degree. That produces some asymmetry.
The article says that the bodies are expected to precess which is kind of like a wobble, I guess, but a very specific one.
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Only if they are sufficiently prolific and redundant.
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Lame /. posters do tend to wobble. Is it still confirmable by observation if no one wants to observe it?
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Now THAT is a summary (perhaps with the exception of point 4 which gets -1:redundant). Take note slashdot editors.
I might as well be asking for millions of dollars to fall out of the sky.
Too bad I can't mod you up.
Re:For us plebs... (Score:5, Informative)
Now THAT is a summary
Actually I recommend reading the article. It's short, understandable, and contains other cool facts about these neutron stars.
Also, as for that last "proved" bit, the article ends with:
"It's not quite right to say that we have now 'proven' General Relativity," Breton said. "However, so far, Einstein's theory has passed all the tests that have been conducted, including ours."
Re:Relativity vs. Quantum (Score:4, Insightful)
So, more evidence supporting general relativity, but we still insist on viewing it as an approximation of a quantum-mechanical system (like how Newtonian physics can be viewed as an approximation of relativity).
Um, no, no one insists that you view it that way.
My understanding is that relativity has been directly observed several times, whereas quantum theory is still just based on the interpretation of a series of controlled laboratory experiments, which mostly amounts to sifting through the wreckage of a high-energy collision and trying to derive the original state from the leftover pieces.
No. Relatively and quantum theory are only directly observed on the pages of scientific journals, since they're theories and that's where you observe theories being printed. If you mean the predicted effects of the theory have been observed, this is true, but the same is equally true of quantum theory, in far more contexts that you mention (just as relativistic effects have been observed in more than just the bending of light during an eclipse).
Isn't it about time to abandon the concept of the graviton and just accept that gravity is not a fundamental force, but is simply the observed effect of the curvature of spacetime due to the presence of matter and energy?
Nope. Impatience does not suit science. Easier problems have taken multiple centuries to get right -- quantum theory is barely a century old, and has been one of the most spectacularly successful theories in the history of science. It has rough edges and will take time to work it all out, to be sure, but if it suggests something is right, it takes a bit more than a short period of time looking with inadequate instruments and incomplete understanding to declare it definitely wrong on the subject.
There's a saying in engineering: When all you have is a hammer, everything starts to look like a nail.
Of course it does, to an engineer. Engineers rarely have the patience for actual science. Taking a few centuries to hone a tool isn't practical. But science isn't about practicality.
Re:Relativity vs. Quantum (Score:5, Interesting)
My understanding is that relativity has been directly observed several times, whereas quantum theory is still just based on the interpretation of a series of controlled laboratory experiments, which mostly amounts to sifting through the wreckage of a high-energy collision and trying to derive the original state from the leftover pieces.
Oh, just based on a series of controlled laboratory experiments. Unlike relativity??
I have no idea what "directly observed" means, but quantum mechanical behavior is no less directly observed than relativistic behavior. In fact, it is far better studied, since atomic physics is more accessible to experiments than relativistic physics. And it by no means is limited to high energy colliders (which is where you tend to see relativistic effects the most, by the way); atomic spectra, basically all of chemistry, condensed matter and material science, lasers, etc. all depend on quantum physics. Indeed, the quantum theory of electrodynamics is the most precisely verified theory in the history of physics; some of its predictions (like the electron g factor) are accurate to something like 12 decimal places when compared to experiments.
Isn't it about time to abandon the concept of the graviton and just accept that gravity is not a fundamental force, but is simply the observed effect of the curvature of spacetime due to the presence of matter and energy?
If you accept that matter is described by quantum mechanics, then general relativity is wrong, because you can't consistently couple a classical field to a quantum source. (Consider what happens when you want to describe the gravitational field of matter which exists in a quantum superposition of states.) Believe me, if it were that easy to produce a theory of gravity which is consistent with what we know about matter, people wouldn't have been searching for 50+ years for a theory of quantum gravity.
Once you accept that gravity needs to be quantized, then you are inevitably led to something like a graviton: it's what you get when you quantize the linearized approximation to general relativity, and is actually more general than that: any field which couples to stress-energy (which is the source of gravity in general relativity) is described by a rank-2 tensor, which in quantum mechanics means a spin-2 particle (graviton). A theory of quantum gravity won't have gravitons as truly fundamental — the perturbative theory of gravitons is inconsistent — but any such theory (e.g., string theory, loop quantum gravity) will necessarily have graviton-like behavior as a low energy limit, assuming that it also has a relativistic theory of gravity (like general relativity) as a classical limit. That is not inconsistent with GR's description of gravity as curved spacetime: that's the classical behavior of a graviton-like field, although different theories recover that limit in different ways. (String theory has strings which vibrate in graviton-like ways which are observationally indistinguishable from spacetime curvature; other theories try to quantize geometry directly.)
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This has always bugged me; how in the heck do you quantize geometry like |x>?
|x> isn't geometry, it's a position variable. Geometry is described by a metric (or a connection), i.e., a tensor field. Simple perturbative quantization of a rank-2 tensor (the graviton field) doesn't work, but one can hope to try more subtle approaches. In the quantum geometry of loop quantum gravity, for instance, you represent a spatial eigenstate as a spin network, whose edges carry quanta of area and whose vertices carry quanta of volume.
I was under the impression there wasn't a good way to do that without losing isotropy.
That's the problem that many straightforward discrete appr
Re:Relativity vs. Quantum (Score:5, Insightful)
My understanding is that relativity has been directly observed several times, whereas quantum theory is still just based on the interpretation of a series of controlled laboratory experiments, which mostly amounts to sifting through the wreckage of a high-energy collision and trying to derive the original state from the leftover pieces.
Nope. Quantum mechanics is vastly, overwhelmingly, massively tested. Compared to general relativity, quantum mechanics is easy to test in the lab, and there are many many many experimental validations of it
And general relativity, also, is getting to be well tested.
Both theories have passed all the tests that they have been put to.
The problem is: quantum mechanics becomes important for things that are very small. General relativity becomes important for objects with strong gravity. The only range where you can test both of them together is if you can find objects that are both extremely small, and have extremely high gravity. Unfortunately, that realm is outside the experimental range of any experiments, now or anytime in the forseeable future.
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Maybe. There's still some hope we might get some results in a lab. There are ongoing experiments to measure gravity to high precision, at very small distances, which might reveal some interesting results. The chance that the LHC could produce mini black holes would probably also shed some light on the problem.
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My understanding is that relativity has been directly observed several times, whereas quantum theory is still just based on the interpretation of a series of controlled laboratory experiments, which mostly amounts to sifting through the wreckage of a high-energy collision and trying to derive the original state from the leftover pieces.
Congratulations you have viewed Quantum Theory in action; that computer you used to post this message is solidly based on Quantum Mechanics. No Quantum mechanics, no CPU.
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Term limits. That's all I ask for when it comes to Congress. Reps longer than Sens. How anyone could look me in the eye and say someone like Strom Thurmond was still in touch with todays society at his age when he retired compared to when he was first elected, IHNI.
Re:Robert C. Byrd Green Bank Telescope? Bah! (Score:4, Insightful)
Being out of touch with today's society is one of the most important functions of the Senate.
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Robert Byrd [wikipedia.org] was a Kleagle and Exalted Cyclops in the Ku Klux Klan, and opposed desegregation of the armed forces to such an extent that he did not volunteer for service during World War II.
It is also worth mentioning that he opposed the Iraq War resolution vociferously, as well as the creation of the Homeland Security department, and has endorsed Barack Obama for president, despite Obama's loss in Byrd's home state in a rather race-baiting campaign.
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Don't get me wrong, Einstein surely was a bright cookie, and came up with some very accurate results, but he was a man afterall - can't be expected to have *everything* right first go.
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In fairness to Einstein, his cosmological constant is frequently invoked as a possible source of Dark Energy. So wrap your head around this, it's possible that Einstein may yet be proven to have been right about an idea that he once called his "greatest mistake." And that to me is simply a mind-blowing possibility.
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I'm not trying to rag on Einstein, I'm just saying he wasn't an omniscient god. For that matter, no one is.
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