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General Relativity Is At Least 99.95% Right
ultracool writes to mention a ScienceDaily piece on compelling proof of general relativity. A team at the University of Manchester have used three years' worth of data on a pair of pulsars as a litmus test, against which they've benchmarked Einstein's theory. From the article: "Though all the independent tests available in the double pulsar system agree with Einstein's theory, the one that gives the most precise result is the time delay, known as the Shapiro Delay, which the signals suffer as they pass through the curved space-time surrounding the two neutron stars. It is close to 90 millionths of a second and the ratio of the observed and predicted values is 1.0001 +/- 0.0005 - a precision of 0.05%. A number of other relativistic effects predicted by Einstein can also be observed. 'We see that, due to its mass, the fabric of space-time around a pulsar is curved. We also see that the pulsar clock runs slower when it is deeper in the gravitational field of its massive companion, an effect known as "time dilation."'"
. . .they are not a proof.
Only mathematics has proofs, but observations that support a theory demonstrate that the model has predictive value. Observations that do not support a theory demonstrate that the model is, at best, incomplete.
Ignoring the predictive value of a model, whether it is complete or not, demonstrates that you are an idiot. Within its limits of significance Newton's theory of gravitation is still just as "correct" as Relativity.
Facts are not proofs, but they are facts.
KFG
I think 99.95% is about as close to dead-on-balls-accurate as it gets with our current knowledge of the universe; I mean, there's always a margin for error in absolutely everything, it's just one of the facts of the chaotic universe in which we live. Still, it just goes to show how far ahead of the game (and of the times) Einstein was.
Einstein's still my hero. He's the Samuel L. Jackson of science.
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Mathematics is a closed system, for which we know all the rules (because we define them). Thus, things can be proven as being objectively true, false, or unprovable (for as given set of axioms, there are many self-consistent sets).
Physics and the other sciences, on the other hand, are faced with the dilemma that we can never observe all the behaviour of everything in the universe at once, and thus we are forever working with partial data sets, and fitting our theories to them. As a result, the best we can say is that the theory we have put together fits the observed data to a high degree of precision - but that this may be invalidated at any time by new phenomena. See, for example, the progression from Newtonian mechanics to Relativity, or the long-running debate over the nature of light.
there is no such thing as "fabric of space-time". It's a convenient buzzword but it doesn't mean anything
Of course it means something: it is a summary of the distance and time measurements we make, and can be described in terms of geometrical curvature. If it didn't mean anything, then it wouldn't have any observable consequences.
Things work as if Einstein was right, but there is no evidence that he was right.
You're splitting hairs that don't exist. "Working as if Einstein was right" is "evidence that he was right". It's the only kind of evidence possible.
If you pass a current through a wire it generates a magnetic field. If that field crosses another wire it generates a current in that wire.
That's not necessarily true. A static magnetic field doesn't induce a current in a wire. You might be talking about alternating current, which produces a time-varying magnetic field.
It's exactly as if the magnetic field moved from one wire across the other.
I don't know what you mean by a magnetic field "moving", but certainly the magnetic field of one wire can intersect the position of another wire.
The flaw is that if you wrap both wires through an iron donut all the field is inside the iron - absolutely NO field is detected anywhere around either wire.
Perhaps I'm visualizing the geometry wrong, but your statement appears to be false.
The theory is false, but it is "exactly as if" it were true.
What theory? That the (time-varying) magnetic field produced by one current can induce a current in another wire? That theory is always true. (Of course, you have to take into account induction from other objects which may cancel that current.)
Likewise, Einstein's theory may give correct answers even though nobody actually knows why.
It is not possible to know "why" a theory is true, at least if that theory regards some fundamental phenomenon. It's possible to explain "why" some approximate theory is true by deriving it from a more fundamental one, assuming the more fundamental theory is true.
For one thing, plasma physicists can easily explain a lot of effects in electrical terms, relying on laboratory observations instead of imagined theories.
Nonsense. Plasma physicists use theories just like any other physicist does. Those theories of course are electromagnetic in nature.
Astronomers ignore plasma physics because nobody ever taught it to them.
More nonsense. Plenty of astronomers use plasma physics. What are you, an Alfven plasma cosmology crackpot?