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."
Re:And that, boys and girls, (Score:0, Interesting)
I'm not sure if you're talking about Einstein or the present-day researchers. If you're talking about Einstein, it goes much deeper than study.
Take a brilliant mind, give it to Jewish parents, and then try to crush it under the intense pressure of early 20th century Germany. The result is an explosion.
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.
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:Can't be right (Score:5, Interesting)
Feynman's take was that light is *always* particles. He was unequivocal about that.
Relativity vs. Quantum (Score:1, Interesting)
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).
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.
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?
There's a saying in engineering: When all you have is a hammer, everything starts to look like a nail.
Re:Einstein: Really Smart (Score:1, Interesting)
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: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.)
Re:And yet... (Score:2, Interesting)
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!
Re:And that, boys and girls, (Score:5, Interesting)
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: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.
Re:And that, boys and girls, (Score:3, Interesting)
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 in productive thought before there is any connection with logical construction in words or other kinds of signs which can be communicated to others". Albert Einstein in a letter to Jacques Hadamard.
A more contemporary example of visual thinking is given by James Gleick from "The Life and Science of Richard Feynman", Vintage Books, New York, 1992.
"Visualization - you keep repeating that", he (Feynman) said to another historian, Silvan S. Schweber, who was trying to interview him
Feynman: "What I am really try to do is bring birth to clarity, which is really a half-assedly thought-out-pictorial semi-vision thing. I would see the jiggle-jiggle-jiggle or the wiggle of the path. Even now when I talk about the influence functional, I see the coupling and I take this turn - like as if there was a big bag of stuff - and try to collect it in away and to push it. It's all visual. It's hard to explain."
Re:hypothesis - 1 of 4 scientific terms (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.
>>it's just that the question becomes too vague to have a definite answer.
No matter how it's phrased, the hammer will hit the Earth first. I know it sounds a bit pedantic of me to make this distinction, but I've always found it amusing since it's the go-to example most scientifically minded people use to show how science trumps common sense, but (in this case) common sense is correct. (Even if it's accidentally correct.)