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Examining Gravity Waves
Joseph "JoeDaMac" Haake writes "Sometime within the next two years, researchers will detect the first signals of gravity waves -- those weak blips from the far edges of the universe passing through our bodies every second. Predicted by Einstein's theory of general relativity, gravity waves are expected to reveal, ultimately, previously unattainable mysteries of the universe."
Would this help unify quantum gravity and GR? Could it give evidence to bolster string theory? The results of this experiment should be very interesting.
On the ither hand, it could be affected by the whole varying-alpha thing. If something that fundamental is wrong, I think their data will be much less useful.
The LISA experiment, which gets mentioned in passing, is really quite audacious - three spaceships orbiting the sun in a clever rotating triangle pattern, 5 million miles apart from each other, and detecting changes in distance between each other to an accuracy of 20 picometers!
In essence, it's just a really, really big version of the Michelson interferometer we all played with in 1st year physics - I remember the thrill back then of realising what tiny changes in distance you could discern with just a couple of mirrors, a lamp and something to measure the recieved intensity.
It's exciting to witness the nascence of an entirely new form of astronomy.
Then we'd have to remove der liebe Herr Einstein from the pedestal of science, and put someone else there, someone who "saw clearly where everyone else saw nothing".
We didn't do that to Issac Newton did we?
I am very firmly convinced that the universe is far stranger than even the most brilliant minds alive today or yesterday ever give it credit for. I'm also very firmly convinced that no matter what mathmatical model we try to cram the universe into, we'll always find exceptions and things we don't understand. We'll find evidence to back up existing theories and postulates, yes, but we will also find evidence that takes current theories in a back alley, beats them across the head with a lead pipe, and then steals their credit cards.
Look at the research being done on gravity suppression or-- dare I say it-- anti-gravity. This research is considered quackerie and bad science by legitimate scientists who come across it. The fact remains, however, that this guy's research has such a huge potential to undermine existing theory and completely rewrite the books concerning propulsion that Boeing has made a major investment in his work.
One day, maybe one day soon, some scientist or group of scientists will make a major refinement on Einsteinian 'General Relativity' just as Einstein made a major refinement on Newtonian 'Classical Physics'. That doesn't mean that the work Newton did or the work Einstein did weren't major acheivments in and of themselves. It doesn't mean that they don't predict a great deal of what's going on, both out there in the cold reaches and here on Earth.
If you beleive that Einstein is 100% correct about everything he theorized then you're going to be in the same boat as people who beleived Newton was 100% correct. We don't know everything and we never will. Get over it already.
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Perhaps the most exciting thing about them is that we may well not know what it is we're going to observe. We think black holes, for sure. But who knows what else we might find?"
Jabba-The-Hut doing the Wild Thing.
"When we get a signal, we want to know what is generating that signal," Suen explained. "To determine that, we do a numerical simulation of a system, perhaps a neutron star collapsing, in a certain configuration, get the waveform and compare it to what we observe. If it's not a match, we change the configuration a little bit, do the comparison again and repeat the process until we can identify which configuration is responsible for the signal that we observe."
Sounds to me like they may be changing their model to fit the data in such a way that they won't know for sure it is a match. For example, a signal roughly fits the model of a black-hole forming, but not quite. They then keep tinkering with the black-hole formation model until it matches the signal. But in reality the signal could actually be something not related to black holes. They are putting the cart before the horse it seems.
It seems they would have to match a specific electromagnetic observation(s) to the gravity wave event to verify. Otherwise it is just a guess.
I could see some justifiable confidence if the signals were complex, and were only slightly off the models. In other words, near dead-ringer matches of something that would be too much of a coincidence to be something completely different generating the same (expected) complex signal. But I doubt we are at this stage in both the models and accuracy of the signal detection.
Table-ized A.I.
Could Einstein have come up with the mathematical models if Newton hadn't beat him to it? I don't know, but I'm also not positive that, given the solid foundation Einstein had, Newton could have predicted relativity.
Today's Sesame Street was brought to you by the number e.
I wonder if they will be at all able to measure the speed of a graviton with this current setup. It seems as though they are having enough trouble just detecting them in the first place though. I think this is a first step towards a new branch of physics that uses gravitons in experiments. For instance, some spin-2 thermodynamics could be experimentally demonstrated if gravitrons could be isolated and easily detected. This is probably not going to happen any time soon, but LIGO is a big first step towards that goal.
If gravity moved at the speed of light, then the Earth, in it's orbit, would "see" the Sun where it was about 8 minutes ago. Over geologic time, this changes the orbit. Over the life of the solar system, Earth's orbit isn't stable. So, gravity much act faster. One estimate of the speed of gravity is that it must be at least 10^15 times faster than light. That means that the wavelengths may be very short. So, using light interferometry to detect them may be futile. There may still be things to learn from the experiment, however, even if it isn't about gravity.
-- Stephen.
I don't think we can compare the two considering that they come from completely different times , when "science", meant completely different things.
Would you still think Newton was a genius if I told you that his Principia was a mere fraction of what he spent his life doing, and in fact was a quite well-known alchemist? How about the fact that he believed that he could predict the future by reading scripture (see: Temple of Solomon). Or read the last bit of the Principia, where he believed that the tails of comets were what provided us with water and nutrients so that we could survive. His work in alchemy and scriptures comprised the vast majority of his life.
But let's remember that prior to Newton (and afterwards, for awhile) there was no such thing as an equals sign. Imagine doing calculus completely geometrically. Also remember that for the first time in history there was a theory that agreed completely with observation. And how about the fact that the Principia was the final nail in the coffin for the geocentricity.
Then there's Einstein, who was ardently opposed to the revolution that he began (Quantum revolution), and which has resulted in the most tested and highly tested theory in scientific history (note that I'm not saying it's correct). Or that as late as 1895 he may have believed in an ether.
Then again, Einstein did "kick off" quantum mechanics with the photoelectric effect. And the fact that he completely "jacked around" with the foundations of physics by redefining things like space, time, and even reality, indicates a view of the world unlike any scientist had before him.
I've listed all of this because what we define as important factors in determining who was greater is inherently and unavoidably biased by our view of the world and the history that we know. Both of these men were revolutionaries who changed the way that we look at the world. They saw a new paradigm that no one else did, and that is something that only happens, oh, every few centuries in physics.
Incidentally, Newton did NOT do away with absolute space, but adamantly believed there to be one (check out Definition 8, Scholium, in the Principia). Oh yeah, and he did account for the retrograde motion of Mars. Galileo did that first (successfully), though.
The fact that GR is a specialized field doesn't say much, considering that Newtonian mechanics has been around for over 300 years, while GR isn't even 100 yet. More time to mull over mechanics has given scientists more time to take avantage of it. Remember we may go to another star with the help of Einstein.
Things aren't so clean in the history of science. There never was, and probably never will be, a single leader in any science who heads up a revolution. To do so is completely unscientific, as science is a society, not a dictatorship. Newton didn't lead the Copernican revolution, and neither did Copernicus, or Galileo, or Brahe, or DesCartes, or Kepler. Einstein (definitely) didn't lead the quantum revolution, just as Bohr, Schrodinger, Pauli, Pauling, Dirac, or Heisenberg didn't. It evolved, it had it's bumps and bruises. Read Thomas Kuhn's "On The Structure of Scientific Revolutions" for more.
I've noticed a lot of people think "this person did this, and this person did this..." instead of "this person was a driving force in this thought, and this person contributed to this scientific program...". I guess that's just a personal thing, and I'm sure someone will argue with me over this, but concepts like calculus or GR aren't invented, they evolve, like animals evolve. And concepts die, too, to be replaced by bigger, more powerful and robust concepts.
That's just my take on science in general, and I'm sure I'll change it at some point, but I figured I'd voice it anyways.
The best way to predict the future is to invent it.