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The Speed Of Gravity Revealed
redwolfoz writes "New Scientist is reporting that the speed of gravity has been measured for the first time. 'The landmark experiment shows that it travels at the speed of light, meaning that Einstein's general theory of relativity has passed another test with flying colours.' Researchers made the measurement of the fundamental physical constant with the help of the planet Jupiter. One important consequence of the result is that it will help constrain the number of possible dimensions in the Universe."
The same way an electric field doesn't have a charge, but affects objects that do have a charge. Gravitational/electric fields are -created- by masses/charges. And don't confuse gravity with gravity waves (the speed of which being what are measured here).
.25 to be kinda ridiculous? So based on their measurements, the speed of gravity could actually be anywhere from 30% slower to 20% faster than light. I mean, the article makes it sound like they're just assuming the real number is 1.0 c because anything else would be really surprising. Or maybe the article is wrong. Or I'm mis-reading it. But at the moment, it doesn't sound like "passing with flying colors" to me.
By the way, did anyone else find the quoted margin of error of
The enemies of Democracy are
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> Try telling Sonny Bono that.
Au contraire! Blunt force trauma is all about electromagnetsm. (I suppose there are a few places where it's also about electroweak interactions, but that's a hell of a lot more trauma than I care to talk about. *g* :)
At any rate, gravitational forces had accelerated Sonny pretty gently, and he was doing just fine until electrostatic forces from a nearby tree intervened.
Sonny was a silly clam (silly clam? I repeat myself) who tried to make the electrons in his body occupy the same space as the electrons in aforementioned tree. (For a guy who claimed to be a great physicist, L. Ron Hubbard sure didn't teach his disciples much about the Pauli Exclusion principle or Van der Waals forces.) Sonny Bono's failure to grasp rudimentary physics can be seen as yet another case of evolution in action.
From that they worked out that gravity does move at the same speed as light. Their actual figure was 0.95 times light speed, but with a large error margin of plus or minus 0.25.
So, really, they're triumphantly announcing that the speed of the light is somewhere between 0.7 c and 1.2 c, and just supposing it has to be c for everything to make sense.
Physicists have been accused of being loose with rigour, but this is really stretching it.
You can't prove a physical theory - you can either show that it fits experimental evidence (in which case it might be right), or that it doesn't (in which case you've disproved it).
This experiment shows that a key assumption of GR is consistent with real life. That's it. That's all we can do, and that's all that is being claimed - observations of Jupiter give (roughly) the results we'd expect if gravity travels at c.
I think we should assume more of the author. Think of it this way: Using General Relativity, you can predict what the gravitational field will be. His experiment measured what the field actually was. If the predictions match the measurement, the theory is confirmed (or at least not disproven).
Almost. If the American GOVERNMENT has anything to do with it. The people and scientists are not on the whole evil and destructive like our government is.
Your definition of evil must be the common "has different priorities or beliefs than I do and isn't perfect"
There are better choices for a definition of evil, like the following that applies to Saddam Hussain:
"kills millions, brutally supresses all opposition and all human rights, hires the worst profesional torturers and rapists in history"
You know I assumed that George Senior was full of shit when he called Saddam "another Hitler".
I was wrong. The problem here is that our media doesn't care enough to actually inform us of all the slaughter and oppression around the world and our local do-gooder activists are so busy hating their republican neighbors that they couldn't be bothered to check out the possibilty that they are occasionally right.
Cognitive dissonance makes it easier to believe whatever propaganda is floating around as long as it isn't our propaganda.
The situation in the Middle east is complicated, so of course we know nothing about it. It's scary but the people currently in the White House actually know more about that issue than the activists.
I don't want the "total information awareness" geeks reading my email. But you know, I can oppose some policies of my government without doing a full "you evil bastard" hissy fit.
Rocky J. Squirrel
It's much more likely the ringing comes from the air right next to the polished gong surface suddenly heating up.
There's a similar confusion about what drives those "solar radiometer" things - you know, a little black-and-white paddlewheel inside an evacuated glass ball that spins when you shine a light on it? People often say the reason they run is photon momentum, when the actual explanation is that the black sides of the paddles are hotter than the white sides, so when the few gas molecules left inside the ball hit the paddles, they leave the black sides going faster than the white sides.
The proof of this is the direction the paddlewheel turns - it turns white-side-first, and a photon-mass explanation would have the paddle turning black-side-first. If you put a paddlewheel inside a REAL hard vacuum, with a REAL low friction bearing, and REALLY isplate it from outside vibration, it turns the right way. See here for a more coherent and complete explanation.
To a Lisp hacker, XML is S-expressions in drag.