Posted on 04/19/2005 5:20:02 PM PDT by PatrickHenry
"It depends. Are gravity waves longitudinal or transversal? In other words, are they like sound waves where the oscillation parallels the direction of propagation, or are they like light waves where the electric field oscillates perpendicular to the direction of propagation?"
Great question. Sound is longitudinal because the medium is compressed by the energy from the sound source. Light is transversal because the electric and magnetic fields collapse as they propogate the photon.
As a wild guess, I'd say transversal. There's no medium to compress. Gravity is supposed to have quanta like light as well, (although I suppose it's far smaller, since gravity is a far weaker force).
I'd say we'll have a better idea after this satellite records gravity waves--if it does.
"Detecting gravitational waves would be nice. It would be a way to confirm the speed with which gravity propogates, which is still an open question."
Gravity propogates at c. (the speed of light)
That has been known for a while now.
Bones
Thanks for the ping!
From what I understand, that is an assumption, not a fact. Its assumed because nothing is supposed to travel faster than light, but others assume gravity propogates instantaneously.
I really don't know much about gravity waves, but the article mentions detecting the polarization of them. Polarization only makes sense for transverse waves. There is no way a longitudinal wave can be polarized.
"100 quatloos on the newcomer!"
I will have to look up the specifics.. but an expirement was done some time ago, which had something to do with Jupiter occulting some star.. in which the observations indicated that gravity propgates at the speed of light.
It's been so long (years) since I read that article, I will have to try and search for the info again..
Again I could be wrong, because it's been a while... but that is how I remember it. Will post if I find it, you might be right.
Bones
We had at least one thread on that, right here on FreeRepublic. But it was about 2 or 3 years ago. Maybe more.
Ah.. I just skimmed the artcicles so far but will read them later.
So the experiment did say that but then there was debate over it.. interesting.. thanks for finding that, I had been wondering.
Bones
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