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yes virginia, gravity does move at the speed of light - don't let the bastards grind you down.
taumeson
taumeson
yes virginia, gravity does move at the speed of light
New Scientist reports that gravity moves at the speed of light.

Hmm. Pretty interesting. Sad, really, as one of the most mystifying and least understood forces in the universe has some of the shine removed from its cachet.

Wonder what this'll do to the various models.
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swolfe From: swolfe Date: January 8th, 2003 08:28 am (UTC) (Link)
so, back to the two particles in an empty universe...they'd move together at the speed of light? would that be the total of their velocities? or would it be 2c?

i'm thinking each one would have v = c/2...
taumeson From: taumeson Date: January 8th, 2003 01:05 pm (UTC) (Link)
i'm thinking each one would have v = c/2...

That's the answer...gravity can't exert a force on the two objects to make them come together greater than the speed of light.

i would imagine that it would be slightly less than "c", actually, because you'd have to factor in their vibrational motion (is that brownian motion? i.e. the motion that occurs when near absolute zero?) and that when they vibrate towards each other while moving towards each other, they can't move faster than c.
qed From: qed Date: January 8th, 2003 08:40 am (UTC) (Link)
I think the speed of gravity is predicted by general relativity, so I don't think this requires any correction. I'm pretty sure this was an expected result, it just took a lot of experimental cleverness to prove it.

And two particles in an empty universe still move at the speed of light.
dravenfrost From: dravenfrost Date: January 8th, 2003 02:49 pm (UTC) (Link)
What if they were initially moving away from each other at the speed of light? Would gravity never catch up to them?
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