Re: Gravity Question

In article <l_HIg.75729$fV1.64636@xxxxxxxxxxxxxxxxxxxxxxxxx>,
Pete <petenfay@xxxxxxxxxxxxxxxx> wrote:

If the Sun vanished in an instant would all the orbiting objects instantly
fly off into the universe or would they fly off one by one starting with the
nearest one to the Sun. Newtonian gravity or special relativity?

According to this page on John Baez's website:

http://math.ucr.edu/home/baez/physics/Relativity/GR/grav_speed.html

a finite speed for gravity would make planetary orbits unstable under
Newtonian physics. In general relativity (special relativity is not
about gravity) gravity propagates at light speed.

This New Scientist article from 2003:

http://www.newscientist.com/article.ns?id=dn3232

(which incidentally quotes John Baez!) describes an experiment
indicating that it propagates at the speed of light. It explicitly
mentions the case of the sun vanishing.

-- Richard
.

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