Woah!
Who said that gravity operates instantaneously? There is
no observation that justifies this 'Newtonian' statement, and
lots of evidence from special and general relativity that gravity
obeys the speed limit set by the speed of light. The dynamics of our
solar system, with light travel times up to several hours, would be
very different if gravity acted instantaneously. The calculation of
planetary positions and their mutual gravitational influences would
lead to different predictions for where the planets are in the sky
at a specific time, especially for the planets beyond Jupiter where
the light travel times are the longest.
Return to Dr. Odenwald's Gravity
page at the Astronomy Cafe Blog.