Quote:
Originally Posted by Betonov
Does this mean that gravity travels with the speed of light ??
Answering the question if the sun just disapeared would Earth take a straight line at that same moment or would we still follow an orbit for 8 more minutes.
That's what I get from this
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Gravity is actually described by two theories: Historically, it was Newton who first proposed a theory (Newton's Law of Universal Gravitation) while Einstein described gravity more accurately in his general theory of relativity. So, according to Einstein's theory gravity or better, gravitational waves, travel with the speed light just as light does, since it behaves like a wave.
Now, if we suppose that the sun suddenly disappears, we will take notice of the phenomenon 8 minutes after it happened, because 8 min is -approximately- the amount of time that has to elapse, before light arrives to earth (the distance between sun and earth is approximately 150 million km). As to what happens to earth, well, earth would abandon its elliptical orbit flying off in a straight line, just like you said. Next, it
might be possible that earth could "catch up" with an outer planet since (earth) will be travelling with a greater speed. However, the sun has enough fuel for another 5 billion years so i believe we're quite safe for the time being.
