According to theory of general relativity,the light from a distant star in its path bent due to gravity of sun.Why it was not trapped in sun's orbit (to revolve around the sun)?

1 Answer
Dec 17, 2017

Stars are not massive enough to curve light into orbit.

Explanation:

General relativity does predict that the path of light passing close to a star gets bent. This was proved during the 1919 solar eclipse.

What is actually happening is that the star's mass causes spacetime to curve. As light always follows a geodesic, the four dimensional equivalent of a straight line, its path follows the curvature of spacetime.

Now spacetime is hard to curve. It takes a lot of mass to make spacetime curve. So, even massive stars only bend light a small amount.

The only thing which can cause light to curve all the way around it is the event horizon of a black hole. A black hole is where a large mass is compressed into a small volume. At an event horizon spacetime is so curved that nothing, not event light can escape.