The existence of Black Holes is based on the idea that gravity can influence (bend) light rays in some manner. It is a simple premise - can a strong source of gravity effect light rays as they pass by, even though photons have no mass?? This has been a favorite enigma of comologists and other scientists for many years.
In forming his General Theory of Relativity, Albert Einstein used his famous thought experiments to try to prove that gravity can effect light rays. He claimed that acceleration creates the same effect on a beam of light as gravity and are therefore equivalent. "The Principle of Equivalence". Although their effects are similar (but not exactly the same) they are not equivalent. Inertial acceleration is an inertia requirement that states a certain force must be exerted on a body for it to accelerate at a certain rate”. Gravity is just one of the primary energy/forces of nature that fulfills this requirement.
One of the ideas that misled Einstein to his conclusion was his thought experiment, that states: a body dropped in an accelerating elevator behaved in exactly the same manner as it would if was dropped on the surface of Earth. If someone was inside the elevator there would be no way of knowing whether the elevator was "resting" on the ground or accelerating out in space.
Actually, the effects in both cases, are similar but not exactly the same. The truth is, Gravity causes bodies, dropped from various heights in the room "resting" on the ground, to fall at different rates of acceleration (due to their different distances in the room, to the center of gravity of the Earth) where as, all bodies in the accelerating elevator would seem to "fall" at exactly the same rate. This is true whether it takes place in a small room or dropped from an airplane at different altitudes in the sky.
Another factor that adds doubt to Einstein's thought experiment is - the room was not actually "resting" on the ground - it was actually in a constant state of "restrained acceleration" as is everything else that is "resting" on the surface of the earth. Its acceleration was constantly being restrained by the obstructional force of the earth’s surface, (rather then just resting on the Earth's surface with no force being exerted on it). If this obstructional force is removed the body will immediately resume falling.
In both cases, the elevator is in a state of acceleration one caused by the force of gravity the other caused by the electromotive force of the electric motors propelling the elevator upward.
Actually the displacemnet of the star's light passing by the sun was an optical (passing through the corona) rather then a gravitational phenomena.
Donald L. Hamilton author: "The MIND of Mankind": Human Imagination, the source of Mankind's tremendous power!
http://novan.com/mind.htm
http://novan.com/cosmol.htm (Cosmology for the 21st Century)