Every object has mass and anything with mass has gravity. We only notice the effect with big things, such as planets and stars. An apple has a gravitational field but it is so tiny that we are unaware of it. Drop the apple and it falls to Earth. This is because the gravitational field of the planet is millions of times more than that of the apple so the effect provided by the apple is drowned out. (more…)
It was not until Einstein and his General Relativity Theory that anyone thought that gravity could affect light.
Previously, Isaac Newton’s theory was that an object had to have mass to be affected by gravity. Since light does not have mass, under newtonian physics, it would be unaffected by the gravitational pull of an object.
We now know that light’s trajectory can be altered by gravity. According to Einstein’s theory, any object with mass alters the shape of space-time. Anything moving (more…)