Answer:

yesi know

Explanation:

Here is the short version: according to general relativity, which has passed every experimental and observational test to date and is a fantastically accurate theory of gravity, gravity is the bending of spacetime by mass-energy. Gravity doesn’t affect light; light travels along straight lines in spacetime. However, mass-energy turns those straight lines into curved paths. This is famously illustrated here:Light travels along the grid lines; as you can see, near the mass these lines stop being straight and become curved. This is the bending of light by gravitation — it is not that light is affected by gravity, it is that space itself is literally bent by mass-energy: this is gravitation (and this picture is actually a pretty fair representation of what does happen in GR).

And we know that this is true, because we can observe it. Here’s an example:

The Einstein Cross is a single quasar which splits into five images (the central image isn’t visible to the naked eye) due to gravitational bending of its light rays by a foreground galaxy. This is known as “gravitational lensing”. Here’s another example:

hat’s the end of the short version. If you want the longer version, keep reading…

Up until 1905, everybody would have believed that gravity didn’t act on light. Well, Newton thought light would bend in a gravitational field, but Newton believed (on the basis of observation) that light consisted of very small particles, which he called “corpuscles”. (Newton pointed out that shadows had sharp edges, which would happen if light was a stream of particles, each of which traveled in a straight line; however, if light were a wave, some of it would bend around an obstacle, creating a fuzzy outline of a shadow). He had no reason to believe that these were massless. But after Thomas Young showed that light was a wave in 1804 with his famous double-slit experiment, people believed that light would be unaffected by gravity. This belief was reinforced in the 1860’s when James Clerk Maxwell showed that light always traveled at a specific velocity,  c . If it always traveled at a specific velocity it couldn’t be accelerated by anything, including the gravitational force.