how does gravity affect light if light does not have mass?

Question

well, they say gravity only affect things that are consisted of mass, or something that can be affected indirectly by gravity like sound. but what about light? we all know light has no mass, so how CAN it be affected?

Answer 1

Light is not bent by gravity. Light travels in a straight line in space and the gravitational field of a large planet or star warps space itself. So from our perspective light appears to bend when it is actually following the curvature of space.

Answer 2

How Does Gravity Affect Light

Answer 3

By definition, a photon (packet of light) has no mass. However, some people trying to explain some of its more peculiar properties (like the fact that we know it pushes on thing) have established an "upper limit" of a photon's mass at 4 x 10-48 grams (4E-48 g). In any case, they do have momentum, and everyone agrees on that (even though yes, momentum = mass * velocity).



However, the real thing is that light isn't affect by gravity. It's sort of an optical illusion on a stellar scale. The gravity isn't working on the photon, but instead, intense gravitational fields are distorting space-time -- we've all seen the heavy weight being dropped onto a flexible grid and how it "bends space." Well, all of the stars and black holes distort space like that, but three-dimensionally, which is sort of funny to think about.



Anyway, when you light doing strange things, like gravitational lensing, or being "sucked" into a black hole, what's happening is that the photon are just following the new "curvature" of space. If the distortion of space leads them into a black hole, that's where they go. If the distortion kind of refracts light around so that distant objects become visible (gravitational lensing), it's doing it because it's following the "fabric" of space.

Answer 4

First of all gravity doesnt affect light (or photon) at all. Second thing is photon has got some mass but it is negligible. If gravity affects the light as you says then Jupiter which is fifth planet from sun and which is more greter in size and gravitional force than any other planet in our solar system can attract light from sun easily by his great gravitional force, but my friend reality is different. Jupiter gets very nigligible light from sun as compared to earth though it has greater size and gravity. In short gravity does not affect light (or photons) and photons are nothing but very small particles which are everywhere in our solar system.

Answer 5

By General Relativity, mass warps Space-Time. We perceive the warp as a force, but it is really that Space-Time is curved. Light follows the curve.