Does gravity affect speed of light?

Question

Does gravity affect speed of light. Consider a light wave escaping from earth. Since gravity is a force, It should affect the light particles.
But if the speed of the light is same in space and as well as in earth,
then what is effect of gravity's pull on light (consider there are hell lot of planets and stars with high gravity)

Does gravity affect speed of light. Consider a light wave escaping from earth. Since gravity is a force, It should affect the light particles.
But if the speed of the light is same in space and as well as in earth,
then what is effect of gravity's pull on light (consider there are hell lot of planets and stars with high gravity)

Consider that you are running and somebody is trying to pull you backwards. It does affect your speed right?. then why not the similar theory is not applicable for light?

Answer 1

Actually, it does and it doesn't. It depends on how you define speed. Locally the speed of light is always the same--this means that at any point (or rather, any sufficiently small 4-D patch of spacetime) a measurement of c will always yield the same result.

On the other hand, if you define speed as "how long it takes for light to travel from point A over there to point B over here in a Euclidean straight line," then the measurement can yield a different result depending on what massive objects are in the vicinity of the light's path, because the light seems to bend about. This is the effect of gravitational curvature.

It so happens that the light travels along the shortest path--called the geodesic of the space you're in--but that this path is not necessarily a straight line. Hence extreme cases like the bending of light around a black hole at the event horizon, where the light never seems to get from "there" to "here," can seem to produce gross deviations from the vacuum speed. But when the distance and time are appropriately measured along the geodesic--or equivalently if the measurement is done locally--then the speed in vacuum is always the same.

The statement of the principle of relativity concerns local measurements only--and in this sense the speed of light is a constant.

Answer 2

Gravity Speed Of Light

Answer 3

The gravity bends light. This has been tested and verified. This proves one thing. Photos do have mass. Once they have mass they should be affected when light tries to escape from a gravitational field. The lack of understanding of the light leads to several controversial statement. I don't know is there any measurements of speed of light under zero gravity in vacuum. There is a red shift phenomena of light well documented and used to measure the speed of stars, galaxies etc. If the assumption of constant light speed is true then one explanation could be the frequency shifts downwards towards red. This will reduce the energy of the light. A force reduces the energy. The energy reduction can be reduced speed or red shift. This is the only possible explanation feasible at this time. I strongly suggest read some research papers on this issue.

Answer 4

Gravity does not affect the speed of light. Gravity can only bend light. The acceleration of gravity in a black hole is equal or greater than the speed of light, which is why light cannot escape - nothing to do with slowing down the speed of light. The speed of light can only be slowed down by allowing it to travel through a medium. The speed of light in vacuum is constant.

Answer 5

Great question, yahoo should give you bonus points for asking questions like this.
Velocity is distance displaced divided by time, gravity will not increase the speed of light but it might and probably does slow it down, gravity alters time, gravity does have an affect on the path of light, electromagnetic radiation must eventually come across a black hole in its infinite travels, maybe light can orbit large gravitational Fields!

Answer 6

Gravity does effect the speed of light. This is because sometimes the Astronomers and Scientist are able to confirm the presence of a body many many light years away in space ( a star or something as such) by the way the gravity bends light. Logically if Gravity can bend light it is a given then that it can also effect its speed.

Also think about Black holes, these are massive objects with the highest extreme gravity. A black hole is an object predicted by general relativity with a gravitational field so strong that nothing can escape it, not even light. This should also prove that gravity can and does effect Light.

Answer 7

The speed of light is a constant, in the space which is mostly vacuum. So gravity does not affect the speed of light. However, it can bend a ray of light. If a beam of light is passing over a massive body, due to gravity its path will be bent towards the massive body. This was proved recently in an astronomical observation in connection with testing the theory of relativity.
Dialation of time owing to speed is an entirely different phenomenon and it has nothing to do with the gravity.

Answer 8

You are right! Consider a black hole that has such a high gravitational attraction and is so small that you can get very near the center of gravity. If someone within the black hole shined a flashlight up into the heavens, the photons would shoot upwards then turn around and fall back to the center of gravity (like shooting bullets up into the air on earth!). That of course is why it is a "black" hole; no light can escape. The sun and even earth would have a similar but much weaker attraction for escaping light. The escape velocity from the surface of earth is about seven miles per second; much slower than the speed of light. The inverse square law shows why the gravitational attraction increases almost without limit as you approach the center of gravity. On earth, the crust prevents us from getting closer and the mass would have to be concentrated into a singularity (as in a black hole) to exhibit maximum pull.

Answer 9

This is where the cooky crumbles.
If you believe light has mass than the laws of gravitational physics related to masses apply.Hence speed of light is affected.

However if you believe light has no mass or volume and only posseses energy what ever you may call it it is, than the gravitational laws of Newtonian Physics do not apply .
Therefore gravity does not change the Velocity of light.

No one has proved yet that the Velocity of light on Earth is the same as that of outer Space.

If light is affected by mercury gravity than its also affected by other planets or galaxies as well.They call it gravitational lensing.

Answer 10

The speed of light is unaffected by gravity. BUT, the travel time of light from one place to another is affected by gravity. This is because what we call gravity (..according to Einstein's relativity) is actually a curvature in space caused by the presence of mass. Light, like everything else, must follow the geometry of space, and if the space through which a particular beam of light travels is curved then it will take that beam longer to get from point 'A' to point 'B' than if there was no curvature.