Can light be accelerated by a black hole's gravity?

[Andrejck]

I would just like to say I am in no way a physicist, so what I propose could be just well...wrong, not possible or just ridiculous.

Well the other day I was watching a documentary called "Through the wormhole" with Morgan Freeman. And it got me thinking about a lot of stuff.

So the first question i have for you is:

Is it possible for light to be accelerated by the gravity of a black hole, if it were to go at just the correct angle, much like a spaceship could theoreticly be accelerated with the help of some of the planets gravitational fields.
So in short my question is could light brake its own speed limit.

 

[Rick88]

Light is composed by tiny particles called photons, which are massless.
Only something with a definite mass can feel a gravitational attraction towards another body, as the gravitation force is given by:

F=GmM/r²,

where G is just constant, m and M are the masses of the two interacting objects and r their separation.
You can see that if you let m=0 (so considering a photon), it simply gives F=0.

So no, light cannot travel faster than the speed of light (which makes sense!)

 

[Kevin_Axion]

But you must understand that light follows the curvature of space-time along geodesics, therefore it can interact with gravity, it also has energy.

 

[Rick88]

But you must understand that light follows the curvature of space-time along geodesics, therefore it can interact with gravity, it also has energy.

It does because other massive objects do curve the space-time and photons travel through it. But that does't make them go faster.

 

[Kevin_Axion]

I know, I wasn't refuting your statement, I was responding to the original poster.

 

[Rick88]

Oh, my bad :)

it's further information for Andrejck, anyway :)

 

[Kevin_Axion]

It's fine, but when you say massive objects curve space-time it isn't fully correct because mass-energy curves space-time, therefore light can.

 

[Rick88]

True, but I guess it's a negligible curvature.

 

[Andrejck]

Thx for the anwser guys ^^.

Now another question:

Do we know in which direction is the center of the universe, I know we don't know our position in the universe compared to its center or point of origin but, do we know the direction in which that point could be?
Like, if you throw a rock in a pond and watch the ripples you know from where they come even if you don't exactly know where the rock fell in.

 

[russ_watters]

We are of course at the center of what we can see, but the universe itself apparently (based on mathematical models and observation) does not have a center.

 

[Chronos]

A 'center' cannot be defined without topological boundaries. So, the question is - how do we trace the edges of the universe? Current observational evidence strongly suggests the CMB [our best guess at an 'edge'] is equidistant in all directions. We are left with the choice between Earth as the center, or, there is no center of the universe.