If nothing with mass can travel faster than the speed of light, then....?

Question

Then how is it that light cannot escape a black hole? Given that the photons are travelling at the maximum velocity attainable, how could a black hole have enough gravitational energy to prevent even light from escaping? Is this not a pardox? If nothing can have a higher energy than a photon moving at the speed of light, how can a black hole put it in?

Answer 1

Einstein's general relativity states that gravity creates a curvature in the space-time continuum, that is the path of light. note that Einstein defined gravity as a "geometric" curvature in a four-dimensional surface.. also know as space-time. that is why light can be deflected by a massive object such as stars and we have the phenomenon known as gravitational lensing that can be observed. at very high gravitational fields, the space-time continuum is "steeply" curved, making light bend and go back to its source.

Answer 2

The photon has a positive mass, it is very small, but it is there.

Since photons have mass they are attracted by gravity and can be bent by gravity; this is called gravitational lensing and is very useful in astronomy (http://en.wikipedia.org/wiki/Gravitational_lensing).

The very slight mass of a photon is the only mass that can survive going at the speed of light. If any other mass tries to then it is converted into energy, including photons. This is how a black hole can suck in light.

According to Wikipedia: http://en.wikipedia.org/wiki/Photon
“The photon differs from many other elementary particles, such as the electron and the quark, in that it has zero rest mass.”

A photon has zero rest mass, but what about when it is moving? We can slow light down, but we can’t stop it and still have a photon. It seems that stopping light destroys the photon (The speed of light drops in an atmosphere, and even more in water). Remember that when you block a photon it is reflected and the photons that are reflected into your eye gives you your vision. So just putting up a solid surface won’t stop a photon, only redirect it.

Gravity is a property of all objects as far as we know only something with mass can be effected by gravity, therefore the moving photon must have some sort of tiny mass. The tiny mass would be the energy of a photon divided by the speed of light squared because of E=mc^2, so like I said the mass is very tiny and only present when it is moving. If it was a truly massless particle then how could it be affected by gravity?

The event horizon of a black hole is the point where you can't get out and all the laws of physics break down. This is the point where something has to exceed the speed of light to leave the black hole, since nothing can do that nothing can escape. We can't see any events beyond the event horizon.

Answer 3

Reread your statements and I think you'll find that one of the assumptions is false.
"If nothing can have a higher energy than a photon moving at the speed of light..." -- This isn't true. Kinetic energy depends on an object's mass and velocity, and while the photon has maximum velocity, the mass is very small. What happens if an object much much larger than a photon has slightly lower velocity? The object has more energy.
That said, given the enormity of black holes in mass, it's possible (and true) that the gravitational energy exceeds that of a photon's kinetic energy.

Answer 4

No one know what happens once you cross the event horizon of a black hole (this is where no light or anything else can escape from the black hole). It is possible that you'll be traveling faster than speed of light, which also means that you're also traveling backwards in time. Yes, you can't travel faster than light when you're outside the event horizon. But currently there is physical theory to describe what happens within the event horizon. As a matter of fact, Special and General Relativity tells us that at the event horizon time appears to stop.

Answer 5

The key to understanding what you're asking is to realize that everything, including photons of light, are embedded in space. Secondly, we know that the geometry (..shape..) of space is altered by the presence of mass. We call this distortion of space 'gravity.' The gravity (..distortion of space..) is so great inside a black hole that it can actually be turned back on itself. Since photons must follow the contours of space, they too will be turned back into the black hole.

Answer 6

A black hole is a dead star. It's gravity is so great that nothing can escape, not even light. If you could weigh the material in a black hole, 1 teaspoon would weigh 100 tons

Answer 7

This is not really a paradox...the problem is in how the question is posed. Gravitation is not energy as such. It is better to think of it as a property of the universe, like distance or time.

Answer 8

Gravitation is not mass.