Why can't light escape a black hole?

Question

But if light moves at a constant speed relative to its observer, then gravity can not prevent light from travel forward. I was thinking that the light is still moving at the speed of light, however the relative speed for an observer outside the black hole time passes so slowly that they can not observe light escaping the black hole. However wouldn't a theoretical observer in the black hole perceive the light as escaping the black hole as their peception of time would be approaching infinitely faster than an observer outside the black hole?

Answer 1

Black Hole:
A black hole is a super dense object that has an intense gravitational pull. There are two parts to a black hole, a singularity and a event horizon.

The event horizon is where the force of gravity becomes so strong that even light is pulled into the black hole. Although the event horizon is part of a black hole, it is not a tangible object. If you were to fall into a black hole, it would be impossible for you to know when you hit the event horizon.

The singularity is not really a tangible object either. According to the General Theory of Relativity the Singularity is a point of infinite space time curvature. This means that the force of gravity has become infinitely strong at the center of a black hole. Everything that falls into a black hole by passing the event horizon, including light, will eventually reach the singularity of a black hole. Before something reaches the singularity it is torn apart by intense gravitational forces. Even the atoms themselves are torn apart by the gravitational forces.


Light from a Black Hole:
One of their basic properties of black holes is that they trap light. According to the special theory of relativity (and also according to the general theory since it contains the special theory) that nothing exceeds the speed of light.

The particles of light, called the photons lose energy when travelling out of a gravitational field and appear to be redder to an external observer. . The stronger the gravitational field, the more energy the photons lose because of this gravitational redshift. The extreme case is a black hole where photons from within a certain radius lose all their energy and become invisible.

Another view of the same phenomenon is that the light can not escape out of a black hole as it can not go pass the event horizon. The event horizon is the point outside the black hole where the gravitational attraction becomes so strong that the escape velocity (the velocity at which an object would have to go to escape the gravitational field) equals the speed of light. Since according to the relativity theory no object can exceed the speed of light that means nothing, not even light, could escape the black hole once it is inside this distance from the center of the black hole.

A more fundamental way of viewing this (the same phenomenon) is that in a black hole, the gravitational field is so intense that it bends space and time around itself so that inside the event horizon there are literally no paths in space and time that lead to the outside of the black hole: No matter what direction you went, you would find that your path led back to the center of the black hole, where the singularity is found.

Black Hole Radiation:
Recent attempts to understand black holes on a quantum level have indicated that they radiate thermally (they have a finite temperature, though one incredibly low if the black hole is of reasonable size) that is proportional to the gradient of the gravity field. This is due to the capture of virtual particles decaying from the vacuum at the horizon. These are created in pairs and one of them is caught in the black hole and the other is radiated externally. This has been interpreted by Hawking as a tunneling effect and as a form of Unruh radiation. This may give some clever and knowledgeable researcher enough information to figure out what's happening at the center someday.

Answer 2

First, you have to understand that gravity can affect the path of light. I think it was Einstein who predicted this and it was verified during a solar eclipse. The light from stars was bent by the sun's gravitational field, causing them to be seen in unusual places.

So if you now believe that light can be affected by gravity, then it isn't much further of a leap to believe that the gravity field could be so strong that not even light is able to leave. Every object has an "escape velocity" which is the minimum amount of energy needed to leave the surface. For Earth it's about 18000 mph. If the Earth had a lot more mass this number would increase to the point where the escape velocity was greater than even the speed of light. This could be done if a large star collapsed into a very small point.

Answer 3

light is composed of "particles" or packets of energy known as photons. By the special theory of relativity, we know that while photons lack any sort of rest mass, they have a psuedo mass by virtue of the energy they transmit at the speed of light. This means that they are affected by gravity. That's part 1 of the answer to your question.

Part II: In any gravity well, even the gravity that the mass of your body causes, there is what is called escape velocity. That is the velocity needed for any object with mass (a baseball, rocket, or even light via it's moving momentum from part one) to leave orbit (or falling pattern) around that gravity source. For a person, escape velocity is so incredibly small that it may as well not exist. For earth, the escape velocity is high enough that it takes massive rockets to leave earth orbit. A black hole is an entirely different. For a black hole, within the event horizon (the line of "no return" per se) the escape velocity is higher than the speed of light, meaning that NOTHING, not even light can escape the gravity well (since light has gravitational effect via part I, it gets pulled back in). In fact, that is what distinguishes where the event horizon around a black hole is: the line at which the escape velocity for the gravity well becomes greater than the speed of light.

Answer 4

Your assumption that light travels at a constant speed for all observers is only true when the observers are inertial. This is where special relativity is applicable.

The moment you include gravity, this is no longer true. General relativity relates the curvature of spacetime (gravity) to the energy within it, and vice versa. All objects, including light, take the shortest path between two points. However, when space is curved this is not a straight line.

The curvature of spacetime will cause another observer to see effects such as time dialation and length contraction, and at the 'event horizon' of a black hole, the curvature is strong enough that light is stuck there. Its 'shortest' path leaves it stuck at the horizon.

Answer 5

The gravity at the event horizon is so strong that the escape velocity is greater than the speed of light. That is, any object wishing to escape the black hole would require a velocity greater than that of light.

Answer 6

2 issues be sure the flexibility of the gravitational pull of an merchandise: the mass of the item, and the area from the midsection of the mass of the item. Black Holes are the end results of implosions of stars with a minimum of hundreds of circumstances the mass of our sunlight, so they initiate up off with gravity this is hundreds of circumstances better than our sunlight's gravity. whilst the celeb implodes it turns right into a ingredient in area with a similar mass because of the fact the unique celeb, yet with out top, width or intensity. It turns right into a dimensionless ingredient called a Singularity. because of the fact the Singularity has no dimensions, you may get extremely on the fringe of the midsection of mass of the Singularity (unlike with the unique celeb). you may get so on the fringe of the Singularity that the gravitational pull of the Singularity turns into solid sufficient to dodge even easy from escaping. the area from the Singularity at which easy can not get away the gravitational pull of the Singularity is termed the form Horizon. the form Horizon is the outer boundary of a Black hollow. .

Answer 7

Let's use an example.
On earth, yo need to go at a speed higher than 9.9 meters per second to escape earths gravity. So, all those rockets and space shuttles that you see going to space have to acquire a speed higher than 9.9 meters per second to escape earth's gravity, otherwise the rocket or the space shuttle falls back to earth.
In a black hole, the gravity is so strong that even something going at 300,000 meters per second (speed of light) cannot escape its pull. Thus light particles, called photons are pulled by the black hole. Actually the name "black hole" is because no light escapes from it.

Answer 8

Its because the gravity is so intense that light cant even escape.

Answer 9

Because light is particles of energy, so it is affected by gravity.

Answer 10

gravity