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Physics, Astronomy & Cosmology / In black holes, are the event horizon and the singularity one and the same?
« on: 19/10/2013 15:50:45 »
Thoughts about a black hole
What I know from a black hole is that it has an event horizon and a singularity.
I’ve been thinking about these concepts. The event horizon is the place from which the gravity escape velocity is greater then the speed of light, so supposedly nothing could get the speed to escape from it. The singularity however is the center point with (almost?) infinit energy and (almost?) no size.
Now concider this:
Alice and Bob are deciding to check the inner workings of a black hole, because they live near to it anyway. They draw straws and Bob loses so he has to take the space ship to the black hole while Alice stays watching what will happen to him. She wants to see what happens when Bob is going past the event horizon.
There he goes and Alice sees Bob getting closer and closer to the point of no return. She has to reajust her telescope a few times, because of the redshift of light emitted from the backlight of Bob’s spaceship. The light gets redder and redder and Bob’s spaceship is getting smaller and smaller, and he is traveling slower and slower so it seems. After days of watching, almost no light is coming from Bobs spaceship and he doest get any further while he has almost reached the point of no return. She draws the conclusion he will never reach the horizon and she will never see him back again.
Now Bob’s story:
Bob took a spaceship from which he could take a look outside both at the front and at the back. He also took a telescope to watch Alice for the last time while he is getting closer and closer to the point of no return. He also has to reajust his telescope a few times, because of the bright blue-shifted light emitted from Alices her telescope (she placed a laser on it so Bob could see where she is). Also (due to the gravitational field he is entering) he sees the universe around him develop quicker and quicker. Light is getting brighter and brighter.
Watching the other side, he can still see the event horizon being black and all, but it is getting smaller and smaller. Then, in an ultrabright flash, everything in the universe seems to happen at the same time (in fact it is happening really quick), and then… everything ends.
What I want to say is that my conclusion would be:
The event horizon is the same as the singularity.
The size of the event horizon is dependent on the reference frame from where you look at it. From close to the black hole it is smaller, because you are inside the gravitational field from it.
Is this conclusion correct? When no, where am I going wrong?
What I know from a black hole is that it has an event horizon and a singularity.
I’ve been thinking about these concepts. The event horizon is the place from which the gravity escape velocity is greater then the speed of light, so supposedly nothing could get the speed to escape from it. The singularity however is the center point with (almost?) infinit energy and (almost?) no size.
Now concider this:
Alice and Bob are deciding to check the inner workings of a black hole, because they live near to it anyway. They draw straws and Bob loses so he has to take the space ship to the black hole while Alice stays watching what will happen to him. She wants to see what happens when Bob is going past the event horizon.
There he goes and Alice sees Bob getting closer and closer to the point of no return. She has to reajust her telescope a few times, because of the redshift of light emitted from the backlight of Bob’s spaceship. The light gets redder and redder and Bob’s spaceship is getting smaller and smaller, and he is traveling slower and slower so it seems. After days of watching, almost no light is coming from Bobs spaceship and he doest get any further while he has almost reached the point of no return. She draws the conclusion he will never reach the horizon and she will never see him back again.
Now Bob’s story:
Bob took a spaceship from which he could take a look outside both at the front and at the back. He also took a telescope to watch Alice for the last time while he is getting closer and closer to the point of no return. He also has to reajust his telescope a few times, because of the bright blue-shifted light emitted from Alices her telescope (she placed a laser on it so Bob could see where she is). Also (due to the gravitational field he is entering) he sees the universe around him develop quicker and quicker. Light is getting brighter and brighter.
Watching the other side, he can still see the event horizon being black and all, but it is getting smaller and smaller. Then, in an ultrabright flash, everything in the universe seems to happen at the same time (in fact it is happening really quick), and then… everything ends.
What I want to say is that my conclusion would be:
The event horizon is the same as the singularity.
The size of the event horizon is dependent on the reference frame from where you look at it. From close to the black hole it is smaller, because you are inside the gravitational field from it.
Is this conclusion correct? When no, where am I going wrong?