Stephen Hawking's new way of perceiving black holes !
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ChaosKnight
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Alright, i read in "A Brief History of Time" that if an astronaut fell into a black hole, and sent out a pulse every second, an observer far away would measure longer and longer intervals between pulses. The final pulse just before the astronaut falls through the event horizon takes forever to arrive.
This suggests to me that:
(1) To an observer far away, the astronaut takes a infinite amount of time to fall into the black hole.
(2) Light went into orbit along the event horizon, so it never reaches us.
So which is right?
This suggests to me that:
(1) To an observer far away, the astronaut takes a infinite amount of time to fall into the black hole.
(2) Light went into orbit along the event horizon, so it never reaches us.
So which is right?
(1) To an observer far away, the astronaut takes a infinite amount of time to fall into the black hole shld be right.
However, i am unsure why we can still the astronaut as he falls in... although we know the fact that light can't escape from the black hole itself ! haha. strange isn't it ?
cheers,
wenyi
However, i am unsure why we can still the astronaut as he falls in... although we know the fact that light can't escape from the black hole itself ! haha. strange isn't it ?
cheers,
wenyi
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QuantumGravity
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zong
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Well actually.. BOTH statements are correctChaosKnight wrote:Alright, i read in "A Brief History of Time" that if an astronaut fell into a black hole, and sent out a pulse every second, an observer far away would measure longer and longer intervals between pulses. The final pulse just before the astronaut falls through the event horizon takes forever to arrive.
This suggests to me that:
(1) To an observer far away, the astronaut takes a infinite amount of time to fall into the black hole.
(2) Light went into orbit along the event horizon, so it never reaches us.
So which is right?
The astronaut takes an infinite amount of time to fall into the black hole because our methods of measuring his fall has failed. Any signal that the astronaut sends inside or at the event horizon cannot escape the black hole. Therefore we'll never get that signal. And from there, can we deduce that the astronaut will take infinity to enter the black hole? NO, it is precisely because we know he has entered the black hole that's why we don't get the signal.
At the event horizon, anything will take at least a little more than light speed to escape from the black hole. At the event horizon itself, light neither has the energy to escape, nor would it go into the black hole. THAT IS, assuming the light is at least shone tangential to the event horizon. Anything aimed INTO the black hole must fall in, since it's path was already meant to be that way. So the light that orbits the event horizon must either be tangential or trying to move away from the black hole.
Information about the black hole is still all very theoretical and imaginary, don't worry if you don't understand because it took me some time to understand when i first read it, too...
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ChaosKnight
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If (1) is true then the paradox stands. We should only observe blackholes of minimum size.
Allow me to state my initial question in a different manner to clear the confusion.
Suppose there is a star, with mass just enough to form a black hole. At the end of its life, it collapses to form the smallest black hole possible.
Now, you want to increase the mass of the hole, so you throw your most hated enemy in. But he takes forever to pass the event horizon. You will see him at the horizon, smiling smugly at you for all time. The hole's mass doesn't increase.
Not only your enemy, anything you throw in. If the star was any more massive at the beginning, its collapsing outer layers will also be stopped at the horizon.
So, all black holes should be on the verge of forming or just barely formed. But how is it supermassive holes are detected?
Allow me to state my initial question in a different manner to clear the confusion.
Suppose there is a star, with mass just enough to form a black hole. At the end of its life, it collapses to form the smallest black hole possible.
Now, you want to increase the mass of the hole, so you throw your most hated enemy in. But he takes forever to pass the event horizon. You will see him at the horizon, smiling smugly at you for all time. The hole's mass doesn't increase.
Not only your enemy, anything you throw in. If the star was any more massive at the beginning, its collapsing outer layers will also be stopped at the horizon.
So, all black holes should be on the verge of forming or just barely formed. But how is it supermassive holes are detected?
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zong
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Sorry ChaosKnight, I'm here to debunk your myth again... Where do you get these paradoxes from? They are really untrue, as far as I can see... Not that I don't like you okay haha.. I love thinking about such questions
If you want to say that "the car hasn't fallen in because the car is still in front of me", you are wrong. Remember, of light that cannot escape, they form a ring at the event horizon. NONE of that light reaches you! So how would you be able to see it forever? If you did really see it, then what image of the car must have been sent before the car fell in. And this light would eventually reach your eyes, and then disappear. Which is why previously I said, the images would fade slowly, but over a course of time not infinity.
Another loophole of this myth, as already pointed out by me in the previous post, is that the car doesn't take forever to fall through! It is because our methods of communication have broken down, which is why you eventually don't get his signals at all. And this breaking down of communication should mean that he HAS fallen in, not that he CANNOT fall in. So the mass of the black hole increases, and CAN be observed by us.
Going by the logic of a "static black hole size", where the mass of this black hole doesn't increase at a certain limit because the mass "takes infinity to fall through(bear in mind this is false)", then this means that there also exists a smaller mass where black holes can form, because we can take it that some other part of the mass also takes infinity to fall through. By this recursion, the limit must be zero, since all mass have a chance of taking infinity to fall through. Then there cannot be black holes. Now THAT is a paradox. A paradox created because the basic assumptions have been wrong..
Sorry again Chaos, my replies are aimed at the question not the person ok don't be mad at me for keeping the contradiction on your replies...
If you want to say that "the car hasn't fallen in because the car is still in front of me", you are wrong. Remember, of light that cannot escape, they form a ring at the event horizon. NONE of that light reaches you! So how would you be able to see it forever? If you did really see it, then what image of the car must have been sent before the car fell in. And this light would eventually reach your eyes, and then disappear. Which is why previously I said, the images would fade slowly, but over a course of time not infinity.
Another loophole of this myth, as already pointed out by me in the previous post, is that the car doesn't take forever to fall through! It is because our methods of communication have broken down, which is why you eventually don't get his signals at all. And this breaking down of communication should mean that he HAS fallen in, not that he CANNOT fall in. So the mass of the black hole increases, and CAN be observed by us.
Going by the logic of a "static black hole size", where the mass of this black hole doesn't increase at a certain limit because the mass "takes infinity to fall through(bear in mind this is false)", then this means that there also exists a smaller mass where black holes can form, because we can take it that some other part of the mass also takes infinity to fall through. By this recursion, the limit must be zero, since all mass have a chance of taking infinity to fall through. Then there cannot be black holes. Now THAT is a paradox. A paradox created because the basic assumptions have been wrong..
Sorry again Chaos, my replies are aimed at the question not the person ok don't be mad at me for keeping the contradiction on your replies...
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ChaosKnight
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Don't worry about it, zong. Nothing personal. First off it's not a myth to be "debunked". It's simply i noticed some things i read are a contradiction to observation, that's why i'm seeking clarification.
You see, in the end the paradox hinges on whether (1) is true.
Alright, riddle me this: within strong gravitational fields, time slows down. Will time come to a standstill if the gravitational field is strong enough to trap light?
You see, in the end the paradox hinges on whether (1) is true.
Alright, riddle me this: within strong gravitational fields, time slows down. Will time come to a standstill if the gravitational field is strong enough to trap light?
interesting notion... but why would the image "fade away", since all information will be cut off at the event horizon, the image should just disappear suddenly instead; that is if the object has fallen into the event horizon.zong wrote:...And this light would eventually reach your eyes, and then disappear. Which is why previously I said, the images would fade slowly, but over a course of time not infinity....