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simulacrum
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Posted 04/23/04 - 07:08 AM:	#21
Quick question: Does an event horizon get larger as matter gets taken in by a singularity?
Just in time to be late.--simulacrum

geoff23
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Posted 04/23/04 - 07:10 AM:	#22
simulacrum wrote: Quick question: Does an event horizon get larger as matter gets taken in by a singularity? The area inside the event horizon increases, yes.
The poets did not win; the philosophers surrendered. (Umberto Eco)

simulacrum
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Posted 04/23/04 - 08:15 AM:	#23
Alright then, slow question: Is there some sort of constant in which the surface area that is the event horizon would grow in ratio to a certain amount of mass consumed by a singularity?
Just in time to be late.--simulacrum

Distortion
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Posted 04/23/04 - 09:06 AM:	#24
weqweq wrote: As far as I understand time would stop at the event horizen, as that is the point where light cannot excape. Gravity slows down time, would not the force of gravity at the event horizen be enougth to stop time. Nop, sorry. Time only 'stops' where the curravture of space is infinite - ie, the singularity. Since a singularity is a point of infinite density, it therefore has an infinitely small volume. Time only slows past the event horizon - the event horizon only signifies the point at which the curvature of space is so great that light cannot escape.
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wuliheron
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Posted 04/28/04 - 04:08 PM:	#25
A black hole is simply when gravity overcomes the escape velocity of light. You look at it, shine a light on it, and there is nothing to see because all the light, 100%, is swollowed up. Not a single photon is reflected. The basic idea was first formally proposed a hundred years before Einstein. As for rips in spacetime and whatnot, those are scientific ideas that arose from Einstein's theory of Relativity and the concept of a singularity (not to be confused with a black hole.) A singularity is a mathematical concept with no physical evidence whatsoever to support it's existence. Whereas a black hole can possess well defined limits, a singularity would by definition have at least one magical property beyond the kin of any science. Theoretically, nothing really enters a black hole beyond the event horizon. Anything that falls in, as far as well can tell, is converted into pure energy and collects just beneigth the event horizon. In addition, modern string theory predicts that black holes can not shrink to indefinitely small sizes or what is called a singularity. If one could keep falling beyond the event horizon as in the case of a singularity, then one would achieve faster than light velocities and all bets are off. Theoretically, only tachyons can move faster than light, and time for them runs backwards. In addition they require increasing amounts of energy not to accelerate as we do, but to slow down. All of this is pure and unadultrated speculation, the stuff of science fiction which highlights the weak parts of modern theoretical physics.

BenMurrell7
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Posted 05/05/04 - 01:17 PM:	#26
As you tried to approach the black hole you would find that time slowed down, and eventually it would slow down to the point that it stopped moving completely, so you could never get there - you would just be left, half ripped-apart, in a zone where time had completely stopped. Im a bit confused on this one, geoff23. Time is a man-made measurement, corect? I just do not see how time can cease to be some places and continue on elsewhere. Does this have anything to do with Xenos paradox?

Socrastein
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Posted 05/05/04 - 03:03 PM:	#27
vechical was travelling at light speed (which is impossable as it would have infinate mass), and a light is shinned from the back to the front, then the light woud never reach the front. This analogy of an accelerating vechical is simaler to the effect of a black hole. (not perfectly accurate, but it helped ne to understand.) Not accurate at all, in fact. The light would shine forward just as fast as if you were sitting in your car in a parking lot and shined it. You could still look in the mirror and see yourself in real time, for example, travelling at the speed of light. Light is NOT a speed limit, it is a constant, from every single point of reference. If you tried to "chase" a beam of light, you could never get beside it and be flying along with it at C - it would always move away from you at C. If you don't believe me, study up on Einstein.
"The time has come for people of reason to say enough is enough. Religious faith discourages independent thought, it's devisive, and it's dangerous." -Richard Dawkins

Socrastein
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Posted 05/05/04 - 03:11 PM:	#28
Time is a man-made measurement, corect? Yes, measurement of time is man-made (seconds, minutes, what not) but not time itself. It can cease here and continue there because time is completely relative. There is no "universal time" that you can set your watch to. For example, their have been experiments done in which atomic clocks, one left on earth and one put in a space ship travelling around the world at obviously pretty high speeds, were before completely in sync, and after the spaceship clock was behind the earth one by tiny tiny fractions of a second. Same thing with gravity - one clock on the bottom floor of a high building, where there's more gravity, and one on the top floor. Leave them long enough, and the bottom one loses a fraction of a second. At high speeds and high gravitational fields time slows down - carry this fact to its conclusion, and at C and infinite gravitational pull you get no passage of time. If for example you could somehow travel around at C, no time would pass for you. You would either instantly be however many years in the future when you slowed back down, or you would just never experience anything again, assuming that you traveled around that fast for eternity. Every seen Lost in Space, the movie? Notice that when they hit warp speed, time freezes for them with that cool blurry freeze effect until they arrive at their destination. I love it when Sci-fi gets it right
"The time has come for people of reason to say enough is enough. Religious faith discourages independent thought, it's devisive, and it's dangerous." -Richard Dawkins

weqweq
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Posted 05/06/04 - 11:10 AM:	#29
Socrastein wrote: Not accurate at all, in fact. The light would shine forward just as fast as if you were sitting in your car in a parking lot and shined it. You could still look in the mirror and see yourself in real time, for example, travelling at the speed of light. Light is NOT a speed limit, it is a constant, from every single point of reference. If you tried to "chase" a beam of light, you could never get beside it and be flying along with it at C - it would always move away from you at C. If you don't believe me, study up on Einstein. There is a big difference between traveling at almost light speed, and light speed. At light speed time would slow down to the point where it stops. Therefore, since time has stoped the light wouldnt hit the front of the vechical (from the perception of the person in the vechical, Which to some extent cannot pecive anything at all as time would have stoped) the 0.00~0001 seconds (or how ever long) it would take the light to hit the front would not come to pass. this was my reason. If chasing a beam of light and traveling at light speed, it would not get further away as no time would past, although it would if you were traveling at 99% of light speed. (i think )
"The idea is like grass. It craves light, likes crowds, thrives on crossbreeding, grows better for being stepped on" - Ursla K. LeGuin, The dispossessed "The most accurate map possible would be the territory, and thus would be perfectly accurate and perfectly useless." - Neil Gaiman, American Gods

Socrastein
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Posted 05/06/04 - 09:35 PM:	#30
You do think, admirably, but my friend you are thinking wrong. I am not trying to offend or belittle you, but rather teach you. No matter how fast you're travelling, C is constant from every reference point. Like I've said before, it's not a speed limit, its a constant. If you're travelling in a car at near C (99.999999%) and you look in the mirror, light reflects back just as fast as if you look at your bathroom mirror. Turn on your headlights, and the light shines forward from them at C and reflects back off things like you were in your parking lot. So says relativity, and if you still don't believe me, then I'll back myself up so you don't have to keep taking my word for it http://www.physlink.com/Education/AskExperts/ae169.cfm http://www.wonderquest.com/HeadlightsSpeedy.htm http://van.hep.uiuc.edu/van/qa/sec...ativity/20020820161059.htm Hope that helps clear things up.
"The time has come for people of reason to say enough is enough. Religious faith discourages independent thought, it's devisive, and it's dangerous." -Richard Dawkins

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