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ArcticMyst Security by Avery

Black Holes???

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chIno said:
[quote author=seoguy link=1237870126/0#3 date=1238432020]If I remember correctly, virtual particles do not mess-up the conservation of mass/energy because they pop "out" of existence as quickly as they pop in. But when the pair gets separated by being on opposite sides of the event horizon, that forces it's twin in the "outside world" to become a "real" particle, instead of a fleeting virtual one. The energy for this particle has to come from somewhere, so it is debited from the mass/energy of the black hole that ate it's twin, kinda like a withdrawal from it's Paypal acct! ;)

escape velocity being grater than that of the speed of light
[highlight]
Actually, I believe the more accurate way of looking at this is that space-time is so warped that there is no path that will lead out of the event horizon - every path curves you back in![/highlight]

my question is, is nothing ever faster than the speed of light...

Actually, I believe the theory prevents a particle from "crossing" the lightspeed threshhold, i.e. - going from subluminal to superluminal speeds. From what I've been told, there is nothing in Einstein's theories that prevents a particle from traveling faster than light (i.e. - the theoretical "tachyon" particle, which can travel faster than light, it just can't go any slower!)

Also, remember that this speed limit applies to particles moving through space. There is no such FTL "speed limit" for how fast the fabric of space itself can move! For example, I believe during the "inflationary period", the universe is thought to have expanded much faster than lightspeed! This also explains why there is a limit on the "observable" universe, and why we cannot see galaxies that exist beyond it. This "no speed limit for space itself" is also the basis for the hypothetical "warp" drive.

...and does it apply to energy in every form...

There is also the very interesting "quantum entanglement", in which an entangled particle is somehow able to communicate it's state to it's twin instantaneously over any distance! Scientists are still scratching their heads trying to figure-out exactly how this happens - some have speculated a magical faster-than-light particle is exchanged between the two, another theory has it that the particles actually communicate with each other backwards in time to the point where they first became entangled!

Quantum Physics can be a real mind-blower at times! ;)


wow, never though of it that way! :eek: ......[highlight]BUt wouldnt you have a discontinuity in the first place,[/highlight] so how would a particle even go through the event horizon if there is no space-time to travel through???
... and thanks guys for all the responses, i thought the post was just gonna die after 2 :([/quote]


ok so i did more reading and if im not mistaken....(first of all can i quote myself??? :-? :-? :-? cus its kind of weird lol) i guess a better way to see it is that gravity in the first place is just what we feel due to the warping of space-time, because the warping creates a difference in potential energy, and matter wants to be in the "lowest energy state" thats why it "falls towards the largest mass" (think of it this way, if you throw something up, it gains potential energy) and the more massive something is, the more it warps space-time. So for a black hole, the space-time field around it, its warped so much that it creates a huge difference in potential energy that not even light can overcome. And apparently, there is no work done when mass moves through an equipotential field, that is a field that has exactly the same potential all throughout. So thats why stuff moves in outer space without slowing down.... Although there is always gravitational fields everywhere in our universe, but in "outer space", since gravity is proportional to (1/r^2) its negligible.
 





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I think our brains need to evolve much more for for us to completely understand, but until then we should try to understand as much as we can.

Devin.
 
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Black holes are actually very well understood. Basic calculus provides the necessary mathematics to calculate the Schwarzschild radius of any given black hole mass. There are other relativistic conditions that must be accounted for such as frame dragging in a rapidly rotating black hole but it does not require much more advanced mathematics to tackle these concepts. The formation of black holes are very predictable and have been understood for years and even the supermassive black holes are well accounted for.

As with so many things in physics, however, as we approach a singularity, the physics of relativity fade and are supplanted by quantum mechanics. It is the quantum world that play havoc with black holes. A singularity can be described but can never be observed. Because the event horizon prevents information from being retrieved there can be no measurements either directly or indirectly about the singularity. I think the answers from the quantum perspective will be advanced with the LHC since the actual formation will be observed.

I like to think of a singularity like the concept of infinity. Infinity can be described but it is completely intangible because we can never reach it. We can describe it mathematically by approaching it but the math collapses when we reach it. Even doing simple derivatives we must remember that an infinite solution represents a left or right limit not a finite answer.
 
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I recently attended a lecture by Dr. Hawking and I liked the explanation he gave on how black holes can evaporate and why mini black holes evaporate but larger ones usually don't.

From quantum physics, if a particle is tightly defined to a position in space (like in a black hole), then its velocity becomes very uncertain, even to the point where there is a chance that the velocity may be greater than the speed of light. If that happens, then by definition it can escape the black hole. As more particles escape, the black hole shrinks and even more tightly confines the remaining particles increasing the chances even more that other particles will be able to escape until the whole thing is gone.

Okay, it still sounds crazy though.
 
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WOW!! So then velocity is not relative?? :-? :-?... (i've yet to take a quantum phy class :'( :'() .... but i will soon ;D
 
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Sounds like he is describing his version of the Heisenberg uncertainty principle. If we know the momentum we cannot be sure of a particle location. It is a probabilistic solution that suggests that a particle can appear in a space not expected (i.e. outside the event horizon). We know these things happen. A classic example of this is alpha decay of radioactive materials. How is it that 2 protons and 2 neutrons can overcome the strong nuclear force and simply leave the nucleus? It's not electrostatic repulsion as at short distances (10[sup]-14[/sup]m or so) the strong nuclear force overpowers electrostatic repulsion. The explanation is quantum tunneling based on the Schrodinger equation. The idea of half life is based on a whole sample not on an individual atom. Looking at an atom we my see alpha decay or we may never see alpha decay. There is only a probability it will occur. This type of tunneling might be what Hawking is describing. It's hard to tell these days.
 
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Yeah i had a crash course in quantum tunneling, but still very hard to understand. All i got from it was that everything carries a wave equation and smaller and faster moving particles have a "bigger" wave equation. That is, these smaller particles have a higher probability of acting like a wave but if you actually follow their path they take, they act like a particle!?! :eek:... We just went over this quickly for a basic understanding of fusion and how a star burns... Im starting a physics major at the u here, but every class just leads to more questions, some that even the teacher can't answer (i just get a "im sorry i should know this, its embarassing") :-? :-? :( :( and i realize that every new class i take tells me that my last physics class was wrong or incomplete. and as far as i see, none can ever be completely right, just approximately... I havent had a quantum physics class though, but i hopefully will soon.
 
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535vypj.jpg
 
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White hoes attract argentum ions forming an empty wallet syndrome that takes eons to return from negative mass.
 
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i'm really impressed with the physics level some people got here :eek:
 




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