whats a black hole?

[terminator420]

what is a black hole exactly and how does it work? i mean, does it just suck things into a big ball or what?

[Sammy56]

Black holes are an extremely complex phenomena that are still not completely understood today. A very simple definition would be a black hole is a region of space that has so much mass concentrated in it that there is no way for a nearby object to escape its gravitational pull becasue the escape velocity exceeds the speed of light. I did some searching and found a site that explains it in fairly simple terms much better then I can-

http://cosmology.berkeley.edu/Education/BHfaq.html

If you want something a bit more complex there's-

http://en.wikipedia.org/wiki/Black_holes
http://archive.ncsa.uiuc.edu/Cyberia/NumRel/BlackHoles.html

[Protostar]

A black hole is a star that imploded on itself after that last bit of hydrogen is gone, like our star is going to do in about 500,000 years according to "naked science".

[CrystalSword]

Not quite Proto. A star will keep fusing heavier and heavier elements even after all its hydrogen is gone. How far it can go depends on the star's mass. If a star has many times the mass of our Sun, it can fuse elements all the way up to iron. But fusing iron takes in more energy than it gives out. A star tries to supply this energy by contracting its core, and this contraction can make such a violent implosion that a subsequent explosion occurs. That explosion is a supernova, and the surviving core typically has enough mass to create the black hole, where the escape velocity is faster than the speed of light.

Sol does not have enough mass to produce a supernova, and likewise a black hole. It will simply expand the outer gas layers, create a red giant, and the core (still fusing elements like helium and carbon) will contract. Then the outer gas layers will puff off, leaving the core behind as a small dwarf star.

That's my explanation! :2thumbs:

[Mezurashi]

a Black Hole is where all that extra money you thought you had goes.

[Resentedhalo]

It is also thought by some that a blackhole is also a rip in the space/time fabric, If you believe in membrane theory it could also be a route to another universe or eternal oblivion in liquid space, well apart from all your atoms being split, rearranged and transformed into other matter. :2thumbs:

Resentedhalo.

[CrystalSword]

It is also thought by some that a blackhole is also a rip in the space/time fabric

There are some who say that if a black hole was massive enough (I think I heard a black hole formed from a star with a mass of 3,000 solar masses), the sloping curve of the fabric of space would be a lot more gradual than if it was your average black hole. So instead of being spaghettified a few miles, you'd only be spaghettified a possibly survivable few feet by the time you go by the event horizon. And if the black hole is spinning so that the singularity is a ring, this theory says that you can go though the ring and be spewed out of a white hole in a different universe.

I personally think wormholes are much safer.

[Resentedhalo]

CrystalSword I am impressed with your knowledge of theoretical physics, indeed this would work but would the human body be able to withstand the process of being ripped apart and re-joined for a few feet? What is to say your molecules would rearrange in the correct order on the other side? :amaz:

Resentedhalo.

[nigeyboy]

(I think I heard a black hole formed from a star with a mass of 3,000 solar masses), .

Not quite!

The maximum mass of a star is known as the Eddington Limit. It states for a star to stay together it cannot have more than c.150 solar masses. Any bigger, and the stars outgoing radiation is too great and it blows the extra mass outward.

A star very close to the center of our galaxy (near the x-ray source Sagittarius A*) has been discovered doing just this!!

[CrystalSword]

While it's true a star can't get that big, the theory of survivable black hole travel says that that's how massive the hole has got to be so that the fabric of space time curves gently toward infinity rather than sharply, so that spaghettification could be survivable.

In math terms, the second partial derivatives (of the space-time fabric surface function) should be close to zero and negative, but the limit toward the origin should still be infinity. (Sorry...I couldn't help it!)


indeed this would work but would the human body be able to withstand the process of being ripped apart and re-joined for a few feet? What is to say your molecules would rearrange in the correct order on the other side?
If the fabric of space curves gently enough, the human body would not be ripped apart, just stretched, until the inner event horizon is passed through (if the singularity is a ring, of course) and you enter a new universe out of the white hole. No rearrangement necessary. Still, I'd rather travel via wormhole.

[Sabazi]

It would be nice to be able to find one and send a probe in.

[Sammy56]

The problem is the probe would be torn apart very quickly. Although, in that short amount of time, we might be able to get some interesting date. Another problem is that all the black holes we know of are so far away that a probe would take way to long to get there.

[liberdave]

You know, I was pondering this the other day whilst thinking of sound, what if a black hole is basically like a sonic boom but for light? At one time scientists knew that if you traveled supersonically you would die. And at supersonic speeds can you hear yourself talk? Anyone know? And WTF is up with the neutro stream ejecting out of a black hole that I hear so much about? Are these neutrons traveling superluminally?

...

And while I'm purging some thoughts, the Theory of Relativity states that if you were to travel at the speed of light, everything around you seems (in fact does) to become ageless. So what if a black hole is a "spot" in the time/space fabric that is ageless? And more importantly, say if and only if we are due for a big crunch or some other universe ending event, would a black hole become effective? Would it still hoard light? Would it's contents be uneffected by it's ageless properties? So, let's say that it wasn't included in that big crunch or whatever, you could enter the hole and become immortal! (Well, then if I say that, it brings up a whole nother argument as to the definition of mortality and I save that for the religion or philosophy threads). BUT, if one could acquire the means to survive in an environment with no volume but infinite mass, then you'd but set up then, huh? Anyways, I know very little on these subjects and I hope a kind soul will enlighten us....

[Sabazi]

While it's true a star can't get that big, the theory of survivable black hole travel says that that's how massive the hole has got to be so that the fabric of space time curves gently toward infinity rather than sharply, so that spaghettification could be survivable.

If the fabric of space curves gently enough, the human body would not be ripped apart, just stretched, until the inner event horizon is passed through (if the singularity is a ring, of course) and you enter a new universe out of the white hole. No rearrangement necessary. Still, I'd rather travel via wormhole.
I meant a black hole like this. Although any kind would be nice.