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 Posted: Wed Jul 12, 2006 5:05 pm
Ok i know the typical lazy teacher answer "stars die and make black holes" answer. I'm looking for something more in-depth than that. Also I need explaning why they allegedly have such a strong gravitational force.
Also ive been tossing this idea around in my head for a while (like a day, hey thats a long time for me!) your answer to the former will probobly answer this question for me but could (some)large stars be just weak black holes that have captured light into an "orbit" around it? Or am i just an idiot that needs a hobby? (I'm leaning more towards the latter) confused
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Posted: Wed Jul 12, 2006 5:06 pm
If someone can help me with this ill donate either 500g to the guild or the person (thier choice) that helps me the most.
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Posted: Thu Jul 13, 2006 5:48 pm
Endert Ok i know the typical lazy teacher answer "stars die and make black holes" answer. I'm looking for something more in-depth than that. Well, at the most basic level, gravity compresses things. Normally, things push back with other forces (e.g., the electrostatic repulsion between atoms). However, if there is enough mass, gravity will win, and it will eventually win because more mass = more gravity, whereas this is not usually true for electromagnetism. It is not usually true for EM because there are two charges--like charges repel, opposite charges attract. That means that electromagnetic forces tend to cancel out for large distances, whereas gravity adds more and more. Endert Also I need explaning why they allegedly have such a strong gravitational force. I suspect that this is a misunderstanding. At the same distance, black holes don't have any more gravitaty than anything else of similar mass. If the moon magically became a black hole, its gravity would be completely unchanged as far as the Earth is concerned. It would still orbit the Earth in exactly the same manner. It would be just a lot smaller--about 1/5 of a millimeter in diameter, to be exact. The size difference is what's important. Since it will be much smaller, you can get closer to its center than you can for the actual Moon, which is where the stronger gravity will be observed. Think of Newton's law of gravity, which is a good approximation: F = GMm/r², where G is a constant, {M,m} are two gravitating masses (e.g., {Earth, you}), and r is the distance between their centers. This means that if the Earth had the same mass as it does now, but was half as large in size, then its surface gravity would be four times larger, but at the same distances from the center, nothing at all would be changed. At the most basic level, that's really it--black hole surface gravity is large because black holes are small.
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Posted: Fri Sep 01, 2006 2:30 am
From what I know, when a star dies it loses all its outwards radiation (light, heat etc) and is left only with its core, which has a pretty hefty gravitational pull, its own gravity thererfore causes it to collapse in on itself, and from there I am not 100% sure, sorry if that wasn't much help!
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Posted: Sat Oct 07, 2006 1:45 pm
Iron_Soul From what I know, when a star dies it loses all its outwards radiation (light, heat etc) and is left only with its core, which has a pretty hefty gravitational pull, its own gravity thererfore causes it to collapse in on itself, and from there I am not 100% sure, sorry if that wasn't much help! Your on the right trak but the most commen way they are made is for another star to blow and if they are close the core will gravitational pull at the star dust if thir's enough you get another star that is born on a core of a dead star. next when the fuel runs out on the new star it blows. smatshage the two cores. with cose huge amounts of presser to rip space-time. thuse a black hole is made. mrgreen
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Posted: Wed Mar 14, 2007 9:10 pm
Basically, a big star blows up or crashes into another big star. So after the star goes "boom," the energy from the core pulls it back together - but overshoots. It pulls back much too hard and all the stuff that was in this huge ginormous star is now in a much smaller format. It's very, very dense, and in the center is a singularity of zero length, width, and depth, which is matter but isn't matter (people are still debating this; it is theoretical, after all) and the laws of physics change. Anything that gets too close to the singularity is changed and sucked in past the event horizon, which is the point at which nothing can escape. This force is so great that light can't bend past it; it gets sucked in, too. (Research photons to find out how light can get trapped.) Black holes, theoretically, can evaporate, since they lose Hawking radiation.
One interesting thing about event horizons; since not even light can escape, we can't see what goes on inside since no light comes out. We see with light, so no light = no sight. And once it goes in, it's gone.
I think I did pretty good for layman's terms.
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Posted: Sun Apr 29, 2007 8:20 am
Above me, you stated that nothing can escape.
False. We have witnessed photons and EM rays being emitted from a black hole, which is thought to be causing them to die.
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Posted: Sun Apr 29, 2007 7:42 pm
A star, as we all know, is an on going nuclear reaction. Well, how does it stay compressed? Simple, it's gravity counter acts the forces pushing out. Yet, a star can become unstable on the inside, causing this balance of forces to collapse. When that happens, the star suddenly does not have the gravity to compress the reaction, which not only is allowed to expend, but begins to react faster, and expand faster, and react faster, on and on. Yet, all force from every single reaction that every single atom has it two way. You have all that force on the outside leading to a super nova, but what happens to all that force on then inside? It condenses the center most matter to where the nuclear forces (strong and weak) and electromagnetic forces are overcome by the gravity force. When this happens, a black hole is formed. As for radiation from a black hole, that is a entire other concept, see Hawkins for the details.
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Posted: Sat May 19, 2007 9:45 am
yukiine Above me, you stated that nothing can escape. False. We have witnessed photons and EM rays being emitted from a black hole, which is thought to be causing them to die. Oops. I meant almost nothing. *slaps self* I'll go back and fix it.
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Posted: Wed May 30, 2007 3:10 pm
WOULD YOU LIKE TO KNOW MY ANSWER!!!!!!!!!!!!!????????????
IT CONNECTS TO THE SPACETIME FABRIC. WHEN STARS DIE, THEY TURN INTO WHITE DWARF STARS AND HAVE INCREDIBLE MASS BECAUSE ALL THAT ENERGY GOT STUFFED INTO A BALL THAT'S ABOUT 10 KM BIG OR LESS. THEN SINCE IT'S SO MASSIVE, IT SINKS INTO THE SPACE TIME FABRIC SO YOU SEE THE BLACKHOLE AS A BIG TUBE. IT HAS SUCH GREAT MASS THAT ITS GRAVITY ATTRACTS EVERYTHING TO IT AND THERE IT IS. A SMALL BALL WEIGHING IN AT A MASSIVE MASSIVE MASSIVE WEIGHT! ITS SO INCREDIBLE THAT IT SINKS IN DEEP TO MAKE THE BLACK HOLE LOOK LIKE A FINGER OF A GLOVE.
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Posted: Thu Jun 21, 2007 11:53 am
the easiest way to think about it is in General reletivity. Any mass creates its own indentation in space time, the depth of the indentation is based on its mass and the area of the indentation is based on its volume. So when a giant star gets old and its stability fails it "implodes". forming a very dense mass substance comprised of a the gases the star was made of. Now when this happens the indentaion from the star when it was realy a star all the area of the indentation that was once pred out is now compat to a single partical. the intensive mass makes a deeper depth that creates a gravity well that has such gravitational force that nothing can escape it. Nothing can because not even light can, and nothing can travel faster than the speed of light. thus NOTHING can escape.
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Posted: Tue Jan 15, 2008 1:56 pm
Black holes are made by gravational collapse
When you squeese a lot of matter into a small space the gravatational feild is so strong light cannot escape
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Posted: Tue Jan 15, 2008 6:04 pm
When a star runs out of fuel it subsequently loses the battle between its own personal gravity and that of everything else. This causes the former star to collapse in on itself. With the large amount of gravity that BH's have, almost nothing can escape with the exception of another BH that is thrown into space i.e. rogue black holes and stars that were caught in the gravity as well and escaped.
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Posted: Sat Jan 19, 2008 8:07 pm
ok
first off it is important to know that not all stars be come black holes
only the largest of them (red giants) do. so our sun which is relatively small would not create a black hole because it is not massive enough and it never will be.
a star is kept alive by the burning of gasses such as hydrogen and helium. this keeps the star held together. but as the star grows older the supply of these gasses becomes shorter and the star becomes less and less able to hold its self together so it expands and dims until the supply is drained.
this is the interesting part.
now, stars that are less massive will "die peacefully" meaning that the outer layers of the star, without anything tethering them to the core of the star, will drift out into space leaving the core to become what is known as a white or black dwarf depending on whether or not there are any gases left for the core to burn. these stars are no more than a couple of miles across.
if, however, the star is massive, the outer layers will, instead of drifting out, be pulled in by gravity, collapsing in on themselves. the mass and gravitational pull of the remains of the star will become so overwhelming that it will compress its self to a volume that is unattainable by any other means. an extreme amount of mass in an undefined point, creating a gravitational pull which is nearly inescapable.
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Posted: Sun Jan 20, 2008 9:55 pm
Leon_Everest the easiest way to think about it is in General reletivity. Any mass creates its own indentation in space time, the depth of the indentation is based on its mass and the area of the indentation is based on its volume. So when a giant star gets old and its stability fails it "implodes". forming a very dense mass substance comprised of a the gases the star was made of. Now when this happens the indentaion from the star when it was realy a star all the area of the indentation that was once pred out is now compat to a single partical. the intensive mass makes a deeper depth that creates a gravity well that has such gravitational force that nothing can escape it. Nothing can because not even light can, and nothing can travel faster than the speed of light. thus NOTHING can escape. Except Hawking Radiation.
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