What is a black hole?

Answer 1

"Black holes are the evolutionary endpoints of stars at least 10 to 15 times as massive as the Sun. If a star that massive or larger undergoes a supernova explosion, it may leave behind a fairly massive burned out stellar remnant. With no outward forces to oppose gravitational forces, the remnant will collapse in on itself. The star eventually collapses to the point of zero volume and infinite density, creating what is known as a " singularity ". As the density increases, the path of light rays emitted from the star are bent and eventually wrapped irrevocably around the star. Any emitted photons are trapped into an orbit by the intense gravitational field; they will never leave it. Because no light escapes after the star reaches this infinite density, it is called a black hole."

Answer 2

The concept of a Black Hole is complex, and can be counter-intuitive.

Matter as we know it, exists because forces such as the electromagnetic force and others keep the subatomic particles apart. As the particles get closer this force very strongly keeps them apart, otherwise they would be pulled together by gravity. But if there is enough matter in a small enough space, gravity ends up winning, and the matter collapses - electrons cannot stay distant from the atomic nucleus, and so incredibly dense matter forms, and then even this cannot maintain its structure and collapses into itself further. In a way that is hard for people to imagine, nothing can stop this collapse if enough matter gets into a small enough space, and the matter collapses literally to a point. Not a pinhead size, or any size, but a literal point, zero wide, zero high, zero deep. We cannot imagine such a thing, but physics says that is what happens, and that is a black hole, matter that is so dense it is no longer "matter" in any real sense, but some kind of singularity (or anomaly) in space. Anything that gets too close will also collapse with it the same way, whether matter or energy, even light itself, the fastest thing in the universe. This is how it acquires the name "black hole".

Answer 3

A "black hole" is what happens when a large sun reaches the end of its life. A star like our sun is in a state of equilibrium. The tremendous outward force of nuclear fusion at the core is balanced by the tremendous gravity holding it all in. When the nuclear fuel (hydrogen) begins to run out the sun will expand because of all that mass lost through radiation out into space. The sun will enter its "red giant phase". At some point the outward force of nuclear fusion runs out and the sun collapses, rather quickly too. In a star the size of our sun this simply starts fusing helium, the next heaviest element. However, in a very big star, theoretically, the mass is so great that nothing will stop the collapse and the star "disappears" into what's called a naked singularity, the mass of an entire star occupying the space of a sub-atomic particle. Theoretically, the gravity around such an object nears infinity where not even light can escape.

Answer 4

Black hole is a place in the space which have very high gravitational pull or force which attract all the objects passes near it.

Answer 5

well anyone can tell you that it has strong gravity, even earth has gravity, but im just being more specific (thanks whoever for a thumbs down?)

black holes are not actually holes but named that because they suck everything in.
black holes are made up of basically antimatter, proven by nasa on 10-5-06 and the more specific word is positron. positron is positively charged. matter is made up with electrons which are negatively charged, so when positrons and electrons come together they basically destroy each other and emit x and gamma rays. :)