Question

what black hole actually is?

Answer 1

black hole is a region in the space from which nothing even if light can not come out because of the gravity...

Answer 2

I have studied this in norwegian, so the English won't be so good, sorry

What is, when a star dies out, it becomes a red giant, then a white dworf. If this white dworf has mass bigger than 3 sunmasses, the pressure will be too high, and no known force can stand against the gravitation forces in this white dworf. The materie will in it self compress, and become smaller and smaller, with higher and higher mass percent - until everything is collecting in one single point. The area around this point will have a huuuuuuge gravitation force, and this is what is called - a black hole.

hope this could help! :)

Answer 3

black hole is one phenomenon where all our knowledge of physics break down. it has infinite density where matter is compressed to a zero volume leading to infinite gravity from which nothing, not even light can escape.

Answer 4

To understand what a black hole really is, you must first understand the origin of Black Hole. Black holes, are formed when stars collapse. The "collapsing" means that instead of expanding (Due to the Pauli Exclusion principle) after cooling, they shrink to a point of infinite density. This is due to gravity. There is actually a limit at which the repulsion is less than the attraction of gravity (This is called the Chandrasekhar limit; 1.5x the mass of the sun or more). This "point" at the center of a black hole is surrounded by a gravitational field. You cannot actually see a black hole, because everything, including light, cannot escape from it. You can only infer a black hole exists due to the effects observed in terrestrial motion, and the math behind expansion vs gravity. Black holes have a boundary (called an event horizon), at which you can see light that appears to escape. It is refracted at the edge due to "light cones" (another effect of gravity). The whole concept of a "Black Hole" will be much easier to understand after you understand the General Theory of Relativity. Black holes aren't actually black, by the way. Quantum physics tells us that, because empty space isn't actually empty, the event horizon of a black hole actually emits particles, which you can observe. This horizon emits waves of energy... If only we could harness it. One more thing; to understand why a black hole does not simply expand again after collapsing, you need to realize that the large mass that is now gravity, has actually caused a rip in the "fabric" of space-time. Black holes eventually revert back into regular space, but only after they have released all their mass in gamma rays blasts called quasars. There is a lot to understand, and it does not come all at once. I recommend giving "A Brief History of Time" a read.