What is black hole?

Answer 1

A black hole is an object predicted by general relativity,[1] with a gravitational field so powerful that even electromagnetic radiation (such as light) cannot escape its pull.[2]

A black hole is defined to be a region of space-time where escape to the outside universe is impossible. The outer boundary of this region is called the event horizon. Nothing can move from inside the event horizon to the outside, even briefly, due to the extreme gravitational field existing within the region. For the same reason, observers outside the event horizon cannot see any events which may be happening within the event horizon; thus any energy being radiated or events happening within the region are forever unable to be seen or detected from outside. Within the black hole is a singularity, an anomalous place where matter is compressed to the degree that the known laws of physics no longer apply to it.

Theoretically, a black hole can be any size. Astrophysicists expect to find black holes with masses ranging between roughly the mass of the Sun ("stellar-mass" black holes) to many millions of times the mass of the Sun (supermassive black holes).

The existence of black holes in the universe is well supported by astronomical observation, particularly from studying X-ray emission from X-ray binaries and active galactic nuclei. It has also been hypothesized that black holes radiate an undetectably small amount of energy due to quantum mechanical effects. This is called Hawking radiation.

Answer 2

On earth, if you throw a baseball into the air it will return due to the earth's gravitational attraction resulting from the earth's total mass. Within a black hole, a photon (light) directed outward will return (like a baseball!) due to the tremendous mass that has crushed all atoms and molecules into a tiny dot (singularity) at the center. Because light can not escape, we can not see it and it "looks" like a black hole in space.

Answer 3

A black hole is a huge mass whose magnetic force disallows the escape of anythng...including light. Thus in the heavens we can see a spot that appears to be a hole in the universe. Astronists have labeled this spot Black Hole.

Answer 4

A black hole is basically the region around a singularity. A singularity is a theoretical point of infinite desity, volume and pressure. After a lifetime of a star, it blasts, now that's a super nova but sometimes it contracts, contracts, and keeps contracting into a single point. Now since a star is very heavy and all heavier objects attract lighter objects towards themselves, like the earth around the sun and the moon towards earth, but since a singularity is so heavy it attracts everything towards itself...

...even light...

Answer 5

A BLACK HOLE is an object with such a strong gravitational field that even light cannot escape from its surface.it is formed wen a massive object undergoes uncontrolled contraction because of the inward pull of its own gravity...everything it absorbs will be torn apart...

Answer 6

blackhole is amystery in the space where a star shrinks and forma mass like where apoint (a point means a mass having a size of apoint on the tip of a safety pin )have aweight of more than 3000 elephants think about its density even the light would be attracted by it i believe that it is aconnection between two universes for more details read stephen hawkins "space ina nut shell"