Black hole are the regions in spacetime where the gravitational pull is so strong that nothing, not even light can escape from it.
Black hole is obviously black, but that doesn't mean it is nothing. Actually it reflects no light, hence its black.
The term black hole was coined by John Wheeler.
In my previous posts, i told you that Gravity is the result of curved spacetime and Light also follows the path of spacetime. In simple terms, Light is also affected by Gravity.
Every region has fixed Escape Velocity, the minimum velocity required to escape the planet's gravitational pull. So, Black hole is the region where the escape velocity is more than Speed of Light, and According to Special Relativity, nothing can travel with or faster than Speed of light, Hence nothing can escape Black Hole.
Such regions can only be formed when massive thing is compressed into very very small sphere, where density approaches infinity. Such regions are also called Singularity.
The black hole consist of two parts, Singularity and Event Horizon. Black hole is actually a singularity, but the boundary from which if anything enters can never escape, is known as Event Horizon.
Black holes are formed by compression of star due to its own gravity. I will explain it briefly in future posts.
Black holes also emits Radiation called Hawking Radiation. But i said Nothing can escape from Black Hole, So you might get question that how that radiation escapes. But don't worry in future post, i will explain that too.
Thankyou for reading, Comment your views and Questions...