Black Hole: A Massive, Compact Astronomical Object
A black hole is a massive, compact astronomical object so dense that its gravity prevents anything from escaping, even light. It is called a black hole because it acts like an ideal black body, reflecting no light. According to the theory of general relativity, a black hole has no locally detectable features, but it impacts the fate and circumstances of an object crossing it.
Black Hole: Not Black, Not a Hole
A black hole is not black in color, nor is it a hole. It is formed when massive stars collapse at the end of their life cycle. After it is formed, it grows by absorbing mass from its surroundings. It can become supermassive black holes of millions of solar masses by absorbing other stars and merging with other black holes. It can also be made by the collapse of gas clouds. It is clear that supermassive black holes exist at the center of most galaxies.
Who Discovered Black Holes?
English astronomer and clergyman John Michell was the first astronomer to give the idea that a body can be so big that even light could not escape. French scientist Pierre-Simon Laplace also gave this idea independently. Michell said in a letter written in 1784 that a star with the same density but 500 times the radius of the sun would not let any emitted light escape because its surface escape velocity would exceed the speed of light. He also said that such huge non-radiating bodies can be detected only through their gravitational effects on nearby visible bodies.
Albert Einstein: Theory of Relativity
Albert Einstein developed his theory of general relativity in 1915 after he showed that gravity does influence light’s motion. Karl Schwarzschild found a solution to the Einstein field equations that describes the gravitational field of a point mass and a spherical mass. It is now established that the simplest static black holes have mass but neither electric charge nor angular momentum. These black holes are called Schwarzschild black holes.
Reference : https://www.dnaindia.com/science/report-what-is-black-hole-is-it-really-hole-in-space-details-here-3147156
