History-- The idea of preventing light from escaping as described by general theory of relativity was given by John Michelle. Even the British astronomer Pierre -Simon Laplace came with the same conclusion.
The intense gravitational field left when a giant star collapses. It is called a black hole because not even light can escape. Objects too heavy to be neutron stars collapse to black holes. Formation-
Formation Continued… As the mass increases, so does the gravitational pull. If the gravitational pull is such that even light can escape , then a black hole is formed.
Gravity deforms space time Diagrammatical representation
Event horizon The point at which no light can escape.
A nonrotating black hole has only a “center” and a “surface”.
The black hole is surrounded by an event horizon which is the sphere from which light cannot escape
The distance between the black hole and its event horizon is the Schwarzschild radius (R Sch = 2GM/c 2 )
The center of the black hole is a point of infinite density and zero volume, called a singularity
Falling into a black hole Falling into a black hole gravitational tidal forces pull spacetime in such a way that time becomes infinitely long (as viewed by distant observer). The falling observer sees ordinary free fall in a finite time.
A rotating black hole (one with angular momentum) has an ergo sphere around the outside of the event horizon
In the ergo sphere, space and time themselves are dragged along with the rotation of the black hole
1-Accertion disks and gas jets. 2-Strong Radiation emissions 3-Gravitational lensing Techniques for finding black holes
Types of Black Holes-- 1-Supermassive Black holes. 2-Stellar- mass black holes. 3-Intermediate mass black holes.
Advantages and Disadvantages-- They can be significant in this way: 1-Individual modes may dominate the time evolution of some perturbation, and a whole set of them could be used to completely describe this time evolution. The disadvantages are that – 1-when a black hole evaporates information is really gone. 2-Due to this there is trouble in energy conservation. 3-Invariance in time predictability.
References--- 1-www.google.com. 2-www.wikipedia.com. 3-Anatony on Black holes.