Black hole

Black hole is a term used in astrophysics to describe a region of space-time exhibiting gravitational acceleration so strong that nothing—no particles or even electromagnetic radiation such as light—can escape from it. The theory of general relativity predicts that a sufficiently compact mass can deform space-time to form a black hole.

History

The idea of a body so massive that even light could not escape was first proposed by English geologist John Michell in a letter written to Henry Cavendish in 1783. The term "black hole" was coined many years later in 1967 by American astronomer John Wheeler.

Formation

Black holes are formed from the remnants of large stars following a supernova explosion. If the core remnant of a supernova has a mass greater than about three solar masses, the force of gravity overwhelms all other forces and produces a black hole.

Properties

Black holes have three "observable" properties: mass, spin (angular momentum), and electric charge. These properties are measurable through their effects on nearby matter and energy.

Types of Black Holes

There are three types of black holes: stellar black holes, supermassive black holes, and intermediate-mass black holes. Stellar black holes are formed by the gravitational collapse of a single massive star. Supermassive black holes, which are found at the center of nearly all currently known massive galaxies, have masses ranging from millions to billions of solar masses. Intermediate-mass black holes are thought to form through the merging of smaller black holes and stars.

Black Hole Paradox

The black hole information paradox, proposed by Stephen Hawking, is one of the most intriguing mysteries about black holes. It suggests that physical information could permanently disappear in a black hole, which is a direct violation of quantum mechanics.

See Also

• Event horizon
• Hawking radiation
• Schwarzschild radius
• Singularity (physics)