Black Holes

Black holes are regions of spacetime where gravity is so intense that nothing, not even particles and electromagnetic radiation such as light, can escape from it. The theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole.

The boundary of the region from which no escape is possible is called the event horizon. Although the event horizon has an enormous effect on the fate and circumstances of an object crossing it, according to general relativity it has no locally detectable features. In many ways, a black hole acts like an ideal black body, as it reflects no light.

Scientists have identified three main types of black holes: stellar-mass black holes, intermediate-mass black holes, and supermassive black holes. Stellar-mass black holes form when massive stars collapse at the end of their life cycles, typically ranging from 5 to 50 times the mass of our Sun.

Supermassive black holes, found at the centers of most galaxies including our Milky Way, can contain millions or even billions of solar masses. The first image of a black hole's event horizon was captured in 2019 by the Event Horizon Telescope, revealing the supermassive black hole at the center of the M87 galaxy.

In 1974, Stephen Hawking proposed that black holes are not completely black but emit radiation due to quantum effects near the event horizon. This Hawking radiation causes black holes to slowly evaporate over time, posing fundamental questions about the conservation of information in quantum mechanics.

The black hole information paradox remains one of the most intriguing unsolved problems in theoretical physics. It questions whether physical information could permanently disappear in a black hole, violating quantum mechanics principles. Recent research suggests that information might be preserved through quantum entanglement and holographic principles.