What is a black hole?

A black hole is defined as a region in space where the gravitational pull is so strong that nothing, including light, can escape from it. This characteristic leads to the phenomenon where no radiation is emitted from the black hole itself, rendering it invisible against the backdrop of space.

The key point about a black hole is its event horizon, which is the boundary around the black hole beyond which no information or matter can return. Because light cannot escape, it creates a situation where, from an external observer's perspective, the area appears completely black, explaining the name “black hole.”

Understanding the nature of black holes involves recognizing that they don't emit radiation like stars or other celestial bodies. Instead, they can be detected through the effects of their powerful gravitational field on nearby matter, which can emit radiation as it spirals into the black hole, but the black hole itself remains undetectable directly by emitted light.

This fundamental aspect distinguishes black holes from other astronomical bodies, such as stars, which shine brightly due to nuclear fusion, or asteroids, which are much smaller celestial objects.