Why do astronomers call a black hole ''black''?

Answer 1

Simply put, the existence of black holes is consequential to the laws of physics. If you have enough matter and it's concentrated enough, there will be a point at which the escape velocity is higher than the speed of light and a black hole forms. For more detailed reasons as to why black holes exist, a separate study of each type would help, primordial black holes are believed to have been generated by processes during the creation of the universe; stellar black holes are the result of events in stellar evolution, supermassive black holes result from attrition of matter during the formation of galaxies.

Answer 2

A black hole is called a black hole because due to its density and therefore intense gravity, nothing, not even light, can escape it. Though it has extreme mass, it is not a light source, and it will not reflect any light, so it appears as a "black hole" in the universe.

As a black hole has massive gravity, light from objects behind it will "bend" around the black hole and an observer will see what is called gravitational lensing. The effect of the lensing will be greatly pronounced because a black hole deforms spacetime dramatically. A black hole is a point in space where something is, but because the "thing" that is there generates extreme gravity, it will not be visible under any conditions. It was natural to apply the term black hole to this phenomenon.

Some background:

A black hole is a collapsed star that was 5-10 times the mass of our sun. It happens when the star begins to fuse iron in its core and implodes. The core could collapse completely and create a black hole, or it could dissipate and leave a neutron star. A black hole does not emit light, seeing as nothing is observable past the Event Horizon. Therefore, you could have an accretion disc (only with a black hole that has a rotation), and see it, but you would not be able to see the black hole.

A black hole is called a black hole because nothing, not even light, can escape it. Though it has extreme mass, it is not a light source, and it will not reflect any light, so it appears as a "black hole" in the universe.

As a black hole has massive gravity, light from objects behind it will "bend" around the black hole and an observer will see what is called gravitational lensing. The effect of the lensing will be greatly pronounced because a black hole deforms spacetime dramatically. A black hole is a point in space where something is, but because the "thing" that is there generates extreme gravity, it will not be visible under any conditions. It was natural to apply the term black hole to this phenomenon.

A black hole is called that because when viewing it with the naked eye (visible light spectrum), the phenomenon appears to be a 2-D "hole" in space (or spacetime.) An actual Black Hole is much more complicated than a hole in space, however.

Answer 3

A black hole is a cosmic body of extremely intense gravity from which nothing, not even light, can escape. A black hole can be formed by the death of a massive star. When such a star has exhausted its internal thermonuclear fuels at the end of its life, it becomes unstable and gravitationally collapses inward upon itself. The crushing weight of constituent matter falling in from all sides compresses the dying star to a point of zero volume and infinite density called the singularity. Details of the structure of a black hole are calculated from Albert Einstein's general theory of relativity. The singularity constitutes the centre of a black hole and is hidden by the object's "surface," the event horizon. Inside the event horizon the escape velocity (i.e.,the velocity required for matter to escape from the gravitational field of a cosmic object) exceeds the speed of light, so that not even rays of light can escape into space. The radius of the event horizon is called the Schwarzschild radius, after the German astronomer Karl Schwarzschild, who in 1916 predicted the existence of collapsed stellar bodies that emit no radiation. The size of the Schwarzschild radius is thought to be proportional to the mass of the collapsing star. For a black hole with a mass 10 times as great as that of the Sun, the radius would be 30 km (18.6 miles).

Only the most massive stars-those of more than three solar masses-become black holes at the end of their lives. Stars with a smaller amount of mass evolve into less compressed bodies, either white dwarfs or neutron stars.

Answer 4

A black hole is black because it absorbs all light that hits it reflecting nothing.

Answer 5

The gravity of a black hole is so strong that, within a certain radius, not even light can escape. Therefore a black hole is completely black.

Answer 6

Because even light is trapped by its gravity, so it is literally a black hole in space.

Answer 7

because it gives off no light