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.
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.
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.
A black hole is black because it absorbs all light that hits it reflecting nothing.
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.
Because even light is trapped by its gravity, so it is literally a black hole in space.
because it gives off no light
That's because they actually observed it.
By observing the movement of nearby objects. The gravity of the black hole will accelerate such an object according to Newton's Second Law (F=ma). More specifically, the details of the orbit of a star that moves around the black hole will vary, depending on the black hole's mass.
Our galaxy does not contain "a" black hole, it contains thousands, perhaps millions, of them.Astronomers believe there is a supermassive black hole near the center of the galaxy, with a mass of about 4 million solar masses. They reached this conclusion, among other things, by observing objects moving around it. This makes it possible to make an estimate of the mass. Some of the objects are quite near the ... object, whatever it is, and astronomers know of nothing except a black hole that can have such a large mass in such a small space.
The supermassive black hole that hosts the galaxy NGC 1277, in the constellation Perseus, is currently the largest black hole in our visible universe with a mass equivalent to 17 billion suns. In 2012, astronomers have discovered this small galaxy about 250 million light-years from Earth.
You can't, if you call it in the black hole being inside the event horizon; that is if you mean inside the 'black' portion of the hole. If you say near the black hole, then it depends on how close and how much thrust, fuel and mass your ship has.
Astronomers know because they have studied star patterns and placements and know when there has been a change between where there is a black hole and where there isn't one.
By observing the movement of nearby objects.
Astronomers indicate the probability of us all really going to be sucked into a black hole to be quite low.
A black hole, exoplanets. It has always been inferred.
A black hole or a worm hole :) good luck
You cant see a black hole because the gravitational pull of it is so strong that not even light can escape from it. Astronomers find them through observing the space matter that they pull into them, not the hole itself.
Black holes do not emit light, so we cannot observe them directly
Astronomers believe that black holes exist in the center of every universe. They even think that there may be a black hole in the center of our galaxy, the Milky Way
Astronomers say that there are several, possibly many, black holes, all a long way from Earth.
Astronomers look for black holes by searching for their effects (the hole itself by definition can't be seen). Some of the possible effects are gravitational lensing and electromagnetic radiation from the hole's accretion disk.
That's because they actually observed it.
Astronomers