What are black holes?

Black holes
A black hole is a cosmic mass with enormous gravity, which pulls everything around it to the light, and the black hole is formed when a huge star dies, and this occurs when the star exhausts all its internal thermonuclear fuel in the last stages of its life to reach the so-called uniqueness, in which its size is zero, and its density does not die Although black holes cannot be seen, they account for about 90% of the content of the universe, and American physicist John Wheeler named it in 1969.

The Genesis of Black Holes
Black holes arise when giant stars explode in the final stages of their lives, and these explosions are called supernovae, which scatter most parts of the star into empty space, and these explosions may leave cold remnants where no-nosed mergers do not occur, unlike The smaller stars in which the merger occurs, as these processes help to produce energy and constant external pressure, balanced with the gravitational forces of the inner gravity resulting from the mass of the star itself, the absence of these forces in the cold remnants of the big star leads to the collapse of the star on itself, as the black hole shrinks Emerging to a zero size, and infinite density no body can escape from its enormous gravity to light, the star light itself is trapped in its orbit, so this dark star is known as the black hole.

Black holes pull planets, light, or any other cosmic object in case they pass near them, and then these objects reach the point of no return, which means that they entered the state of horizon, a condition that is impossible for this material to escape from the black hole, because that requires that the speed of movement of this object be faster  of the speed of light to escape it.

Types of black holes
There are three main types of black holes, where the star type is determined by its mass and size, and these types are:

  • Small black hole: known as the primitive black hole, or base, scientists believe this type of hole is the size of an atom, but its mass is enormous.
  • Medium-sized black hole: This is called the most common star black hole, which can be about 20 times larger than the sun's mass, can be placed inside a 16-kilometer-diameter ball, and there are dozens of star black holes within the Milky Way galaxy.
  • Large black holes: so-called massive black holes, the mass of which are about a million suns, can be placed inside a ball that is roughly the diameter of the solar system, and scientific evidence suggests that each large galaxy has a massive black hole at its center, The large black hole at the center of the Milky Way galaxy is called the arc, whose mass is equal to a mass of 4 million suns, and can be placed within a diameter roughly equal to that of the sun.