Black hole

Start writing...Black holes are some of the strangest and most fascinating objects in space. They're extremely dense, with such strong gravitational attraction that not even light can escape their grasp.
Black holes are expected to form via two distinct channels. According to the first pathway, they are stellar corpses, so they form when massive stars die. Stars whose birth masses are above roughly 8 to 10 times mass of our sun, when they exhaust all their fuel — their hydrogen — they explode and die leaving behind a very compact dense object, a black hole. The resulting black hole that is left behind is referred to as a stellar mass black hole and its mass is of the order of a few times the mass of the sun.

Not all stars leave behind black holes, stars with lower birth masses leave behind a neutron star or a white dwarf. Another way that black holes form is from the direct collapse of gas, a process that is expected to result in more massive black holes with a mass ranging from 1000 times the mass of the sun up to even 100,000 times the mass of the sun. This channel circumvents the formation of the traditional star, and is believed to operate in the early universe and produce more massive black hole seeds.
Black holes were predicted as an exact mathematical solution to Einstein's equations. Einstein's equations describe the shape of space around matter. The theory of general relativity connects the geometry or shape of shape to the detailed distribution of matter.

The black hole solution was found was by Karl Schwarzschild in 1915, and these regions — black holes — were found to distort space extremally and generate a puncture in the fabric of spacetime. It was unclear at the time if these corresponded to real objects in the universe. Over time, as other end products of stellar death were detected, namely, neutron stars seen as pulsars it became clear that black holes were real and ought to exist. ?
Black holes grow by the accretion of matter nearby that is pulled in by their immense gravity. Hawking predicted that black holes could also radiate away energy and shrink very slowly. Quantum theory suggests that there exist virtual particles popping in and out of existence all the time. When this happens, a particle and its companion anti-particle appear. However, they can also recombine and disappear again. When this process occurs near the event horizon of a black hole, strange things can happen. Instead of the particle antiparticle pair existing for a moment and then annihilating each other, one of them can get by gravity and fall into the black hole, while the other particle can fly off into space. Over very long timescales, we are speaking about timescales that are much much longer than the age of our universe, the theory states that this trickle of escaping particles will cause the black hole to slowly evaporate.
Albert Einstein first predicted the existence of black holes in 1916, with his general theory of relativity. The term "black hole" was coined many years later in 1967 by American astronomer John Wheeler. After decades of black holes being known only as theoretical objects.

The first black hole ever discovered was Cygnus X-1, located within the Milky Way in the constellation of Cygnus, the Swan.
Black holes can be big or small. Scientists think the smallest black holes are as small as just one atom. These black holes are very tiny but have the mass of a large mountain. Mass is the amount of matter, or "stuff," in an object.

Another kind of black hole is called "stellar." Its mass can be up to 20 times more than the mass of the sun. There may be many, many stellar mass black holes in Earth's galaxy. Earth's galaxy is called the Milky Way.

The largest black holes are called "supermassive." These black holes have masses that are more than 1 million suns together. Scientists have found proof that every large galaxy contains a supermassive black hole at its center. The supermassive black hole at the center of the Milky Way galaxy is called Sagittarius A. It has a mass equal to about 4 million suns and would fit inside a very large ball that could hold a few million Earths