Black holes are some of the unusual and most interesting objects in outer space. They are extremely dense, with a gravitational attraction so strong that even light cannot escape its reach if it gets close enough.


Albert Einstein first forecasts the existent of black holes in 1916, with his general theory of relativity. The term “black hole” was coined many years later in 1967 by the American astronomer John Wheeler. After decades of black holes becoming known only as theoretical objects, the first physical black hole discovered was discovered in 1971.



Strange black hole facts

If you fall into a black hole, the theory has long suggested that gravity would stretch you like spaghetti, although your death would come before reaching the singularity.


A 2012 study published in the journal Nature suggested that quantum effects would make the event horizon act much like a wall of fire, which would make you die instantly.


Black holes don’t stink. Suction is caused by throwing something in a vacuum, which is definitely not the massive black hole. Instead, objects fall into them just as they fall into anything that exerts gravity, such as Earth.


The first object considered as a black hole is Cygnus X-1. Cygnus X-1 was the subject of a 1974 friendly bet between Stephen Hawking and his physical partner Kip Thorne, with Hawking betting that the fountain was not a black hole. In 1990, Hawking recognized defeat.


It is possible that miniature black holes have formed immediately after the Big Bang. The rapidly expanding space may have compressed some regions into small, dense black holes less massive than the sun.
If a star passes too close to a black hole, the star may break.


Astronomers estimate that the Milky Way has between 10 million and one billion stellar black holes, with masses approximately three times larger than those of the sun.


Black holes remain excellent food for science fiction books and movies. Check out the “Interstellar” movie, which relied heavily on Thorne to incorporate science. Thorne’s work with the film’s special effects team led to a better understanding of scientists about how distant stars could appear when viewed near a rapidly rotating black hole.



Bright light over binary black holes

In 2015, astronomers who used the Gravitational-Wave Observatory with a laser interferometer (LIGO) detected gravitational waves from the fusion of stellar black holes.


We have more confirmation of the existence of black holes of stellar mass that are larger than 20 solar masses; these are objects that we did not know existed before LIGO.


The LIGO observations also provide information on the direction in which a black hole rotates. When two black holes spiral around each other, they can turn in the same direction or in the opposite direction.


There are two theories about how binary black holes formed. The first suggests that the two black holes in binary form at about the same time, of two stars that were born together and died explosively at about the same time.

The companion stars would have had the same turning orientation as the others, so the two black holes that were left as well.


Under the second model, black holes in a stellar group sink into the center of the group and pair up. These partners would have random turning orientations compared to each other. The LIGO observations of the accompanying black holes with different turning orientations provide stronger evidence of this formation theory.



The black hole looks like

Black holes have three “layers”: the external and internal event horizon, and the singularity.

The event horizon of a black hole is the boundary around the mouth of the black hole, beyond which light cannot escape.


The inner region of a black hole, where the object’s mass is located, is known as its singularity, the only point in space-time where the mass of the black hole is concentrated.


Scientists cannot see black holes as stars and other objects can see in space. Instead, astronomers must rely on detecting the radiation emitted by black holes as dust and gas attract dense creatures. But supermassive black holes, which located in the center of a galaxy, can envelop from the thick dust and the surrounding gas, which can block revealing emissions.