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Black Hole Outflows From Centaurus A. Author; ESO/WFI.

15 Great Facts About Black Holes

Black holes are locations in space that has high gravity which pulls matter so much and cannot allow it to get out including light. What makes gravity so strong in black holes is the fact that there is a tiny space where mass is squeezed into. Black holes usually form when a star dies and collects.

Black holes are invisible to people because no light can be able to get out. However, scientists have been using space telescopes to find black holes. These space telescopes help in observing how other stars very close to the black holes act in different manners than other stars.

There are various sizes of black holes ranging from small to largest. The smallest black holes are believed to have formed during the formation of the universe. These small black holes are believed to be as small as an atom but have mass as large as a mountain.

Other than the small and big black holes, there are stellar black holes that are up to 20 times more than the sun’s mass. Scientists believe that there might be several stellar mass black holes in the Milky Way, Earth’s galaxy. The largest of all black holes are known as supermassive black holes which are believed to have more than one million suns when combined.

Here are the 15 Great Facts About Black Holes:

1. Gravitational Pull is Strong at Black Holes and can Trap Light & Electromagnetic Waves

Simulation of Material Orbiting close to a Black Hole. Author; ESO/Gravity Consortium/L. Calçada.

Black holes are fascinating in several ways. They are known to be regions in space where enormous amounts of mass are packed and form a tiny volume.

The tiny volume formed creates a gravitational pull that is so strong. The gravitational pull around the black holes is massive in that light and electromagnetic waves cannot escape from them.

2. The First Discovered Black Hole was Located within the Milky Way

Cygnus X-1 was the first ever black hole to be discovered by scientists within the Milky Way’s sign of Cygnus, the Swan. In 1964, the gas the black hole sucked from a blue supergiant star in near orbit served as the first indication of the black hole to astronomers. The gas from the black hole heated up to the point where it released satellite-detectable high-energy X-rays and gamma-rays as it spiraled into the black hole.

Cygnus X-1 was supposed to be 6,070 light-years away from Earth. However, according to three studies published in 2011, new data indicated that the black hole is 7,240 light-years away. Black hole Cygnus X-1 is thought to be larger than what the scientists imagined because of the properties of the object.

Read 15 Fascinating Facts About Space.

3. Black Holes are Sometimes Formed from the Remains of Massive Stars

A black hole. Image by Genty from

There are many theories on how black holes are formed. It is believed that primordial black holes formed millions of years ago in the early universe after the big bang.

Stellar black holes, medium-sized black holes, form when the center of a massive star collapses into itself. The collapse can also cause a supernova (meaning an exploding star) that makes it blasts part of the star into space.

Supermassive black holes are believed to have formed during the formation of the galaxies they are located in. Scientists have also revealed that supermassive black holes sizes are similar to the size and mass of the galaxies they are in.

4. Black Holes can be Grouped into Four Categories

Scientists have grouped or divided black holes into four categories. The black holes are put into categories according to their mass. They include stellar, supermassive, intermediate, and primordial black holes.

Stellar-mass black holes are formed when a star that has more than 8 times the mass of the sun collapses, rebounds, and explodes. If the star has a mass that is 20 times the sun, it forms a stellar-mass black hole.

Supermassive black holes are located in large galaxies including the Milky Way found in their centers. They have thousands to billions of times of mass more than the sun.

Intermediate-mass black holes are believed to have been formed from the collision between stellar and supermassive black holes. Primordial black holes are believed to have been formed in the first-second afterbirth of the universe. However, there is no proof of their existence as they could have evaporated.

5. The Largest Black Hole has a Mass of Over 66 Million Times that of the Sun

An extraordinary outburst was produced by a black hole in a nearby galaxy. Author; NASA/CXC/Curtin University/R. Soria.

Ton 618 contains the biggest black hole ever discovered in the known cosmos. This is a hyper-luminous Lyman-alpha clump with a 6.6×1010 solar mass black hole. Its bulk is roughly 66 billion times greater than that of the Sun.

The distance between Earth and this enormous black hole is believed to be approximately 18.2 billion light-years. This black hole is found between Canes Venatici and Coma Berenices. Ton 618 is one of the brightest objects in the universe and is the core of its galaxy.

6. Black Holes are Known to Distort Spacetime

Black holes are believed to be able to distort spacetime and make it curve around the event horizon. The fact that a black hole is massive and spins so fast, spacetime is wrapped around it.

Einstein made his general theory of relativity by combining the three dimensions of space and time into the concept he called spacetime. Spacetime is an elastic sheet that gets bent by the weight of objects placed upon it. The massive weight and spinning of black holes make spacetime bend and twist as well.

7. The Event Horizon Borders Around a Black Hole

The Event Horizon of a black hole. Author; Event Horizon Telescope.

Even though black holes are massive regions that are dangerous, they also have borders around them. The surface or border of black holes is known as the event horizon.

Event horizons are defined as the boundary where an object requires a velocity of more than the speed of light to escape. Any matter and radiation cannot get out of the event horizon.

8. Hawking Radiations are Emitted by Black Holes

In 1974, renowned physicist Stephen Hawking made a prediction about black hole radiations. He made the prediction that black holes emit radiations which came to be known as Hawking radiation.

The Hawking radiation describes the particles emitted by the black holes which implies that they have temperature inversely proportional to their mass. The smaller the black hole is, the hotter it glows.

Also, read the top 10 facts about Stephen Hawking.

9. Black Holes Slowly Lose Mass over Time due to Emitted Radiation

A black hole. Image by günter from

Black holes usually undergo evaporation which is thought to be caused by Hawking radiation. The evaporation of black holes is because Hawking radiation lowers their mass and spinning energy.

As a result, it is anticipated that black holes that do not acquire mass through other methods will eventually contract and disappear. This would happen very slowly for all but the tiniest black holes.

10. Black Holes Make Objects Undergo Spaghettification when they Fall in Them

When objects fall into black holes, they undergo several changes. The major change they undergo is known as spaghettification, a term mostly used in astrophysics. Spaghettification is a tidal effect that is brought about by gravitational fields.

Objects tend to be stretched toward the direction of the black holes, getting compressed perpendicular. They are then distorted and stretched apart like spaghetti.

11. They are Used for Scientific Researches

A person observing a fantasy light. Image by Stefan Keller from

Even though they are known to be dangerous, black holes are important in several scientific types of research. They are used for testing theories that explain how the universe works on various scales example in GR and Quantum Physics. Black holes are also used to measure gravitational waves and study matter’s behaviors in extreme conditions.

12. There is a Supermassive Black Hole Located in the Center of the Milky Way

There are several black holes in the universe with the Milky Way containing a supermassive one. The Sagittarius A* is the supermassive black hole found in the center of the Milky Way.

The supermassive black hole, Sagittarius A*, is located near the border of the constellations Sagittarius and Scorpius. It is visually close to the Butterfly Cluster (M6).

Read 15 fascinating facts about space.

13. Black Holes are Extremely Dense Objects

An illustration of a black hole. Image by Gerd Altmann from

Many people might be mistakenly taking black holes to be actual ‘holes’. However, black holes are not holes but extremely dense objects. These dense objects contain enormous gravitational fields which are dangerous as no object can get out of them when they fall in.

14. Study of Black Holes has Led to Discovery of Quasars and Active Galactic Nuclei

Astronomers and scientific studies of black holes have led to the discovery of quasars and active galactic nuclei. An active galactic nucleus is defined as a compact region that is located at the center of a galaxy.

The galactic nuclei have much higher than normal luminosity over a portion of the electromagnetic spectrum. A quasar is a supermassive black hole that is actively feeding up on the material. The material that quasars feed on makes them have swirled disks that are heated up and shine so brightly.

15. Black Holes are Invisible

Mini-Jet Found Near Milky Way’s Supermassive Black Hole. Author; NASA, ESA, Gerald Cecil.

Even though black holes usually absorb light, they are invisible. The reason they are invisible is that no light can escape from them.

However, this phenomenon has not prevented scientists and astronomers from observing them. By the use of space telescopes with special instruments, black holes can be found and the behavior of the material on them observed quickly.

The researches that have been made on the black hole are not the last as scientists and astronomers want to learn more about them. Black holes can be dangerous but they are fun to study.

Read 10 Best Facts about the Space Needle.