In this article, we will look into 25 Most frequently asked questions about Black Holes. In this vast Universe, there are lot of unimaginable and mysterious astronomical object exists . One such mind blowing object is Black Hole. For many decades now, astronomers has been researching and trying to find more and more about this. Black holes are known to be the most destructive force of the Universe. It has gravitational effects so severe that it can even bend the light passing nearby causing the phenomenon of gravitational lensing. We will see some of the most frequently asked questions about this topic in below section.

25 Most Frequently Asked Questions About Black Holes

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1. What is a black hole ?

Ans. A black hole is a region in space time which has gravitational force so incredible that nothing can escape from its gravity, not even light.

2. What is inside a black hole ?

Ans. A black hole is a singularity which contains tremendous amount of mass in almost no space.

3. How are black holes formed ?

Ans. The most commonly known way a black hole forms is by stellar death. As stars reach the ends of their lives, most will inflate, lose mass, and then cool to form white dwarfs. More on National Geographic.

4. Are black holes real ?

Ans. Yes they are very real and exists all across the Universe.

5. What does a black hole look like ?

Ans. It appears as a dark circle silhouetted by an orbiting disk of hot, glowing matter.

6. Who discovered black holes ?

Ans. Einstein first predicted the existence of black hole in his theory of relativity. Later on astronomers discovered the first physical black hole in 1971 based on this theory.

7. When will black holes hit earth ?

Ans. As per the current report, there is no danger of the Earth (located 26,000 light years away from the Milky Way's black hole) being pulled in to a black hole.

8. Do black holes die ?

Ans. The death of Black hole will depend upon the gain in mass due to external factors. Black holes that do not gain mass are likely to shrink and evaporate over the time. This is because of the hawking radiation which reduces the mass and rotational energy of the black holes.

9. How many types of black holes are there ?

Ans. There are basically four types of black holes:-

• Stellar
• Intermediate
• Supermassive
• Miniature

10. What is Event Horizon ?

Ans. It is the boundary of black hole where the velocity needed to escape exceeds the speed of light. It is also called the boundary of no escape.

11. Which is the first black hole discovered ?

Ans. Cygnus X-1 was the first black hole discovered in the 1960’s, and it’s 10 times more massive than the Sun.

12. How many black holes are in the Milky way ?

Ans. Astronomers estimate that the Milky Way has anywhere from 10 million to 1 billion stellar black holes, with masses roughly three times that of the sun.

13. Which black hole is closest to earth ?

Ans. A tiny black hole called 'The Unicorn' lies a mere 1,500 light-years from us and is just three times more massive than the sun.

14. Which is the biggest black hole ever discovered ?

Ans. The biggest black hole ever discovered is known as J2157. It is an enormous black hole which weighs about 34 billion times the mass of the Sun and is consuming the mass of a normal star on a daily basis.

15. How do black holes die ?

Ans. Usually black holes do not die as there will always be some mass around it to survive upon but in theory it can evaporate through hawking radiation.

16. What happens when two black holes collide ?

Ans. When two black holes collide, it will merge and form a large black hole. This event is a very violent event which sends ripples across the space time fabric of the Universe. These ripples are called gravitational waves.

17. Will the sun become a black hole ?

Ans. According to a calculation, the mass of the sun is not enough to become a black hole. Instead, it will end up as a white dwarf.

18. How many black holes are in the Universe ?

Ans. According to an estimate, 40 quintillion, stellar-mass black holes populate the observable universe, making up approximately 1% of all normal matter.

19. How long do black holes last ?

Ans. A supermassive black hole with a mass of 1011 (100 billion) M☉ will evaporate in around 2×10100 years. Some monster black holes in the universe are predicted to continue to grow up to perhaps 1014 M☉ during the collapse of superclusters of galaxies. Even these would evaporate over a timescale of up to 10106 years.

20. How much does a black hole weigh ?

Ans. A black hole mass can vary from twenty solar mass to even one million times solar mass.

21. Where are black holes located ?

Ans. There are no fixed place to locate a black hole. It can be located anywhere in the universe but according to a study super massive black holes always located in the center of the galaxy. Astronomers detects the presence of black hole by observing their effects on nearby stars and planet.

22. When was the first black hole discovered ?

Ans. The first physical black hole ever discovered was spotted in 1971.

23. Which device was used to detect Gravitational waves for the first time ?

Ans. LIGO(The Laser Interferometer Gravitational-Wave Observatory)

24. Who coined the term 'black hole' ?

Ans. Princeton physicist John Wheeler is the first one to coin the term.

25. What is Ergosphere ?

Ans. It is a region located outside a rotating black hole's outer event horizon.