What Are Black Holes?

A black hole is a place in space where gravity power is so much that even light can not get out. This can happen when a star is dying.

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Black hole is a cosmic body of extremely intense gravity from which nothing, not even light, can escape. A black hole can be formed by the death of a massive star.

Because no light can get out, people cannot see black holes. They are invisible. Space telescopes with special instruments or devices can help detect black holes.

How Do Black Holes Form?

When a massive star has exhausted its internal fuels in its core at the end of its life, the core becomes very unstable and gravitationally collapses inward upon itself, and the star’s outer layers are blown away. The crushing weight of constituent matter falling in from all sides compresses the dying star to a point of zero volume and infinite density called the singularity.

If the core remnant of a supernova of a massive stars exceeds about two solar masses, it continues to contract. The gravitational field of the collapsing star is predicted to be so powerful that neither matter nor light can escape it. The remnant then collapses to a black hole.

I have attached a photo of a  super massive black hole which was recently detected by (EHT) Event Horizon Telescope. This super massive black hole is present at the center of the massive galaxy M87, about 55 million light years from Earth.

How big Black Holes Are?

Size of black holes depends on two things, 1st is black hole's mass which is measured in solar masses and the 2nd is its volume (how much space it takes up). So, the size of black hole totally depends on its masses. 

Different black holes have different sizes. Stellar size black holes are typically 10 to 100 solar masses, while the supermassive black holes present at the centers of galaxies can be millions or billions of solar masses. Now, you can differentiate how big they are.

The super massive black hole Sagittarius A Star (Sagittarius A*) which is present in our center of Milky Way galaxy is about is 4.3 million solar masses where as super massive black hole present in the center of Andromeda galaxy is about 200 million solar masses.

I hope you like this article about Black holes. If you have something to share or you have opinion do leave your comment below.