The Basics of Black holes

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Our universe is a beautiful place, it contains everything we know about and everything we aspire to know about. It gave us birth and one day, unfortunately, will bestow upon us death. There are an infinite number of secrets hidden inside the cosmos and this organization is entirely dedicated to uncovering them, we strive to spread the love for science to as many as possible!

Black Holes

What is a black hole? A black hole is a celestial entity with an infinite amount of gravitational force. This happens as it has an infinite amount of mass compressed into a small 1-dimensional point called a singularity. Due to this it warps the fabric of spacetime (will be discussed in another post) so much that not even light can escape its gravitational pull once it crosses a certain point.

Formation:

We all have heard at least a little bit about what a black hole is and what it can do, but very few know about its formation.

Everything begins with the death of a star. 

Stars have a continuous chemical reaction going on within them, hydrogen combines with hydrogen to form helium, helium combines with helium to form carbon and so on. This continuous process releases energy in the form of radiation.

This radiation released by the star keeps a balance with the amount of gravity the star has. Hence, preventing the star from collapsing in itself.

Slowly and steadily the elements inside the star keep combining to form heavier elements. When this series reaches the formation of iron, here comes the problem. The reaction that creates iron does not release any energy, so when a lot of iron gets accumulated at the core, the gravity and radiation balance is broken.

Gravity overpowers the star’s radiation and the star collapses in itself, also creating a supernova explosion.

Now, depending on the size of the star there are two things that can happen, A neutron star might form or if the star is dense enough a black hole is formed.

Components:

• Event Horizon: The boundary around a black hole beyond which nothing traveling at the speed of light or slower than the speed of light can escape. In other words the point of no return.
• Singularity: The 1-dimensional point inside a black hole which is known to have an infinite density and gravity.
• Accretion disk: A rotating disk of matter formed around the black hole under the influence of its gravity.
• Ergosphere: The region around a black hole through which energy is able to escape.

What’s inside a black hole?

Let us assume that somehow you got yourself inside a black hole(highly unlikely), what would happen to you? Let’s find out.

Well, the time taken to die painfully will vary according to the size of the black hole. The larger the black hole is the more time you have to live as the singularity would be farther from the event horizon, and smaller the black hole the lesser time you have to live.

Once inside the black hole, observers (if any) will see the light reflected off you red-shifting. This is a phenomenon observed while looking at far away galaxies, this shows that the object reflecting the light is moving farther away.

Once you get closer to the singularity your body will start going through a process called spaghettification. The gravitational pull would be so high here that it would be stronger for every cell in your body that is closer to the singularity. Eventually your body would elongate like spaghetti (hence the term) and would eventually rip you apart.

This could be one of your fates, but as nobody actually knows what would happen if you entered into a black hole we can hypothesize it to be anything.

There are various possibilities:

1. It could be a connection to another dimension
2. It could be the path to another universe
3. It could lead us to a different part of our universe
4. It could maybe take us into the past

Anything could be possible!

The Death of a black hole:

Even Massive and dense bodies like black holes have a certain life span. All black holes in our universe are slowly dying, which means they are losing their mass day by day through something called Hawking radiation (Named after the great physicist Stephen Hawking).

To understand the action of Hawking radiation and how it affects black holes we are going to have to look at the universe at a sub-atomic level. When we observe processes that take place at this level the usual laws of physics are rendered useless and a new branch of science takes over called quantum mechanics.

When we look at empty sections of our universe they are not exactly empty. Our universe is very chaotic at the sub-atomic level, pairs of virtual particles are continuously created and removed from existence through their action on one another.

These pairs of virtual particles usually consist of a particle and its anti-particle, when both of these come together they self annihilate.

This process is happening everywhere, continuously, billions of particles spawn into existence and vanish immediately. How does this affect black holes?

As these particles spawn everywhere in space they also formed near black holes, but it gets interesting when these virtual pairs are created exactly on their even horizon.

Hawking radiation:

When virtual particle pairs form on the event horizon of a black hole hawking radiation is created.

Hawking radiation is nothing but the term given to radiation a black hole emits, this energy cannot be created from the black hole as according to thermodynamics ‘Energy cannot be created nor Destroyed’ . Then where does this come from?

On the event horizon pairs of virtual particles tend to lose one particle out of the pair into the black hole, this ejects the other one out into space. The particles ejected out get converted into a real particles and form this radiation.

The particles ejected out need energy to turn into real particles, this energy is given up the black hole and results in it losing some of its mass.

Slowly and steadily over a very long period of time Black Holes evaporate into nothing through this process .

Even though this is a continuous process it might take millions of years for a Black Hole to lose even a fraction of its mass. The only bodies left at the end of our universe would theoretically be Black Holes who would have sucked in all the mass in our universe and would slowly fade away into a sea of nothing, leaving the universe in a possible eternal darkness.

Thank you!