If light cannot escape me, what hope have you?

Gargantua, a black hole from the movie “Interstellar”.

Psst.. if you hear music, don’t panic! I added it for an immersive reading experience. Scroll down and pause if you don’t want the ambient music.

Hello again!

Today I bring to you a topic that is very close to my heart..

I go ‘Stephen Hawking mode’ when I hear about this topic, so please bear me if I am exaggerating some/all things in this one.. I’ll try my best to keep you guys entertained!
So here we go..

A black hole.

What is it? How do they form? Why do such voids even exist?
Fear not!

I shall try my best to enlighten you about such puzzling anomalies..

Who else could predict the unpredictable other than the great Albert Einstein back then, when technology was in its childhood days, developing itself for the greater future we currently are in..

He predicted black holes in 1916 and the term ‘black hole’ was coined in 1967 by John Wheeler, a theoretical physicist; in plain English, those who use mathematics to describe certain aspects of nature.

The first black hole was discovered in 1971.
When you reach the event horizon, all hope of escape is gone. For instance, imagine going up the Niagara falls with a row boat.

If you are still not sure about the gravity of this topic (pun intended, lol), I shall elaborate it for you..

By definition, a black hole is a region in space having a gravitational field so intense that no matter OR radiation can escape. Black holes are formed when giant stars die. And by giant I mean, at least 20 times the size of the sun.


A Dying star

As the nuclear energy within a star starts running out, gravity starts to overcome pressure, increasing core density and gravitational force.



Nuclear reaction stops and the star explodes as a supernova, expelling outer parts of the star into space.

By definition, a supernova is the explosion of a star.


Collapsing star

And then the core collapses under its own weight into a single point of infinite density, singularity.

Black hole


Gravitational forces at this stage are so strong, even light cannot escape from its pull. The image above is a moment captured from the movie “Interstellar”, one of my all time favorites. Now, putting aside the fantasy stuff, let’s get into the technicality of a black hole..

A black hole consists of three “layers” – the singularity, the outer and inner event horizons.

Event horizon is the boundary where when you reach, there is no coming back. Once a particle crosses the event horizon, it cannot leave. The black hole sucks all matter with it’s intense gravitational pull. An interesting thing about the event horizon is that gravity is constant across it.

The singularity is where the main part comes in picture.

In the center of a black hole is a gravitational singularity, a 1 dimensional point containing huge mass in an infinitesimally small space, where density and gravity becomes infinite and space time curves infinitely. This is where our laws of physics betray us, they cease to operate and everything seems incomprehensible.

What is space-time curvature?

The image below is a quick answer to the above question..

Space-time curvature

According to a hypothesis, a black hole’s singularity remains hidden behind its event horizon, in that it is always surrounded by an area which does not allow light to escape, and therefore cannot be directly observed. The only exception the hypothesis allows(known as a “naked” singularity) is the initial Big Bang itself!


Theoretically there are 3 types of black holes;

  1. Stellar black holes

They form where massive stars collapse. Masses ranging from 5 to several tens of solar masses (The solar mass (M) is a standard unit of mass in astronomy, equal to approximately 1.99 × 1030 kilograms. It is used to indicate the masses of other stars, as well as clusters, nebulae and galaxies. ~source: Wikipedia)


2. Supermassive black holes (Quasars)

These type of black holes can have a mass equivalent to billions of suns. They likely exist in the centers of most galaxies including our own, The Milky Way. We are unaware of how a supermassive black hole forms, but are predicted to be a by-product of a galaxy formation. They are also known as Quasars.

A Supermassive black hole

3. Miniature black holes

Though miniature type black holes are undiscovered until now, they are thought to have been formed shortly after the “Big Bang”. They are assumed to have much smaller mass than that of our Sun.

Another division separates black holes that spin (possess angular momentum) from those that don’t spin.

Einstein’s General Theory

The great German physicist Albert Einstein found another way to explain how space, light and matter would behave close to a black hole. In his General Theory of Relativity of 1915, Einstein proposed that the gravitational pull of an object such as a black hole would result into curving of space, in the same way that a person can curve a trampoline. A massive object creates a large dent in space into which light and matter would fall. The denser the object, the greater the dent. A black hole, being the densest of all, creates a dent so deep that nothing can escape from it. There’s so much to talk about Einstein’s General Theory of Relativity that I would like to dedicate a separate blog post for it alone.

Black holes are invisible, but it is possible to detect them by studying their effects. Astronomers observing a star called Cygnus X-1 saw that it was giving off enormous amounts of energy. They discovered that this huge, hot blue star was being dragged around in a circle by an unseen object, with a huge gravitational pull. That unseen object, astronomers now believe, is a black hole, which is tearing gas from the star. The gas forms a whirling disc before plummeting into a black hole. As it falls, it travels faster and faster until it moves almost at the speed of light itself. Close to the hole, the gas becomes so hot it emits massive amounts of energy.

That’s all for today guys. Thanks for reading.

2 thoughts on “If light cannot escape me, what hope have you?

  1. Your post is visually good and quite succinct. Just a bit of misinformation. Supernovas are not just explosions of a dying star. It depends on the initial mass of the star.

    1. White Dwarf Explosion : When all the hydrogen in the core of stars, with mass similar to our sun, converts into helium, the stars begin to contract. This leads to hydrogen burning phase in the outer layers of the star. The “radiation pressure” due to this burning then pushes the outer layers until all the gas diffuses diffuses in the ambient medium. Meanwhile, the Helium at core further converts into Carbon further contracting the core. This is how nebulas are formed. Now, depending upon the initial mass of the core, the collapse of the star stops either at Helium or Carbo-Oxygen in the core, where the gravitational collapse is balanced by the radiation or something known as “electron degeneracy pressure”. These cores are called White Dwarfs (size nearly size of earth). Further, in a binary star system, the white dwarfs “accrete” matter from its companion star. If the mass of the white dwarf due to this accretion reaches “Chandrashekar Limit” (1.4 times mass of sun), the helium or carbon goes into runaway nuclear reactions and the star explodes. These are TYPE IA supernovas.

    2. Neutron Star/Black Holes: If the mass of star is very high, the electron degeneracy pressure cannot hold the gravity and the core further collapse. This leads to formation of iron in the core and further disintegration of atoms into electrons, protons and neutrons. The electrons and protons further forms neutrons through inverse beta decay (not quite sure about this). So at the end you now have a very small neutron core(of diameter about 10km) with “neutron degeneracy pressure” now balancing the gravity. The formation of neutrons from Iron is a very fast process and it takes only few seconds to form. Hence there must be huge amount of energy release to collapse a core of size of earth to a size of nearly 10kms. This release of energy is TYPE IB and TYPE II supernovas. Further, if the neutron degeneracy pressure also fails to balance gravity (if the initial mass of the star is more than nearly 30 times mass of Sun), nothing could stop the collapse of the core. All the matter then collapses to a single point in spacetime with infinite density. These are TYPE IIB supernovas which leads to a formation of BLACK HOLES.

    I know I am not a good writer, and your blog is not wikipedia, but I thought I should share something I know to clarify “Nuclear reaction stops and the star explodes as a supernova”. 🙂


    1. Thank you very much for an informative comment. I aimed at simplicity while writing so that it wouldn’t strain the readers’ mind. If I get into technicalities so much, very few people would take interest in reading the actual content of the post which comes later on. Well, you have a point as well, the topic has so many branches coming out, handling all of them at once becomes an arduous effort. Anyway, thanks for the reply and I’ll try my best to elaborate some points furthermore if required henceforth.. by the way you are the first commenter ever on this website/blog.


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