If you remember, in 2014, there was a blockbuster film by Director Christopher Nolan, Interstellar. In this film, space-related concepts, such as wormholes, black holes, and alien planets, were depicted in a scientifically accurate way.

But perhaps the most shocking scene was at the end of the film. When in the climax, the main character of the film Cooper falls into a Black Hole. In the film, the name of the black hole was Gargantua. Cooper falls into the black hole with his spacecraft.

Initially, everything was black all around him, Complete darkness. But as he falls deeper, He notices some grain-like particles. These particles hit his spacecraft and caused scratches on it. There were some flashes of light, some sparks, and his spacecraft caught fire. He was forced to eject from his spacecraft and he kept falling into the black hole. And suddenly, he found himself in a five-dimensional space.

A five-dimensional tesseract. It was a mind-boggling experience. A place where he could communicate with his past self, by using gravity. Seeing these scenes, you might have wondered.

if it is possible. Does this exist in a black hole? If we fall into a black hole, what will we see? Come, let’s try to understand that “Black holes” remained largely unknown until the 20th century.

A black hole is a region in space where the force of gravity is so strong not even light can escape. From the outside, you can’t tell what is inside a black hole. Black holes haunt our universe. Dark centers of gravity. That swallows everything in their path.

Einstein’s Theory of Relativity: (Discovery of Black Hole)

Let’s begin with the beginning of this story, friends. The history of black holes isn’t very long. 100 years ago, no one knew about black holes. Because of Einstein’s Theory of Relativity, black holes were later discovered.

Friends, there are two parts to the theory. The Special Theory of Relativity, and the General Theory of Relativity. The Special Theory of Relativity published by Einstein in 1905, tells us how speed influences time.

If you are in a spaceship that is going very fast, if the speed is too high, time will slow down for you. Relative to the people not on the spaceship, back on Earth. The word relative is very important because when you are in a spaceship, you won’t feel the time slowing down.

You would think that time is flowing at the same speed as it normally does. But when you’ll get back to the Earth, you’ll find out that there was a difference in the flow of time. This is known as Kinematic Time Dilation not only speed, but even gravity can also result in time dilation as shown by Einstein in his General Theory of Relativity.

This was developed by him in 1915. The more gravitational force you experience; the more time will slow down for you. This is known as Gravitational Time Dilation.

And this was depicted amazingly in Interstellar. When Cooper and his team land on the Aqua Planet, one hour on that planet equals 7 years on Earth. This happened on the planet because the planet was very close to the Gargantua black hole. So the gravitational force of the black hole impacted the time.

This was another conclusion drawn by Einstein. Gravitation affects almost everything. Not only are physical objects attracted by the force of gravitation, but they attract heat, sound, and light as well. Friends, this means that there can be such objects in the universe that have such a high gravitational force that they can completely absorb light.

If there are such objects, it means that they’d be completely black. We won’t be able to see them. Because not even light can escape them. Friends, this is exactly what Black Holes are. But when Einstein presented his Theory of General Relativity the concept of black holes was merely theoretical back then.

Einstein knew that gravitation influences light. Theoretically, objects that can absorb light were possible. But Einstein did not know that there were actual black holes. When Einstein was alive, the concept of black holes seemed weird to him. He knew that there could be such things, theoretically.

But then, theoretically, the existence of infinity is also possible. But realistically, practically, he did not believe that such things existed in reality. By the time he passed away, not even the term Black Holes was invented.

The term Black Hole was used for the first time by a magazine in 1964. But only after 1967, did the term gain popularity when physicist John Wheeler popularized it.

How Black Holes are formed?

Even though the term black hole sounds quite sensational, it is a misleading name. Black Hole. It might sound like there’s an actual hole there. But that’s not the case. There’s no hole in the space. Black holes are formed by stars.

So there’s some material at its center. But in the stars, even though our Sun is a star, there’s a continuous nuclear fusion reaction at their center. These reactions produce heat and light.

The heat being produced sends a force outwards, and at the center of the star, there’s the force of gravity, this helps the star remain intact and alive. This is how the stars maintain equilibrium throughout their lives, the forces pushing outwards due to the reaction, and the forces pulling inwards due to gravity.

But these reactions take place when a fuel exists. Either Hydrogen or Helium. The fuel wouldn’t always be there. It would get burned up at some point. And when the fuel ends, there wouldn’t be any forces pushing outwards. And the gravitational force pulling inwards wouldn’t be countered by an equal force, so that star will collapse on itself because of its gravity. This will take a long time.

The Golden Ring Around Black Hole:

The golden ring around the black hole is hotter than a million degrees Celsius. The closer they get to the black hole, the faster they revolve around it The particles revolve so fast, that they get rubbed together and compressed which causes them to start glowing.

They emit electromagnetic radiation, which is mainly X-rays. This accretion disk was depicted very accurately in the movie, the only thing they got wrong was that it wasn’t orange.

Human eyes cannot see X-rays. X-rays lay outside the spectrum of visible light. We simply represent it in an orange-yellowish color so that we can represent it. The real color of this disk would be closer to blue. In 2019, the first photo of a black hole was taken. Even in this, the yellowish-orange color was used to represent this accretion disk.

One thing that you can notice in the actual photo, that you might not notice in the movie, is that the particles on one side are brighter than the other side. There’s a simple reason for that. the particles spinning toward us seem brighter to us, and those that are spinning away from us, seem dimmer.

This is due to the Doppler beam effect. When you see the real photo of this black hole, you can look at this blurred photo and interpret the direction of the spinning particles. The brighter area is coming towards us, and the dim area is going away from us.

Coming back to the image from the movie, another interesting thing that you’d notice is that the accretion disk gives off an optical illusion due to gravity. It makes it seem that the disk covers the top and bottom of the black hole. It seems like this because gravity bends the light. The area hidden behind the disk when viewed from the front the light coming from the area, has to move over it because it gets bent by gravity.

If you look at the black hole from the top, it will look like a normal, round disk. We get this illusion only when viewing the black hole from the sides. Apart from this, when you enter the black hole, you will see a last circle of light.

It is the Photosphere. The gravity in this area is so strong that the light starts orbiting the black hole. What is light made of? Photons. The Photons start orbiting the black hole. This means that if you reach this area of a black hole alive, it is theoretically possible to see the back of your head, since the light is traveling in a circle, in the formation of a ring.

After this point, is the boundary of the black hole. This is known as the Event Horizon. It is considered a boundary because, after this point, the gravity is so strong that even the light cannot escape. Everything is black beyond this point. If you are falling into a black hole, and you have crossed the event horizon, theoretically, there’s no chance of you escaping. If not even light can escape it.