If there is an astronomical object that is particularly scary it is the black holesextreme places where the very concepts of space and time on which our reality is based. In reality there is no need to be afraid: the closest black hole to us is located at 1600 light years away, so you will never end up inside one of these cosmic monsters. To help us on this hypothetical journey, someone comes to us realistic simulation of NASA, which you can see in the video attached to this article.
What happens when you enter a small black hole: spaghettification
So let’s take the Earth and shoot it towards the smallest black hole we know of, which has 3.8 times the mass of the Sun. Gravity is so intense that the side of the Earth facing the black hole feels much more gravitational pull than the other side, and this literally deforms our planet, stretching it. These deformations of the earth’s crust cause very violent earthquakes and volcanic eruptions like they have never seen before. These deformations generate friction and therefore a lot of heat, which goes to warming our planet until it turns into a gigantic oven. The atmosphere also deforms, and this causes winds that can blow even at thousands of km/h. It would be a global apocalypse.
This stretching becomes more and more extreme until our planet disintegrates with us on top, becoming a streak of particles aligned towards the black hole. Physicists call this transformation into a giant plasma spaghetti “spaghettification”. Spaghetti Earth enters the black hole and no one will know anything about it until the end of time.
What happens with a supermassive black hole (4.3 million times the mass of the Sun)
However, there is a trick to prevent the Earth from being spaghettified, and it’s a bit counterintuitive: we have to enter a much larger black hole. In fact, the smaller the black holes, the denser they are, and therefore they distort spacetime more, causing more violent effects.
If we want to enter more or less intact we must therefore enter a supermassive black hole. Let’s therefore replace the small black hole with the one at the center of our galaxy, Sagittarius A*a monster from 4.3 million times the mass of the Sun to 26,000 light years from us.
Here, this material spirals inside the black hole in a flat structure called “accretion disk”. The enormous mass of Sagittarius A* causes material to fall into it at very high speed, and friction heats the accretion disk to over 10 million °C. To prevent the Earth from vaporizing, it is better not to make this disc. But even so, in addition to catastrophic earthquakes and volcanic eruptions, the Earth would be hit by intense gamma rays fired by material in the accretion disk. Our atmosphere is good at absorbing them, but up to a certain point: they would be deadly to all life forms. To survive we would have to retreat into underground anti-atomic bunkerswhile the world outside is in total chaos.
As we get closer we see the theory of general relativity by Albert Einstein in action. Everything appears completely distorted to us, because spacetime is so curved that even the trajectories of light completely deviate. Standing there we could see each other from behind, precisely because the light goes around in circles.
What happens inside a black hole: the extreme deformation of spacetime
Here we are, from this moment we are inside, we have passed theevent horizonthat is, the mathematical boundary of the black hole, so we actually passed it without realizing it.
But I warn you: we can only go from here speculationsbecause we don’t know what exactly is in a black hole. The physics over there is “broken,” so to speak, and by definition we cannot have observations of the interior of a black hole. However, we can make some conjectures based on the physics we know.
We are now headed towards the center of the black hole, which physicists call “singularity”. This is also amathematical entity more than physics: it simply indicates the point at which, according to the equations of relativity, the density and curvature of spacetime are infinite.
The light in there is so distorted that everything appears completely crazy to us. The darkness advances before us and becomes bigger and bigger while the external universe shrinks to an ever smaller window. The inside is dark because light does not have enough speed to propagate in such a distorted spacetime. All we feel is an irresistible pull towards the singularity.
An attraction that doesn’t last long in reality, because once we get here we are accelerating so much that it barely takes us some millionth of a second to get there.
