What’s Inside a Black Hole?

What’s Inside a Black Hole? Could we get into a spaceship in one of them?. Mathematics Hannah Fry and geneticist Adam Rutherford plan to answer several on their show “The Curious Cases of Rutherford and Fry,” chose to start with this one.

“Sounds fun!” Exclaimed Fry.

“Nobody knows much about black holes, that’s why they’re so fantastic,” said the cosmologist Andrew Pontzen, which baffled us a bit because we had called him to contribute his knowledge … and lack of knowledge, apparently.

“Not only do we not understand them well but what little we understand exposes the strangest phenomena of physics,” he added.

Let’s do it

Let’s start with the basics: what is a black hole.

“Essentially a black hole is a heap of matter in a space so small that nothing can come out, not even the light, ” explains Pontzen.

“Imagine that you could pack in a space far more than you would have thought possible until it became so dense that it had its own gravity force.”

And the best ingredient we know to make a black hole are stars that, at the end of their lives, undergo a gravitational collapse and reach a point of infinite density.

It is estimated that there are about 100 million black holes in the Milky Way.

The problem is that we can not see them …

But then, how did we find out they existed?

The first person to conceive the idea was the English Reverend John Michell, a geologist, astronomer and one of the great forgotten scientists of history.

In 1783 he proposed the existence of ” dark stars ” – the Newtonian version of the black hole – whose gravitational field was so large that even light could not escape.

But it was only thanks to mathematics that the presence of black holes began to be accepted.

While serving in the German army during World War I, Karl Schwartzchild solved Albert Einstein’s equations and calculated how large the mass would have to be to have such a strong gravitational force as to prevent light from flowing out.

However, astronomers continued to regard the idea of ​​black holes as ” absurd “, with many refusing to accept that a dead star could produce an invisible but immense hole in the fabric of space and time.

Moreover, if by nature they were invisible, how could they be sure that they really existed?

The movement of the stars

Are we talking about hypothetical entities that are said to exist because mathematics and physics confirm that they could be there?

” We have credible evidence that there are objects that behave exactly as black holes would,” the astrophysicist Sheila Rowan told the BBC.

“Observing the way stars and gas move in some regions of space tells us that there is a huge amount of mass crowded into a small space with super-gravitational gravitational effects,” Rowan added.

“It is true that we can not see them but the recent observations of LIGO (the Advanced Observatory of Laser Interferometry of Gravitational Waves) have been able to detect in gravitational waves in space created by mergers of immense black holes billions of years ago,” he adds The expert.

To fly!

Now yes: if we mounted a spaceship and got into a black hole, what would happen?

“The first thing you would feel when diving into a black hole is that the force of the tide is so powerful that it pulls you out of your head with more force than the one that pulls your feet and stretches you until you are ‘spaghetti’,” says Pontzen.

“If your body is very strong in theory you could survive that stretch and, assuming you are, there are several theories about what you would find in there,” he continues.

“One of the possibilities is ‘the wall of fire’ which, as the name implies, you would find a band of fiery particles that would fry you like a potato.”

If you do not suffer such a fiery fate, you could explore it, but only to satisfy your own curiosity, because – remember – you can enter, but never leave.

Those who stayed on Earth

Those who were not enthusiastic about traveling to the black hole but watched, would see something completely different.

“If those in the ship said goodbye by shaking the hand, we would see that the movement would become slower and slower until at the horizon of the event – the entrance to the hole – the image would freeze and become less intense” , Explains Sheila Rowan.

“The gravitational force is so strong that it pulls even the information it is trying to get out, so the image grows paler, slower and smaller, until it freezes.”

And that is precisely what Relativity tells us: the same event seen by observers from different places may not look the same.


Inside, you keep exploring, but the force constantly pulls you toward the center of the black hole.

“That,” Pontzen points out, “is technically known as ‘singularity,’ which is when everything that has fallen into the hole is piled up in the nucleus so that it is infinitely small but infinitely dense.”

Also, when you finally become part of that unique nucleus, you probably will not have the form of a human being, not even a spaghetti or fried one.

“And the terrible news is that physics is in serious trouble because eventually all our numbers explode … we just do not know what happens when you get to the center of a black hole,” laments the cosmologist.


  • What ‘s inside a black hole ?
  • Everything that has entered it
  • The problem is that we do not know in what state it is all that
  • And we’ll never know until someone gets inside one of them
  • But that trip is dangerous : you finish or turn spaghetti or fried or crashed against the nucleus or, perhaps, all the above
  • Although from outside you will only be slower and blurry.