All matter is pulled toward the center of black holes by unimaginable gravity, according to our partner The Conversation.
In a black hole, space is completely shrunken on itself.
This is what has been called the “black hole singularity”: the energy of matter falling towards it becomes infinite, and time ceases to exist.
This analysis was conducted by Gilles Bogaert, CNRS physicist and historian of science at the University of the Côte d'Azur.
Certainly nothing.
Emptiness, nothing but emptiness.
But what if something falls into the black hole?
Is there something more inside the hole?
Well no.
This is where the mystery thickens: it does nothing more inside, because inside there is always emptiness.
But how is this possible?
It's because black holes have many secrets...
Let's imagine a lost astronaut… He took off his autopilot and he made his rocket go straight towards one of the biggest black holes ever seen, one that would be the size of the solar system.
He rushes towards it, happy, and he moves away from you and you see him jumping with joy through the window.
A horizon beyond which nothing is visible
As it approaches the black hole, you see its color change, more orange, red, dark red, and you see it jump less and less quickly.
You keep this frozen image for a long time where it seems to be levitating above the ground, at the moment when it has disappeared forever behind the horizon of the black hole.
Because if the black hole does not have a surface, it has a horizon, so called because nothing that happens beyond is visible.
He, aboard his rocket, didn't feel anything special as he passed the horizon and he continues to dance on the spot in front of the window.
He'll soon start to feel he's being dragged too fast, so he flips his rocket and puts full throttle out of the trap, and speeds up to light speed, but she can't fight the fall.
Then it will start to stretch but really stretch, worse than spaghetti.
Because his feet want to go faster towards the center than his head.
It's starting to hurt a lot, and he has time to realize that he's going to end up dislocated – when his rocket cracks.
He's right: that's what happens.
All the matter is attracted towards the center under the effect of a gravity of a power of which we have no idea, which stretches and dislocates everything.
What happens when matter arrives at the center of the black hole?
It's the end of the journey, it's the end of everything, even time, and that's where our knowledge stops, too.
When time ceases to exist
Because the theory – which we owe to Albert Einstein – which was valid until then, and made it possible to make the calculations on which this far-fetched story of the lost astronaut is based, becomes false: you can no longer stretch out your arm or anything, the space is completely stunted on itself.
This has been called the black hole singularity.
The energy of matter falling towards it becomes infinite, and time ceases to exist.
Like infinity in nature, it doesn't exist, we deduce one thing, it's that we don't know.
It is believed that all ordinary matter has disappeared.
In the black hole, there is therefore not, after this adventure, one more rocket and one more lost astronaut.
There is always emptiness.
But one thing has changed: the mass of the black hole has increased because the mass of the rocket and its unfortunate pilot has been added to it.
And its size has also increased, because the size of a black hole is proportional to its mass (that's strange!).
Still, there is no more matter inside, but the horizon is bigger.
A word of advice: as a black hole of the mass of the Sun has a radius of about 3 kilometers, a black hole which is the size of the solar system like the one considered above has a radius of 10 billion kilometers a mass of about 3 billion times the mass of the sun.
For such black holes, the gravity-stretching effects are only really felt once inside the black hole (these are called "tidal effects").
For the smaller black holes which have a mass of the order of that of a star, we feel them well before entering them.
My advice: do not approach these black holes there.
Our "BLACK HOLES" file
Recently, Olivier Minazzoli found a new theory of gravity, which he calls “entangled relativity”, and which seems to correspond better to Einstein's own intuitions about nature.
This new theory is identical to that of Einstein for the solar system.
But for black holes, at the singularity level, she predicts that gravity could become repulsive.
The scenario above could therefore be a little different on the end.
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This analysis was written by Gilles Bogaert, CNRS physicist and science historian at the Université Côte d'Azur.
The original article was published on
The Conversation website
.
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