In the book White Holes, Carlo Rovelli presents a theory of what happens in a black hole

Carlo Rovelli: White Gaps. Ursa 2024, 159 p.

When a massive star runs out of fuel, it collapses. Its own gravity crumples the extinguished giant to the size of a ping-pong ball, but its huge mass draws even light into itself.

This creates a black hole from which nothing can escape. We’ve all learned this if we’ve read anything about black holes.

But what happens in a black hole? And what happens to the black hole in the end?

Italian quantum gravity researcher, theoretical physicist Carlo Rovelli answers with his own theory in a book published in Finnish by Ursa.

The mass of the collapsing star bends space, which stretches out into a long funnel. The ever-shrinking mass at its bottom falls and falls until…

In the extreme conditions at the bottom of the funnel, Einstein’s equations stop working. The star becomes an extremely dense Planck star, which moves into the sphere of influence of quantum phenomena.

At very high densities, the quanta create a pressure that prevents compression. A quantum leap occurs.

Planck’s star begins to expand again and pops like a rubber ball back towards the event horizon.

This is how a black hole becomes a white hole. Eventually, what’s left of the star flies out.

White people gaps are not a generally accepted fact, but their existence is disputed.

The essential thing in the book is not the truth about black and white holes, but how Rovelli describes the development of the theory and doing science in general.

He has previously written space and for nature, several bright and eloquent works that make the everyday thinker’s brain wriggle in a way that produces pleasure.

Quantum mechanics usually causes a headache for the layman, but Rovelli turns it into uplifting literature as well.

Bridge times he tells how it works. When he writes, he has two readers in mind. The other doesn’t understand anything about physics. The other already knows everything.

Both want to read only the essentials. Those who don’t know can’t digest the details and those who know don’t want to read them again and again. That’s why everything unnecessary should be left out of the books.

Thanks to that, Rovelli has time to refer to Dante’s works alongside the history of astronomy and discuss free will in passing.

When reading, you can experience a cosmic connection to both the universe and humanity, which, despite all its poverty, is capable of amazing scientific and cultural achievements.

How then we can get reliable information about black holes and other oddities of the universe?

One way is to go and look. Much new information is based on new precise observations.

However, you cannot go to the bottom of a black hole and you cannot see there, because there is no light coming from there.

You have to go there with the power of thought. It is also possible to invent something new by starting with known things and rearranging them.

A white hole is one solution to Einstein’s equations—in fact, the same solution that describes a black hole. Only time has been reversed.

The idea was invented ten years ago by Rovell’s student at the time, Hal Haggard. He presents his insights on a blackboard at the beginning of the book.

A white hole is like a black hole in a movie going backwards. Like a basketball bouncing off the ground.

An idea after receiving the pair sled does a lot of calculations. Without them, the hand would be mere imaginations. Since the math matches, they have a valid hypothesis.

The Big Bang can also be a big cosmic bounce, where the previous collapsing universe reached its maximum possible total density, bounced back, and began to expand.

In a black hole, the bounce is made by one star, but the physics is the same.

In black time freezes in the gap, because gravity slows down the passage of time. It is a measured fact.

From the outside, everything happens extremely slowly in the opening. From the inside, however, the bounce runs quickly.

Falling into the black and white gap would therefore be a shortcut to the distant future.

“It would be a way to temporarily hide outside the flowing time and wait in safety while the eras slowly change to another.”

Basketball and the black hole do not eventually bounce back quite the same way they fell.

A black hole loses energy as Hawking radiation. At the same time, it decreases. When it bounces into a white hole, it doesn’t have the energy to grow as big as the black hole was.

The white hole remains small and radiates weakly. Eventually it fades away into nothingness.

Rovelli trusts the theory but still isn’t sure it’s true.

No white holes have been detected. Or maybe it is, but it has not been understood.

Astronomers have discovered that the universe is full of mysterious dark matter.

A part of dark matter could perhaps consist of billions of small and subtle white holes that float in the universe as lightly as dragonflies, Rovelli writes. Perhaps.

“What if everyone else is right and we are wrong. – – After all, doing science is exactly like this. The goal is not to convince those around you, but to understand reality. Things will clear up, in their own way and in their own time.”