Black holes are the most mysterious, attractive and feared regions in the universe. A dense and dark mass that “eats” everything around it. It is known that nothing that goes into one of them can come out, but whatwhat if you walk into a black hole? Here we explain it to you!
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A black hole is an extremely dense object from which light cannot escape. They are a key consequence of how gravity works: When a large amount of mass is compressed into a small enough space, the resulting object rips through the fabric of space and time, becoming what is called a singularity.
The gravity of a black hole is so powerful that it is able to attract nearby material and “eat” it. In addition, it distorts space itself, making it possible to see the influence of an invisible gravitational pull on stars and other objects.
Since no light, including X-rays, can escape inside a black hole’s “event horizon” – as the region from which there is no return is known – telescopes study them through the surrounding environments. In these areas, matter is heated to millions of degrees as it is drawn into the black hole and glows in the X-rays.
Astronomers classify black holes according to their mass, as the amount of matter inside them is called. The smallest can be the size of an atom, although they have the mass of a mountain; the so-called “stellar” can have a mass up to 20 times greater than that of the Sun; and the “super-huge”, which are equivalent to the mass of more than 1 million soles.
Scientists have found evidence that every large galaxy contains a super-massive black hole at its center. In the case of the Milky Way, the galaxy where the Solar System is located, it is Sagittarius A, which has a mass equivalent to about 4 million suns.
According to NASA, a stellar-mass black hole can form in a matter of seconds, after the collapse of a large star. Another alternative is by merging two dense stellar remnants, called neutron stars.
A neutron star can also merge with a black hole to make a bigger one; or two black holes can collide. Mergers also create black holes rapidly and produce waves in spacetime called gravitational waves.
Much of what is known about the interior of black holes comes from the general relativity theory by Albert Einstein.
According to this theory, distant observers would only be able to see what happens in regions located outside the event horizon, but the “affected” himself would experience a completely different reality, with two characteristics:
- If you enter the event horizon, you would not realize that you have entered, since your perception of space and time would change completely.
- The gravitational field of the black hole would compress you horizontally and stretch you vertically, a phenomenon that scientists call “spaghetti” or “noodle effect.”
Stephen Hawking, in his book A Brief History of Time, explained that if an astronaut fell into a black hole, he would be affected by the gravitational gradient, that is, the difference in the force of the gravitational attraction depending on its orientation.
In this way, if you fell feet first into the black hole, gravity would be stronger at your feet than at your head. This difference in gravitational attraction would cause your body to stretch vertically and at the same time compress horizontally.
The laws of physics would prevent a human from surviving the spaghetti process, but how painful and at what point death would occur will depend on the size of the black hole, and how far away the event horizon is from the center.
Another theory is that of John Polchinski, author of the “paradox of the wall of fire”, who confronts the theory of general relativity with the quantum theory of Einstein. According to Polchinski, an astronaut would encounter a wall of fire just inside the hole, which would destroy it.
Although the spaghettiization of an object the size of a human being has never been observed, in 2020, the telescopes of the European Southern Observatory (ESO) detected the closest noodle effect recorded to date: about 215 million light years from Earth. .
The detected black holes are too far away to attract any matter from the Solar System. However, scientists have observed that black holes destroy stars, a process that releases an enormous amount of energy.
Scientists also rule out the Sun ever becoming a black hole, since it is not big enough to explode; instead, it will give way to a dense stellar remnant called a white dwarf.
In the hypothetical scenario that the Sun becomes a black hole with the same mass that it has today, it would not affect the orbits of the planets, since it would maintain its gravitational influence. In this way, the Earth would continue to rotate around the Sun … or the black hole.