The Gaia space telescope discovered two black holes literally (by space standards) in the vicinity of the Sun: up to 1560 light-years away, the other a little further, 3800 light-years.
The most terrible: black holes “slept” and did not show themselves in any way. Maybe this one sleeps right next to you. A black hole cannot be seen, but they are usually seen by watching them gobble up matter. Matter, on its last gasp, glows, emits, so to speak, a light cry for help before disappearing forever into the bowels of a black hole. It is these glows that usually give out black holes that eat and, so to speak, champ loudly.
And what if the hole does not deign to eat at the present time? The merit of the space telescope is that he was able to notice. By the classical method: companion stars are located next to both black holes. The telescope detected some swaying of the companions, caused by the fact that next to them are invisible black holes. This is a wonderful method that has been working in astronomy for a couple of centuries, but in our case it helped to literally see the invisible.
Both holes are quite large, about ten times the size of the Sun, which makes the discovery creepy. While astronomers argue that such holes, apparently, represent a new class of objects, and are going to even slightly rewrite the picture of stellar evolution, let’s think about something else. Completely invisible, huge objects that can destroy the Earth and even the entire solar system, located close to us and discovered only by accident … Is it dangerous?
Actually, yes. The property of a black hole is that it sucks everything it can reach into itself, and no force, by definition, can resist the gravity of a hole. Everything that falls into the hole disappears forever. In fact, black holes dissolve very slowly, emitting “Hawking light”, but what comes out of the hole is not quite the same substance that got there. So, black holes are very dangerous.
For the reasons mentioned above, we are still detecting either very large black holes or those that happen to have something else near them, in our case, companion stars. But holes can be very small. A hole the size of a soccer ball will destroy the Earth. Nothing prevents such a hole from forming somewhere and flying to us, as interstellar asteroids do.
A number of scientists are trying to explain the strange phenomena in the history of the Earth by collisions with such mini-holes. For example, the asteroid that killed the dinosaurs is a black hole. And the Tunguska meteorite too. A strange thing from heaven that destroyed the biblical cities of Sodom and Gomorrah. Of course, this could be. So, in the case of the Tunguska meteorite, the version about a mini-black hole, literally a few millimeters in size, would explain a lot. But of course there is no evidence.
Perhaps, sooner or later, science will discover a way to see black holes the way we see simple stars. For example, fixing the notorious Hawking radiation (radiation from the depths of a black hole, theoretically predicted by Stephen Hawking and never observed). And maybe a surprise awaits us – for example, an anti-Earth orbiting in antiphase with us, a kind of planet Nibiru, which mystics have been talking about for a long time. Or maybe it will turn out that there are no such small black holes in nature.