Why asteroids did not destroy life on a young Earth

Life on Earth exists today due to the fact that there are no large “super-Earths” in the solar system, whose attraction will “aim” the approaching asteroids to other planets, reads the article posted in the electronic library arXiv.org

“Asteroids, as a rule, are a great threat to any form of life – it is enough to look at the dinosaurs to verify this statement, on the other hand, they are extremely important for its inception, as they can be one of the main sources of water and” life blocks “for Earth and other planets, where there is life. ” – Rebecca Martin (Rebecca Martin) from the University of Nevada in Las Vegas (USA) tells.

The Earth at the moment is the only planet known to us, on the surface of which there is life. Over the past ten years, astronomers have discovered about two thousand planets, many of which resemble the Earth in size and physical properties, but are most likely deprived of life.

These discoveries made scientists think about what distinguishes our planet from all its “cousins,” and what features of its birth and evolution could make it suitable for the emergence of the first living beings and their survival over the last 3.5-4 billion years. Martin and her colleagues discovered one of the similar features of the solar system, which can explain the absence of life on other planets.

Watching the birth of the Earth and other planets in the virtual version of the solar system, scientists changed its architecture, adding or removing from it the planet. When planetologists “inserted” a large “super-Earth” into it, placing it in the orbit of a hypothetical Phaethon, a nonexistent planet between the orbit of Mars and Jupiter, and in the interval between Venus and Earth, something unusual happened.

It turned out that the appearance of a large stony planet, even at sufficiently large distances from the Earth, led to the fact that our planet began to be bombarded with a huge amount of asteroids for a very long time after its formation. On the average, the appearance of such a planet between the Earth and Venus increased the number of asteroids that fell to Earth by 1.5-3 times.

The increase in collisions, as scientists explain, will happen because gravity of the “super-Earth” will conduct the motion of asteroids living in the zone between the orbits of Mars and Saturn and periodically approaching the Earth. The presence of a large planet in the inner part of the solar system would noticeably “stretch” their orbits, forcing them to come closer to the Earth more often and periodically fall on its surface.

Fortunately, there is no such planet in the solar system, due to which the Earth avoided the fall of a large number of large asteroids after the birth of life on its surface. On the other hand, almost all the exoplanet systems known to us, where there are potential “Earth twins”, have similar planets, which can partly explain why scientists have not yet found traces of extraterrestrial life.

Interestingly, the presence of such an object beyond the Earth’s orbit on the contrary would reduce the frequency of collisions of asteroids with our planet. According to scientists, this would also have a negative impact on the chances of the Earth’s birth, since then on its surface would get much less water and “bricks” of life in the first stages of the existence of the solar system.