Life in the solar system could have originated on Mars, not Earth

New study suggests that the organic molecules that allowed life to begin were present on Mars about 4.5 billion years ago. And while these critical components may have hit Earth around the same time, it was on the Red Planet that life found its most favorable conditions.

Earth and Mars are planets in the inner solar system, consisting of four rocky planets and an asteroid belt. Shortly after their formation, these terrestrial planets were severely bombarded by a shower of asteroids.

The movement of the tectonic plates of the Earth led to the fact that these "projectiles" fell into the interior of the planet. The surface of Mars, on the other hand, is stationary, which means that rocks that crashed into it in the distant past remain in place and can be studied.

By analyzing 31 Martian meteorites, the authors of the study sought to answer a number of fundamental questions about their origin. For example, until now, scientists have not determined where these ancient stones came from - from the inside or outer solar system, and whether they carried any organic material that could allow the development life.

Using ultra-precise measurements of chromium isotopes, the scientists identified the meteorites as carbonaceous chondrites from the outer part of the system. Based on the prevalence of such rocks on Mars and the fact that ice usually makes up 10% of their mass, the authors calculated that these "guests" brought enough water to Mars to cover the entire planet with a thickness of up to 307 meters.

Remarkably, carbonaceous chondrites from the outer solar system also transported organic molecules such as amino acids to the inner solar system. These compounds are essential for the formation of DNA and likely provided the raw materials that allowed life to begin.

Conditions on Mars may have been ideal for life at this early stage, but not on Earth. After this period, something catastrophic happened to potential life on our planet, added Bizzaro.

It is believed that a collision occurred between the Earth and another planet the size of Mars. It was a massive catastrophe that shaped the Earth-Moon system and at the same time wiped out all potential life on Earth.

Taken together, these results indicate that life likely had a better chance of flourishing on Mars than on Earth during the formative years of the inner solar system, the authors say research.