Life In Our Solar System May Not Have Begun On Earth
It’s human nature to place ourselves at the center of our own universe, which is probably why most scientists have operated under the assumption that, since Earth is the only planet we know of hosting life currently, life must have begun here.
It turns out that may not be true, though.
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New research suggests that the organic molecules that enabled life to emerge were present on Mars 4.5 billion years ago. They may have found their way to Earth around the same time, but it seems clear that Mars was where it all began.
Earth and Mars were formed around the same time, and both endured a bombardment of asteroids, too. The rocks became assimilated into the planets’ crust, but on Earth, plate tectonics mean the meteor’s remains got sort of sucked into the planet’s interior.
Not so on Mars, where the stationary surface means the rocks are still there and available for study.
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In this study, the authors analyzed 31 Martian meteorites, looking to discover whether they came from the inner or outer Solar System, and whether they carried any of the organic material that could have allowed life to develop.
They identified them as carbonaceous chondrites, which means they came from the outer Solar System, and determined these impacts meant Mars was covered in around 1,007 feet of water at the time.
These types of meteorites are known to have transported organic molecules like amino acids to the inner Solar System, which are essential for the formation of DNA and the emergence of life.
“At this time, Mars was bombarded with asteroids filled with ice. It happened in the first 100 million years of the planet’s evolution. Another interesting angle is that the asteroids also carried organic molecules that are biologically important for life.”
While the conditions on Mars would have then been ideal for life, a catastrophic event on Earth ensured the opposite was true.
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“It is believed that there was a gigantic collision between Earth and another Mars-sized planet. It was an energetic collision that formed the Earth-Moon system and, at the same time, wiped out all potential life on Earth.”
Therefore, the authors concluded that life had a better chance of beginning and thriving on Mars during the formative years of the inner Solar System.
Oh, how things have changed in 45 billion years.
