What if life is a contagious, interplanetary disease?

Around 4 billion years ago, Earth was under attack. The planet’s surface was bombarded by asteroid after asteroid and a whole host of other interstellar rocky bodies amidst the chaos of a young universe. But after this time of chaos, life — in the form of microorganisms — began to emerge.

That life could spring from a catastrophic asteroid impact may seem paradoxical, but according to one popular theory of how life arose on Earth, the two events may be far more interconnected than you might think.

The theory of panspermia suggests that life didn’t originate on Earth at all. Instead, it originated elsewhere in the universe, and was transported to our planet through interstellar objects that traveled between planetary systems — including the asteroids that smashed into Earth all those billions of years ago.

Now, scientists say they have new evidence for the theory. In the paper, they detail how a meteor’s close encounter with Earth in 2017 allowed them to calibrate the number of interstellar objects that may have carried life from our planet to another star system.

“Could such an object potentially transfer life from one system to another?” Abraham Loeb, professor at Harvard University and lead author of the paper tells Inverse. “It turns out, nature is more imaginative than we are.”

How life spreads through the universe

The idea of life traveling between planetary systems had been on Loeb’s mind for a while before the meteor grazed the Earth’s atmosphere above Western and South Australia on July 7, 2017.

The meteor is around 30 cm in size and reached a minimum altitude of 58.5 kilometer in the atmosphere of Earth. It went from an Apollo-type orbit around the Earth to a Jupiter-family comet orbit, meaning that it got close enough to Earth to break through our atmosphere, before being deflected into Jupiter’s orbit. Finally, like a giant swatting away a gnat, Jupiter ejected it from the Solar System entirely.

The close encounter was reported in a paper published in December, 2019.

(For the source of this, and many other equally intriguing articles, please visit: https://www.inverse.com/article/62234-study-on-panspermia-theory/)