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Life may seed from planet to planet in TRAPPIST-1 system, study finds

trappist 1 life seed
In February, NASA announced the discovery of seven Earth-sized exoplanets in the TRAPPIST-1 system, three of which orbited in the habitable zone. Now, researchers from the University of Chicago have concluded that, if life does exist in that solar system, it could feasibly be transferred from planet to planet.

It won’t be easy for this to happen though. Sebastiaan Krijt, one of the researchers behind the study, told Digital Trends that a number of conditions have to align. “Life must develop on one of the planets, an impact has to eject life-bearing material from that planet, and this material needs to avoid being sterilized during the initial impact, the transfer to, and the impact onto another habitable planet,” he said.

The concept of life seeding from one planet to another (known as lithopanspermia) has been speculated for decades. Some experts even argue that life on Earth may have originated elsewhere, brought here by an asteroid many millions of years ago. Having previously discussed the idea with his co-author, Tim Bowling, Krijt decided to test out the hypothesis in the TRAPPIST-1 system after February’s announcement.

The researchers ran several simulations of rocks being expelled from the TRAPPIST-1 planets, which are relatively tightly packed within the sun’s habitable zone. In total they tallied 100,000 simulated trajectories and found that, with the right conditions, life could feasibly transfer in a period as short as 10 years.

Still, Kirjt admits there’s a lot of uncertainty and the likelihood of all the conditions being met is rare. “What our research suggests however, is that surviving the journey between planets should be much easier in a compact system like TRAPPIST-1 than in, for example, our own solar system, because the timescales associated with transport in TRAPPIST-1 are orders of magnitude shorter,” he said.

A paper detailing the study was published this week in The Astrophysical Journal Letters.

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