What's new on TRAPPIST-1 system? Life forms from one planet can spread to others in just 10 years

Earlier in February, the US space agency NASA announced the discovery of the first known system of seven Earth-like planets around a single star, called TRAPPIST-1, made by its Spitzer Space Telescope.

This system of seven rocky worlds - all of them with the potential for water on their surface - is an exciting discovery in the search for life beyond our Solar System.

Triggering a new research into this path-breaking finding of TRAPPIST-1 planets, researchers led by Sebastiaan Krijt, a postdoctoral scholar at the University of Chicago, analysed whether life forms from one planet can seed life in other planets, owing to their closeness.

The TRAPPIST-1 planets are also very close to each other. If a person was standing on one of the planet’s surface, they could gaze up and potentially see geological features or clouds of neighboring worlds, which would sometimes appear larger than the moon in Earth's sky.

The closeness of the TRAPPIST-1 star - classified as an ultra-cool dwarf - is so cool that liquid water could survive on planets orbiting very close to it, closer than is possible on planets in our solar system.

All seven of the TRAPPIST-1 planetary orbits are closer to their host star than Mercury is to our sun. Three of the planets in the TRAPPIST-1 system are firmly located in the habitable zone.

In the new study, researchers argue that space debris from an asteroid or comet impact could transport bacteria and organisms through the tightly packed system to seed life in other worlds.

“Frequent material exchange between adjacent planets in the tightly packed Trappist-1 system appears likely,” said Sebastian Krijt, lead author of the study.

“If any of those materials contained life, it’s possible they could inoculate another planet with life.”

NASA estimated that the TRAPPIST-1 exoplanets are at about 40 light-years (235 trillion miles) from Earth – which means the system of planets is relatively close to us, in the constellation Aquarius.

For TRAPPIST-1, the probability is too high and that the process of material transfer to other planets could occur in just 10 years, as per simulations conducted by the researchers.

“Transport between planets f and g stands out as being particularly fast and effective, with some material being transferred within 10 years of being released,” the team said.

The study has been published in Astrophysical Journal Letters.