Bouncing comets could spread life across the universe

Scientists suspect that comets may have delivered the organic ingredients necessary to cook up life on Earth, and new research shows how exoplanets could have received these special deliveries from comets, too.

In the last few decades, scientists have been learning more about the so-called "prebiotic molecules" found within comets that could have led to life. For example, in 2009, samples retrieved from Comet Wild 2 during NASA's Stardust mission were found to contain glycine, an amino acid and a building block of protein. The European Space Agency's Rosetta mission also detected organic molecules in the atmosphere of Comet 67P/Churyumov-Gerasimenko between 2014 and 2016.

But these organic molecules might get destroyed during a high-speed, high-temperature impact with a planet. That means scientists had to find scenarios where a comet crash in another solar system would be slow enough for these the ingredients for life to survive intact.

For solar systems with stars similar to the sun, the lowest velocity impacts would be most likely in where multiple planets are tightly packed together, the researchers found through their simulations. Scientists have dubbed these types of planetary systems "peas-in-a-pod systems." A comet traveling from the outer reaches of such a system would get slowed down as it bounces between the orbits of these planets.

Meanwhile, the team's simulations suggest there might be "unique challenges for life" on rocky planets surrounding red dwarf stars, officially known as M-dwarf stars. A comet's chance at seeding life there could be doomed, especially if the planets are more widely spaced. It's an exciting time, being able to combine advances in astronomy and chemistry to study some of the most fundamental questions of all.

Edited by : www.linkedin.com/in/priyanka-v23

Credits : https://www.space.com/comets-bouncing-seed-life-on-exoplanets