Science News

Super Earths are common in orbits around distant stars

New Delhi: Planets are assembled in the disk of debris surrounding a newborn star, from the leftover waste material. The conventional understanding, based on the architecture of our own Solar System was that rocky worlds form in tight orbits around the host star, while in the outer regions, giant planets are formed. When telescopes began spotting Hot Jupiter exoplanets, gas giants in tight orbits around their host stars, scientists knew that these worlds had to have migrated inwards as there simply was not enough leftover material at such close distances from the host star.

Now, a team of astronomers have revealed that there is nothing stopping Super Earths, or planets that are up to about ten times as massive as the Earth forming in the outer reaches of star systems. There is plenty of material available for such worlds to form, and it is not necessary that only giant planets (ice or gas) have to form in the outer regions of a star system. The team have also announced the discovery of a planet about twice the size of the Earth, orbiting its host star at the same distance Saturn orbits the Sun in the Solar System. A paper describing the findings has been published in Science.

Life on Super Earths

As Super Earths have a greater surface area than the Earth, they provide more surface area and might be superhabitable. The stronger gravity also means that they can retain their atmospheres better. The taller mountains would more readily erode away, and such worlds are likely to be covered by archipelagos of islands. An excess of coastlines would make conditions favourable for life to emerge, thrive and diversify. The crushing gravity would make locomotion expensive for the life forms, who would find it much more difficult to jump or run than Earthlings. Time may be slower for these super earthlings. The crushing gravity also means that escaping super earths with chemical propulsion would be extremely challenging, requiring massive rockets many times the size of pyramids.