Discovering a planet is a feat on its own that not too many people can boast. Now imagine discovering a new type of planet, one that has high chances of harboring life to boot. Dr. Madhusudhan and his colleagues at the University of Cambridge did just that.
Their new planets, coined ‘Hycean worlds’ (from hydrogen and ocean) are, as the name suggests, ocean worlds with a hydrogen rich atmosphere. These planets can get up to 2.6 times the radius of the Earth, which makes them large for rocky worlds and small when it comes to gassy planets, falling in between the so-called super-Earth’s and mini-Neptunes.
They are thought to have a solid surface like earth like planets, but covered by one giant ocean with a thick atmosphere above like gas giants, presenting themselves as a true hybrid. The only downside is that they can get very hot in normal conditions, with temperatures up to 200 degrees Celsius (or about 400 F).
Constraints for life arising
However, Madhusudhan found a solution for that to, by looking at the less traditional ones. Since we know that the Hycean worlds with normal orbits around their stars are too hot, the scientists simulated the planets in two other situations. The first was done assuming that the planet was tidally locked, with just one side pointing towards the star at all times (like our Moon.) In this case the night side of the planet would reach temperatures that are just right for life. These worlds were dubbed dark Hycean planets.
The other type that was explored was the so-called cold Hycean planet, where it was assumed that the planet had somehow lost its host star, flying solo through space. In this case the entirety of the planet would be warm enough to support life.
On top of that, it is believed that there may be a lot of these type of planets around, as the size and mass range where the Hycean’s fall into is very common in our universe. Therefore, some of these worlds are already selected as candidates for biomarker research with the soon-to-launch James Webb Space Telescope (JWST). Although do not hold your breath for E.T., as most scientists do not believe that these planets could support much more than microbial life due to their limited chemical diversity.