News pieces like this are amazing to me. Twenty-five years ago we were acquainted only with planets in our own solar system. Today we know of hundreds, and they are no longer all just data points. We are beginning to get glimpses of worlds totally different from what we see circling our own sun.
Zachary Berta, from the Harvard-Smithsonian Center for Astrophysics (CfA):
GJ 1214b is like no planet we know of. A huge fraction of its mass is made up of water.
About 75% water, according to best calculations. A likely atmosphere of superheated steam (just ignore that part of the old diagram, right, that says “hydrogen and helium”). It orbits just over a million miles from its red dwarf star. A year lasts 38 hours. Surface temperature: almost 500 degrees F.
The high temperatures and high pressures would form exotic materials like ‘hot ice’ or ‘superfluid water’, substances that are completely alien to our everyday experience.
Well, literally, pretty hot. The closest solar system analogue? Ganymede, Jupiter’s largest moon, a mix of ice and rock.
Here’s a comparison in size with planets we know a little bit better: