Planets in our solar system are categorised as either terrestrial (the inner rocky worlds of Mercury, Venus, Earth and Mars), gas giants (Jupiter and Saturn) or ice giants (Uranus and Neptune).

Beyond our solar system, we find other types of planets such as “lava worlds” and “hot Jupiters”.

Now the Hubble Space Telescope has a new flavour of world to add to the planetary cocktail: the catchily named, GJ1214b.

Enshrouded by a thick, steamy atmosphere and weighing in at seven times the mass of Earth, GJ1214b is a waterworld that is unlike anything scientists have seen before.

The planet, which is about 2.7 times the diameter of Earth, has a thick atmosphere made up almost entirely of water vapour and, compared to Earth, is more water than rock.

The steamy waterworld orbits a red dwarf star every 38 hours at a distance of just 1.3 million miles, which, at about 450 degrees Fahrenheit, makes it a pretty hot. These high temperatures combined with high pressures mean that the interior of the planet could be home to all sorts of mysterious substances like “hot ice” or “superfluid water”.

The new research was carried out by the Harvard-Smithsonian Center for Astrophysics.