Which is the newest discovered planet?
To be precise, the 3 newly designated dwarf planets are Ceres (in the asteroid belt) Pluto (a Kuiper Belt Object) and Eris (a Scattered Disk Object), Charon (Pluto’s largest moon) is not, however, one of them. However they are none of them newly discovered (1801, 1930 and 2003 respectively) and I think the questioner is asking about the earthlike Gliese 581c discovered 2 weeks ago that is 20.4 light years away in the constellation Libra. Certainly Phil Q seems to think so. WHAT WE KNOW ABOUT GLIESE 581c? (1) The planet is terrestrial (rocky) of 50% greater radius than Earth and about five times Earth’s mass. Its year is 12.9 Earth days long. The mean surface temperature has been estimated to lie between -3 °C (for a Venus-like albedo) and 40 °C (for an Earth-like albedo), suggesting the possibility of liquid water on a solid surface. However, given the closer-orbiting Neptune-mass planet, the system has undergone planetary migration and Gliese 581 c may have formed beyond the frost lin
