Starless planets may be habitable after all

The radioactive decay of elements in a planet’s core could keep it warm enough to maintain liquid water, even if it was no longer orbiting its star

URL: http://feeds.newscientist.com/c/749/f/10898/s/12d6d9cb/l/0L0Snewscientist0N0Carticle0Cmg20A9280A0A50B20A0A0Estarless0Eplanets0Emay0Ebe0Ehabitable0Eafter0Eall0Bhtml0DDCMP0FOTC0Erss0Gnsref0Fspace/story01.htm