Nomad planets seeding life throughout the universe? "According to new calculations, planets adrift in space without a "home" solar system are abundant in the universe and scientists have proposed that these nomad planets might not only sustain life, but transport it as well."
One extremely cool planet-like object could have a particularly diverse history - it may have spent much of its youth as hot as a star. The current temperature of the object is 100-150 degrees Celsius, intermediate between that of the Earth and Venus. But the object shows evidence of a possible ancient origin, implying that a large change in temperature has taken place.