According to massive amounts of empirical geological evidence, the earth has most likely suffered from a "complete" freezedown and near loss of any sign of life, twice in its four and a half billion year history.
... but life has also survived a total of SIX massive impacts (Uhm, six, definable, still, that is) from asteroids capable of impacting the mantle of the earth and subsequently evaporating the entire ocean base.
It becomes apparent to some scientists that life may have begun, been stopped and begun again, on this lonely little planet, special because it is one of the rare ones with actual liquid water upon its surface and a large moon nearby capable of causing constant tidal activity, and yet, here I am, all evolved and shit, posting on the internet.