jeffdanielk
Favorite Answer
Astronomers were very surprised that the tiny moon Enceladus has guysers and geologic active. So nobody really knows how small a geologically active body can be.
Anonymous
Europa has double the water of earth but its frozen. When sun becomes red giant and earth is toasted to a crisp --- Europa can have habitable temperatures and liquid running water.
However its unclear if oxygen to breathe will ever be there on europa. If plants can somehow be grown oxygen maybe produced. It's then possible to live there
But again all this is billions of years away
Ruel The Midianite
Io and Europa are geologically alive because they are tidally compressed by Jupiter's gravitational field. Otherwise they'd be dead. So it depends on the tidal forces on the moon or planet.
Nyx
Won't know that until we find some sort of indication of life beyond Earth.