Life on Europa: A possible energy source
By Ron Cowen
In contemplating likely habitats for life beyond Earth, planetary scientists rank Jupiter’s moon Europa as a prime candidate. A boatload of circumstantial evidence suggests that beneath the icy surface of this moon lies a vast ocean. And where there’s water, there could be life.
If life on Earth is any guide, however, organisms cannot live by water alone. They also need energy. Scientists have proposed that the same source of heat that may have melted ice and created a Europan ocean may also generate plumes of warm water that could be fueling life. Theoretical calculations, however, don’t offer convincing proof that this source—flexing caused by the gravity of two of Europa’s sibling moons and Jupiter—was ever strong enough to create subterranean plumes.