This is an artist's concept of a plume of water vapor thought to be ejected off of the frigid, icy surface of the Jovian moon Europa, located 500 million miles from the Sun. Hubble Space Telescope spectroscopic measurements lead scientists to calculate that the plume rises to an altitude of 125 miles and then probably rains frost back onto the moon's surface. Previous findings already point to a subsurface ocean under Europa's icy crust.
