Galileo Galilei discovered Jupiter's moon Europa in 1610. More than four centuries later, astronomers are still making discoveries about its icy surface. With a diameter of almost 2,000 miles, an orbit equivalent to 3.5 Earth days and a mass about 65 percent of Earth's Moon, Europa is considered by some scientists a likely place to look for present-day environments suitable for life.
For decades, scientists have been speculating that life could exist in beneath the icy surface of Jupiter’s moon Europa. Thanks to more recent missions (like the Cassini spacecraft), other moons and bodies have been added to this list as well – including Titan, Enceladus, Dione, Triton, Ceres and Pluto. In all cases, it is believed that this life would exist in interior oceans, most likely around hydrorthermal vents located at the core-mantle boundary.