The best chance of discovering life beyond Earth may not be where you'd expect. Today's weather forecast for Europa, Jupiter's fourth largest moon, is 280 degrees below Fahrenheit. A layer of ice several miles thick coats its fractured surface, with 1,000-foot ice cliffs piercing a pitch-black sky. It's devoid of atmosphere, bombarded by fierce radiation, about 485 million miles from the sun, at times nearly 600 million miles from Earth-and Kevin Hand can hardly wait to get there.
Hand works at the Jet Propulsion Laboratory (JPL), which is under contract with NASA, researching Europa and preparing to send an orbiting probe there. "When it comes to the search for life beyond Earth, NASA's mantra has long been 'follow the water.' Well, the water is on Europa." Planetary scientists believe a global ocean of liquid water swirls beneath the icy surface. "Europa is about the size of our own moon," Hand explains. "Its vast ocean is likely more than 60 miles deep (Earth's ocean depths reach only about seven miles). That means Europa may harbor two to three times the volume of all liquid water on Earth."
Last Updated: 22 July 2011