Looking for Life
In the salty ocean under the icy surface of Jupiter's moon Europa, robots might someday search for life. Such a mission is likely decades away. But scientists look to extreme organisms that live far beneath the surface of oceans on Earth for a sense of what a journey to this far-off moon might reveal. Might there also be life in the dark ocean of Europa?
LIFE IN A DEEP OCEAN: GIANT TUBEWORMS
ON EARTH: Miles below the surface of Earth's oceans, so-called hydrothermal vents release water heated by volcanic activity. Researchers have discovered giant tube worms living at these vents, fed not by energy from sunlight but by heat from the planet's interior. Bacteria living inside the worms use the heat to transform gasses at the vents into food for their hosts, which grow up to eight feet (three meters) long.
ON EUROPA? If gasses also flow up from a rocky layer under Europa 's ocean, life like this might exist there, too.
ON EARTH: Researchers are looking carefully for life, miles below the frozen surface of Antarctica. In the ice above Lake Vostok, one of the many freshwater lakes that exist under the ice, researchers found evidence that microbes lived there. Scientists hope eventually to drill all the way down into the lake--and they expect to find microbes there, too.
ON EUROPA? If microbes can exist under Antarctica's ice, maybe the saltwater ocean under Europa's icy surface has microbial life, too.