Is there life out there?

摘要

IN THE late 1970s, two different voyages of discovery transformed our ideas about alien life. In 1977, hydrothermal vents were found, belching out "smoke" in the Galapagos rift at the bottom of the Pacific Ocean. The smoke was actually a superheated fluid rich in hydrogen, methane, hydrogen sulphide and minerals essential to life. The chimneys were host to never-before-seen creatures, thriving in a place we had previously thought was completely and utterly lifeless. Two years later, in 1979, NASA's Voyager spacecraft flew past Jupiter and gathered the first evidence that some of the gas giant's moons contained oceans.