Of the 173 known moons orbiting the eight major planets of our solar system, only one ― Saturn’s Titan ― has an atmosphere, lakes and streams.
And that’s not all. There’s also speculation that Titan ― half the size of Earth ― could harbor life forms or be a possible future home for Earthlings. The provocative moon was even featured in Kurt Vonnegut’s 1959 novel The Sirens of Titan, which tells the story of a millionaire on a quest for the ultimate meaning of existence.
To study this remarkable moon, NASA launched its Cassini spacecraft in 1997. After maneuvering through the asteroid belt between Mars and Jupiter, Cassini finally arrived at the Saturnian system in 2004. It found liquid methane lakes and seas replenished by rain from hydrocarbon clouds, as well as evidence that Titan is home to a giant internal ocean.
But despite the abundance of images and data Cassini has accumulated thus far, it will soon stop transmitting information back to Earth. Next September, the spacecraft will begin its final mission: a death plunge through the gap that separates the rings of Saturn from the planet.