Measurements from the Cassini spacecraft orbiting Saturn, made between 2006 and 2011, indicate that Saturn's largest moon may have a layer of liquid water under its icy surface.
This intriguing moon, called Titan, is already notorious for having an atmosphere thicker than Earth's -- something no other known moon has. Under Titan's atmosphere, Cassini has shown us lakes and rivers made of methane (liquid swamp gas) and not water. The temperature in that cold region of the solar system is always low and Titan's frigid surface is at something like - 290 degrees Fahrenheit.
At such temperatures, water on the surface is frozen solid -- in fact, "rocks" on Titan (photographed by our little lander) are made of water ice. But the new measurements indicate that below its outer icy shell, Titan may contain an ocean of liquid water. At such temperatures, water on the surface is frozen solid -- in fact, "rocks" on Titan (photographed by our little lander) are made of water ice. But the new measurements indicate that below its outer icy shell, Titan may contain an ocean of liquid water.
This is not the only moon in the solar system where astronomers suspect that liquid water may exist underground -- several of Jupiter's moons, especially the one called Europa -- also show indications of a sub-surface ocean.
At such temperatures, water on the surface is frozen solid -- in fact, "rocks" on Titan (photographed by our little lander) are made of water ice. But the new measurements indicate that below its outer icy shell, Titan may contain an ocean of liquid water. At such temperatures, water on the surface is frozen solid -- in fact, "rocks" on Titan (photographed by our little lander) are made of water ice. But the new measurements indicate that below its outer icy shell, Titan may contain an ocean of liquid water.
This is not the only moon in the solar system where astronomers suspect that liquid water may exist underground -- several of Jupiter's moons, especially the one called Europa -- also show indications of a sub-surface ocean.
And, a much smaller moon of Saturn's, called Enceladus, has steamy geysers of salt water erupting from giant cracks. Water seems to be a common substance in the solar system (and the universe) and we are detecting it as vapor, as solid ice, and -- increasingly -- in liquid forms under the surface of other worlds.
For more on the Titan story, see:
http://science.nasa.gov/science-news/science-at-nasa/2012/28jun_titanocean/
