[LINK] "Is There a Kraken in Kraken Mare? What Kind of Life Would We Find on Titan?"

[rfmcdonald]

At Universe Today, Paul Patton speculates about plausible biochemistries for life on Titan.

Could there be life on Saturn’s large moon Titan? Asking the question forces astrobiologists and chemists to think carefully and creatively about the chemistry of life, and how it might be different on other worlds than it is on Earth. In February, a team of researchers from Cornell University, including chemical engineering graduate student James Stevenson, planetary scientist Jonathan Lunine, and chemical engineer Paulette Clancy, published a pioneering study arguing that cell membranes could form under the exotic chemical conditions present on this remarkable moon.

In many ways, Titan is Earth’s twin. It’s the largest moon in the solar system and bigger than the planet Mercury. Like Earth, it has a substantial atmosphere, with a surface atmospheric pressure a bit higher than Earth’s. Besides Earth, Titan is the only object in our solar system known to have accumulations of liquid on its surface. NASA’s Cassini space probe discovered abundant lakes and even rivers in Titan’s polar regions. The largest lake, or sea, called Kraken Mare, is larger than Earth’s Caspian Sea. Researchers know from both spacecraft observations and laboratory experiments that Titan’s atmosphere is rich in complex organic molecules, which are the building blocks of life.

All these features might make it seem as though Titan is tantalizingly suitable for life. The name ‘Kraken’, which refers to a legendary sea monster, fancifully reflects the eager hopes of astrobiologists. But, Titan is Earth’s alien twin. Being almost ten times further from the sun than Earth is, its surface temperature is a frigid -180 degrees Celsius. Liquid water is vital to life as we know it, but on Titan’s surface all water is frozen solid. Water ice takes on the role that silicon-containing rock does on Earth, making up the outer layers of the crust.

The liquid that fills Titan’s lakes and rivers is not water, but liquid methane, probably mixed with other substances like liquid ethane, all of which are gases here on Earth. If there is life in Titan’s seas, it is not life as we know it. It must be an alien form of life, with organic molecules dissolved in liquid methane instead of liquid water. Is such a thing even possible?

It is, actually.