Wednesday, 18 July, 2018

Is There Life on One of Saturn's Moons?

NASA  JPL-Caltech  Space Science Institute NASA JPL-Caltech Space Science Institute
Theresa Hayes | 30 June, 2018, 15:47

The plumes of salty water shooting out of Saturn's ocean moon Enceladus have just ponied up one of the most significant ingredients for habitability: large organic molecules rich in carbon.

Enceladus is the sixth largest moon of Saturn and is only about 505 kilometers in diameter.

Powerful hydrothermal vents mix up material from the moon's water-filled, porous core with water from the moon's massive subsurface ocean - and it is released into space, in the form of water vapor and ice grains.

While this isn't concrete proof of life on Enceladus, the discovery of complex molecules, combined with liquid water and hydrothermal activity, means it is possible.

The scientists made their findings using data collected by NASA's Cassini spacecraft during a flyby of the moon on October 28, 2015, before the end of its mission.

The Enceladus findings come after data earlier this month showed organic compounds on the surface of Mars and seasonal fluctuations of atmospheric methane, marking some of the strongest evidence ever that Earth's neighbor may have harbored life. But now there's even more exciting news: heavy organic compounds containing hundreds of atoms arranged in rings and chains.

"While we have found large molecules outside of Earth before, this is the first time they have been detected emerging from a liquid water ocean", says Morgan Cable of NASA's Jet Propulsion Laboratory, who looks for life in improbable places on Earth.

"We are, yet again, blown away by Enceladus".

Saturn's moon Enceladus is one of the most promising places in the Solar System to look for extraterrestrial life.

"Previously we'd only identified the simplest organic molecules containing a few carbon atoms, but even that was very intriguing". Previous flybys also revealed the presence of a global subsurface ocean and a rocky core. Scientists believe the molecular hydrogen forms as a result of the interaction between water and rocks when it's in a hydrothermal environment.

The discovery was detailed in a newly published study in the journal Nature.

As National Geographic reports, before the Saturn-exploring Cassini spacecraft committed suicide in 2017 by plunging itself into Saturn's atmosphere, it had sent back mountains of data - data that is still being crunched to this day. There may well be huge polymers - many-segmented molecules such as those that make up DNA and proteins - still waiting to be discovered. The tiny world's bright white surface results in part from a snow of material originating from the towering plume of icy particles at Enceladus's south pole.

Dr Postberg said the case for alien life on Enceladus is mounting, but as it stands there are no follow up Cassini missions planned.

Scientists think that the organic material is injected into the ocean by hydrothermal vents on the floor of Enceladus' ocean - something akin to the hydrothermal sites found at the bottom of the oceans on Earth, which are one of the possible environments that scientists investigate for the emergence of life on our own planet.