Sunday, 17 February, 2019

Ocean world near Saturn hotter-than-ever contender for life

Theresa Hayes | 21 April, 2017, 19:50

NASA has announced that Enceladus has habitable conditions, making it the first known celestial world in the Solar System that can support life apart from Earth. These new findings show that Enceladus "has almost all of these ingredients for habitability".

Thanks to Cassini, organic chemicals-carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur-which are the basic building blocks of life, were seen spraying forth from the "tiger stripe" cracks on the cold surface of the moon.

The findings, published in the journal Science, indicate "there is chemical potential to support microbial systems", he added. There's a subsurface ocean on Enceladus where Cassini researchers found hydrogen gas pouring in, which could be an energy source for life.

Chemical analysis of the plume suggested conditions favourable for methanogenesis - the generation of methane by microbes that use hydrogen and carbon dioxide to obtain energy.

"Hydrogen is a source of chemical energy for microbes that live in the Earth's oceans near hydrothermal vents", said SwRI's Dr. Hunter Waite, principal investigator of Cassini's Ion Neutral Mass Spectrometer (INMS).

"This is the closest we've come, so far, to identifying a place with some of the ingredients needed for a habitable environment", shared Thomas Zurbuchen, the associate administrator for NASA's Science Mission Directorate at Headquarters in Washington. However, in a major breakthrough, two of NASA's veteran missions have found compelling evidence of life on one of Saturn's moon Enceladus.

As for Europa, an icy moon orbiting Jupiter similar in size to Earth's, NASA reports that its "plumes could be a real phenomenon" by popping up in the same region in 2016 as it did in 2014. Cassini passed close enough to Enceladus - less than 30 miles from the moon's surface - to cross through one of these geysers. That's how the Cassini team found hydrogen in the water. The spacecraft detected chemicals in plumes of gas and ice that burst from Enceladus.

Writing in the journal Science, the United States team led by Dr Hunter Waite, from the Southwest Research Institute in San Antonio, Texas, concluded: "Our analysis supports the feasibility of methanogenesis as an energy-releasing process that can occur over a wide range of geochemical conditions plausible for Enceladus' ocean".

Cassini has no instruments that can detect life, so it will be up to future robotic visitors to seek out possible life on Enceladus, the scientists said.

NASA's Saturn probe Cassini observed a plume of water from a crack in Saturn's moon. Hopefully, NASA's Europa Clipper mission, which is planned for launch in the 2020s will be able to verify if this is the situation or not.

NASA's Planetary Science Division Director, James Green, said: "We're pushing the frontiers".