‘Potential alien habitat on Saturn’
RESEARCHERS report in the Science journal that the jets of ice and gas gushing from the moon’s south pole contain molecular hydrogen, a chemical characteristic of hydrothermal activity.
On Earth, hydrogen provides fuel for communities of organisms that live around vents on the sea floor.
Its presence on Saturn’s icy moon suggests that this alien world, which harbours a salt-water ocean encased in a frozen crust, has the right conditions to give rise to microbial life.
“For a microbiologist thinking about energy for microbes, hydrogen is like the gold coin of energy currency,” said Peter Girguis, a deep sea biologist at Harvard University, who was not involved in the research.
“If you had to have one thing, one chemical compound, coming out of a vent that would lead you to think there’s energy to support microbial life, hydrogen is at the top of that list.” Everything scientists know about biology on Earth suggests that life is irrepressible. It thrives in clouds, in caves, in lakes of melt water buried 800m beneath the ice sheets of Antarctica in boiling water plumes that gush from the ocean’s deepest, darkest depths. Almost no environment is too extreme, as long as water, organic molecules and a bit of energy are available for organisms to exploit.
Enceladus (pronounced “en-SELLa-dis”) provides all three. It’s looking more and more like the most habitable spot in our solar system beyond Earth and scientists best target yet in the search for alien organisms.
And it might not be alone. Images from the Hubble Space Telescope suggest that plumes much like those on Enceladus are also spewing from Jupiter’s moon Europa, Nasa announced.
Like Enceladus, Europa harbours a subsurface salt-water ocean and could contain organic molecules. Knowing that two worlds in the solar system might meet these requirements, “it’s very possible that we have life out on one of those moons”, said Mary Voytek, a senior scientist for Astrobiology at Nasa, who was not involved in the research.
Enceladus’ geysers have made it a target in the search for extraterrestrial organisms ever since the Nasa space probe Cassini detected them in 2005.
The plumes are rich with water and organic molecules and the force with which they gush from the surface suggests that they are driven by a hydrothermal system two-and-a-half times more powerful than the one that powers Yellowstone’s geysers and bubbling hot springs. They are also physical evidence of the water in the moon’s interior, which is heated by the gravitational pull of Saturn. – Washington Post