The discovery of eruptions of liquid water on a little-known moon of Saturn has added it to the small, highly select group of places in the solar system that could plausibly support life.
The moon, Enceladus (pronounced en-SELL-ah-dus), is only 300 miles wide, and planetary scientists expected that it would be nothing more than a frozen chunk of ice and rock.
Instead, the National Aeronautics and Space Administration’s Cassini spacecraft has spotted the eruptions.
“It’s startling,” said Dr. Carolyn Porco of the Space Science Institute in Boulder, leader of the imaging team for Cassini. A package of 11 scientific papers about Enceladus appears in today’s issue of the journal Science.
“I wouldn’t be surprised to see the planetary community clamoring for a future exploratory expedition to land on the south polar terrain of Enceladus,” said Porco, lead author of one of the Science papers. “We have found an environment that is potentially suitable for living organisms.”
Parts of the Cassini spacecraft were desinged and built in Colorado by Lockheed Martin. Cassini’s imaging team, led by Porco, is based at the Space Science Institute.
Life requires at least three essential ingredients – water, heat and carbon-based molecules – and Enceladus may possess all three.
As Cassini flew through the plumes of tiny ice crystals rising into space from the eruptions, it also detected simple carbon-based molecules such as methane and carbon dioxide, which suggest more complicated carbon molecules might lie on the moon’s surface.
The lack of a crater suggests that the heat is not the result of a meteor impact.
Based on initial observations, some scientists think that this warm region near the south pole may have somehow persisted for millions or billions of years, sufficient time for life to arise.
Porco said their calculations eliminated the possibility that the particles were produced by warm vapor rising off warm ice at the surface. The best explanation, she said, is that pockets of liquid water exist under high pressure below a few tens of yards of ice. When the ice ruptures, the water shoots out and immediately freezes into ice crystals.