Cassini sweeps through plume

Images and data from one of Saturn’s moons were sent earlier this week to JPL scientists in La Cañada Flintridge, indicating the possible presence of a liquid ocean beneath the surface of the tiny Enceladus that may contain the conditions necessary for life.

Information was gathered in a flyby Monday morning as part of the Cassini mission to Saturn, currently five years underway, in which NASA hopes to learn more about the exact composition of bodies existing within the planet’s rings.

During this seventh flyby of the moon Enceladus, known as E-7, the spacecraft concentrated its sonar and photographic efforts on a liquid plume emitted through fissures at the moon’s south pole, according to Bonnie Buratti, a JPL astronomer who’s been on the project since the craft’s initial launch into space in 1997.

Though the craft has come closer to the surface in past flybys, this is the first time it’s been sent directly into the plume itself, which was discovered in 2005, Buratti said.

“This is where water, frozen, is coming out from a liquid ocean underneath, causing these huge geysers,” Buratti said, adding that the plume may reach heights of 200 to 400 kilometers, or about 125 to 250 miles.

Data obtained by the craft’s rapid swing through the plume, clocked at speeds of about five miles per second, is still being analyzed by JPL mission team members and will be released to the public as it is collected.

NASA reported on its website Tuesday that the Cassini spacecraft had weathered the flyby well and was sending images and data from its travels back to earth for analysis.

“Previous flybys detected water vapor, sodium and organic molecules,” the site continued, “but scientists need to know more about the plume’s composition and density to characterize the source, possibly a liquid ocean under the moon’s icy surface.”

Scientists have located several areas throughout the universe where the conditions necessary for the most basic forms of life are thought to exist. But Saturn’s moons, and the levels of sodium being found in their cosmic liquids, give hope such conditions may exist within our own solar system.

If so, changes on Titan and Enceladus would serve as snapshots back into Earth’s own distant past, Buratti said.

“We would get a view of what our planet might have looked like in the past,” she said.

Encedalus, and its larger counterpart Titan, may hold keys to the primitive nature of beginnings of life on Earth. Data recovered from the spacecraft’s speedy swoop into a cloudy plume emitted by fissures on the moon’s South Pole is still being analyzed for nitrogen and sodium levels, according to Buratti.

“If we have liquid water or a source of heat and organic molecules, it has all the conditions in which life arose on earth,” she added.

Researchers on the project, initially scheduled to last seven years, are seeking an extension that would allow them to observe the Saturnian system through at least half of the planet’s rotational year, equivalent to more than 29 Earth years. In this time they would hope to learn more about organic molecules on Titan’s surface, whether there is rain on the moon and further similarities between them and Earth.


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