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One of the most inhospitable places in our solar system just might hold the answer to the question: Are we alone in the universe?

Scientists are looking at the outer solar system — the planets of Jupiter, Saturn, Uranus and Neptune, and what's below the surface of their moons — for the answer to that great mystery.

"The interior oceans of icy moons may be the best place to search for life in our solar system and beyond," said Robert Pappalardo, a senior research scientist at NASA's Jet Propulsion Laboratory in Pasedena, Calif.

Last week, scientists announced the discovery of a new ocean of liquid water — as big or bigger than Lake Superior — at the south pole of Saturn's moon Enceladus. The findings were based on data sent back by Cassini, a NASA-European spacecraft.

"We suspected an ocean. This is better evidence," Pappalardo said in an interview before his lecture, "Ices and Oceans in the Outer Solar System," at the Nebraska Union Monday evening. About 100 people, mostly students, were in attendance.

Pappalardo served as project scientist for the Cassini Equinox Mission from 2008-2010. The Enceladus discovery was based on gravitational readings made by Cassini after it flew through geysers shooting up into the atmosphere.

Pappalardo said it was risky decision to have Cassini fly through the geyser plumes because they didn't know how the spacecraft would react. It went through several times without a hitch.

"I'm proud and happy to see this result of something that was put into motion years ago," Pappalardo said.

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Cassini is in the 17th year of its mission and has made more than 100 flyovers of Saturn's largest moon, Titan. Its mission will be extended for several years in hopes of finding more geological evidence to support their conclusions that vast oceans do exist below the icy moons.

Scientists don't expect to find whales or fish in these subsurface ocean, but rather single-cell life forms, possibly living in oceans that are vastly different from our own, Pappalardo said.

He is currently working on the Europa Clipper, a spacecraft that would investigate whether Jupiter's icy moon Europa could harbor life. Magnetic field readings taken by the Galileo spacecraft lead scientists to believe that it has a salty interior ocean.

Pappalardo believes that Europa, which is about the size of Earth's moon, is the most promising place to find life in our solar system.

He said more missions are needed to gather more evidence of what's below Europa's icy surface, where temperatures are minus 280 degrees.

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