Ocean science adapted for other worlds

An artist's conception shows the Huygens probe descending through the smoggy atmosphere of Titan, Saturn's largest moon. Titan may well hold hydrocarbon-rich lakes and seas.
An artist's conception shows the Huygens probe descending through the smoggy atmosphere of Titan, Saturn's largest moon. Titan may well hold hydrocarbon-rich lakes and seas.NASA
/ Source: The Associated Press

The skills and technology used to explore the extreme depths of Earth’s oceans will soon find work in outer space. Scientists are making plans to probe the icy seas of Jupiter’s moons and drop a lander to the bizarre gasoline-like lakes of Titan, a moon of Saturn.

“The possibilities of studying the extraterrestrial oceans in the solar system is now real,” said Torrence Johnson, a scientist at the Jet Propulsion Laboratory.

Johnson, speaking here Saturday at the national meeting of the American Association for the Advancement of Science, noted that researchers are drawing up plans to send a spacecraft called the Jupiter Icy Moons Orbiter to Ganymede and Europa. The two Jupiter moons may be covered with oceans under miles-thick layers of ice.

Oceanography, said Johnson, is no longer just an Earth science.

“The universe is awash with water,” he said. “Europa probably contains twice as much water as all of the oceans of Earth.”

Ice-penetrating radar
Early plans call for orbiting the Jovian moons with a spacecraft that can measure tides and penetrate ice with special radar. These are techniques that oceanographers have used to probe the Earth’s waters.

Later plans would mean landing packages on the icy surfaces and perhaps drilling down, searching for liquid water, the most likely domain of life, Johnson said.

Some researchers believe radioactive and tidal heating may form deep reservoirs of liquid water beneath the ice of Jovian moons, and that life forms may exist there, enduring the extreme pressures and darkness. Oceanographers have found some bacteria living in such conditions in Earth’s dark depths.

Borrowing from oceanographers
Johnson said planetary scientists are leaning on long-tested techniques that oceanographers have used. For example, ice-drilling techniques are being refined for studies of Lake Vostok, a huge pool of water submerged beneath Antarctica's ice.

“We are turning to our oceanographic colleagues who make things work at the unbelievable pressures,” said Johnson.

Studies for the exploration of the oceans of Jupiter’s moons will be completed next year. Johnson said NASA will draw up the final plans for the project.

Taking aim at Titan
Exploration of the surface of Titan, a moon of Saturn, will start even sooner. The Cassini spacecraft, launched seven years ago, will reach Saturn in July and drop a probe to the moon’s surface next January.

Titan, a frigid world about half Earth’s size, is the only moon in the solar system with a thick atmosphere. Smog generated by a thick nitrogen atmosphere four times denser than the Earth’s obscures Titan’s surface.

“Titan is the largest piece of unexplored real estate in the solar system," said Ralph Lorenz, a University of Arizona planetary scientist and a leader of the Cassini project.

Radar images from Earth telescopes and infrared photos from the Hubble Space Telescope have penetrated Titan’s smog and detected bright and dark regions.

An analysis of the infrared data suggests the dark regions are seas of methane and ethane, hydrocarbons that could form compounds similar to gasoline.

“The simplest explanation may be that these smooth areas are lakes or seas,” Lorenz said.

Organic oceans?
Deep below the surface of Titan, through miles of ice, scientists believe there may be oceans of liquid water, perhaps saturated with organic compounds that could support life.

“If you introduce microbes into that then they may survive,” Lorenz said.

He said if internal heat from Titan caused water to geyser up into the atmosphere, the resulting chemistry would produce many organic molecules, perhaps forming amino acids necessary for life. Lorenz also said meteor impacts have probably blasted craters on Titan, melting the ice.

“It will be interesting to explore how far Titan has gone toward organizing life,” he said, But, he added, “I don’t expect to find any living Titans.”

If, as scientists expect, the sun turns into a red giant hundreds of millions or even billions of years from now, that would warm up chilly Titan and could well give a kick-start to organic chemistry, Lorenz said. He envisioned the Titan of the far future as an "antifreeze-rich water world."

"That isn't the sort of world where you or I might want to live," he said, "but it might well be favorable to the evolution of life."

This report includes information from MSNBC's Alan Boyle.