Image: Europa
NASA / Ted Stryk
An image of Europa from NASA’s Galileo spacecraft shows plains of bright ice, long cracks and dark patches that likely contain both ice and dirt.
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updated 11/16/2011 2:35:17 PM ET 2011-11-16T19:35:17

New research shows that the jumbled ice blocks crowning the surface of Jupiter's icy moon Europa are signs of large liquid lakes below, a key finding in the search for places where life might exist beyond Earth.

Drawing from studies of underground volcanoes in Iceland and Antarctica, scientists ran computer models to see if the chaotic formations on Europa's surface could be explained by the same geologic processes seen on Earth.

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PHOTOS: Moons of Jupiter

"We looked at melt underneath the ice, and the fracture and collapse of ice shelves," Britney Schmidt, a postdoctoral fellow at the University of Texas at Austin's Institute for Geophysics, told Discovery News.

"We come with these large pockets of water that form lakes. As they melt, they actually break up the ice above it, like what you see on Earth," she said.

SCIENCE CHANNEL: Take a tour of Titan, Callisto and Europa!

The study provides "the best model so far" for the ice formations on Europa, Paul Schenk, a staff scientist with the Lunar and Planetary Institute in Houston, wrote in an email to Discovery News.

"If we go back with penetrating radar instruments we should be able to see into the ice shell, determine the stratigraphy of the layers in the shell and verify which model works best," Schenk said.

Europa, which is slightly smaller than Earth's moon, is believed to have a large ocean of salty water beneath its frozen crust.

"Europa has more water than all of Earth's oceans," planetary scientist Simon Kattenhorn, with the University of Idaho, told Discovery News.

While the ocean itself is of interest to scientists searching for life beyond Earth, a mechanism to churn the surface ice and subsurface water makes Europa an even more compelling target.

NEWS: Europa, Jupiter's Moon, Could Support Complex Life

The vigorous mixing of ice and water provides one mechanism for nutrients and energy to get from the frozen surface to the ocean below.

"It's exciting for biology," Schmidt said.

A mission to Europa is second on planetary scientists' wish list after a sample return mission from Mars.

"Europa is likely to have a deep ocean of liquid water beneath its icy crust, making it an object of enormous interest as a possible abode for life," planetary scientist Steve Squyres, with Cornell University, testified at a Congressional hearing this week.

ANALYSIS: Jupiter's Moon Europa Helps Solve Stripey Mystery

Schmidt's research will be published in a future issue of Nature and appears on the publication's website Wednesday.

The headline on an earlier version of this story incorrectly referred to Europa as a Saturn moon rather than a moon of Jupiter.

© 2012 Discovery Channel

Photos: Jewels from Jupiter

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  1. Jupiter loses a stripe

    The weather on Jupiter is changeable, as these before-and-after pictures show. The photograph on the left shows Jupiter as seen in June 2009. The photo on the right, taken on May 9, 2010, reveals that one of the planet's prominent dark cloud belts has faded away. The lightening of the South Equatorial Belt is due to atmospheric changes. Both pictures were taken by Anthony Wesley, an amateur astronomer in Australia. (Anthony Wesley via The Planetary Society) Back to slideshow navigation
  2. Family portrait

    Launched in 1989, the Galileo spacecraft has photographed Jupiter as well as several of the giant planet's satellites. Here's a montage that shows Jupiter's Great Red Spot and the four largest moons. From top, they are Io, Europa, Ganymede and Callisto. (NASA) Back to slideshow navigation
  3. Cratered Callisto

    Callisto is considered the most cratered celestial body in the solar system. The false-color overlay at right exaggerates the moon's surface features, including the Valhalla impact structure near the center of the disk. (NASA) Back to slideshow navigation
  4. Dark face

    Colors are enhanced in this view of Ganymede's trailing hemisphere, highlighting the moon's polar caps. The violet color indicates where small particles of frost may be scattering light on the blue end of the spectrum. (NASA) Back to slideshow navigation
  5. Cloudy weather

    The mosaic at left shows the true colors of the cloud patterns in Jupiter's northern hemisphere. The rendition at right uses false colors to represent the height and thickness of the cloud cover. (NASA) Back to slideshow navigation
  6. This is the Spot

    A true-color picture captures the subtle shadings of Jupiter's Great Red Spot, a massive, long-lived storm system in the planet's thick atmosphere. (NASA) Back to slideshow navigation
  7. A big splash on Europa

    A computer-generated perspective view shows the Pwyll impact crater on Europa, an ice-covered moon of Jupiter. The heights are exaggerated, but the central peak indicates that the crater may have been modified shortly after its formation by the flow of underlying warm ice. (NASA) Back to slideshow navigation
  8. A blast at Io

    This image of Io, thought to be the solar system's most volcanically active world, shows the plumes of two eruptions. One plume can be seen at the very edge of the disk, the other is puffing up from the dark volcanic ring near the center of the disk. (NASA) Back to slideshow navigation
  9. Lava light

    An active volcanic eruption on Jupiter's moon Io flares in an image taken in February 2000 by the Galileo spacecraft. The dark L-shaped lava flow to the left of center marks the site of energetic eruptions in November 1999 at Tvashtar Catena, which is a chain of giant volcanic calderas. The two small bright spots at left side of image are sites where molten rock is exposed to the surface at the toes of lava flows. (NASA) Back to slideshow navigation
  10. Crazy quilt

    The thin crust of Europa's Conamara region is criss-crossed by craters, cracks and lines - indicating that the surface ice was repeatedly disrupted. The colors, which are enhanced in this view, show where light ice crystals and dark contaminants have settled onto the surface. (NASA) Back to slideshow navigation
  11. A moving moon

    In a picture taken in April 2001 by NASA's Cassini spacecraft, the moon Io looks like a marble set against the background of Jupiter. Io is the giant planet's third-largest satellite. (NASA) Back to slideshow navigation
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  1. Anthony Wesley via The Planetary Society
    Above: Slideshow (11) Jewels of Jupiter
  2. Image:
    Y. Beletsky / ESO
    Slideshow (12) Month in Space: January 2014

Explainer: Six frontiers for alien life

  • Image: "The Day the Earth Stood Still"
    20th Century Fox

    In "The Day the Earth Stood Still," a remake of the 1951 science-fiction classic, an alien named Klaatu (played by Keanu Reeves, right) visits Earth to save us humans from ourselves. The story is a work of science fiction, with the emphasis on fiction, says Seth Shostak, a senior astronomer at the SETI Institute and a technical adviser on the film. For example, to be able to detect a dangerous buildup of carbon dioxide in our atmosphere and come save us from global warming, an alien that could travel at light speed would have to reside no more than about 50 light-years away. "I doubt that there are any aliens that close," Shostak says. And even if there are, "they might not care about our problems."

    Scientific accuracy aside, Shostak says the film could hook a new generation on space science, just as the original film helped direct his career, which is dedicated to the search for E.T. As kids stumble out of the theater, they might ask, do aliens exist?

    Click the "Next" arrow above to explore the evidence, from the scientifically plausible to the incredible.

  • With so many stars, alien life is probable

    Image: Cluster of young stars in the Milky Way
    NASA

    Shostak notes that there is no direct proof for any life beyond Earth, but the universe is home to a lot of stars. And as research over the past decade has shown, perhaps at least 50 percent of those stars harbor planets. Shostak estimates there are 1 trillion planets in the Milky Way alone. "Surely some of them have undergone what Earth has undergone and developed life, and eventually what we call sentient life," he says. The argument, he notes, is simply one of probability. "If we are the only intelligent beings in the galaxy, or for that matter in the universe, then we are truly a miracle," he says. This image from the Hubble Space Telescope shows a cluster of young stars in the Milky Way.

  • Water worlds abound in our solar system

    Image: Enceladus
    NASA/jpl/space Science Institute

    Water is a key ingredient for life as we know it. And liquid water, it turns out, is fairly common in our local solar system. For example, evidence is mounting that liquid water may flow underneath the surface of Mars. Europa, a moon of Jupiter, appears to have a liquid ocean. So too might the Jovian moons Callisto and Ganymede. Saturn's moons Titan and Enceladus, shown here, may be watery. Even Venus might have a bit of liquid water in its atmosphere. "There you already have seven other worlds that might have liquid water, just in our backyard. So that's kind of encouraging news," Shostak says.

  • Life evolved 'quickly' on Earth

    Image: unusual rock structures
    Abigail Allwood

    Scientists estimate that planet Earth is about 4.5 billion years old. The earliest evidence for life comes from 3.4 billion-year-old mats of bacteria called stromatolites in Australia. Since even bacteria are biologically complex, scientists think they arose from life forms that got a foothold on Earth even earlier. "That suggests it wasn't terribly improbable, the evolution of life, because it happened very quickly," Shostak says. The caveat, of course, is that Earth could have won the evolutionary equivalent of the lottery, and no place else is quite so lucky.

  • Life thrives in extreme environments

    Image: Desulforudis audaxviator bacterium
    G. Wanger / JCVI / G. Southam /

    Almost everywhere scientists go on Earth, they find life: the cold, dark depths of the oceans; snuggled up to piping-hot hydrothermal vents; buried under the Antarctic ice; and in South America's parched Atacama Desert. "Life can adapt to really tough conditions and, of course, most of the universe is going to be filled with habitats that are tough," Shostak says. For example, Mars is a harsh environment, but some of the microbes found on Earth, including the one shown here found deep in a mine, could survive beneath the surface of the Red Planet, he notes. These findings of so-called extremophiles have allowed scientists to scale back their list of requirements for extraterrestrial life. "We just say it has to have some liquid water, and maybe that's it," Shostak says.

  • E.T. might be calling from afar

    Image:  'Wow' signal
    Courtesy of Jerry Ehman / Bigear

    Shostak and his colleagues at the SETI Institute frequently harness some of the world's largest radio telescopes to home in on distant stars for a telltale signal of alien communications. Although their searches have raised a few alarms, the signals have been dismissed as human-caused interference, such as noise from a passing satellite. Contact remains elusive. Undaunted, the scientists keep searching. Meanwhile, a signal detected on Aug. 15, 1977, during a search with Ohio State University's Big Ear Observatory, continues to pique interest because it has never been explained. "It was impressive enough to encourage the astronomer who found it to write 'Wow!' on the printout," says Shostak. Follow-up experiments to detect it again, however, have failed. "You can say it was E.T. and then he went off the air. You may never know," Shostak says. "But it is not science to say it was E.T."

  • Some see evidence that 'aliens' have visited

    Image: Fictional alien corpse
    Justin Norton  /  AP

    Somewhere around half the people in the U.S. believe that aliens have already visited us. To back their claims, witnesses have presented snapshots of flying saucers and debris from crash landings. None of the evidence, however, convinces Shostak. Nor does he buy into theories that the world's governments are coordinated and efficient enough to collectively keep what would be the world's biggest secret. "That's hard for me to believe," he says. Such doubt does little to stop the tide of tourists coming to places such as Roswell, N.M., the site of a purported UFO crash more than 60 years ago. This fake alien at a museum is a commonly photographed attraction.

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