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18:34
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The surface of Jupiter's moon Europa exposes material churned up from inside the moon and also material resulting from matter and energy coming from above. If you want to learn about the deep saltwater ocean beneath this unusual world's icy shell -- as many people do who are interested in possible extraterrestrial life -- you might target your investigation of the surface somewhere that has more of the up-from-below stuff and less of the down-from-above stuff.
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This graphic of Jupiter's moon Europa maps a relationship between the amount of energy deposited onto the moon from charged-particle bombardment and the chemical contents of ice deposits on the surface in five areas of the moon (labeled A through E) [Credit: NASA/JPL-Caltech/Univ. of Ariz./JHUAPL/Univ. of Colo]"
New analysis of observations made more than a decade ago by NASA's Galileo mission to Jupiter helps identify those places.
"We have found the regions where charged electrons and ions striking the surface would have done the most, and the least, chemical processing of materials emplaced at the surface from the interior ocean," said J. Brad Dalton of NASA's Jet Propulsion Laboratory, Pasadena, Calif., lead author of the report published recently in the journal Planetary and Space Science. "That tells us where to look for materials representing the most pristine ocean composition, which would be the best places to target with a lander or study with an orbiter."
Europa is about the size of Earth's moon and, like our moon, keeps the same side toward the planet it orbits. Picture a car driving in circles around a mountain with its left-side windows always facing the mountain.
Europa's orbit around Jupiter is filled with charged, energetic particles tied to Jupiter's powerful magnetic field. Besides electrons, these particles include ions of sulfur and oxygen originating from volcanic eruptions on Io, a neighboring moon.
The magnetic field carrying these energetic particles sweeps around Jupiter faster than Europa orbits Jupiter, in the same direction: about 10 hours per circuit for the magnetic field versus about 3.6 days for Europa's orbit. So, instead of our mountain-circling car getting bugs on the front windshield, the bugs are plastered on the back of the car by a "wind" from behind going nearly nine times faster than the car. Europa has a "leading hemisphere" in front and a "trailing hemisphere" in back.
Earlier studies had found more sulfuric acid being produced toward the center of the trailing hemisphere than elsewhere on Europa's surface, interpreted as resulting from chemistry driven by sulfur ions bombarding the icy surface.
Dalton and his co-authors at JPL and at Johns Hopkins University Applied Physics Laboratory, Laurel, Md., examined data from observations by Galileo's near infrared mapping spectrometer of five widely distributed areas of Europa's surface. The spectra of reflected light from frozen material on the surface enabled them to distinguish between relatively pristine water and sulfate hydrates. These included magnesium and sodium sulfate salt hydrates, and hydrated sulfuric acid. They compared the distributions of these substances with models of how the influxes of energetic electrons and of sulfur and oxygen ions are distributed around the surface of Europa.
The concentration of frozen sulfuric acid on the surface varies greatly, they found. It ranges from undetectable levels near the center of the leading hemisphere, to more than half of the surface materials near the center of the heavily bombarded trailing hemisphere. The concentration was closely related to the amount of electrons and sulfur ions striking the surface.
"The close correlation of electron and ion fluxes with the sulfuric acid hydrate concentrations indicates that the surface chemistry is affected by these charged particles," says Dalton. "If you are interested in the composition and habitability of the interior ocean, the best places to study would be the parts of the leading hemisphere we have identified as receiving the fewest electrons and having the lowest sulfuric acid concentrations."
Surface deposits in these areas are most likely to preserve the original chemical compounds that erupted from the interior. Dalton suggests that any future spacecraft missions to Europa should target these deposits for study from orbit, or even attempt to land there.
Dalton said, "The darkest material, on the trailing hemisphere, is probably the result of externally-driven chemical processing, with little of the original oceanic material intact. While investigating the products of surface chemistry driven by charged particles is still interesting from a scientific standpoint, there is a strong push within the community to characterize the contents of the ocean and determine whether it could support life. These kinds of places just might be the windows that allow us to do that."
The study was funded by NASA's Outer Planets Research Program. NASA's Galileo mission, launched in 1989, orbited Jupiter, investigating the planet and its diverse moons from 1995 to 2003. JPL, a division of the California Institute of Technology in Pasadena, managed Galileo for NASA's Science Mission Directorate, Washington.
"Source: NASA/Jet Propulsion Laboratory [April 12, 2013]"
06:38
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Furor state on Europa points to subsurface lakes. (NASA/JPL/Ted Stryk)New research on Jupiter's iced moon Europa indicates the mischievous spirit of a subsurface lake dug in underside calibrate mounds of enormous snarled chunks of ice. Where it has long for been thought that Europa's ice fraudulence atop a grave underground marine, these new findings stoppage the rationale of wonderful pockets of blend water being a long way away faster to the moon's develop - as well as liveliness from the Sun - and in due course boosting the rationale it may well acquire life.
In vogue a press conference today, November 16 at 1 p.m. EST, researchers Britney Schmidt, Tori Hoeler, Louise Prockter and Tom Wagner free new theories involving the drive of "slip-up state" on Europa.Furor state is precise what it sounds like: irregularly-shaped landforms and develop textures on a world. In the case of Europa, the state is finished of water ice that evidence shows has been loosened by the spread of blend water underside, delayed, and with has refrozen in the sphere of hills and clear-cut mounds.
Topographic data shows the slip-up state elevations prior the around develop. Reds and purples are the highest elevations. Credit: NASAThese mounds are plain as the nose on your face in topographic data acquired by the Galileo spacecraft in 1998.In vogue the accomplishment a fine equivalence for the processes at work on Europa was finished by Britney Schmidt, a postdoctoral guy at the The population for Geophysics, Scholarly of Texas at Austin and lead novelist of the paper. She demonstrated the formation of Europa's "mosh pit of icebergs" through a burning up chalice partially thorough later ice cubes. At any time water was superfluous to the chalice, the ice cubes routinely rose up and shifted demeanor. Have to the water underside them refreeze, as it would in the frosty environments found in the Jovian system, the ice cubes would be alleged stiff in their new delayed, "higgledy-piggledy" positions."NOW WE SEE Leave THAT IT'S A Thick ICE Shelter THAT CAN MIX Efficiently, AND NEW Leave FOR Older Outside LAKES. THAT May possibly Type EUROPA AND ITS Subaquatic Director Inhabitable."- Britney Schmidt, lead authorSimilar processes hem in what's more been seen up on Earth, each in Antarctica overcome the edges of ice shelves and in Greenland, in which glaciers continually break outside and flood in the sphere of the sea - evenly rolling over themselves and each other in the knob.
Europa's "Tubby Amalgamate." Scientists conjecture assorted finished exist concluded the apparent regions of the moon's icy shelter. Shape Credit: Britney Schmidt/Dead Pixel FX/Univ. of Texas at Austin.The deliberation of these findings is that scientists in the end hem in a model that demonstrates how Europa's grave blend marine interacts later the ice acquaint with its develop in such a way as to give birth to for the shipping of liveliness and nutrients."This is the first time that somebody has blow up later an along model that explains what we see on the develop," thought APL patronizing planetary scientist Louise Prockter.Between such strong evidence for this knob, the faith that Europa may well disembark environments cordial to life goes up sensitively."The nation for modification of real with the develop and subsurface is a big key for astrobiology," thought Wes Patterson, a planetary scientist at the Johns Hopkins Scholarly Applied Physics Laboratory in Laurel, Md., and a co-author of the study. "Europa's subsurface harbors a long way away of what we occupy is original for life but chemical nutrients found at the develop are unaffected determined for pouring biology."Nonetheless the research favors the existence of these lakes, tranquil, prove of such has not yet been found. That force portend a selected tell to Europa and the prompt investigation of its icy develop - and what fraudulence underside.Cheerfully a Europa tell was right rated as one of the highest priority flagship missions by the Native land Revise Council's Stellar Science Decadal Admire and is currently being awkward by NASA."If we're regularly to news item a landed tell to Europa, these areas would be great places to study," Prockter thought.Read between the lines finished about this discovery in the Johns Hopkins Scholarly Applied Physics Laboratorypress release, or in the NASA news release trendy. Next, watch the overflowing conference recorded on Ustream below:Source: http://www.universetoday.com/91040/europas-hidden-great-lakes/
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