Europa"s Ocean Is Only Skin Deep!
Beauty Is Only Skin Deep--A Proverb Europa is a fascinating, icy little moon that orbits the gas-giant planet Jupiter.
This frigid little world, discovered in 1610 by Galileo Galilei, harbors a gigantic ocean of liquid water beneath a shattered, tortured crust of ice.
Europa is the sixth largest moon in our Sun's enchanting family, and few bodies have enticed astronomers as much as this cracked and jumbled little world, because where there is water, there is the possibility--though not the promise--of life as we know it to exist.
In March 2013, planetary scientists announced that the enormous ocean of liquid water beneath Europa's shattered egg-shell of an icy crust, likely makes its way to the surface in some places.
This suggests that astronomers may not need to drill down very deep in order to study it! Europa is one of the four large Galilean moons of Jupiter, named in honor of their discoverer, who found them when he was gazing up into the dark night sky over Padua with his small, primitive "spyglass"--one of the earliest telescopes.
The other Galilean moons, the bewitching sisters of Europa, are Io, Ganymede, and Callisto.
Both Ganymede and Callisto are icy-rocky worlds, and Ganymede is the largest moon in our Solar System.
Io, however, is a little ball of hell, pockmarked with volcanoes, and heavily splotched with sulfur.
For a long time, weird and jumbled regions of ice disruption on Europa, called the chaos terrains, were viewed by astronomers as bizarre regions whose origins were cloaked in mystery.
Regions like the chaos terrains were observed no where else in our Solar System.
Now, it is thought that these strange terrains were formed by the sloshing of a subsurface body of liquid saltwater.
Although Europa was visited by the two sister spacecraft Pioneer 10 and Pioneer 11 in the early 1970s, and the twin Voyagers in 1979, these early flybys frustratingly sent back to the curious eyes of fascinated astronomers only some very dim and grainy pictures.
However, these early images revealed enough about the tantalizing moon to make it intriguing.
Pale yellow icy plains were observed in the Voyager images.
The plains were also mottled with red and brown regions.
Long cracks were seen, and they extended for thousands of miles over the shattered icy crust.
On our own planet, similar cracks suggest features like deep canyons and tall mountains.
However, nothing higher than a few kilometers was observed on the little moon.
In fact, Europa proved to be one of the smoothest worlds in our entire Solar System! NASA's highly successful Galileo spacecraft (1989-2003) imaged Europa during a flyby on September 7, 1996.
Galileo viewed Europa's surface much more closely than the Pioneers and Voyagers, and it revealed to astronomers a very bewitching and bizarre surface crust that looked like shattered glass, repaired by an icy paste that was oozing up from below.
The most detailed pictures of Europa show even more signs of slush lurking beneath its icy coating.
Europa is slightly smaller than Earth's own Moon, and its surface temperature could easily freeze an ocean solid over a span of only several million years.
However, planetary scientists think that warmth derived from a game of tidal tug-of-war between Europa and its parent planet, Jupiter, as well as with other sister moons, is keeping Europa's subsurface ocean in a life-friendly liquid state.
This process, termed tidal heating, refers to a series of actions whereby the gravitational tugs of a nearby object (or objects) flex and bend and contract and expand another object mercilessly.
This constant churning causes the victimized object, in this case Europa, to warm up considerably and be much more balmy than its substantial distance from our searing-hot Star, the Sun, would otherwise allow it to be.
Based on evidence released in March 2013, astronomers now suggest that chloride salts bubble up from Europa's global ocean of liquid water, and jitter-bug up to the icy surface where they are heavily pelted with sulfur from the many volcanoes pock-marking Jupiter's innermost, hellish sister-moon, Io.
As a March 5, 2013 NASA Jet Propulsion Laboratory Press Release notes: "If you could lick the surface of Jupiter's moon Europa, you would actually be sampling a bit of the ocean beneath.
" Only Skin Deep A March 2013 paper by Dr.
Mike Brown, an astronomer at the California Institute of Technology (Caltech) in Pasadena, California, and Dr.
Kevin Hand from the JPL, also in Pasadena, details the most robust evidence so far obtained that there is indeed a vast salt water ocean sloshing beneath Europa's shattered, frozen crust--and that in some places the liquid water actually makes its way to the surface! The astronomers have spotted chemicals on Europa's frigid surface that could only originate from the immense global liquid-water ocean beneath.
This suggests that the two are in contact, and this can potentially provide a peek into the watery environment that possibly can host life.
"We now have evidence that Europa's ocean is not isolated--that the ocean and the surface talk to each other and exchange chemicals," Dr.
Brown, the study's lead author, explained in the March 6, 2013 Space.
com.
"That means that energy might be going into the ocean, which is important in terms of the possibilities for life there.
It also means that if you'd like to know what's in the ocean, you can just go to the surface and scrape some off," he continued to note.
This finding is based on some of the best data of its kind obtained since NASA's Galileo mission indicated that a chemical interaction was taking place between the salty global ocean and the icy crust of Europa.
Europa's ocean is believed to cover the entire moon, and is approximately 60 miles (100 kilometers) thick, sloshing beneath a very thin cracked icy coating that composes the crust of the little world.
The infrared spectrometer aboard Galileo was incapable of providing the details necessary to identify some of the chemicals on the surface.
However, by using the Keck II Telescope perched on Mauna Kea in Hawaii, and its OSIRIS spectrometer, Brown and Hand have succeeded in identifying a spectroscopic feature on Europa's crust that suggests the existence of a mineral called epsomite, which is a magnesium sulfate, that probably formed by the oxidation of a mineral that originated in the global ocean below.
Brown and Hand began their investigation by mapping the distribution of pure water ice as opposed to everything else.
The spectra revealed that even Europa's leading hemisphere sports a large quantity of non-water ice.
Then, at low latitudes on the trailing hemisphere--which is the region showing the greatest concentration of non-water ice--they discovered a very small, and not-previously detected dip in the spectrum.
After conducting a series of tests, the two researchers determined that they had spotted the unmistakable signature of magnesium sulfate.
The magnesium sulfate is most likely formed by the irradiation of sulfur shot off from Io and, Brown and Hand deduce, magnesium chloride salt born in Europa's vast subsurface ocean.
Chlorides like sodium and potassium chlorides, which are expected to be present on Europa's icy, cracked crust, are not usually detectable because they show no definitive infrared spectral features.
However, magnesium sulfate does reveal itself, and the authors of the study think that the chemical make-up of Europa's ocean may closely resemble the salty oceans of our own planet.
Europa is a prime target in the search for life beyond Earth, Dr.
Hand said in the March 5, 2013 JPL Press Release.
He further noted to the press that "If we've learned anything about life on Earth, it's that where there's liquid water, there's generally life.
And of course our ocean is a nice salty ocean.
Perhaps Europa's salty ocean is also a wonderful place for life.
" The study will be published in the Astronomical Journal.
This frigid little world, discovered in 1610 by Galileo Galilei, harbors a gigantic ocean of liquid water beneath a shattered, tortured crust of ice.
Europa is the sixth largest moon in our Sun's enchanting family, and few bodies have enticed astronomers as much as this cracked and jumbled little world, because where there is water, there is the possibility--though not the promise--of life as we know it to exist.
In March 2013, planetary scientists announced that the enormous ocean of liquid water beneath Europa's shattered egg-shell of an icy crust, likely makes its way to the surface in some places.
This suggests that astronomers may not need to drill down very deep in order to study it! Europa is one of the four large Galilean moons of Jupiter, named in honor of their discoverer, who found them when he was gazing up into the dark night sky over Padua with his small, primitive "spyglass"--one of the earliest telescopes.
The other Galilean moons, the bewitching sisters of Europa, are Io, Ganymede, and Callisto.
Both Ganymede and Callisto are icy-rocky worlds, and Ganymede is the largest moon in our Solar System.
Io, however, is a little ball of hell, pockmarked with volcanoes, and heavily splotched with sulfur.
For a long time, weird and jumbled regions of ice disruption on Europa, called the chaos terrains, were viewed by astronomers as bizarre regions whose origins were cloaked in mystery.
Regions like the chaos terrains were observed no where else in our Solar System.
Now, it is thought that these strange terrains were formed by the sloshing of a subsurface body of liquid saltwater.
Although Europa was visited by the two sister spacecraft Pioneer 10 and Pioneer 11 in the early 1970s, and the twin Voyagers in 1979, these early flybys frustratingly sent back to the curious eyes of fascinated astronomers only some very dim and grainy pictures.
However, these early images revealed enough about the tantalizing moon to make it intriguing.
Pale yellow icy plains were observed in the Voyager images.
The plains were also mottled with red and brown regions.
Long cracks were seen, and they extended for thousands of miles over the shattered icy crust.
On our own planet, similar cracks suggest features like deep canyons and tall mountains.
However, nothing higher than a few kilometers was observed on the little moon.
In fact, Europa proved to be one of the smoothest worlds in our entire Solar System! NASA's highly successful Galileo spacecraft (1989-2003) imaged Europa during a flyby on September 7, 1996.
Galileo viewed Europa's surface much more closely than the Pioneers and Voyagers, and it revealed to astronomers a very bewitching and bizarre surface crust that looked like shattered glass, repaired by an icy paste that was oozing up from below.
The most detailed pictures of Europa show even more signs of slush lurking beneath its icy coating.
Europa is slightly smaller than Earth's own Moon, and its surface temperature could easily freeze an ocean solid over a span of only several million years.
However, planetary scientists think that warmth derived from a game of tidal tug-of-war between Europa and its parent planet, Jupiter, as well as with other sister moons, is keeping Europa's subsurface ocean in a life-friendly liquid state.
This process, termed tidal heating, refers to a series of actions whereby the gravitational tugs of a nearby object (or objects) flex and bend and contract and expand another object mercilessly.
This constant churning causes the victimized object, in this case Europa, to warm up considerably and be much more balmy than its substantial distance from our searing-hot Star, the Sun, would otherwise allow it to be.
Based on evidence released in March 2013, astronomers now suggest that chloride salts bubble up from Europa's global ocean of liquid water, and jitter-bug up to the icy surface where they are heavily pelted with sulfur from the many volcanoes pock-marking Jupiter's innermost, hellish sister-moon, Io.
As a March 5, 2013 NASA Jet Propulsion Laboratory Press Release notes: "If you could lick the surface of Jupiter's moon Europa, you would actually be sampling a bit of the ocean beneath.
" Only Skin Deep A March 2013 paper by Dr.
Mike Brown, an astronomer at the California Institute of Technology (Caltech) in Pasadena, California, and Dr.
Kevin Hand from the JPL, also in Pasadena, details the most robust evidence so far obtained that there is indeed a vast salt water ocean sloshing beneath Europa's shattered, frozen crust--and that in some places the liquid water actually makes its way to the surface! The astronomers have spotted chemicals on Europa's frigid surface that could only originate from the immense global liquid-water ocean beneath.
This suggests that the two are in contact, and this can potentially provide a peek into the watery environment that possibly can host life.
"We now have evidence that Europa's ocean is not isolated--that the ocean and the surface talk to each other and exchange chemicals," Dr.
Brown, the study's lead author, explained in the March 6, 2013 Space.
com.
"That means that energy might be going into the ocean, which is important in terms of the possibilities for life there.
It also means that if you'd like to know what's in the ocean, you can just go to the surface and scrape some off," he continued to note.
This finding is based on some of the best data of its kind obtained since NASA's Galileo mission indicated that a chemical interaction was taking place between the salty global ocean and the icy crust of Europa.
Europa's ocean is believed to cover the entire moon, and is approximately 60 miles (100 kilometers) thick, sloshing beneath a very thin cracked icy coating that composes the crust of the little world.
The infrared spectrometer aboard Galileo was incapable of providing the details necessary to identify some of the chemicals on the surface.
However, by using the Keck II Telescope perched on Mauna Kea in Hawaii, and its OSIRIS spectrometer, Brown and Hand have succeeded in identifying a spectroscopic feature on Europa's crust that suggests the existence of a mineral called epsomite, which is a magnesium sulfate, that probably formed by the oxidation of a mineral that originated in the global ocean below.
Brown and Hand began their investigation by mapping the distribution of pure water ice as opposed to everything else.
The spectra revealed that even Europa's leading hemisphere sports a large quantity of non-water ice.
Then, at low latitudes on the trailing hemisphere--which is the region showing the greatest concentration of non-water ice--they discovered a very small, and not-previously detected dip in the spectrum.
After conducting a series of tests, the two researchers determined that they had spotted the unmistakable signature of magnesium sulfate.
The magnesium sulfate is most likely formed by the irradiation of sulfur shot off from Io and, Brown and Hand deduce, magnesium chloride salt born in Europa's vast subsurface ocean.
Chlorides like sodium and potassium chlorides, which are expected to be present on Europa's icy, cracked crust, are not usually detectable because they show no definitive infrared spectral features.
However, magnesium sulfate does reveal itself, and the authors of the study think that the chemical make-up of Europa's ocean may closely resemble the salty oceans of our own planet.
Europa is a prime target in the search for life beyond Earth, Dr.
Hand said in the March 5, 2013 JPL Press Release.
He further noted to the press that "If we've learned anything about life on Earth, it's that where there's liquid water, there's generally life.
And of course our ocean is a nice salty ocean.
Perhaps Europa's salty ocean is also a wonderful place for life.
" The study will be published in the Astronomical Journal.
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