Hola amigos: A VUELO DE UN QUINDE EL BLOG., hemos recibido de la Agencia Espacial NASA, la información de un satélite Encelado de Saturno muestra actividad hidrotermal tal como sucede en La Tierra : Nave espacial Cassini de la NASA ha proporcionado a los científicos la primera evidencia clara de que la luna de Saturno Encelado muestra signos de actividad hidrotermal actual que pueden parecerse a la observada en los océanos profundos de la Tierra. Las implicaciones de tal actividad en un mundo distinto del nuestro planeta abren posibilidades científicos sin precedentes.
NASA nos dice: "Estos resultados se suman a la posibilidad de que Encelado, que contiene un océano bajo la superficie y muestra actividad geológica notable, podría contener los entornos adecuados para los organismos vivos", dijo John Grunsfeld astronauta y administrador asociado del Directorio de Misiones Científicas de la NASA en Washington. "Los lugares de nuestro sistema solar, donde se producen los ambientes extremos en que la vida pudiera existir puede acercarnos más a responder a la pregunta: ¿Estamos solos en el Universo."
NASA, agrega : "
"Estos resultados se suman a la posibilidad de que Encelado, que contiene un océano bajo la superficie y muestra actividad geológica notable, podría contener los entornos adecuados para los organismos vivos", dijo John Grunsfeld astronauta y administrador asociado del Directorio de Misiones Científicas de la NASA en Washington. "Los lugares de nuestro sistema solar, donde se producen los ambientes extremos en que la vida pudiera existir puede acercarnos más a responder a la pregunta: ¿Estamos solos en el Universo.".
More information..............
This cutaway view of Saturn's moon Enceladus is an
artist's rendering that depicts possible hydrothermal activity that may be
taking place on and under the seafloor of the moon's subsurface ocean, based on
recently published results from NASA's Cassini mission.
Image Credit:
NASA/JPL
NASA's Cassini spacecraft has provided scientists the first clear evidence
that Saturn’s moon Enceladus exhibits signs of present-day hydrothermal activity
which may resemble that seen in the deep oceans on Earth. The implications of
such activity on a world other than our planet open up unprecedented scientific
possibilities.
“These findings add to the possibility that Enceladus, which contains a
subsurface ocean and displays remarkable geologic activity, could contain
environments suitable for living organisms,” said John Grunsfeld astronaut and
associate administrator of NASA's Science Mission Directorate in Washington.
“The locations in our solar system where extreme environments occur in which
life might exist may bring us closer to answering the question: are we alone in
the Universe.”
Hydrothermal activity occurs when seawater infiltrates and reacts with a
rocky crust and emerges as a heated, mineral-laden solution, a natural
occurrence in Earth’s oceans. According to two science papers, the results are
the first clear indications an icy moon may have similar ongoing active
processes.
This illustration depicts potential origins of
methane found in the plume of gas and ice particles that sprays from Enceladus,
based on research by scientists working with the Cassini Ion and Neutral Mass
Spectrometer.
Image Credit:
Southwest Research Institute
The first paper, published this week in the journal Nature, relates to
microscopic grains of rock detected by Cassini in the Saturn system. An
extensive, four-year analysis of data from the spacecraft, computer simulations
and laboratory experiments led researchers to the conclusion the tiny grains
most likely form when hot water containing dissolved minerals from the moon's
rocky interior travels upward, coming into contact with cooler water.
Temperatures required for the interactions that produce the tiny rock grains
would be at least 194 degrees Fahrenheit (90 degrees Celsius).
"It's very exciting that we can use these tiny grains of rock, spewed into
space by geysers, to tell us about conditions on -- and beneath -- the ocean
floor of an icy moon," said the paper’s lead author Sean Hsu, a postdoctoral
researcher at the University of Colorado at Boulder.
Cassini's cosmic dust analyzer (CDA) instrument repeatedly detected miniscule
rock particles rich in silicon, even before Cassini entered Saturn’s orbit in
2004. By process of elimination, the CDA team concluded these particles must be
grains of silica, which is found in sand and the mineral quartz on Earth. The
consistent size of the grains observed by Cassini, the largest of which were 6
to 9 nanometers, was the clue that told the researchers a specific process
likely was responsible.
On Earth, the most common way to form silica grains of this size is
hydrothermal activity under a specific range of conditions; namely, when
slightly alkaline and salty water that is super-saturated with silica undergoes
a big drop in temperature.
"We methodically searched for alternate explanations for the nanosilica
grains, but every new result pointed to a single, most likely origin," said
co-author Frank Postberg, a Cassini CDA team scientist at Heidelberg University
in Germany.
Hsu and Postberg worked closely with colleagues at the University of Tokyo
who performed the detailed laboratory experiments that validated the
hydrothermal activity hypothesis. The Japanese team, led by Yasuhito Sekine,
verified the conditions under which silica grains form at the same size Cassini
detected. The researchers think these conditions may exist on the seafloor of
Enceladus, where hot water from the interior meets the relatively cold water at
the ocean bottom.
The extremely small size of the silica particles also suggests they travel
upward relatively quickly from their hydrothermal origin to the near-surface
sources of the moon's geysers. From seafloor to outer space, a distance of about
30 miles (50 kilometers), the grains spend a few months to a few years in
transit, otherwise they would grow much larger.
The authors point out that Cassini's gravity measurements suggest Enceladus'
rocky core is quite porous, which would allow water from the ocean to percolate
into the interior. This would provide a huge surface area where rock and water
could interact.
The second paper, recently published in Geophysical Research Letters,
suggests hydrothermal activity as one of two likely sources of methane in the
plume of gas and ice particles that erupts from the south polar region of
Enceladus. The finding is the result of extensive modeling by French and
American scientists to address why methane, as previously sampled by Cassini, is
curiously abundant in the plume.
The team found that, at the high pressures expected in the moon's ocean, icy
materials called clathrates could form that imprison methane molecules within a
crystal structure of water ice. Their models indicate that this process is so
efficient at depleting the ocean of methane that the researchers still needed an
explanation for its abundance in the plume.
In one scenario, hydrothermal processes super-saturate the ocean with
methane. This could occur if methane is produced faster than it is converted
into clathrates. A second possibility is that methane clathrates from the ocean
are dragged along into the erupting plumes and release their methane as they
rise, like bubbles forming in a popped bottle of champagne.
The authors agree both scenarios are likely occurring to some degree, but
they note that the presence of nanosilica grains, as documented by the other
paper, favors the hydrothermal scenario.
"We didn't expect that our study of clathrates in the Enceladus ocean would
lead us to the idea that methane is actively being produced by hydrothermal
processes," said lead author Alexis Bouquet, a graduate student at the
University of Texas at San Antonio. Bouquet worked with co-author Hunter Waite,
who leads the Cassini Ion and Neutral Mass Spectrometer (INMS) team at Southwest
Research Institute in San Antonio.
Cassini first revealed active geological processes on Enceladus in 2005 with
evidence of an icy spray issuing from the moon's south polar region and
higher-than-expected temperatures in the icy surface there. With its powerful
suite of complementary science instruments, the mission soon revealed a towering
plume of water ice and vapor, salts and organic materials that issues from
relatively warm fractures on the wrinkled surface. Gravity science results
published in 2014 strongly suggested the presence of a 6-mile- (10-kilometer-)
deep ocean beneath an ice shell about 19 to 25 miles (30 to 40 kilometers)
thick.
The Cassini-Huygens mission is a cooperative project of NASA, ESA (European
Space Agency) and the Italian Space Agency. NASA's Jet Propulsion Laboratory in
Pasadena, California, manages the mission for the agency’s Science Mission
Directorate in Washington. The Cassini CDA instrument was provided by the German
Aerospace Center. The instrument team, led by Ralf Srama, is based at the
University of Stuttgart in Germany.
More information about Cassini, visit:
and
NASA
Guillermo Gonzalo Sánchez Achutegui
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