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November 23, 2011

NASA Probe Data Show Evidence of Liquid Water on Icy Europa

Data from a NASA planetary mission have provided scientists evidence of what appears to be a body of liquid water, equal in volume to the North American Great Lakes, beneath the icy surface of Jupiter's moon, Europa.

The data suggest there is significant exchange between Europa's icy shell and the ocean beneath. This information could bolster arguments that Europa's global subsurface ocean represents a potential habitat for life elsewhere in our solar system. The findings are published in the scientific journal Nature.

"The data opens up some compelling possibilities," said Mary Voytek, director of NASA's Astrobiology Program at agency headquarters in Washington. "However, scientists worldwide will want to take a close look at this analysis and review the data before we can fully appreciate the implication of these results."

NASA's Galileo spacecraft, launched by the space shuttle Atlantis in 1989 to Jupiter, produced numerous discoveries and provided scientists decades of data to analyze. Galileo studied Jupiter, which is the most massive planet in the solar system, and some of its many moons.

One of the most significant discoveries was the inference of a global salt water ocean below the surface of Europa. This ocean is deep enough to cover the whole surface of Europa and contains more liquid water than all of Earth's oceans combined. However, being far from the sun, the ocean surface is completely frozen. Most scientists think this ice crust is tens of miles thick.

Continue reading "NASA Probe Data Show Evidence of Liquid Water on Icy Europa" »

NASA Probe Data Show Evidence of Liquid Water on Icy Europa

Data from a NASA planetary mission have provided scientists evidence of what appears to be a body of liquid water, equal in volume to the North American Great Lakes, beneath the icy surface of Jupiter's moon, Europa.

The data suggest there is significant exchange between Europa's icy shell and the ocean beneath. This information could bolster arguments that Europa's global subsurface ocean represents a potential habitat for life elsewhere in our solar system. The findings are published in the scientific journal Nature.

"The data opens up some compelling possibilities," said Mary Voytek, director of NASA's Astrobiology Program at agency headquarters in Washington. "However, scientists worldwide will want to take a close look at this analysis and review the data before we can fully appreciate the implication of these results."

NASA's Galileo spacecraft, launched by the space shuttle Atlantis in 1989 to Jupiter, produced numerous discoveries and provided scientists decades of data to analyze. Galileo studied Jupiter, which is the most massive planet in the solar system, and some of its many moons.

One of the most significant discoveries was the inference of a global salt water ocean below the surface of Europa. This ocean is deep enough to cover the whole surface of Europa and contains more liquid water than all of Earth's oceans combined. However, being far from the sun, the ocean surface is completely frozen. Most scientists think this ice crust is tens of miles thick.

Continue reading "NASA Probe Data Show Evidence of Liquid Water on Icy Europa" »

October 17, 2011

Europa Lander Open Forum

The Europa Science Definition Team (SDT) has been tasked by NASA Headquarters to consider a lander option for Europa. As part of the information gathering effort, the Europa SDT will solicit input from the scientific community at large. A Town Hall meeting consisting of presentations and discussion is scheduled for the afternoon immediately following the upcoming OPAG meeting in Pasadena, on Thursday October 20, from 1:30 to 5:00 pm. Please see: http://icpi.nasaprs.com/opag

Details from recent lander design studies will be presented, followed by community presentations and open discussion. Brief presentations are solicited relating to topics such as: potential science objectives and priorities, instrument techniques, landing environment and sites, sample handling, and astrobiological context.

Requests for brief (~5-minute) presentations on relevant topics will be accepted until the week of the event.

Interested parties unable to attend in person are encouraged to join electronically. Video conferencing details may be found at the OPAG web site: http://www.lpi.usra.edu/opag/

Note that registration for OPAG does not confirm participation in the Forum.

Please forward questions or RSVP to Steve Vance (svance@jpl.nasa.gov).

October 3, 2011

Comparative Survival Analysis of D. radiodurans and the Haloarchaea N. magadii and H. volcanii Exposed to Vacuum Ultraviolet Irradiation

Comparative Survival Analysis of Deinococcus Radiodurans and the Haloarchaea Natrialba Magadii and Haloferax Volcanii, Exposed to Vacuum Ultraviolet Irradiation

Ximena C. Abrevaya, Ivan G. Paulino-Lima, Douglas Galante, Fabio Rodrigues, Pablo J.D. Mauas, Eduardo Corton, Claudia de Alencar Santos Lage
(Submitted on 29 Sep 2011)

The haloarchaea Natrialba magadii and Haloferax volcanii, as well as the radiation-resistant bacterium Deinococcus radiodurans, were exposed to vacuum-UV (V-UV) radiation at the Brazilian Synchrotron Light Laboratory (LNLS). Cell monolayers (containing 105 - 106 cells per sample) were prepared over polycarbonate filters and irradiated under high vacuum (10-5 Pa) with polychromatic synchrotron radiation. N. magadii was remarkably resistant to high vacuum with a survival fraction of ((3.77 ± 0.76) x 10-2), larger than the one of D. radiodurans ((1.13 ± 0.23) x 10-2). The survival fraction of the haloarchaea H. volcanii, of ((3.60 ± 1.80) x 10-4), was much smaller. Radiation resistance profiles were similar between the haloarchaea and D. radiodurans for fluencies up to 150 J m-2. For fluencies larger than 150 J -2 there was a significant decrease in the survival of haloarchaea, and in particular H. volcanii did not survive. Survival for D. radiodurans was 1% after exposure to the higher V-UV fluency (1350 J m-2) while N. magadii had a survival lower than 0.1%. Such survival fractions are discussed regarding the possibility of interplanetary transfer of viable micro-organisms and the possible existence of microbial life in extraterrestrial salty environments such as the planet Mars and the Jupiter's moon Europa. This is the first work reporting survival of haloarchaea under simulated interplanetary conditions.

Full paper

Comments: Draft version (without figures), Accepted for publication in Astrobiology
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:1109.6590v1 [astro-ph.EP]
Submission history
From: Ximena Celeste Abrevaya [view email]
[v1] Thu, 29 Sep 2011 17:02:52 GMT (131kb)

November 5, 2010

Postdoctoral Fellows: Stability of Clathrates Hydrates in Planetary Conditions: Applications to Icy Moons

The Laboratory of Plantetology and Geodynamics of CNRS/University of Nantes, France, invites applications for one postdoctoral position in the field of experimental synthesis of clathrate hydrate for planetological applications. The proposed work is part of the NASA Astrobiology Institute Project 08-NAI5-0021 (Astrobiology of Icy Worlds: Habitability, Survivability, and Detectability) and is funded by the University of Nantes.

The two objectives of the postdoctoral researcher are:

* to study experimentally the stability of methane clathrate hydrate in aqueous melts under various conditions of pressure and temperature within the range of the icy moons mantles. The influence of ammonia and salts will be explored.

* to investigate the binary system H2O-CO2 in order to constrain the effect of pressure (depth) on both the clathrate stability and the solvus evolution.

Continue reading "Postdoctoral Fellows: Stability of Clathrates Hydrates in Planetary Conditions: Applications to Icy Moons" »

February 20, 2010

The Origin of Titan's Methane

The origin of the atmosphere of Saturn's largest moon, Titan, has been an enduring mystery for decades. Scientists from NAI's Arizona State University team think they may finally have an answer. They tested the recently popular hypothesis that methane in Titan's atmosphere originated in hydrothermal systems deep within Titan. Their work was made possible by chemical data that were acquired when NASA's Cassini spacecraft passed through a plume of water and other compounds from Enceladus.

Using a geochemical model, the team deduced that Titan's atmospheric methane has much less deuterium than would be expected if the methane were produced in a hydrothermal system. The implication is that Titan's methane is a primordial chemical species that was accreted by the moon during its formation.

While Titan's methane probably came from accreted ices, the analysis of the ASU team suggests that the other major constituent of Titan's atmosphere, molecular nitrogen, could have come from within Titan's core. This work advances the understanding of the origin and evolution of the bioessential elements carbon and nitrogen on icy worlds in planetary systems. More information can be found in the December 2009 issue of Icarus.

Source: NAI Newsletter

November 9, 2009

University of Washington Astrobiology Seminar: Kevin Hand, "Joule Heating of the South Polar Terrain on Enceladus"

Date/Time: Tuesday November 10, 2009 2:30PM Pacific

Speaker: Kevin Hand (Jet Propulsion Laboratory)

Abstract: The plumes and observed heat flux in the South Polar Terrain of Enceladus remain a considerable mystery. We report that Joule heating in Enceladus - resulting from the interaction of Enceladus with Saturn's magnetic field - may account for several, to a few tens of megawatts of power across the observed "tiger stripe" fractures. Electric currents passing through subsurface channels of low salinity and just a few kilometres in depth could supply a source of power to the South Polar Terrain, providing a small but previously unaccounted for contribution to the observed heat flux and plume activity. For more information and participation instructions: http://astrobiology.nasa.gov/nai/seminars/detail/164 [Source: NAI Newsletter]

October 27, 2009

Ice in the Solar System...in Your Classroom

Exploring Ice in the Solar System is a series of lessons for K-5 classrooms developed by the NAI Carnegie Institution of Science Team and the NASA MESSENGER mission. Twelve lessons span topics from ice in everyday life, to exploring ice in the polar regions of Earth, to icy places on Mars and Europa, to life in ice. Each standards-aligned lesson consists of substantive background information, inquiry-based activities, teaching tips, resources, a photo gallery, and strategies for differentiated instruction and evaluation. [Source: NASA Astrobiology]

December 16, 2008

ENDURANCE Dives Under the Ice in Antarctica's Lake Bonney

Scientists have brought the ENDURANCE underwater vehicle to Lake Bonney, a perpetually ice-covered salt lake located in Antarctica's McMurdo Dry Valleys.

ENDURANCE, an autonomous vehicle designed to swim untethered under ice, will spend a month creating three-dimensional maps of the underwater environment. It also will collect data on the environmental conditions and take samples of microbial life. If all goes well, in the future NASA could send a similar probe to explore the ocean on Jupiter's icy moon Europa.

Read the daily blog entries written by scientists in the field as they work in Earth's coldest environment, testing the limits of ENDURANCE.

Continue reading "ENDURANCE Dives Under the Ice in Antarctica's Lake Bonney" »

June 17, 2008

The Astrobiology of Icy Worlds

Overview:

The 2008 Summer School program will be focussed on the exploration of icy worlds orbiting the giant planets of our Solar System. These satellites are important astrobiology targets in the exploration plans of space agencies as refl ected in the successes of the Galileo mission to Jupiter and the Cassini-Huygens mission to Saturn.

Continue reading "The Astrobiology of Icy Worlds" »

May 23, 2008

Recently Published Research from the NAI

Wandering Poles on Europa

A new study in the May 15th issue of Nature from NAI’s Carnegie Institution of Washington Team reveals that Europa’s poles may not have always been located in the same place. Using images from three NASA spacecraft, Voyager, Galileo, and New Horizons, the study mapped surface features on Europa and matched them with a pattern predicted if Europa had experienced an episode of ~80 degree true polar wander. This movement of the pole and subsequent change in rotation axis is only possible if Europa’s outer shell is decoupled from the core by a liquid layer, so the study also reinforces evidence for the presence of an ocean on Europa.

Continue reading "Recently Published Research from the NAI" »

March 24, 2008

NAI Director's Seminar: "Earth's Low Temperature Life: An Analog for Mars and Europa"

Presenters: Jody Deming and James Staley (University of Washington)

Date/Time: Monday, March 31, 2008 11:00 AM Pacific

For more information and participation instructions: http://nai.arc.nasa.gov/seminars/seminar_detail.cfm?ID=119

January 2, 2008

Energy, Chemical Disequilibrium, and Geological Constraints on Europa

Astrobiology December 2007, 7(6): 1006-1022

http://www.liebertonline.com/doi/pdfplus/10.1089/ast.2007.0156

Europa is a prime target for astrobiology. The presence of a global subsurface liquid water ocean and a composition likely to contain a suite of biogenic elements make it a compelling world in the search for a second origin of life. Critical to these factors, however, may be the availability of energy for biological processes on Europa.

Continue reading "Energy, Chemical Disequilibrium, and Geological Constraints on Europa" »

Hydrothermal Systems in Small Ocean Planets

Astrobiology December 2007, 7(6): 987-1005

http://www.liebertonline.com/doi/pdfplus/10.1089/ast.2007.0075

We examine means for driving hydrothermal activity in extraterrestrial oceans on planets and satellites of less than one Earth mass, with implications for sustaining a low level of biological activity over geological timescales. Assuming ocean planets have olivine-dominated lithospheres, a model for cooling-induced thermal cracking shows how variation in planet size and internal thermal energy may drive variation in the dominant type of hydrothermal system--for example, high or low temperature system or chemically driven system.

Continue reading "Hydrothermal Systems in Small Ocean Planets" »

November 2, 2007

NAI Icy Worlds Focus Group Discussions on Outer Planet Flagship Studies

The NAI Icy Worlds Focus Group met at NASA Ames Research Center on September 20 and 21, 2007. Discussions included a review of the astrobiology potential of four flagship missions to: Europa, Titan, Enceladus, and the Jupiter System. Ron Greeley, the Focus Group co-chair, will share the assessments of the Focus Group with the four mission study leads and NASA Headquarters. [Source: NAI Newsletter]

August 11, 2007

Special Session "Return to Europa" at the 2007 fall AGU Meeting

A special session titled "Return to Europa" will be held at the 2007 fall AGU meeting in San Francisco (Dec. 10-14) [ http://www.agu.org/meetings/fm07 ]. This is an exciting opportunity for presentations on Europa research and analog studies which inform our understanding of this fascinating satellite, and which set the stage for its future exploration. The deadline for abstract submissions is September 6 at 23:59 UT (4:59 pm PDT, 7:59 pm EDT). [Source: NAI Newsletter]

August 7, 2007

NASA Astrobiology Institute Sponsors Icy Worlds Group Workshop

September 20, 2007 to September 21, 2007

The NAI Icy Worlds Focus Group will hold a workshop from September 20-21, 2007 at NASA Ames Research Center. The workshop will concentrate on mission-related astrobiology issues relating to our Solar System’s icy moons such as Europa, Titan, and Enceladus. Participants will share their work, making presentations and assessments of the four NASA-sponsored mission studies, and considering the measurements and instruments appropriate for astrobiological exploration of icy objects.

February 28, 2007

Salinity of Europa's Ocean

New research from NAI's SETI Institute Team published online in Icarus today outlines the empirical range of salt concentrations permitted for Europa's ocean. Solutions within the range imply high, near-saturation salt concentrations and require a Europan ice shell of less than 15 km thick, with a best fit at 4 km ice thickness. The paper examines the implications for subsurface habitability. [source: NAI Newsletter]

February 11, 2007

NAI Director's Seminar "New and Emerging Perspectives on Late Precambrian 'Snowball Earth' Glaciation"

Speaker: Tim Raub (Yale University), Date/Time: Monday, February 26, 2007 11AM PST

Background: Using atmospheric chemical models of a Snowball Earth, scientists from NAI's Alumni Virtual Planetary Laboratory Team showed that, during long and severe glacial intervals, a weak hydrological cycle coupled with photochemical reactions involving water vapor would give rise to the sustained production of hydrogen peroxide. The peroxide, upon release from melting ice into the oceans and atmosphere at the end of the snowball event, could mediate global oxidation events.

Continue reading "NAI Director's Seminar "New and Emerging Perspectives on Late Precambrian 'Snowball Earth' Glaciation"" »

July 25, 2006

Follow The Methane (and Ethane)

Cassini Radar Finds Hydrocarbon Lakes on Titan

"The Cassini spacecraft, using its radar system, has discovered very strong evidence for hydrocarbon lakes on Titan. Dark patches, which resemble terrestrial lakes, seem to be sprinkled all over the high latitudes surrounding Titan's north pole. Scientists have speculated that liquid methane or ethane might form lakes on Titan, particularly near the somewhat colder polar regions."

July 23, 2006

Green ice, Ravens, Ice Caves and the Movie ‘Contact’

Towards the end of our summer expedition while flying back to Eureka from our camp on Axel Heiberg, I spotted a lake with what appeared to be green ice on it.

Continue reading "Green ice, Ravens, Ice Caves and the Movie ‘Contact’" »

July 17, 2006

Precursors for Europa Submersibles?

Undersea Vehicles to Study Formation of Gold and Other Precious Metals On the Pacific Ocean Floor, WHOI

"The joint expedition includes a 32-day WHOI research program funded by the U.S. National Science Foundation to the Pacmanus vent sites in the Eastern Manus Basin. The remotely operated vehicle Jason will be used to survey and map the vent areas around an Ocean Drilling Program hole drilled in 2000."

June 8, 2006

Enceladus Focus Group

Following on the recent Cassini discoveries of geysers, organics, and excess heat emanating from the south polar terrain of Enceladus, and the exciting implications of these findings for possible subterranean chambers of liquid water, we are forming an Enceladus Focus group to begin a community-wide conversation about this fascinating moon.

Continue reading "Enceladus Focus Group" »

May 26, 2006

Europa Focus Group Presentations Now Available

The NAI sponsored workshop of the Europa Focus Group at NASA Ames Research Center, from February 27 - 28, 2006, involvied 115 participants. Presentations from this successful meeting are now available at: http://astrobiology.asu.edu/focus/europa/discuss/discuss.html

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