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Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 5, 8 February 2005
Marsbugs: The Electronic Astrobiology Newsletter
Volume 12, Number 5, 8 February 2005
Editor/Publisher: David J. Thomas, Ph.D., Science Division, LyonCollege, Batesville, Arkansas72503-2317, USA.
Marsbugs is published on a weekly to monthly basis as warranted by the number of articles and announcements. Copyright of this compilation exists with the editor, but individual authors retain the copyright of specific articles. Opinions expressed in this newsletter are those of the authors, and are not necessarily endorsed by the editor or by LyonCollege. E-mail subscriptions are free, and may be obtained by contacting the editor. Information concerning the scope of this newsletter, subscription formats and availability of back-issues is available at The editor does not condone "spamming" of subscribers. Readers would appreciate it if others would not send unsolicited e-mail using the Marsbugs mailing lists. Persons who have information that may be of interest to subscribers of Marsbugs should send that information to the editor.
Astronomers using the Keck I telescope in Hawaii are learning much more about a strange, thermal "hot spot" on Saturn that is located at the tip of the planet's south pole. In what the team is calling the sharpest thermal views of Saturn ever taken from the ground, the new set of infrared images suggest a warm polar vortex at Saturn's south pole—the first to ever be discovered in the solar system. This warm polar cap is home to a distinct compact hot spot, believed to contain the highest measured temperatures on Saturn. A paper announcing the results appears in the February 4th issue of Science. Additional information is available at [
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Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 5, 8 February 2005
Articles and News
Page 1MELTING MARS
From Astrobiology Magazine
Page 2TITAN: A WORLD OF ITS OWN
By Seth Shostak
Page 2HIGH VOLTAGE MARS
By Leslie Mullen
Page 3ASTRONOMERS DISCOVER BEGINNINGS OF "MINI" SOLAR SYSTEM
NASA/JPL release 2005-022
Announcements
Page 4JOIN THE CELEBRATION OF NATURAL SELECTION: DARWIN DAY AT THE ESSIG IS TUESDAY, FEBRUARY 8
By Barry Bergman
Page 4THE JOINT INTERNATIONAL SYMPOSIA FOR SUBSURFACE MICROBIOLOGY (ISSM 2005) AND ENVIRONMENTAL BIOGEOCHEMISTRY (ISEB XVII)
American Society for Microbiology release
Mission Reports
Page 5PUBLICATION OF ESA/UK COMMISSION OF INQUIRY INTO BEAGLE 2
British National Space Centre (BNSC) release 2005/38
Page 5CASSINI SIGNIFICANT EVENTS FOR 27 JANUARY - 2 FEBRUARY 2005
NASA/JPL release
Page 7MARS EXPLORATION ROVERS UPDATES
NASA/JPL releases
Page 7GREEN LIGHT FOR DEPLOYMENT OF ESA’S MARS EXPRESS RADAR
ESA release 08-2005
Page 9MARS GLOBAL SURVEYOR IMAGES
NASA/JPL/MSSS release
Page 9MARS ODYSSEY THEMIS IMAGES
NASA/JPL/ASU release
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Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 5, 8 February 2005
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Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 5, 8 February 2005
MELTING MARS
From Astrobiology Magazine
Based on an AGU report
3 February 2005
Injecting synthetic "super" greenhouse gases into the Martian atmosphere could raise the planet's temperature enough to melt its polar ice caps and create conditions suitable for sustaining biological life. In fact, a team of researchers suggests that introducing global warming on the Red Planet may be the best approach for warming the planet's frozen landscape and turning it into a habitable world in the future. Margarita Marinova, then at the NASAAmesResearchCenter, and colleagues propose that the same types of atmospheric interactions that have led to recent surface temperature warming trends on Earth could be harnessed on Mars to create another biologically hospitable environment in the solar system. In the February issue of Journal of Geophysical Research-Planets, published by the American Geophysical Union, the researchers report on the thermal energy absorption and the potential surface temperature effects from introducing man-made greenhouse gases strong enough to melt the carbon dioxide and ice on Mars.
"Bringing life to Mars and studying its growth would contribute to our understanding of evolution, and the ability of life to adapt and proliferate on other worlds," Marinova said. "Since warming Mars effectively reverts it to its past, more habitable state, this would give any possibly dormant life on Mars the chance to be revived and develop further."
The authors note that artificially created gases—which would be nearly 10,000 times more effective than carbon dioxide—could be manufactured to have minimal detrimental effects on living organisms and the ozone layer while retaining an exceptionally long lifespan in the environment. They then created a computer model of the Martian atmosphere and analyzed four such gases, individually and in combination, that are considered the best candidates for the job.
Their study focused on fluorine-based gases, composed of elements readily available on the Martian surface, that are known to be effective at absorbing thermal infrared energy. They found that a compound known as octafluoropropane, whose chemical formula is C3F8, produced the greatest warming, while its combination with several similar gases enhanced the warming even further.
The researchers anticipate that adding approximately 300 parts per million of the gas mixture in the current Martian atmosphere, which is the equivalent of nearly two parts per million in an Earth- like atmosphere, would spark a runaway greenhouse effect, creating an instability in the polar ice sheets that would slowly evaporate the frozen carbon dioxide on the planet's surface. They add that the release of increasing amounts of carbon dioxide would lead to further melting and global temperature increases that could then enhance atmospheric pressure and eventually restore a thicker atmosphere to the planet.
Such a process could take centuries or even millennia to complete but, because the raw materials for the fluorine gases already exist on Mars, it is possible that astronauts could create them on a manned mission to the planet. It would otherwise be impossible to deliver gigaton-sized quantities of the gas to Mars. The authors conclude that introducing powerful greenhouse gases is the most feasible technique for raising the temperature and increasing the atmospheric pressure on Mars, particularly when compared to other alternatives like sprinkling sunlight-absorbing dust on the poles or placing large mirrors in the planet's orbit.
Read the original article at
An additional article on this subject is available at
TITAN: A WORLD OF ITS OWN
By Seth Shostak
From Space.com
3 February 2005
OK, everyone anticipated that Titan was going to be interesting, but few expected it to be weirder than Michael Jackson. Two weeks ago, as the Huygens probe parachuted through this distant moon's oily, pumpkin skies, a less-than-consumer-grade 0.04 megapixel camera was trained on the landscape ten miles below. It saw a hostile shoreline, riven with tributaries, and what appears to be a (possibly dry) lake.
Imagine the luck: a shoreline and a lake. Try dropping a penny on a big map of your home state, and see how often it lands on a bit of shoreline topography. Not often, unless you live in Minnesota. The implication is that Titan is pockmarked with ponds; it's Minnesota trapped in the mother of all winters. Daytime temperatures are an unpleasant -180°C (-290°F).
Read the full article at
HIGH VOLTAGE MARS
By Leslie Mullen
From Astrobiology Magazine
7 February 2005
Mars is often enveloped by planet-wide dust storms—their biting winds choke the air and scour the arid surface. Tornado-like dust devils dance across the planet so frequently that their numerous tracks crisscross each other, tracing convoluted designs in the red soil. Such weather conditions would make life a hardship for any future explorers on Mars. According to Sushil Atreya, Professor and Director of the Planetary Science Laboratory at the University of Michigan, these storms also may have prevented life from ever existing on the martian surface.
Dust particles in a storm create an electrostatic charge whenever they strike one another or the ground. In field experiments led by William Farrell of NASA's GoddardSpaceFlightCenter, electrical fields of 10 kilovolts per meter were measured in dust devils on Earth. Such experiments suggest that dust devils on Mars could generate very large electric fields of about 5 to 20 kilovolts per meter. These electric fields would cause gas molecules in the martian atmosphere to break down. For example, when the electric fields break down water vapor (H2O), they would produce hydroxyl radicals (·OH). According to Atreya, these hydroxyls would eventually help form hydrogen peroxide (H2O2).
The sun probably generates some hydrogen peroxide by photo-dissociating water vapor in the upper atmosphere. But Atreya estimates the dust storms might result in 200 times more hydrogen peroxide gas in the atmosphere than the sun could produce, since most of the water vapor on Mars is close to the surface—right where the dust storms occur.
"The amount of hydrogen peroxide becomes so large, the atmosphere cannot hold any more of the gas," says Atreya. "So it begins to snow out of the atmosphere, and settles on to the surface as hydrogen peroxide dust."
Left: "I think the ingredients of the [martian] biosphere should be martian. That would be the most interesting situation." —Chris McKay. Image credit: University of Arizona. Right: "I think it's increasingly evident that there is a large inventory of water on Mars." —Lisa Pratt. Image credit: NASA.
Hydrogen peroxide is a strong oxidant, and would destroy any organic materials existing on the planet's surface. Since life as we know it is based on organic chemistry, the hydrogen peroxide dust would snuff out any chances for such life to appear there.
The lack of organics on Mars was first established by the Viking landers in 1976. The two landers conducted four experiments to try to detect life, and one of these experiments showed that the surface of Mars was entirely devoid of carbon compounds. Because the thin Martian atmosphere does little to shield the planet from the harsh ultraviolet radiation of the sun, scientists suspected that UV light destroyed some of the organics. They also speculated that oxidizing compounds in the soil, like hydrogen peroxide, also could destroy organics.
But hydrogen peroxide had never been detected on Mars. That changed in 2003, when two groups detected small amounts of hydrogen peroxide in the martian atmosphere. Atreya is a member of the Infrared TEXES spectrometer team, and he says they measured 20 to 50 parts per billion of hydrogen peroxide using NASA's Infrared Telescope Facility in Hawaii. Hydrogen peroxide also was detected by a team led by Todd Clancy of the Space Science Institute in Boulder, Colorado, using the James Clerk Maxwell Telescope in Hawaii.
But, says Atreya, the amount of hydrogen peroxide detected on Mars is not enough to remove all the organics that should be on the surface. Even if there were no indigenous organics on Mars, substantial amounts of organic material should have been delivered to Mars by the many meteorites and comets that have impacted the planet since the early days of the solar system. Large amounts of hydrogen peroxide or another superoxide produced by dust storms could explain why the surface of Mars is so barren today.
Man, machine, and the environment to change. Image credit: ESA.
However much hydrogen peroxide is produced by dust storms, the sun's UV rays would ensure it would not last long in the air, breaking the molecules down after a few days. But if hydrogen peroxide ice particles are bound to the dust particles they ride on, they could mix with the surface soils after they fall out of the atmosphere, allowing them to persist in the environment for much longer. This longer residence time would allow the hydrogen peroxide snow to eventually be converted into other superoxides by surface chemistry.
If water is mixed in with the soil, or if there is sub-surface ice, the hydrogen peroxide eventually would combine with this water. Depending on the concentration of H2O2, this would lower the freezing point of the water, just as salt makes ocean water less apt to freeze on Earth. Thus, while hydrogen peroxide on the martian surface would reduce the chance for life above ground, its presence in subsurface martian water would increase the odds that life could exist beneath the surface.
The dust storms block our view of what is happening on Mars, so to prove the storms really are generating hydrogen peroxide, Atreya says a measuring device would have to be sitting on the surface.
"Surfaces are hard to detect with remote sensing, especially the localized chemicals," says Atreya. "Also, the hydrogen peroxide would be mixed in with the regolith, making remote observations of it even more difficult."
The Mars Rovers Spirit and Opportunity have been traveling on the martian surface for over a year, but they are not equipped to detect hydrogen peroxide or other superoxides. Atreya says that the Mars Science Laboratory (MSL) mission, scheduled for 2009, will include a suite of instruments that are expected to measure the presence of superoxides such as hydrogen peroxide.
"This idea is new, and possibly very important," says Mike Mumma, Director of the Center for Astrobiology at NASA's GoddardSpaceFlightCenter. "It suggests there should be abundant oxidants on dust particles. If it bears out, it could provide a very efficient way for destroying organic compounds much more rapidly than by photochemistry."
Read the original article at
ASTRONOMERS DISCOVER BEGINNINGS OF "MINI" SOLAR SYSTEM
NASA/JPL release 2005-022
7 February 2005
Moons circle planets, and planets circle stars. Now, astronomers have learned that planets may also circle celestial bodies almost as small as planets. NASA's Spitzer Space Telescope has spotted a dusty disc of planet-building material around an extraordinarily low-mass brown dwarf, or "failed star". The brown dwarf, called OTS 44, is only 15 times the mass of Jupiter. Previously, the smallest brown dwarf known to host a planet-forming disc was 25 to 30 times more massive than Jupiter. The finding will ultimately help astronomers better understand how and where planets—including rocky ones resembling our own—form.
This graph of data from NASA's Spitzer Space Telescope shows that an extraordinarily low-mass brown dwarf, or "failed star," is circled by a disk of planet-building dust. The brown dwarf, called OTS 44, is only 15 times the mass of Jupiter, making it the smallest known brown dwarf to host a planet-forming disk. Spitzer was able to see this unusual disk by measuring its infrared brightness. Whereas a brown dwarf without a disk (red dashed line) radiates infrared light at shorter wavelengths, a brown dwarf with a disk (orange line) gives off excess infrared light at longer wavelengths. This surplus light comes from the disk itself and is represented here as a yellow dotted line. Actual data points from observations of OTS 44 are indicated with orange dots. These data were acquired using Spitzer's infrared array camera.
"There may be a host of miniature solar systems out there, in which planets orbit brown dwarfs," said Dr. Kevin Luhman, lead author of the new study from the Harvard-SmithsonianCenter for Astrophysics, Cambridge, Mass. "This leads to all sorts of new questions, like 'Could life exist on such planets?' or 'What do you call a planet circling a planet-sized body? A moon or a planet?'"
This artist's concept shows a brown dwarf surrounded by a swirling disk of planet-building dust. NASA's Spitzer Space Telescope spotted such a disk around a surprisingly low-mass brown dwarf, or "failed star." The brown dwarf, called OTS 44, is only 15 times the size of Jupiter, making it the smallest brown dwarf known to host a planet-forming, or protoplanetary disk. Astronomers believe that this unusual system will eventually spawn planets. If so, they speculate that OTS 44's disk has enough mass to make one small gas giant and a few Earth-sized rocky planets. OTS 44 is about 2 million years old. At this relatively young age, brown dwarfs are warm and appear reddish in color. With age, they grow cooler and darker. Image credit: NASA/JPL-Caltech/T. Pyle (SSC). Image credit: NASA/JPL-Caltech/Harvard-Smithsonian CfA.
Brown dwarfs are something of misfits in the astronomy world. These cool orbs of gas have been called both failed stars and super planets. Like planets, they lack the mass to ignite and produce starlight. Like stars, they are often found alone in space, with no parent body to orbit.
"In this case, we are seeing the ingredients for planets around a brown dwarf near the dividing line between planets and stars. This raises the tantalizing possibility of planet formation around objects that themselves have planetary masses," said Dr. Giovanni Fazio, an astronomer at the HarvardSmithsonianCenter for Astrophysics and a co-author of the new study.
The results were presented today at the Planet Formation and Detection meeting at the AspenCenter for Physics, Aspen, CO, and will be published in the February 10th issue of The Astrophysical Journal Letters.
Planet-forming, or protoplanetary, discs are the precursors to planets.
Astronomers speculate that the disc circling OTS 44 has enough mass to make a small gas giant planet and a few Earth-sized, rocky ones. This begs the question, "Could a habitable planet like Earth sustain life around a brown dwarf?"
"If life did exist in this system, it would have to constantly adjust to the dwindling temperatures of a brown dwarf," said Luhman. "For liquid water to be present, the planet would have to be much closer to the brown dwarf than Earth is to our Sun."