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Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 22, 29 June 2005
Marsbugs: The Electronic Astrobiology Newsletter
Volume 12, Number 22, 29 June 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.
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Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 22, 29 June 2005
Articles and News
Page 1BACTERIA ABLE TO CARRY OUT PHOTOSYNTHESIS IN OCEAN DEPTHS
By Skip Derra
Page 2RUSSIA PLANS TWO NEW MISSIONS TO MARS
From United Press International and SpaceDaily
Page 2NASA'S HUBBLE CHASES UNRULY PLANET
NASA release 05-158
Page 3ELUSIVE EARTHS
By Henry Bortman
Page 4SETTING SETI'S SIGHTS II: ABODES FOR LIFE?
By Douglas Vakoch
Page 4DETOUR: PLANETARY CONSTRUCTION ZONE AHEAD
Harvard-SmithsonianCenter for Astrophysics release
Page 5A FORCE FIELD FOR ASTRONAUTS?
By Patrick L. Barry
Page 7TULIPS ON THE MOON—MOON BASE TO EXPAND LIFE FROM EARTH
By Bernard Foing
Page 7COLORFUL CHLOROPHYLL AROUND MARQUISESISLANDS
NASA Earth Observatory release
Page 8LIFE DETECTION INSTRUMENT PASSES KEY TEST ON ROAD TO MARS
By Robert Sanders
Page 9MARS IN POP CULTURE: FILM
By David Catling
Announcements
Page 10JOIN THE AMERICAN SOCIETY FOR GRAVITATIONAL AND SPACE BIOLOGY
By Paul Todd
Page 10ABSTRACT DEADLINE APPROACHING FOR MARS SOCIETY CONVENTION
Mars Society release
Page 11NATIONAL MARS EDUCATION CONFERENCE
NASA/JPL/ASU release
Page 12NASA FUNDS SPACE RADIATION RESEARCH PROPOSALS
NASA release 05-168
Mission Reports
Page 12CASSINI UPDATES
NASA/JPL releases
Page 15DEEP IMPACT UPDATES
Multiple agencies' releases
Page 18MARS EXPRESS RADAR READY TO WORK
ESA release 34-2005
Page 19MARS GLOBAL SURVEYOR IMAGES
NASA/JPL/MSSS release
Page 19MARS ODYSSEY THEMIS IMAGES
NASA/JPL/ASU release
Page 20MARS RECONNAISSANCE ORBITER STATUS
NASA expendable launch vehicle status report E05-04
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Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 22, 29 June 2005
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Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 22, 29 June 2005
BACTERIA ABLE TO CARRY OUT PHOTOSYNTHESIS IN OCEAN DEPTHS
By Skip Derra
ArizonaStateUniversity release
20 June 2005
A team of researchers, including a photosynthesis expert from ASU, has found evidence of photosynthesis taking place deep within the Pacific Ocean. The team found a bacterium that is the first photosynthetic organism that doesn't live off sunlight but from the dim light coming from hydrothermal vents nearly 2,400 meters (7,875 feet) deep in the ocean. The discovery of the green sulfur bacteria living near hydrothermal vents off the coast of Mexico has significant implications for the resiliency of life on Earth—and possibly on other planets, says Robert Blankenship, a member of the research team and professor and chair of ASU's chemistry and biochemistry department.
"Life finds a way," Blankenship says of the plucky bacteria that were found in a vent field called 9 North off the coast of Mexico. The bacteria apparently live in the razor-thin interface between the extremely hot water (350 degrees Celsius, or 662 degrees Fahrenheit) coming from a flange vent and the very cold water (2 degrees Celsius, or about 36 degrees Fahrenheit) surrounding it.
The research team is led by J. Thomas Beatty of the University of British Columbia, located in Vancouver, British Columbia. They published their discovery in an article titled "An obligately photosynthetic bacterial anaerobe from a deep sea hydrothermal vent," in the June 20 issue of the Proceedings of the National Academy of Sciences. In addition to Blankenship and Beatty, team members are Jörg Overmann and Ann Manske, University of Munich, Germany; Michael Lince, ASU; Andrew Lang,University of British Columbia and University of Alaska, Fairbanks; Cindy Van Dover, College of William & Mary, Williamsburg, VA; Tracey Martinson, University of Alaska, Fairbanks; and F. Gerald Plumley, University of Alaska, Fairbanks and the Bermuda Biological Station for Research, St. George's, Bermuda.
The team collected water samples around the hydrothermal vents of 9 North and surrounding areas. From the samples near the vents, they cultivated a microbe that grew in response to illumination near the thermal vents.
By using DNA analysis, the team classified the microbe as a member of the green sulfur bacteria family, which use light and sulfur to obtain energy. The fact that the organism is obligate means it solely relies on photosynthesis to live.
"This is startling in the sense that you do not expect to find photosynthesis in a region of the world that is so completely dark," Blankenship says.
Sunlight can penetrate 100 meters to 200 meters (about 330 feet to 660 feet) into the ocean, slowly dimming as the depth increases. Because these organisms live nearly 2,400 meters below the surface—almost 1.5 miles down—the team believes they must be getting light from the hydrothermal vent near where they were found.
"These organisms are the champions of low-light photosynthesis," Blankenship says. "These guys have the most elaborate and sophisticated antenna system, which we have studied for a long time in organisms that are relatives of the one discovered near the vents."
Blankenship says the antenna system of the bacteria uses a chlorosome complex, which basically acts like a microscopic satellite dish, to efficiently collect any light it can and transfer it to the organism's reaction center. The reaction center is where the photosynthesis takes place. Blankenship says this discovery is important on two different levels. One is what it means to life on Earth; the other is what it means about where to look for life forms on other planets.
"This shows that photosynthesis is something that is not limited only to the very surface of our planet," he says. "It lets you consider other places where you might find photosynthesis on Earth, as well as on other planets."
For example, Europa, a planet-sized satellite of Jupiter, long has been thought to have some of the necessary attributes to harbor life. But it is far too distant from the Sun for traditional forms of photosynthesis. It is believed that under the ice-covered surface of Europa are liquid oceans—and at the bottom of those oceans it is speculated there might be very hot thermal vents. Those vents could harbor the potential for spawning photosynthetic organisms.
"This find shows us that there is this ability of organisms to survive and live in areas that we wouldn't have imagined possible, and that life is much stronger than what we realized," Blankenship says. "This is just one example of life in extreme environments."
Journal reference:
J. Thomas Beatty et al., 2005. An obligately photosynthetic bacterial anaerobe from a deep-sea hydrothermal vent. Proceedings of the National Academy of Sciences USA, 102(26):9306-9310,
Contact:
Skip Derra
ASU Marketing & Strategic Communications
Phone: 480-965-4823
E-mail:
Read the original news release at
An additional article on this subject is available at:
RUSSIA PLANS TWO NEW MISSIONS TO MARS
From United Press International and SpaceDaily
20 June 2005
Russian space officials said Monday they are preparing two unmanned missions to Mars before 2015. Georgy Polischuk, director general and designer general of the Lavochkin production and science association, was quoted by the Interfax-AVN news agency as saying the first mission is scheduled for October 2009. A research craft will orbit Mars, and then a rover will be dropped on the surface of Phobos—one of the tiny twin martian moons, to collect soil samples to return to Earth. The second mission is intended to land on Mars to conduct various experiments, he added.
Read the full article at
NASA'S HUBBLE CHASES UNRULY PLANET
NASA release 05-158
22 June 2005
A detailed image from NASA's Hubble Space Telescope offers the strongest evidence yet that an unruly and unseen planet may be gravitationally tugging on a dusty ring around the nearby star Fomalhaut (HD 216956). The most detailed visible light image ever taken of a narrow, dusty ring unequivocally shows the center is a whopping 1.4 billion miles away from the star; a distance nearly halfway across our solar system. The most plausible explanation is an unseen planet, moving in an elliptical orbit, is reshaping the ring with its gravitational pull. The geometrically striking ring, tilted toward Earth, would not have such a great offset if it were only being influenced by Fomalhaut's gravity.
An offset of the ring center from the star has been inferred from previous lower resolution submillimeter wavelength telescope observations; and by applying theoretical modeling and physical assumptions. Hubble's sharp images directly reveal the ring's offset from Fomalhaut. The observations provide strong evidence at least one unseen planetary mass object is orbiting the star. If the orbiting object were larger than a planet, such as a brown dwarf star, Hubble would have detected it.
"Our new images confirm those earlier hypotheses that proposed a planet was perturbing the ring," said astronomer Paul Kalas of the University of California at Berkeley. The ring is similar to our solar system's Kuiper Belt, a vast reservoir of icy material left over from the formation of our solar system planets."
The ring's inner edge is sharper than its outer edge, a telltale sign that an object is gravitationally sweeping out material like a plow clearing away snow. Another classic signature of a planet's influence is the ring's relatively narrow width, about 2.3 billion miles. Without an object to gravitationally keep the ring material intact, the particles would spread out much wider.
The suspected planet may be orbiting far away from Fomalhaut, inside the dust ring's inner edge, between 4.7 billion and 6.5 billion miles from the star. The ring is approximately 12 billion miles from Fomalhaut, much farther than our outermost planet Pluto is from the sun. These observations do not directly detect the planet, so astronomers cannot measure its mass. They will use computer simulations of the ring's dynamics to estimate its mass.
Fomalhaut, a 200-million-year-old star, is a mere infant compared to our own 4.5-billion-year-old sun. It is 25 light-years from the sun in the constellation Piscis Austrinus (the Southern Fish). The Fomalhaut ring is 10-times as old as debris disks previously seen around the stars AU Microscopii and Beta Pictoris, where planets may still be forming. If our solar system is any example, planets should have formed around Fomalhaut within tens of millions of years after the birth of the star.
"The size of Fomalhaut's dust ring suggests not all planetary systems form and evolve in the same way—planetary architectures can be quite different from star to star," Kalas said. "While Fomalhaut's ring is analogous to the Kuiper Belt, its diameter is four times greater."
Kalas and his collaborators used Hubble over a five-month period in 2004 to map the ring's structure. They used the Advanced Camera for Surveys' (ACS) coronagraph to block out light from the bright star, so they could see details in the faint ring. One side of the faint ring has yet to be imaged, because it extended beyond the ACS field of view. Astronomers plan to map the entire ring later this summer.
Kalas and collaborators, James Graham of the University of California at Berkeley and Mark Clampin of NASA's GoddardSpaceFlightCenter in Greenbelt, MD, findings appear in tomorrow's issue of the journal Nature. For information about the research on the Web, visit For information about NASA and agency programs on the Web, visit
Journal reference:
Paul Kalas, James R. Graham andMark Clampin, 2005. A planetary system as the origin of structure in Fomalhaut's dust belt. Nature, 435(7045):1067-1070,
Contacts:
Dolores Beasley
NASA Headquarters, Washington, DC
Phone: 202-358-1753
Susan Hendrix
NASAGoddardSpaceFlightCenter, Greenbelt, MD
Phone: 301-286-7745
Donna Weaver
Space Telescope Science Institute, Baltimore, MD
Phone: 410-338-4493
Additional articles on this subject are available at:
ELUSIVE EARTHS
By Henry Bortman
From Astrobiology Magazine
22 June 2005
Geoff Marcy, professor of astronomy at the University of California, Berkeley, and director of the Center for integrative Planetary Science, leads a team of planet-hunters credited with the discovery of more than 100 planets that orbit nearby stars. At a recent symposium on extrasolar planets, Marcy spoke with Astrobiology Magazine Managing Editor Henry Bortman about recent discoveries and the likelihood of finding other solar systems like our own.
Astrobiology Magazine (AM): You've found Jupiter- or Neptune-mass planets orbiting about 6.5 percent of the 1300 stars you've been monitoring in your radial-velocity survey. Almost all of these planets are closer to their host stars than Jupiter is to our own Sun. I know you need to see a planet's complete orbit to figure out its mass and its distance from its star. By now, though, I would imagine you have some strong hints about how many of the remaining stars have Jupiters or Saturns farther out from their stars. What kinds of indications are you getting about the prevalence of giant planets?
Geoff Marcy (GM): Something like 5 percent of the remaining stars show a velocity variation, which has to be due to a companion. But even if we see a linear or near-linear velocity increase, followed by a decrease, you still don't know what the orbital period is, because it could go for decades before it comes back up again. You might have caught it near the top, and now you're catching it going over the top, but it could go down for 3 decades or more. So, sadly, we can't really constrain the orbital period or the mass of a planet, or even know whether it is a planet, based on an incomplete orbit.
Most of them probably are planets. They're probably a Jupiter mass, or a little bit more, out at 5 AUs or 10 AUs or 15 AUs, where the orbital period is 10 or 20 or 30 years. So, as we all would have guessed as children, there probably is a population of Jupiters sitting out there at Jupiter and Saturn-like distances, but we just haven't watched them long enough to confirm that.
That's what's happening with many of our planets. We first caught them on the rise, then they hooked over. We kept taking data, and now they've come back around. Once the orbit closes, that's when we publish a paper. So we've learned that, with patience, they all become full orbits after a while.
AM: So when all of these orbits have closed, you estimate that you'll end up with about double the number of giant planets that you have now, that roughly 12 percent of the stars will have giant planets?
GM: Yeah. Right now 6.5 percent of our stars have Jupiters and Saturns. That's a done deal. But if you just mildly extrapolate to these longer-period ones, it's probably 12 percent, out to say 20 AUs. So something like 12 percent of all stars have a Jupiter or a Saturn like our own, that is to say, roughly the same mass, in a solar-system-like orbit. On the other hand, 85 percent of the stars don't have a Jupiter or a Saturn, which I think is interesting to note. Some of the planetary systems clearly don't have giant planets. Maybe they don't have any planets. But we can rule out the giant planets.
AM: What about Neptune-mass planets?
GM: We have just found the first three Neptune-class planets, with minimum masses of 15, 18, and 21 Earth-masses. They orbit 55 Cancri, HD 190360, and Gliese 436. For comparison, our Neptune has 17 Earth-masses. Most remarkably, we also found a planet with a likely mass of only 7 Earth-masses, orbiting the star Gliese 876. This planet is probably rocky, a "super-Earth" with a radius only twice that of our Earth. So we have found the first planets that resemble the terrestrial planets in our Solar Systems, albeit larger.
AM: So you know for certain that some 85 percent of your stars don't have a Jupiter or a Saturn. But you can't tell yet whether most of them have a Neptune or only a handful do?
GM: Empirically you're right. Of the 85 percent that show definitively they don't have a Jupiter or a Saturn, they could have Neptunes, they could have Earths, and so on. But we have no information. If you wanted my guess, any star that's reasonably isolated—single stars, or stars that have a distant stellar companion—almost certainly had a protoplanetary disk around it when it was young, and those disks almost have to make planets. This is a guess, so put a red flag about what I'm about to say. Based on theory, the guess would be that protoplanetary disks did exist around virtually all of the stars that we currently don't see any planets around at all. Those stars probably have Neptunes and Earths. If you had to bet, you'd bet there are Earth-size, Venus-size, Mars-size, maybe even Neptune-size planets around 80 percent of all the stars, 90 percent, maybe even virtually all of them. It's hard to avoid it.
If I may just elaborate, because it's a very exciting issue for astrobiology and the prevalence of Earths in the galaxy: the only way a star can form is by gas accreting onto the star, and it does so conserving angular momentum, creating a disk. And then the viscosity of that disk drains the material onto the star. So almost every star must have had a protoplanetary disk for a few million years. And therefore, it almost certainly must have made Earths. Why would some disks make Earths and Jupiters and others not? So, the odds are that our non-detections, the 85 percent of the stars that haven't yet shown planets still have lower-mass planets. That would be the bet, without any evidence.