Marsbugs: The Electronic Astrobiology Newsletter
Volume 11, Number 43, 9 November 2004
Editor/Publisher: David J. Thomas, Ph.D., Science Division, Lyon College,
Batesville, Arkansas 72503-2317, USA. dthomas@lyon.edu
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,
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Articles and News
Page 1
TRACKING ANCIENT EARTH'S OXYGEN LEVELS
PROVIDES BACKDROP FOR EVOLUTION; MU
PROFESSOR HELPS DISCOVER METHOD TO
ESTIMATE SULFATE, OXYGEN LEVELS IN ANCIENT
OCEANS
University of Missouri-Columbia release
Page 5
ASTROBIOLOGY SESSION AT EGU: GETTING READY
FOR ASTROBIOLOGY PLANETARY EXPLORATION
European Geosciences Union release
Mission Reports
Page 5
CASSINI-HUYGENS UPDATES
NASA/JPL/ESA/University of Arizona releases
Page 7
SPIRIT ADDS CLUES ABOUT HISTORY OF ROCKS IN
MARTIAN HILLS
NASA/JPL release 2004-269
Page 2
OUT WITH THE BIMA, IN WITH THE ATA
By Robert Sanders
Page 3
STUDYING SLIME (CAVE LIFE, PART II)
By Penny Boston
Page 8
SHIVA: ANOTHER K-T IMPACT? (DINOSAUR
EXTINCTION, PART III)
By Leslie Mullen
MARS EXPRESS: TITHONIUM CHASMA, VALLES
MARINERIS
ESA release
Page 9
MARS GLOBAL SURVEYOR IMAGES
NASA/JPL/MSSS release
Page 9
MARS ODYSSEY THEMIS IMAGES
NASA/JPL/ASU release
Page 3
Page 5
EXPLODED STAR POSSIBLY AFFECTED HUMAN
EVOLUTION
By Robert Roy Britt
Announcements
Page 5
NAI 2005: THE BIENNIAL MEETING OF THE NASA
ASTROBIOLOGY INSTITUTE
NASA Astrobiology Institute release
TRACKING ANCIENT EARTH'S OXYGEN LEVELS PROVIDES
BACKDROP FOR EVOLUTION; MU PROFESSOR HELPS
DISCOVER METHOD TO ESTIMATE SULFATE, OXYGEN LEVELS
IN ANCIENT OCEANS
University of Missouri-Columbia release
14 October 2004
Geologists have long considered sulfate, a common salt dissolved in seawater,
as the key to determining how and when life evolved. On the ancient Earth,
acquiring enough ocean sulfate measurements to accurately define the
ecological conditions during evolution has been a serious challenge. Now, a
novel method for extracting sulfate from ancient rocks has enabled a research
team including University of Missouri-Columbia geological science professor
Tim Lyons to uncover new evidence for sulfate levels in prehistoric oceans.
Lyons and his collaborators, whose findings are published in the scientific
journal, Nature, say their results are important because the amount of sulfate
in seawater tracks the amount of oxygen present at that same time. Scientists
want to know when and how fast oxygen accumulated in the prehistoric
oceans and atmosphere because many forms of life on Earth, particularly
multicellular organisms, could not flourish without it.
In their report, Lyons and his colleagues say they were able to confirm a prior
suspicion that the rise in ocean sulfate levels, and therefore the oxygenation of
the atmosphere, was a protracted process that extended 1 billion to 2 billion
years after the first accumulation of oxygen in the atmosphere 2.3 billion
years ago. The new estimates suggest that during the time period from
roughly 2.3 billion to 1.2 billion years ago, the amount of sulfate grew from
less than 1 percent to no more than 15 percent of today's value.
"If the increase in oceanic sulfate and atmospheric oxygen indeed extended
over more than a billion years, that undoubtedly affected how and when many
forms of life evolved," Lyons said.
The researchers conducted their research by analyzing 1.7 billion-year-old and
1.2 billion-year-old ocean sediments. Some of the measurements came from
gypsum, a sulfate-containing mineral, from the arctic region of Canada. They
also extracted sulfate from ancient limestone, which is more abundant than
gypsum, using a method they helped pioneer. To estimate levels of sulfate in
ancient seawater, the team first measured the ratio of sulfur isotopes within
the sulfate. Isotopes are atoms of the same element with different numbers of
neutrons in their nucleus. In recent times, the isotopic composition of sulfate
has varied little, which is consistent with the high concentrations of sulfate in
modern seawater.
"We saw something really different," Lyons said. "We saw very rapid
isotopic variability, which suggests there wasn't much sulfate in the early
ocean and that oxygen in the atmosphere remained comparatively low for
more than 80 percent of Earth's history."
Joining Lyons in the research were Linda Kah from the University of
Tennessee-Knoxville and Tracy Frank of the University of Nebraska.
Read the original news release at
http://www.missouri.edu/~news/releases/lyonssulfate.html.
An additional article on this subject is available at
http://www.spacedaily.com/news/early-earth-04o.html.
Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 43, 9 November 2004
OUT WITH THE BIMA, IN WITH THE ATA
By Robert Sanders
University of California-Berkeley release
2
hydrogen, but since molecular hydrogen is hard to measure, we look at the CO
as a proxy."
29 October 2004
UC Berkeley's Hat Creek Observatory in northern California is undergoing a
sea change as the nine 6.1-meter radio antennas of the Berkeley-IllinoisMaryland Array (BIMA) are dismantled and trucked south to the Inyo
Mountains near Bishop to make way at the observatory for the world's largest
radio telescope, the Allen Telescope Array (ATA). All the pedestals and six
of the nine BIMA reflector dishes are now resting at Cedar Flat near the
California-Nevada border, awaiting better weather so that the remaining three
dishes can make the long journey via backroads and freeways with a Highway
Patrol escort. Next year, these nine antennas will be set up and joined by the
six 10.4-meter radio dishes of Caltech's Owens Valley Radio Observatory to
form a new Combined Array for Research in Millimeter-wave Astronomy
(CARMA) dedicated to galactic, extragalactic and solar system astronomy.
CARMA is a joint venture of Caltech, UC Berkeley, the University of Illinois
at Urbana-Champaign and the University of Maryland.
The first convoy of reflectors detours past Nevada’s Pyramid Lake
on its way to Cedar Flat. The reflectors are 21 feet wide, so the
Highway Patrol closed off sections of road to allow the trucks to
pass. Image credit: Dick Plambeck.
The high-elevation Cedar Flat site is better for millimeter-wave astronomy
than Hat Creek, Plambeck said, because there is less water vapor to interfere
with radio observations. Conversely, Hat Creek is situated in a shallow valley
in the southern Cascade range and thus has less radio interference, which
could disrupt the sensitive measurements planned with the ATA.
Nine pedestals and six reflector dishes rest at the Cedar Flat site in
the Inyo Mountains of eastern California, where they eventually
will be joined by six other telescopes operated by Caltech to form
the Combined Array for Research in Millimeter-wave Astronomy.
Image credit: Dick Plambeck.
The move is a prelude to construction of an ambitious 350-dish radio array at
Hat Creek, which, when completed, will be the largest radio telescope in the
world. It will be used to observe everything from black holes to distant
galaxies, while at the same time searching for intelligent signals from space.
The first 32 6.1-meter radio dishes of the ATA should be erected at Hat Creek
by the end of the year, with first observations possible by spring.
Planning for the BIMA move started earlier this year, with UC Berkeley's
Radio Astronomy Laboratory splitting each antenna in two and then
contracting with Bigge Crane and Rigging to truck the pedestals and reflectors
to Cedar Flat. The pedestals arrived without incident via three convoys in
September. The extra-wide dishes were transported this month, requiring a
Highway Patrol escort that often flagged cars off to the side of the road to
allow passage of the trucks, which, with their 21-foot-wide loads, took up two
lanes of traffic. The trek involved a detour north of Reno to Pyramid Lake to
avoid underpasses and low-hanging electrical wires around the "Biggest Little
City in the World." The final convoy arrived at the 7,300-foot Cedar Flat site
on October 15.
The first convoy of reflectors arrives at Cedar Flat. October 14,
2004. Image credit: Curt Giovanine.
The full 350-antenna ATA will have unprecedented sensitivity over a large
range of wavelengths centered in the centimeter radio band, spanning the
equivalent of about four and a half octaves. The receivers of most radio
telescopes span less than half an octave, and optical telescopes span perhaps
one or two. The wavelength range stretches from 2 to 50 centimeters,
including the important 21.1-centimeter radio emissions of cold hydrogen that
have allowed astronomers to map the Milky Way galaxy's spiral arms.
"It went quite smoothly, so far, but we still have three dishes to go. Hopefully
everything will go well," said Dick Plambeck, a research astronomer who
helped coordinate the move.
The 15 telescopes of the CARMA array will be movable, so that astronomers
can trade off the sensitivity of a closely packed array with the fine resolution
of the array when spread out, Plambeck said. Astronomers wanting to
measure the emission from carbon monoxide throughout a big molecular
cloud might want the antennas close together, while those mapping the dust
disk around a distant star might spread out the antennas to resolve the pinpoint
source. The array will be most sensitive in the radio bands around 1
millimeter and 3 millimeters.
"People have used the BIMA array to learn about the chemistry in a cold
molecular cloud, to find the total mass of a star-forming region, or to track a
cloud's motion and dynamics," he said. "Molecular clouds are mostly
Telescope reflector dishes and pedestal sit side by side
at Cedar Flat. Image credit: Curt Giovanine.
As astronomers use the ATA to study galaxies, dust clouds or black holes,
others will be analyzing the radio signals for patterns that indicate they came
from intelligent civilizations far, far away. The ATA is a joint project
between UC Berkeley and the SETI Institute of Mountain View, CA, funded
by $25 million from investor and philanthropist Paul G. Allen, and another $1
million from former Microsoft Chief Technology Officer Nathan P.
Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 43, 9 November 2004
Myhrvold. Another $16 million is needed to expand the array from 32 to 206
dishes, on the way to a full 350-dish array. Some development costs also are
being funded by the National Science Foundation.
Read the original article at
http://www.berkeley.edu/news/media/releases/2004/10/29_carma.shtml.
STUDYING SLIME (CAVE LIFE, PART II)
By Penny Boston
From Astrobiology Magazine
1 November 2004
Penny Boston is one of the leaders of the SLIME team—that's Subsurface
Life in Mineral Environments. She studies bizarre microorganisms that live,
often under extreme conditions, in subterranean caves. At the recent NASA
symposium "Risk and Exploration: Earth, Sea and the Stars," in Monterey,
California, she talked about the relevance of her work below ground on Earth
to the search for life on other worlds. Astrobiology Magazine will present her
talk in two parts. In this second part she describes some of the cave
environments she has explored and the life forms she has encountered and
explains what caves can teach us about extraterrestrial life.
Cave environments are radically different from the surface. Exploration of
caves in Saudi Arabia by a very well known caving team, John and Susie Pint,
has shown that even in these very hot blasted sand deserts, when you get into
these very large bell-shaped caves there are diveable pools. The air in these
caves is near saturated humidity. It's a complete change from the overlying
environment, even in caves that are not sealed. Just the barrier of above and
below provides this radically different environment. This is a big message for
astrobiology, that what is dominant on the surface of a planet is not
necessarily the key to where you have to go to look for the life.
Left: Penny Boston and Diana Northup taking a pH or ORP measurement in
the Ragu passage (Cueva de las Sardinas. Tabasco, Mexico). Image credit:
Kenneth Ingham. Right: snottites/biovermiculations are slimy, dripping
stalactites made of goo, that contain bacteria in abundance and beautiful
microscopic gypsum crystal formations. Image credit: Diana Northrup.
Cave environments obviously have no sunlight, so any organisms living
within them have to make there living some other way, either by detrital
organic material washing in, or in the case of a lot of organisms we're
studying, by being rock-eaters. These guys are disaggregating the parent rock
with the organic acids that they give off, and then other organisms come along
within these little micro-communities and oxidize the metals in the rock. This
is how they get the energy to run their entire ecosystem. Caves are very high
humidity environments. In contrast to the surface they're very thermally
stable; even a cave with a big gaping open entrance still remains very
thermally consistent on the interior. Nutrients are usually very low. They're
very rich mineral environments. And there's no conventional weather. So it is
a very different planet in the near-crustal caves than it is on the surface.
As a result of all these tremendously different conditions that you get in caves,
the caves are unique mineral factories. There are vast numbers of unique
mineral formations that are found in caves. The explanations for the
occurrence of these are very much in their infancy. One of the things that we
are working on extensively is which of these types of mineral-formation
processes are biogenic. It turns out that there are a lot of them. And the
organisms are not simply passive observers or users of the environment, they
are mineralogically interactive. They are changing the caves. They are
actually interacting with the bedrock and they are guiding, and in some cases
controlling, the kinds of mineral deposits that are left.
3
surface, little miniature planetary systems within our own crustal
environment.
Not only do caves house these amazing arrays of organisms, but also they're
wonderful preservation environments. Not only do the organisms live there,
but they often self-lithify. They're engaged in self-fossilization while they're
alive. There are some formations known as "U loops" in Lechuigilla Cave
that look very organic. They're entirely rock now. But we have been studying
their living counterparts in modern caves, and we can see that the U loops are
clearly the fossil remains of microbial mats that were inhabiting Lechuigilla 4
to 6 million years ago, when the cave was actively forming. When we
examine the fossils in this material, we find fossil microbial filaments and
mats and even preserved drapey biofilms. So if you are looking for
biosignatures, caves are the place to look.
There are a number of different kinds of exotic environments that we work in
in caves. We tend to pick them for their specific chemical properties. We're
looking for caves that have poisonous atmospheres, that are very hot, that are
very cold, that are extreme in some sense, so that we can look at the limits to
life on this planet, and learn what adaptive strategies may be used by life on
other bodies in the solar system.
Cueva de Villa Luz is one of the most amazing caves that we're studying. It's
a sulfuric-acid-saturated cave in Tabasco, Mexico. Gases from the nearby
volcano, El Chichonal, come into this cave and make it an extremely
poisonous environment within which to work. There are tremendous amounts
of hydrogen sulfide, carbon monoxide, carbon dioxide, even aldehydes and
other noxious things in there. It requires complete protection form that
environment. But this is the most biologically rich cave of any that we've ever
seen. And it's because of these poisonous gases. These poisonous gases are
not poisonous to the organisms that are living there. It's home sweet home.
We're not looking at extreme environments just to look at extremes where
organisms are just barely hanging on. We're looking at them to look for
organisms for which that is the most comfortable environment, because those
are representatives of what we may find as the average conditions on other
bodies.
So, we're trying to write the field guide to unknown life. This is a really tough
thing to do. But the place where it makes the most sense to do this is in these
kinds of protected and evolutionarily sequestered environments. A lot of the
material we look at doesn't even look alive. In one cave we found this white
muddy looking stuff on the walls. It was living mud. It was made out of cells
and filaments that coat themselves with calcite minerals. These organisms are
actively producing this material in caves all over the world. In another
location we found these little tiny white dots on the walls. These organisms
were busy dissolving basalt in a lava tube and making their living there. So
even though something may not look alive—and sometimes we have to work
very hard to show that it is alive—all of these environments contain amazing
life forms that also leave traces of themselves.
The kind of cave work that we do is also giving us operational experience that
is very valuable to future life-detection missions, whether they be robotic or
ultimately crewed teams in the future. We are operating in extreme
environments that are hazardous, with a sensitive indigenous alien biology. In
this case the alien biology is on our own planet. But nevertheless it's very
different from our surface environment. We have to take precautions to avoid
contaminating them, while at the same time managing not to kill ourselves off.
So the caves are out there. I know that as time goes on and we explore the
planets in the solar system, we'll find better and better ways of detecting them.
We'll find ways to get into them. We'll find ways to drill into them, which
will be a lot easier than sinking a core down into solid rock. And they will
have amazing structures, amazing minerals, and perhaps even amazing life.
Read the original article at http://www.astrobio.net/news/article1276.html.
SHIVA: ANOTHER K-T IMPACT? (DINOSAUR EXTINCTION,
PART III)
By Leslie Mullen
From Astrobiology Magazine
3 November 2004
I would venture to say that the bulk of the organisms that we find are novel;
they're not known to science. From one little cave puddle to the next, we have
perhaps 80 percent novel organisms. These are truly evolutionarily selfcontained environments. Many of them are physically isolated from the
According to the Earth Impact Database, there are two craters—the 180
kilometer-wide Chicxulub crater in Yucatan, Mexico and the much smaller
Boltysh crater in eastern Ukraine—that date back to the Cretaceous-Tertiary
Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 43, 9 November 2004
4
(K-T) extinction 65 million years ago. Yet Sankar Chatterjee, a paleontologist
at Texas Tech University in Lubbock, says the catalog overlooks several
craters, including Shiva, a large, underwater crater off the coast of India. He
says this crater measures 600 by 400 kilometers, and was made by an
enormous meteorite measuring 40 kilometers across. The Shiva crater is
shaped like a teardrop, and Chatterjee thinks this is because the meteorite hit
the Earth at a low angle.
"The K-T extinction was definitely a multiple-impact scenario," he says,
pointing to two other craters not listed in the impact database: the Small Point
structure off the coast of Maine, and the Silverpit crater in the North Sea.
These craters are not listed in the catalog because, despite the claims of their
discoverers, they have not been independently confirmed to be the result of
meteorite impacts. Doubt was cast on the impact origin of the Silverpit crater
earlier this year, when it was reported in the journal, Nature, that Silverpit
instead may be a sinkhole depression caused by salt withdrawal.
Christian Koeberl, a geochemist at the University of Vienna in Austria, says
too many people are crying impact every time they see a round hole in the
Earth's crust. Craters can result from many other natural processes, including
volcanic eruptions. Koeberl says that, ever since Chicxulub was confirmed as
the likely cause of the K-T extinction, "now everybody gets on the impact
bandwagon."
"A lot of people who have not the foggiest idea about how to really recognize
an impact crater, and wouldn't be able to tell a shocked quartz grain from a
tectonically deformed one if their life depended on it, call everything that is
vaguely circular an impact crater," he says.
Other than being a round hole in the ground, an impact crater will have
evidence of the sudden violent force that punched a hole in the Earth's crust.
For instance, there will be impact breccia, which is lighter, smashed-up rock
that fills the crater after impact. Microscopic shards of "shocked quartz"crystals that shattered in the shock waves of an impact—often will be present.
Minerals other than quartz, such as zircon, also may show signs of shock and
exposure to high pressure. The heat of impact can often produce glass as well.
Geologists also look for an ejecta blanket radiating out from the crater. Above
average amounts of iridium and other siderophile ("iron-loving") elements
provide some of the strongest evidence for a meteorite impact, since those
elements are rare on the surface of the Earth but can often be found in
meteorites. But not every impact crater will have all these attributes. Some
meteorites don't contain iridium, for instance, so not every impact crater can
be expected to be rich in that element.
Diagram of Shiva impact area. Image credit: Sankar
Chatterjee.
"There's not even ambiguous evidence, or inconclusive evidence," says
Koeberl. "There are a couple of people that keep pushing for some crater in
the Indian Ocean, but this is inconsistent not only with the regional geology
and geophysics, but also with anything we know about impact cratering."
Yet Chatterjee feels sure that Shiva is an impact crater. One indication of an
impact origin, he says, is that the floor of the Shiva crater is missing most of
the lithosphere—the brittle outer shell of the Earth that includes the crust (the
continents and the ocean floor) and the uppermost part of the mantle.
Chatterjee says the large meteorite that created the Shiva crater could have
easily shattered the lithosphere, and by doing so may have triggered plate
tectonics. He says the rate of India's northward movement increased around
65 million years ago, and he suspects this was due to the Shiva impact.
Geologists who study plate tectonics agree that the Indian plate's northward
movement did speed up, but say this acceleration probably occurred before the
K-T extinction. For instance, Jerome Dyment, a geologist with the Institut de
Physique du Globe de Paris, says the plate sped up about 69 million years
ago—moving from 8 to 18 centimeters per year. This faster rate was
sustained for about 20 million years, and then slowed as India began to plow
into the Eurasian continent.
At the time of the K-T extinction, India was an island located over the
Reunion hotspot. Hotspots are fixed points where hot material from the
mantle rises to the Earth's surface. This underground welling flooded portions
of India with a vast amount of lava. Today, these cooled lava fields are called
the Deccan Traps. The slow outpouring of Deccan lava probably began a few
million years before the K-T extinction. Then about 65 million years ago, the
trickle became a torrent.
Left: Chatterjee with his younger son, Shuvo, examining Shuvosaurus. Image
credit: Texas Tech University. Right: the Deccan Traps are one of the largest
volcanic provinces in the world. It consists of more than 6,500 feet (>2,000
m) of flat-lying basalt lava flows and covers an area of nearly 200,000 square
miles (500,000 square km) (roughly the size of the states of Washington and
Oregon combined) in west-central India. Estimates of the original area
covered by the lava flows are as high as 600,000 square miles (1.5 million
square km). The volume of basalt is estimated to be 12,275 cubic miles
(512,000 cubic km) (the 1980 eruption of Mount St. Helens produced 1 cubic
km of volcanic material). The Deccan Traps are flood basalts similar to the
Columbia River basalts of the northwestern United States. This photo shows
a thick stack of basalt lava flows north of Mahabaleshwar. Image credit:
Lazlo Keszthelyi.
Koeberl admits that identifying impact craters is neither easy nor
straightforward, but he is adamant that Shiva is not an impact crater. Koeberl
says not only is there no evidence of impact in the case of Shiva, there is no
crater structure. He calls Shiva, "a figment of imagination."
Around the same time, says Steve Cande from the Scripps Institution of
Oceanography in La Jolla, California, the India-Africa ridge jumped
northwards to the edge of western India. This geologic "jump" caused a sliver
of continent to split off, forming the Seychelles.
"These events are probably associated with the Deccan Traps," says Cande.
"Now, I suppose you might say that all of these events were triggered by a
meteorite impact, but I think most people believe that the Deccan Traps was
the culmination of a mantle plume that was long in the making—millions if
not tens of millions of years."
While geologists haven't pinned down the exact connection between the ridge
jump and the volcanic event that triggered the Deccan Traps, Dyment says
that most believe both events may be the result of the head of the Reunion
hotspot finally reaching the Earth's surface.
"Such large volcanic events and associated ridge jumps also have been
observed in the Atlantic," notes Dyment, pointing to similar activity in the
north Atlantic near Iceland 54 million years ago and in the central Atlantic
between North America and Africa 180 million years ago.
But Chatterjee believes the geologic activity in India is best explained by a
massive meteorite impact. For further proof, he points to alkaline igneous
Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 43, 9 November 2004
rock spires that are encased in the Deccan Traps. These spires are rich in
iridium, but the Deccan lava did not contain iridium. How else, he asks, could
the spires have formed if not by a nearby meteorite impact? In addition,
Chatterjee says there is an underwater mountain as high as Mount Everest
within the Shiva crater. He says this structure has been dated to be 65 million
years old, and he thinks it could be the central peak that is often seen within
large impact craters. Finally, Chatterjee says the crater contains shocked
quartz, a key sign of impact. And because the K-T clay boundary layer in
India is one meter thick—the thickest in the world—Chatterjee thinks a
meteorite impact must have been close by.
While all this evidence seems compelling, Chatterjee has so far failed to
convince a majority of scientists that it adds up to proof of impact. One
problem, says Simon Kelley, a geologist at the Open University in England, is
that there is not very much information about Shiva available in the peerreviewed journals. Chatterjee published a paper discussing Shiva eight years
ago in the journal, Memoirs of the Queensland Museum, and Shiva is
mentioned in a book about global tectonics that he edited. Most other
information about the crater has appeared in conference abstracts or
proceedings.
"The advance of science normally goes ahead by postulating hypotheses and
then testing them with colleagues by publishing the work," says Kelley. "The
lack of published work on Shiva means I can't really evaluate it against the
normal criteria—so it has to be classed as a hypothesis to be tested."
Until Shiva can be studied more intensively, the crater will remain a
tantalizing possibility rather than hard evidence of another K-T meteorite
impact. Chatterjee says that oil companies and the Indian government control
the site where Shiva is located, and access is extremely limited.
"It's very frustrating," says Chatterjee. "We are so close to solving the riddle,
and yet so far because of the lack of critical drilling and geophysical data. If
Shiva were indeed an impact crater, it would be the largest crater so far
preserved on Earth."
Read the original article at http://www.astrobio.net/news/article1281.html.
EXPLODED STAR POSSIBLY AFFECTED HUMAN EVOLUTION
By Robert Roy Britt
8 November 2004
A star that exploded nearly three million years ago left traces of debris on
Earth and might have affected the course of human evolution, a new study
suggests. When particles from the explosion bombarded Earth's atmosphere
over a long stretch of time, climate change could have forced early humans to
fan out in search of food, the reasoning goes. The evidence is in the form of
extra doses of iron-60, a radioactive isotope of iron that normally occurs on
Earth in lesser quantities. Researchers found the supernova debris in layers of
soil dated to 2.8 million years ago, building a case they opened five years ago
with less concrete data.
Read the full article at
http://www.space.com/scienceastronomy/mystery_monday_041108.html.
NAI 2005: THE BIENNIAL MEETING OF THE NASA
ASTROBIOLOGY INSTITUTE
NASA Astrobiology Institute release
2 November 2004
We invite Members of the NASA Astrobiology Institute and its partners to
participate in the NAI 2005 Meeting through oral presentations, a series of
themed poster sessions, Focus Group discussions and informal meeting time.
The meeting will be held at the University of Colorado, Boulder during April
10-14, 2005, (a three-and-a-half-day meeting), with Sunday, April 10th, set
aside for splinter groups, local field trips, and primer sessions covering topics
in astronomy, geology and biology. Key areas of strength in the Institute will
be featured, such as highlights from the outcomes of the Fall 2003 NAI
Retreat as well as emerging technologies, contributions to NASA missions
and groundbreaking discoveries in astrobiology. We anticipate an engaging
and stimulating event, addressing all aspects of astrobiology and the activities
of the NAI.
5
Science sessions will center around the following themes:

Formation and Evolution of Planetary Systems

Extrasolar Planets

Origins of Life

Societal and Philosophical Issues: What is Life?

Evolution of Life

Tracing Life with Biosignatures

Evolution in the Solar System
Abstract submission and conference registration is open to members of the
current NAI Teams, NAI Focus Groups, NAI International Partners or as an
Invited Guest. Those submitting abstracts will need to identify how they are
affiliated with the NAI and will be asked to name a particular meeting theme
along with several key words. This information will be used to create a
special issue of the journal Astrobiology available at the conference containing
the accepted abstracts.
Key Dates:

Abstract Submission Opens: November 1, 2004

Registration Opens: December 1, 2004

Abstract Submission Deadline: January 13, 2005
Web site: http://nai.arc.nasa.gov/nai2005/
ASTROBIOLOGY SESSION AT EGU: GETTING READY FOR
ASTROBIOLOGY PLANETARY EXPLORATION
European Geosciences Union release
2 November 2004
Both the European Space Agency (ESA) and National Aeronautics Space
Administration (NASA) are planning astrobiology missions for specifically
Mars exploration. To enable best possible results for these missions, one
aspect is the rigorous testing of instrumentation in terrestrial planetary
analogue environments prior to the mission. With astrobiology missions
planned, the aspect of planetary protection further will play an important role
in mission planning.
We therefore invite papers that cover the aspects of analytical instrumentation
for space exploration, testing of such instruments in the laboratory and field,
as well as contributions that deal with issues related to planetary protection
and spacecraft sterilization procedures. With this scheme we hope to facilitate
the exchange of latest knowledge on research and development as well as to
stimulate discussion on future planetary exploration strategies.
European Geosciences Union (EGU) in Vienna, Austria, April 24–29, 2005
Deadline for receipt of abstracts: 21 January 2005
Deadline for pre-registration: 8 April 2005
More information: www.copernicus.org/EGU/ga/egu05/index.htm
CASSINI-HUYGENS UPDATES
NASA/JPL/ESA/University of Arizona releases
The day of descent
ESA release, 4 November 2004
When ESA's Huygens probe plunges into the atmosphere of Saturn's largest
moon, Titan, on 14 January 2005, telescopes on Earth will be watching the
remote world. Observations of Titan from Earth will help to understand the
global condition of the atmosphere, while Huygens is passing through a tiny
section of it. As Huygens drifts down, its instruments and cameras will be
collecting vital information about the atmosphere and surface. The Cassini
mothership will be listening, so that it can later transmit the results to Earth
but, while Cassini is pointing its high-gain antenna at Huygens, it cannot
watch Titan with its cameras. So telescopes on Earth will try to do the job.
The telescopes located around the Pacific Ocean will be used because Titan
will be in view from these areas at the time of the Huygens descent. An
observation from space, by the NASA/ESA Hubble Space Telescope, is also
planned.
The most exciting possibility is that the observations may show a tiny, bright
speck at the moment Huygens enters the atmosphere. This point of light will
be the 'fireball', created by friction as the probe's heat shield hurtles through
the denser parts of the moon's atmosphere and the spacecraft shoots across
Titan's sky like a giant meteor. Although the chances of seeing the fireball are
Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 43, 9 November 2004
faint, the best location to be looking from happens to coincide with the largest
single telescope in the world: the 10-meter Keck telescope. Situated on the
summit of the dormant volcano Mauna Kea, on Hawaii, Keck will be directly
in line with Titan at the moment of the Huygens descent.
In addition to optical telescopes, a string of radio telescopes across America,
Australia, China and Japan will team up to listen for the faint radio signal of
Huygens itself. If they hear this tiny call, they will be able to help determine,
after weeks of processing the Huygens amount of data that will be collected,
the precise landing location for the probe on Titan's surface.
6
The Cassini-Huygens mission is a cooperative project of NASA, the European
Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory,
a division of the California Institute of Technology in Pasadena, manages the
Cassini-Huygens mission for NASA's Science Mission Directorate,
Washington, DC. The radar instrument team is based at JPL.
Cassini Radar Sees Bright Flow-Like Feature across Titan Surface
By Lori Stiles, University of Arizona release, 8 November 2004
Jean-Pierre Lebreton, Huygens Project Scientist, will be in ESA's European
Space Operations Centre (ESOC) at Darmstadt, Germany, during the descent
of the probe. As any space scientist knows, planetary descents can be risky
things. However, Lebreton says that preparations for the day of descent are
going well, and adds, "We have no time to get nervous; there is too much
work to do."
Radar Image Shows Titan's Surface Live and in Color
NASA/JPL image advisory 2004-270, 5 November 2004
Saturn's moon Titan shows a sharp contrast between its smooth and rough
edges in a new false-color radar image. Titan's surface lies beneath a thick
coat of hazy clouds, but Cassini's radar instrument can peer through to show
finer surface features. Scientists have added color to emphasize finer details
on Titan, as shown in the image.
This image can be viewed at
http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini. To provide a
better perspective of the surface features, the color image is shown next to a
black-and-white image that was previously released.
Brighter areas may correspond to rougher terrains, slopes facing the radar, or
different materials. The pink colors enhance smaller details on the surface,
while the green color represents smoother areas. Winding linear features that
cut across dark areas may be ridges or channels, although their nature is not
yet understood. A large dark circular feature is seen at the western (top left)
end of the image, but very few features on Titan resembling fresh impact
craters are seen.
The area shown is in the northern hemisphere of Titan and is about 150
kilometers (93 miles) wide by 300 kilometers (186 miles) long. The image is
a part of a larger strip created from data taken on October 26, 2004, when the
Cassini spacecraft flew approximately 1,200 kilometers (745 miles) above
Titan's surface. The radar instrument works by bouncing radio signals off
Titan's surface and timing their return. This is similar to timing the returning
echo of your voice across a canyon to tell how wide the canyon is.
Approximately 1 percent of Titan's surface was mapped during the October 26
flyby.
This synthetic aperture radar image of the surface of Saturn's moon Titan was
acquired on Oct. 26, 2004, when the Cassini spacecraft flew approximately
2,500 kilometers (1,553 miles) above the surface and acquired radar data for
the first time. The radar illumination was from the south: dark regions may
represent areas that are smooth, made of radar-absorbing materials, or are
sloped away from the direction of illumination. A striking bright feature
stretches from upper left to lower right across this image, with connected
"arms" to the East. The fact that the lower (southern) edges of the features
are brighter is consistent with the structure being raised above the relatively
featureless darker background. Comparisons with other features and data
from other instruments will help to determine whether this is a cryovolcanic
flow, where water-rich liquid has welled up from Titan's warm interior. The
image covers an area about 150 kilometers (90 miles) square, and is centered
at about 45 degrees north, 30 degrees west in the northern hemisphere of
Titan, over a region that has not yet been imaged optically. The smallest
details seen on the image are around 1 kilometer (0.62 mile) across. Features
are less clear at the bottom of the image where the viewing was less
favorable. A faint horizontal seam between the radar beams can be seen half
way up in this image.
A strikingly bright, lobate feature has turned up in one of Cassini's first radar
images of Saturn's moon Titan.
"It may be something that flowed," Cassini radar team member Ralph Lorenz
of the University of Arizona said. "Or it could be something carved by
erosion. It's too early to say.
"But it looks very much like it's something that oozed across the surface. It
may be some sort of 'cryovolcanic' flow, an analog to volcanism on Earth that
is not molten rock but, at Titan's very cold temperatures, molten ice."
The radar image is online at http://saturn.jpl.nasa.gov and
http://www.nasa.gov/cassini.
Contact:
Carolina Martinez
Jet Propulsion Laboratory, Pasadena, CA
Phone: 818-354-9382
Additional articles on this subject are available at:
http://www.astrobio.net/news/article1278.html
http://www.astrobio.net/news/article1285.html
http://cl.exct.net/?fe5d157174610d757d15-fe28167073670175701c72
Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 43, 9 November 2004
7
http://www.space.com/searchforlife/seti_titan_041104.html
http://www.spacedaily.com/news/cassini-04zzzx.html
http://www.spacedaily.com/news/cassini-04zzzy.html
http://www.spacedaily.com/news/cassini-04zzzza.html
http://www.spacedaily.com/news/cassini-04zzzzb.html
http://www.spacedaily.com/news/cassini-04zzzzc.html
http://www.spacedaily.com/news/cassini-04zzzzd.html
http://www.spacedaily.com/news/cassini-04zzzze.html
http://spaceflightnow.com/cassini/041106titancolor.html
http://spaceflightnow.com/cassini/041106huygens.html
http://spaceflightnow.com/cassini/041108dance.html
http://spaceflightnow.com/cassini/041108titanflow.html
http://www.universetoday.com/am/publish/earth_watching_huygens_arrives.h
tml
http://www.universetoday.com/am/publish/something_oozed_titan.html
SPIRIT ADDS CLUES ABOUT HISTORY OF ROCKS IN MARTIAN
HILLS
NASA/JPL release 2004-269
4 November 2004
All the scientific tools on NASA's two Mars Exploration Rovers are still
working well, a full 10 months after Spirit's dramatic landing. The ones on
Spirit are adding fresh evidence about the history of layered bedrock in a hill
the rover is climbing.
NASA's Mars Exploration Rover Spirit used its panoramic camera to take this
image of a rock called "Lutefisk" on the rover's 286th martian day (October
22, 2004). The surface of the rock is studded with rounded granules of
apparently more-resistant material up to several millimeters (0.1 inch) or
more across. The visible portion of Lutefisk is about 25 centimeters (10
inches) across. Image credit: NASA/JPL/Cornell.
Both rovers completed three-month primary missions in April. NASA has
extended their missions twice because they have remained productive longer
than anticipated.
"We're still making good progress even though Spirit has two types of
problems with its wheels," said Jim Erickson, rover project manager at
NASA's Jet Propulsion Laboratory, Pasadena, CA. "We are working around
those problems successfully, but they might be a sign of things to come, as
mechanical parts wear out during our exploration of Mars."
NASA's Mars Exploration Rover Spirit has examined the layered structure of
this rock, called "Tetl," in the "Columbia Hills." This approximately truecolor view was made from frames taken by Spirit's panoramic camera on the
rover's 264th martian day (September 29, 2004). The rock is about 25
centimeters (10 inches) long. Spirit used its microscopic imager to inspect the
region indicated as MI. Image credit: NASA/JPL/Cornell.
"Our leading hypothesis is that these rocks originated as volcanic ash that fell
from the air or moved in ground-hugging ash flows, and that minerals in them
were altered by water," said Dr. Ray Arvidson of Washington University, St.
Louis, deputy principal investigator for the mission.
"This is still a working hypothesis, not a firm conclusion, but all the
instruments have contributed clues that fit," he said. "However, it is important
to point out that we have just begun to characterize the textures, mineralogy
and chemistry of these layered rocks. Other hypotheses for their origin focus
on the role of transport and deposition by water. In fact, it may turn out that
volcanism, water and wind have produced the rocks that Spirit is examining.
We are just beginning to put together the big picture."
A close-up look at the surface of a rock called "Wopmay," inside "Endurance
Crater," shows crevices and spherical concretions. The view combines four
frames taken by the microscopic imager on NASA's Mars Exploration Rover
Opportunity during the rover's 259th martian day (October 15, 2004). The
area shown is about 6 centimeters (2.4 inches) across. This location on
Wopmay was given the informal target name "Twin Otter." Image credit:
NASA/JPL/Cornell/USGS.
Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 43, 9 November 2004
One question for continuing investigations as Spirit heads for rocks higher in
the "Columbia Hills," is what the environment was like when water altered the
minerals. Possibilities include water in the volcanic magma mixture before
the ash erupted, surface water transporting the ash while it was still loose after
the eruption, and ground water soaking through the rocks that solidified from
the accumulated ash.
Some clues for a volcanic-ash origin come from a layered rock dubbed
"Uchben." Researchers pointed Spirit's microscopic imager at a spot on
Uchben scoured with the rock abrasion tool. The images reveal sand-size
particles, many of them sharply angular in shape and some quite rounded.
The angularity is consistent with transport by an eruption. Particles carried
across the surface by wind or water usually tumble together and become more
rounded. Uchben's rounded particles may be volcanic clumps, may be
concretions similar to what Opportunity has found, or may be particles
tumbled in a water environment. Evidence for alteration by water comes
mainly from identification of minerals and elements in the rocks by the rover's
Moessbauer spectrometer and alpha particle X-ray spectrometer.
8
available from JPL at http://marsrovers.jpl.nasa.gov and from Cornell
University at http://athena.cornell.edu.
Contacts:
Guy Webster
Jet Propulsion Laboratory, Pasadena, CA
Phone: 818-354-6278
Donald Savage
NASA Headquarters, Washington, DC
Phone: 202-358-1547
Additional articles on this subject are available at:
http://www.astrobio.net/news/article1287.html
http://www.space.com/news/rover_mystery_041105.html
http://www.space.com/news/rovers_cornell_041105.html
http://www.spacedaily.com/news/mars-mers-04zzzzzzzw.html
http://www.spacedaily.com/news/mars-mers-04zzzzzzzx.html
http://www.spacedaily.com/news/mars-mers-04zzzzzzzy.html
http://spaceflightnow.com/mars/mera/041104science.html
http://www.universetoday.com/am/publish/rover_toolkits_still_full.html
MARS EXPRESS: TITHONIUM CHASMA, VALLES MARINERIS
ESA release
3 November 2004
These images, taken by the High Resolution Stereo Camera (HRSC) on board
ESA's Mars Express spacecraft, show the western end of the Valles Marineris
Canyon system on Mars. The images were taken during orbit 442 with a
ground resolution of approximately 52 meters per pixel. The displayed region
is located at the beginning of the canyon system at about latitude 7° South and
longitude 269° East. The images show the western end of the canyons
Tithonium Chasma and Ius Chasma, part of the Valles Marineris canyon
system, which are up to 5.5 kilometers deep. The whole canyon system itself
is the result of a variety of geological processes. Probably tectonic rifting,
water and wind action, volcanism and glacial activity all have played major
roles in its formation and evolution.
Wheel tracks from NASA's Mars Exploration Rover Opportunity show where
the rover struggled for traction while driving away from "Wopmay" rock
inside "Endurance Crater." The rover looked back for this view from its
navigation camera on its 272nd martian day (October 29, 2004). Image
credit: NASA/JPL.
The rovers' principal investigator, Dr. Steve Squyres of Cornell University,
Ithaca, NY, said, "We have really made headway just in the last several weeks
in understanding these rocks. The most likely origin is debris that blasted out
of a volcano, was transported by air or water to its present location, and settled
out in layers."
Opportunity, meanwhile, examined a lumpy boulder called "Wopmay" inside
"Endurance Crater." The slope of the ground and loose surface material
around the rock prevented Opportunity from getting firm enough footing to
use its rock abrasion tool. Evidence from the spectrometers and microscopic
imager is consistent with scientists' earlier hypothesis that rocks near the
bottom of the crater were affected by water both before and after the crater
formed. The evidence is still not conclusive, Squyres said.
Opportunity is heading toward the base of "Burns Cliff," a tall exposure of
layered rock in the wall of the crater. However, if the rover encounters more
of the poor traction found around Wopmay, planners may change course and
drive up out of the crater.
JPL, a division of the California Institute of Technology in Pasadena, manages
the Mars Exploration Rover project for NASA's Science Mission Directorate,
Washington. Images and additional information about the project are
Tithonium Chasma.
The canyon floors are covered by a dark, layered material, the so-called
'Interior Layered Deposits'. These deposits are marked by a system of
polygonal cracks through which the underlying, lighter-colored rock can be
seen. The Interior Layered Deposits are still a major topic of research. Parts
of the deposits are most probably volcanic, while in other areas a sedimentary
origin has been proposed.
The morphology of the valley flanks has been modified by slumping and
rockfalls. Slumping is when a substantial part of a mountain, cliff or hill
breaks away and slides more or less intact to the bottom of the slope. Some of
the major slumps here are more than thirty kilometers wide. The flanks are
often covered to a large extent by their own talus, or rock debris that has fallen
from the sides of a cliff or steep slope.
The large, deeply eroded Crater Oudemans in the south of the area (bottom of
the image) has a diameter of about 120 kilometers. Around the central mount
of the crater, large plains composed of dark rock can be seen. These plains
are covered by lighter sediments, deposited through the action of the wind.
Several systems of tectonic faults can be seen in the imaged area.
Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 43, 9 November 2004
9
Fretted Terrain Valleys (Released 30 October 2004)
http://www.msss.com/mars_images/moc/2004/10/30/index.html
West Arabia Sedimentary Rocks (Released 31 October 2004)
http://www.msss.com/mars_images/moc/2004/10/31/index.html
Secondary Field (Released 01 November 2004)
http://www.msss.com/mars_images/moc/2004/11/01/index.html
Heavily Cratered Surfaces (Released 02 November 2004)
http://www.msss.com/mars_images/moc/2004/11/02/index.html
Landslide in Coprates (Released 03 November 2004)
http://www.msss.com/mars_images/moc/2004/11/03/index.html
All of the Mars Global Surveyor images
http://www.msss.com/mars_images/moc/index.html.
Tithonium Chasma in perspective, looking east.
The most prominent is the system of Valles Marineris itself, running eastwest. South of Crater Oudemans, smaller tectonic grabens running from the
south-west to the north-east can be seen. To the north of the large canyons,
there are more fault systems. The Valles Marineris region is one of the most
studied areas on Mars. The canyon system is one of the major keys to the
tectonic and volcanic history of this planet. Research on the sedimentary
rocks and the products of erosion can also provide major insights into its
climatic evolution.
Due to the stereo capability of the HRSC, the new image data gained can
provide new insights into the geology of Mars. This will lead to a new, more
precise reconstruction of martian geological history.
Image resolution has been decreased for use on the internet. The color images
were processed using the nadir (vertical view) and color channels. The
perspective views were calculated from the digital terrain model derived from
the stereo channels. The 3D anaglyph image was created from the nadir
channel and one of the stereo channels. Stereoscopic glasses are needed to
view the 3D image.
Read the original news release at
http://www.esa.int/SPECIALS/Mars_Express/SEMY4R0A90E_2.html.
Additional articles on this subject are available at:
http://www.astrobio.net/news/article1286.html
http://www.spacedaily.com/news/marsexpress-04zj.html
http://www.universetoday.com/am/publish/tithonium_chasma_mars.html
MARS GLOBAL SURVEYOR IMAGES
NASA/JPL/MSSS release
28 October - 3 November 2004
The following new images taken by the Mars Orbiter Camera (MOC) on the
Mars Global Surveyor spacecraft are now available.
Crater in Arabia (Released 28 October 2004)
http://www.msss.com/mars_images/moc/2004/10/28/index.html
Landforms in East Candor (Released 29 October 2004)
http://www.msss.com/mars_images/moc/2004/10/29/index.html
are
archived
at
Mars Global Surveyor was launched in November 1996 and has been in Mars
orbit since September 1997. It began its primary mapping mission on March
8, 1999. Mars Global Surveyor is the first mission in a long-term program of
Mars exploration known as the Mars Surveyor Program that is managed by
JPL for NASA's Office of Space Science, Washington, DC. Malin Space
Science Systems (MSSS) and the California Institute of Technology built the
MOC using spare hardware from the Mars Observer mission. MSSS operates
the camera from its facilities in San Diego, CA. The Jet Propulsion
Laboratory's Mars Surveyor Operations Project operates the Mars Global
Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics,
from facilities in Pasadena, CA and Denver, CO.
MARS ODYSSEY THEMIS IMAGES
NASA/JPL/ASU release
1-5 November 2004
Northern Polar Storm Front (Released 1 November 2004)
http://themis.la.asu.edu/zoom-20041101a.html
Cloudy Pole (Released 2 November 2004)
http://themis.la.asu.edu/zoom-20041102a.html
Storm Front (Released 3 November 2004)
http://themis.la.asu.edu/zoom-20041103a.html
Storm and Clouds (Released 4 November 2004)
http://themis.la.asu.edu/zoom-20041104a.html
Storm over Dunes (Released 5 November 2004)
http://themis.la.asu.edu/zoom-20041105a.html
All of the THEMIS images are archived at http://themis.la.asu.edu/latest.html.
NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission
for NASA's Office of Space Science, Washington, DC. The Thermal
Emission Imaging System (THEMIS) was developed by Arizona State
University, Tempe, in collaboration with Raytheon Santa Barbara Remote
Sensing. The THEMIS investigation is led by Dr. Philip Christensen at
Arizona State University. Lockheed Martin Astronautics, Denver, is the
prime contractor for the Odyssey project, and developed and built the orbiter.
Mission operations are conducted jointly from Lockheed Martin and from
JPL, a division of the California Institute of Technology in Pasadena.
End Marsbugs, Volume 11, Number 43.