SPACE & SCIENCE NEWS:
June 2000
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science news: June 2000
Meteorite salt clue to Mars oceans
(Jun. 24, 2000)
Salts found in the interior of the 1.2 billion-year-old Nakhla
meteorite, which originated on Mars,
have yielded the first evidence for the composition of the oceans
once believed to have existed on the Martian surface. Water-soluble
ions, thought to have been deposited in cracks by evaporating brine,
have been identified by Arizona State University Regents Professor
of Chemistry and Geology Carleton Moore, Douglas Sawyer of Scottsdale
Community College, ASU graduate student Michael McGehee, and Julie
Canepa of Los Alamos National Laboratory. The finding, announced in
the July issue of the journal Meteoritics and Planetary Science, indicates
that the Martian oceans had a mineral composition similar in variety
and concentration to that of Earth oceans. "We have concluded that
we have extracted salts that were originally present in Martian water,"
said Moore. "The salts we found mimic the salts in Earth's ocean fairly
closely." |
Major breakthrough: evidence for liquid
water on Mars
(Jun. 22, 2000)
NASA scientists have announced powerful evidence that liquid water
exists on Mars, increasingly
enormously the prospects for subsurface microscopic life. At a press
conference, high-reolution images from the Mars
Global Surveyor spacecraft were shown of steep-sided gullies,
sinuous channels, and deltas of debris, suggesting that liquid water
may lie just below the Martian surface.  The
new results to be officially published on June 30 in a paper in Science
by Michael Malin and Kenneth Edgett, do not claim that water itself
has been detected – only structures that, if found on Earth,
would have been formed by water seeping up from underground. "These
gullies could be on the order of a million years old, or they could
have formed yesterday," says Malin. The images suggest that the water
could exist in a porous layer of rock buried a few hundred meters
below the Martian surface, kept liquid by the pressure exerted by
overlying rock.  The
formation of the Martian gullies may be linked to their location:
more than 90 percent of them occur in the planet's southern hemisphere,
almost all of them on the pole side of 30 degrees latitude. "These
are cooler areas, areas further away from the sunlight and higher
temperatures that you get on slopes that are near to the equator or
face the equator," says Edgett. Water on Mars could be widespread.
About 200 of the 60,000 images produced by Mars Global Surveyor are
said to show evidence of grooves carved by rivers flowing down the
sides of craters in fan-shaped patterns. Since liquid water is considered
a key ingredient for life, these results provide a massive boost for
those who suspect there may be microbes still living on the Red Planet
and will dictate the course of Mars exploration in the near future.
Placing a lander in a watery region will now be a high priority.
For more see msnbc.com,
Spaceref.com,
and BBC
on-line. For more pictures, go here. |
Sweet news for astrobiologists
(Jun. 18, 2000)
The possibility of widespread life in space just came a step closer
with the detection of the sugar molecule glycoaldehyde in a giant
gas cloud near the center of our Galaxy. The breakthrough was made
by researchers using the 12-meter radio telescope on Kitt Peak, Arizona.
Said Jan Hollis of the Goddard Space Flight Center, one of the scientists
involved: "The discovery of this sugar molecule in a cloud from which
new stars are forming means it is increasingly likely that the chemical
precursors to life are formed in such clouds long before planets develop
around the stars." Glycolaldehyde can combine with other molecules
to form the more-complex sugars ribose (a component of DNA and RNA)
and glucose.
For more go here. |
Sensor webs to look for signs of alien
life
(Jun. 14, 2000)
Researchers from the Jet Propulsion Laboratory are carrying out field
trials of arrays of miniature sensors designed to monitor biological
activity on other worlds. The wireless "sensor webs," intended to
give NASA a virtual presence for exploration throughout the solar
system, are being located in specialized gardens at the Huntingdon
Library, Art Collections, and Botanical Gardens in San Marino, California,
where scientists can closely watch the microclimates with their new
equipment. A sensor web consists of a number of small pods, each housing
transducers that collect data from the environment and communication
chips that move the data around the web to primary pods. The information
is then transmitted to the Internet or an overhead satellite. The
pods being tested monitor local temperature, humidity, soil moisture
and light levels. Initial observations will take place in a controlled
greenhouse environment, then progress to a nursery, and on to overlapping
microclimate areas.
For more, go here. |
Salt crystals from the dawn of the solar
system
(Jun. 9. 2000)
Radioisotope dating of salt crystals found within the Zag meteorite,
which fell in Morocco in 1998, indicates they formed within about
two million years of the solar system's birth some 4.57 billion years
ago. This would make them the oldest materials known and suggests
that the primordial solar nebula clumped together into rocky fragments
much more quickly than previously had been assumed. The researchers,
from the University of Manchester and the Natural History Museum in
London, argue that Zag's parent body grew rapidly into a rocky mass
containing water and radioactive elements. The elements' decay produced
enough heat to melt any ice within the rock and caused the liquid
to evaporate altogether. The salt crystals were formed during the
evaporation process, similar to the way salt forms when sea water
evaporates on Earth. Until the discovery of salt in the Zag meteorite,
and early in another object known as the Monahans meteorite (for which
a less precise dating had already been obtained), the oldest materials
in the solar system were thought to be chondrules,
glassy spheres that make up much of the mass of primitive meteorites.
The results are presented in the June 9 issue of Science.
For more details, go here. |
Ohio State's prototype SETI array takes
shape
(Jun. 9, 2000)
Ohio State University's Argus
radio telescope is starting to take shape. An array of eight antennas
has been set up on the roof of the university's ElectroScience Lab.
Researchers plan to use the set-up to find ways to counteract interference,
such as from FM radio and TV stations, that plagues observations made
with radio telescopes. Argus will also serve as a testbed for the
development of a new kind of radio telescope, of which the Square
Kilometer Array is a prime example, that can view the entire radio
sky, from horizon to horizon, at once. Such instruments will play
a key role in future SETI searches.
For a full story, go here. |
Planet search in globular cluster draws
a blank
(Jun. 7, 2000)
A search for Jupiter-like planets in the globular cluster 47
Tucanae, carried out by an international team of astronomers using
data from the Hubble Space Telescope, has so far proved negative.
The work involves checking 34,000 stars in the cluster for signs of
large transiting planets. On a purely statistical basis, of the 27,000
stars checked, 15-20 would be expected to show evidence of transits
by jovian worlds in small orbits. The fact that none have turned up
suggests that the process of inward orbital migration, which explains
why so many of the jovian extrasolar planets found to date are in
such small orbits around their host stars, is for some reason inhibited
in the cluster environment. |
Pristine samples of Yukon carbonaceous
chondrite found
(Jun. 1, 2000)
On January 18 this year a meteoroid about 7 meters across with a mass
of about 200 metric tons detonated in the skies over the Arctic. Eyewitnesses
in Western Canada reported its passage as a brilliant fireball. 
The first fragments of the object, now known to be a carbonaceous
chondrite and named the Taglish meteorite, were discovered shortly
after the fall by a local resident near the spot where the meteorite
hit (see map). Having been notified by NASA scientists (because he
lived near the projected fall-zone) what to do if he came across any
pieces of the meteorite, he placed the specimens in clean plastic
bags and kept them continuously frozen. These are thus the most pristine,
uncontaminated examples of a carbonaceous chondrite, containing ancient,
organically-rich matter, every to become available for laboratory
analysis. The NASA/JSC photo at left shows (from left to right) samples
of the Allende meteorite,
the new meteorite, and the Murchison meteorite which landed in Australia
in 1969.
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