& SCIENCE NEWS: November 2000
home > space
& science news > space & science news: November 2000
|First land life pushed back
over a billion years
||Nov 30, 2000
|Science teams selected for Space Interferometry
||Nov 29, 2000
|High-flying balloon captures
||Nov 24, 2000
|Further signs of liquid water
||Nov 21, 2000
|New phylum of animal discovered
||Nov 20, 2000
||Nov 15, 2000
|Organic matter in Leonid meteors
||Nov 15, 2000
|Bacteria found thriving
in snow at South Pole
||Nov 9, 2000
|Evidence of recent volcanity
activity on Mars
||Nov 3, 2000
|Are there planets in globular clusters?
||Nov 2, 2000
| Earliest appearance of life on land
pushed back over a billion years
(Nov. 30, 2000)
Scientists with NASA's Astrobiology
Institute (NAI) have discovered fossilized remnants of microbial
mats that developed on land between 2.6 billion and 2.7 billion years
ago in the Eastern Transvaal district of South Africa. This pushes
back the earliest evidence of life on land some 1.4 billion years.
It also suggests that an ozone shield and an oxygen-rich atmosphere
existed on Earth 2.6 billion years ago, both necessary conditions
for life on land to emerge. The results are reported in the November
30 issue of Nature.
For more, go here.
Science teams selected for Space Interferometry
(Nov. 29, 2000)
NASA has chosen 10 science teams to spearhead research to be carried
out with the Space Interferometry Mission (SIM), scheduled for launch
in 2009. A major space-based observatory in NASA's Origins Program,
SIM will be the first mission to carry an optical interferometer as
its main instrument. It will combine the light from two sets of four
30-cm- (1-ft.-) diameter telescopes arrayed across a 10-m (33-ft.)
boom to achieve a resolution approaching that of a 10-m-diameter mirror.
This will allow it to perform extremely sensitive astrometry
enabling it to detect very small wobbles in the movement of a star
due to undeen companions. Among other things, SIM will search for
Earth-sized extrasolar planets. One of the principal investigators
will be Geoffrey Marcy,
of the University of California, Berkeley. Other planetary investigators
will include JPL's Michael Shao (Extrasolar Planets Interferometric
Survey) and Charles A. Beichman (The Search for Young Planetary Systems
and the Evolution of Young Stars).
For more, go here.
| High-flying balloon captures mystery
(Nov. 24, 2000)
Researchers from the Indian Space Research Organization (ISRO), Cardiff
University and the University of Wales College of Medicine claim that
a previously unidentified bacterium caught in the filter of an ISRO
balloon may have come from a passing comet. The microbe was captured
at a height of 16 kilometers. But the astrobiology community will
need to see a lot more evidence before it seriously entertains the
claim, particularly as its chief advocate is Chandra Wickramasinghe
who, along with Fred Hoyle,
has long championed the highly controversial idea of microbes arriving
on Earth from space. Commented Wickramasinghe: "[the bacterium] is
so different from anything we've seen before that there are only two
possible explanations." The first, he explained, is that "organisms
have been lifted from the Earth to great heights in the skies and
have somehow multiplied there and changed over time." The second is
"that this is an example of primitive alien life."
Further signs of liquid water on Mars
(Nov. 21, 2000)
New images from Mars Global
Surveyor, obtained on November 10, show more gullies on the Martian
surface that may have been carved by water. The latest pictures reveal
channels on the slopes of some large sand dunes inside the 136-kilometre-wide
Hale crater in the planet's southern hemisphere. They add to a growing
body of evidence gleaned by MGS which suggests that water could exist
in a porous layer of rock buried just below the Martian surface. Winter
in the Martian southern hemisphere begins in mid-December. Over the
next few months, NASA scientists will examine closely new pictures
of the planet in an attempt to bolster their evidence.
New phylum of animal discovered
(Nov. 20, 2000)
Researchers from the universities of Copenhagen and Aarhus, in Denmark,
claim (in Journal of Morphology) to have found a completely
new kind of animal living on algae in a well in Greenland. The 0.1-millimeter
long freshwater organism does not fit into any previously known family
of animals. Named Limnognathia maerski, it shares some characteristics
with certain seawater creatures. However, its discoverers have tentatively
assigned it to a new phylum called Micrognathozoa. Its most remarkable
feature is a set of very complicated jaws that it uses to scrape the
bacteria and algae that it feeds on from underwater moss which freeze
over during the long Arctic winter. L. maerski reproduces through
parthenogenesis. The animal was discovered in 1994 in samples taken
from Isunngua on Disco Island in northwestern Greenland. Now, an entire
colony of females lives in a refrigerator at Copenhagen University.
For more, go here.
(Nov. 15, 2000)
Scientists have long puzzled how the first replicating molecule came
about on Earth. A popular theory is that there was a time, before
DNA and proteins existed,
when primitive life was based on RNA
– a molecule that can serve both as a genetic material and a
catalyst for its own formation. However, RNA itself is so complex
that it's hard to see how it could have been the first replicator.
Now, an international team of biochemists has produced new nucleotides
that can be joined to form a double helix and can be cross-paired
with RNA or DNA strands. The new units, alpha-threofuranosyl nucleotides,
are simpler than those of RNA or DNA, and so, in theory, could have
been manufactured more easily in the prebiological regime. This leads
the team to speculate that there may have been an era before the RNA
World when TNA - threofuranosyl nucleic acid – formed the basis
Reference: K.-U. Schöning, P.
Scholz, S. Guntha, X. Wu, R. Krishnamurthy, A. Eschenmoser, "Chemical
Etiology of Nucleic Acid Structure: The [alpha]-Threofuranosyl-(3'->2')
Oligonucleotide System," Science, 290: 1347-1351 (2000).
| Organic matter in Leonid meteors
(Nov. 15, 2000)
Researchers of the NASA and U.S. Air Force-sponsored Leonid Multi-Instrument
Aircraft Campaign report the astrobiological significance of their
observations of last year' s Leonid
meteor storm in this weeks's special issue of Earth, Moon and
Planets. Their findings have implications for the existence and
survival of life's precursors in comet material that reaches Earth.
Said Peter Jenniskens of Ames Research Center and principal investigator
for the airborne research mission: "Findings to date indicate that
the chemical precursors to life – found in comet dust
may well have survived a plunge into early Earth's atmosphere." Jenniskens
and his colleagues think that much of the organic matter in comet
dust may survive entry into Earth' s atmospheric entry. "Organic molecules
in the meteoroid didn' t seem to burn up," he explained. Another way
in which organic matter can survive the plunge into Earth's atmosphere
was discovered by a team from the Aerospace Corporation, Los Angeles,
who detected the fingerprint of complex organic matter, identical
to space-borne cometary dust, in the path of a bright Leonid fireball.
This "fingerprint" is still under investigation to ensure that trace-air
compounds are not contributing to the detection. Another finding with
potentially important implications for astrobiology is that meteors
are not as hot as researchers had previously believed. "We discovered
that most of the visible light of meteors comes from a warm wake just
behind the meteor, not from the hot meteoroid's head," said Jenniskens.
This wake has just the right temperature for the creation of life'
s chemical precursors, he said. Utah State University researchers
found that, during the meteors' demise in the atmosphere, their rapid
spinning caused small fragments to be ejected in all directions, quite
far from the meteoroid's head. This is an important finding for astrobiology,
because it means that meteors may be able to chemically alter large
amounts of atmosphere.
For more, go here.
Bacteria found thriving in snow at the
(Nov. 9, 2000)
Microbiologist Ed Carpenter of the State University of New York in
Stony Brook and his colleagues have found up to 5,000 bacteria per
millilitre of melted snow from the South Pole. Tests have shown that
the microbes can grow and divide even at -17°C – the coldest
condition the team tested. "Probably they could live at even lower
temperatures," says Carpenter. Bacteria have been found in snow near
the Pole before, but they were thought to have blown in accidentally.
It wasn't believed they could grow in the harsh conditions there,
where temperatures range between -85° and -13°C. DNA tests
have shown that all the organisms belong to previously unknown species.
Their closest relatives are the Deinococcus, well known for
their extremely efficient DNA repair mechanisms. It was not known
why the Deinococcus evolved such high protection, since nowhere on
Earth is ultraviolet radiation strong enough to damage DNA so badly.
However, severe dehydration can harm DNA as much as UV radiation does
– and the Antarctic is a very dry place. This new discovery
adds to the suspicion that life could exist in other environments
previously thought too harsh, such as the polar ice caps on Mars,
the researchers say. The research is described in Applied and Environmental
Microbiology, 66(10): 4514-4517, 2000.
For more, go here
(pre-publication BBC report) and here
(New Scientist report).
Evidence of recent volcanic activity on
(Nov. 3, 2000)
Observations by the Mars Global
Surveyor have been interpreted by astronomers as evidence of vulcanism
on the Red Planet within the past 10 million years or so. Mars has
a number of giant volcanoes, including Olympus
Mons (pictured here) – the largest volcano in the solar
system. Planetary astronomers believe that images sent back by MGS
show molten lavas to the south of Elysium Mons in the fairly recent
past, suggesting that Mars may still be volcanically active. This
has important climatological, and possibly biological, implications.
If some of the Martian volcanoes are still capable of erupting it's
possible that Mars may periodically go through cycles of warming due
to the increased greenhouse effect of released gases, including carbon
dioxide. Such periods could provide a more clement environment for
any vestigial life that remains dormant on the planet today.
For more, go here
Are there planets in globular clusters?
(Nov. 2, 2000)
A survey of 35,000 stars in the globular cluster 47
Tucanae has failed to find traces of planets. The work, to be
reported in Astrophysical Letters in December, involved using
the Hubble Space Telescope to look for tell-tale dips in brightness
due to transits by planets orbiting around them. However, the null
result is not surprising and certainly doesn't mean that globular
clusters are devoid of planets. The survey was only capable of detecting
"hot Jupiters" – large gas giants in tiny, circular orbits –
like those discovered around some Sun-like stars in the solar neighborhood
(and even then the orbit of the planet would have to be virtually
edge-on to our line of sight to enable a transit). These are not the
kind of planets you would expect to find in a globular cluster where
there is a deficiency of heavy elements needed for building planetary
cores. Where the metal content of a star (and by implication the material
available for planet-building) is low, the planets that form around
it are likely to be smaller than those we see in the solar system.
We are only likely to find globular cluster planets – assuming
any exist – when we have the capability to search them for small
gas giants or terrestrial-type worlds. There's the further complication
that we're not even sure of the status of many of the known extrasolar
For more, go here.
For earlier coverage of this story, go here.
BACK TO TOP
> Space & Science news
> November 2000
Other news sections
Latest science news
Living world news
Also on this site:
Encyclopedia of Science
Encyclopedia of Alternative Energy
and Sustainable Living