PLEASE NOTE:
*
CCNet, 6 September 1999
-----------------------
(1) COLLISION COURSE TO EXTINCTION
THE TIMES HIGHER EDUCATION SUPPLEMENT, 3
September 1999
(2) AUSTRALIAN TELESCOPE TO SEARCH FOR NEAR-EARTH ASTEROIDS
Robert Clements <Robert.Clements@dva.gov.au>
(3) AUSTRALIAN OBSERVATORY DEVISES NEW PROGRAMME TO NEAR-EARTH
OBJECTS
Robert Clements <Robert.Clements@dva.gov.au>
(4) NEW PROGRAM ALLOWS INCREASED USE OF U.S. AIR FORCE
TELESCOPE
Ron Baalke <baalke@ssd.jpl.nasa.gov>
(5) EARLIEST ECOSYSTEM RETRIEVED FROM WEST AUSTRALIAN OUTBACK
Andrew Yee <ayee@nova.astro.utoronto.ca>
==============
(1) COLLISION COURSE TO EXTINCTION
From THE TIMES HIGHER EDUCATION SUPPLEMENT, 3 September 1999
An asteroid colliding with Earth could wipe out humanity. Alison
Goddard
reports on research to curb the threat
In 1908, an asteroid exploded above the Tunguska area of Siberia
with
the energy of about 1,000 Hiroshima bombs. If it had hit central
London,
everything within the M25 would have been destroyed. Now
astronomers are
warning that such an event is likely to happen once every
century.
Governments are not noted for acting on long-term risks. But
science
minister Lord Sainsbury recently annouced the creation of a task
force
to assess the threat of an asteroid hitting the Earth. "The
government
has realised there is a problem to be addressed," says Mark
Bailey,
director of the Armagh Observatory and a member of Spaceguard UK,
which
campaigns about the dangers posed by asteroids.
The Health and Safety Executive has developed what it calls the
national
scutiny line, which measures risks in terms of fatalities. If a
British
nuclear power station lay above this line, it would be closed. By
the
same measure, asteroid impacts are also unacceptably dangerous.
Nuclear risk assessor Nigel Holloway of AWE Aldermaston explains:
"The
risk of asteroid impact is about as likely as the accident at the
Chernobyl nuclear power station. We estimate that an accident
like
Chernobyl could happen every few hundred years, and that it would
cause
between 1,000 and 10,000 premature deaths. A large asteroid could
hit
the Earth once every 100,000 to a million years, and at least ten
million people would die in the United Kingdom alone."
The risk posed by an asteroid crashing into Earth is unique.
"First, the
risk to civilisation is mass extinction; secondly, the risk is
predictable, years or decades in advance; and thirdly, it is
avoidable.
The means exist to mitigate the threat, provided we have enough
warning.
These features highlight the urgency of developing a global
spaceguard
programme," says Bailey.
In the United States, work has already begun on identifying large
asteroids. The project, run by the Massachussetts Institute of
Technology, is funded by the US Air Force. Using a telescope
based at
the White Sands Missile Range in Socorro, New Mexico, astronomers
are
searching for asteroids one kilometre across and bigger - the
size that,
according to asteroid theory, wiped out the dionosaurs.
A European research project should look for smaller asteroids
hundred
metres across, Bailey believes. A 1.5-metre telescope in the
southern
hemisphere, sweeping the entire sky, would cost about £1 million
a year
to build an run, he says. Perhaps in three or four years' time it
could
be upgraded to a four-metre wide field telescope costing about
£20
million.
Benny Peiser, a social anthropologist at Liverpool John Moores
University, has studied the consequences of past asteroid
impacts. "For
objects 100 metres across, the environmental effects would be
regional
but the social and political impact would be much worse: people
would be
very scared. The likelihood of such an object hitting the Earth
in our
lifetime is great. There is little we can do about it, except
make the
public aware that they might have to deal with such an
event."
No one has ever destroyed an asteroid, but Bailey says there is a
range
of measures that could be taken. "For example, if an
asteroid 300 metres
across hit the Atlantic, it would create a huge tidal wave. If we
removed the population from coastal areas, it would save millions
of
lives."
There are several proposals for how to avoid asteroid impact,
ranging
from firing nuclear weapons at asteroids to mining them. "We
have
evolved to the extent that mankind has the technology to take
hold of
its future; we are not entirely in the hands of nature,"
says Peiser.
Bailey comments: "There are proposals on paper but we would
need to
develop them. It is a bit like putting a man on the Moon, which
took ten
years. And the earlier we start the survey, the more notice we
will have
of potential disaster."
GOODBY TO ALL THAT CIVILISATION
Benny Peiser believes that asteroid impacts could account for the
collapse of ancient civilisations. It is possible that the
virtually
simultaneous collapse of the first urban civilisations in the
world in
about 2300 BC and a second devastation some 1,000 years later
were
caused by the impact of cosmic debris, he says.
"Scholars who favour earthquakes as the principal cause of
civilisation
collapse argue that the world can expect vast earthquakes every
1,000 to
2,000 years. Scholar who prefer climate change as the principal
cause
argue that severe droughts caused agriculture to fail and that
societies
inexorably fell apart as a result. Yet what was the cause of
these
earthquakes, tidal waves, fire-blasts and climate chances?
"The extent to which past impacts were responsible for
civilisation
collapse, cultural change and even the development of religion
must
remain a hypothesis. But in view of the astronomical, geological
and
archaeological evidence, the hypothesis should not be dismissed
out of
hand."
WHAT IS THIS THING CALLED ASTEROID?
One of the problems with any plan to deflect or destroy an
asteroid on a
collision course with earth is that astronomers do not know
whether
asteroids are rubble or monolithic. Several space missions are
now
trying to learn more about what asteroids are made of.
Last month, a spacecraft called Deep Space 1 took photos of the
near-earth asteroid 1992 KD from six miles away. During the
fly-by, it
took pictures and measured the asteroid's composition, size,
shape,
surface features and brightness.
The first spacecraft to study an asteroid close up was an
American
mission called Galileo. In 1991, it passed the asteroid 951
Gaspra at a
distance of 1,000 miles. Gaspra is believed to be composed of a
mixture
of rocky and metallic minerals. Two years later, Galileo crossed
paths
with asteroid 234 Ida at a distance of 1,500 miles. Ida, an
irregular,
cratered object, has a tiny moon, about 1,5 kilometres across.
The American space agency Nasa's NEAR mission will be the first
spacecraft to orbit an asteroid when it arrives at 433 Eros in
February
2000. It will orbit Eros for at least a year, determining its
mass,
structure, geology, composition, gravity and magnetic field. Eros
is the
largest of the near-Earth asteroids.
Meanwhile, Japan is planning to take samples from an asteroid and
return
them to Earth, on a mission in collaboration with Nasa. Launching
in
2002, MUSES-CN will arrive at asteroid 4660 Nerus in April 2003.
The
spacecraft will also drop a rover onto the surface of the
asteroid,
where it will take high-resolution close-up images of the
surface.
Copyright 1999, THES
==============
(2) AUSTRALIAN TELESCOPE TO SEARCH FOR NEAR-EARTH ASTEROIDS
From Robert Clements <Robert.Clements@dva.gov.au>
The following taken from a kind of email newspaper sent out free
by the
(Australian) ABC (the equivalent of your Beeb, if you've never
been down
under); & is FW FYI....
All the best,
Robert Clements
ABC News
Monday September 6, 1999
NSW telescope to search the skies for earth-killers
A little-used telescope in the west of New South Wales is about
to
get a revamp so it can spot and track earth-threatening
asteroids.
Over the next two years, the telescope at Siding Spring near
Coonabarabran will be equipped with sensors and software to help
the world search for large moving objects in space.
The refurbishment is a collaboration between astronomers at the
Australian National University in Canberra and the University of
Arizona.
The facility will have the job of searching the entire southern
sky
as well as tracking the path of objects which are discovered in
northern hemisphere surveys.
Copyright 1999, ABC
============
(3) AUSTRALIAN OBSERVATORY DEVISES NEW PROGRAMME TO NEAR-EARTH
OBJECTS
From Robert Clements <Robert.Clements@dva.gov.au>
No sooner had i sent the first para then i caught up with last
Thursday's email news. Intriguing to see two items so close
together - esp. in the
light of last week's Lateline piece mentioned on CCNet - cause
& effect?
All the best,
Robert Clements
ABC News
Thursday September 2, 1999
*Observatory devises new program to monitor space objects*
There is concern that three years after the Australian Government
axed a program to detect near earth objects, there is still no
comparable project in the southern hemisphere.
Many research scientists and astronomers agree it is inevitable
that the earth will be hit by a major asteroid and it is just a
matter of when.
Government astronomer James Biggs says the Perth Observatory is
devising a program to monitor objects that have already been
detected.
Dr Biggs says it is hoped that within six months the observatory
will be able to track up to 40 positions a night.
But he says it is important that a detection system be set up to
avert potential disasters.
"No one has been actually known to die from a collision from
outer
space, but the reason is it's a very low probability event, but a
very high consequence if a one kilometre asteroid hits the
earth,"
Dr Biggs said.
"It's going to be a major catastrophe, it will dwarf any of
the
earthquakes and what have you that we've experienced of
late."
Copyright 1999, ABC
=============
(4) NEW PROGRAM ALLOWS INCREASED USE OF U.S. AIR FORCE
TELESCOPE
From Ron Baalke <baalke@ssd.jpl.nasa.gov>
New Program Allows Increased Use Of U.S. Air Force Telescope
University Of U.S. Air Force News Release
September 3, 1999
MAUI, Hawaii - Civilian scientists and astronomers will be given
the
opportunity to use the Air Force's largest and most advanced
telescope
system under a new joint program announced this week during a
five-day
technical conference being held here.
Dr. Joseph Janni, director of the Air Force Office of Scientific
Research, spoke to an audience of more than 300 people about a
research program being established by his office and the National
Science Foundation. The program will allow civilian researchers
to use a 3.67-meter telescope known as the Advanced
Electro-Optical
System atop nearby Haleakala, a 10,000-foot-high mountain.
According to Dr. Janni, the Air Force Office of Scientific
Research
is making $1 million available per year over two years for
civilian
researchers doing work on Maui. The amount being contributed by
the
National Science Foundation has not been finalized.
Working through grants and contracts, researchers will have
access to
this 3.67-meter telescope, recognized as the world's largest
telescope
capable of tracking satellites passing quickly overhead. The
telescope
can be used by multiple groups or institutions because the
telescope's
light can be routed through mirrors to seven independent
experimental
suites on a level beneath the telescope.
Although this large telescope is managed by the Air Force
Research
Laboratory's Directed Energy Directorate, the overall facility is
known as the Maui Space Surveillance System and is under the
control
of the U.S. Space Command. The complex, which also houses other
telescopes, is part of a space surveillance network for
identifying
and pinpointing objects in space.
Additionally, the Advanced Electro-Optical System is being
equipped
with sophisticated instrumentation: lasers and deformable optics
(a mirror that can change its shape) to remove the distorting
effects
of the atmosphere. When fully operational next summer, this
capability
allows scientists to get clear images of objects in space.
According to Maj. Gen. Richard Paul, commander of the Air Force
Research Laboratory which includes the Directed Energy
Directorate
and the Office of Aerospace Research, "This is a win-win
situation
for both the Air Force and the research community. The research
being conducted with these telescopes can lead to improvements in
our space surveillance efforts while providing the researchers
with
access to a new topnotch telescope facility."
Among the capabilities on the complex there are sensors that can
provide radiometry and photometry, plus long-wave infrared and
visible imagery. There are also a 1.6-meter telescope system,
1.2-meter
twin telescopes, a 0.8-meter beam director-tracker, and a
0.6-meter
laser beam director. With more than 6,000 people and a budget of
nearly $2.8 billion, the Air Force Research Laboratory is the
largest
laboratory in the Department of Defense. Its Air Force Office of
Scientific Research is the sole manager of basic research for the
United States Air Force.
Institutions interested in using the complex can call Dr. Herb
Carlson with the Air Force Office of Scientific Research in
Arlington, Va, at (703) 696-7551 or Paul Kervin with the
laboratory's
Directed Energy Directorate in Maui, Hawaii, at (808) 874-1541.
===========
(5) EARLIEST ECOSYSTEM RETRIEVED FROM WEST AUSTRALIAN OUTBACK
From Andrew Yee <ayee@nova.astro.utoronto.ca>
Department of Minerals and Energy
East Perth, Western Australia
Evidence of earliest ecosystems retrieved from West Australian
outback
MEDIA CONTACT: James Bowie, (08) 9222 3527 or 0417 923 297
2 September, 1999
Fossil evidence of what is believed to be the world's earliest
ecosystems has been found and retrieved from the Western
Australian
outback and was today handed over to the Western Australian
Museum
for safekeeping.
The structures, which look like egg cartons, represent a small
area of
exceptionally well-preserved fossil stromatolites (structures
built by
microbes) that existed around 3.46 billion years ago.
The stromatolites probably existed in a volcanic environment at a
time
when the red and dusty Pilbara looked more like the hot-spring
environment of the North American Yellowstone National Park.
The fossilised stromatolites were recently scrutinised by a group
of
international experts in palaeobiology and associates of the NASA
Astrobiology Institute which joined an excursion arranged by the
Department of Minerals and Energy to study the structures.
Director of the Department's Geological Survey Division, Dr David
Blight, said the focus stemmed from an article published in last
month's
Geological Society of America Bulletin claiming that the fossils
provide
the best evidence so far discovered of early ecosystems on Earth
The scientific paper was jointly written by University of
Montreal's
Professor Hans Hofmann, Dr Kath Grey and Dr Arthur Hickman of the
Department's Geological Survey and Dr Ralph Thorpe of the
Geological
Survey of Canada.
Professor Hofmann said that most of the scientists and
palaeontologists
accompanying the excursion agreed that the highly complex shapes
of the
structures were the result of biogenic activity, but they would
carry
out further tests to try and establish the nature of the
structures
beyond all reasonable doubt.
"Unfortunately, studying the fossils wasn't the only
motivating factor
behind the expedition," co-author Dr Grey said.
Dr Grey said it was necessary to remove the slab containing the
fossils
from their bush setting because the ancient stromatolites would
surely
have become one of the 'hottest' items on the international
fossil black
market.
"As these stromatolites were located in a remote area they
could not be
kept under surveillance and would be easy pickings for an
unscrupulous
fossil dealer," she said.
"Once the article was published we knew that people would be
able to
narrow down the location of the fossils so we decided the best
option
was to carefully remove the stromatolites to guarantee their
preservation."
Dr Grey pointed out that the theft this decade of 360
million-year old
fossil fish remains and fossilised dinosaur footprints near
Broome
highlighted the need to protect the State's fossils.
She also said that the intrinsic value of the fossils was
demonstrated
by the interest that NASA was showing in studying ancient
stromatolites.
"Stromatolites are of great interest to the new field of
exobiology and
are being used by NASA as a model for its search for fossilised
life on
Mars," Dr Grey said.
"Studying early forms of life on Earth could provide the
clues needed
for the next Mars Lander mission, which sets out in 2003, to find
evidence that life once existed on the Red Planet."
The fossil locality was initially discovered by a former Director
of the
Department's Geological Survey Division, Alec Trendall. He
visited the
area in 1984 with Doctors Hickman and Thorpe searching for rocks
suitable for isotopic dating.
However, it was not until 1997, when the site was investigated in
more
detail by Professor Hofmann (who was financially supported by the
Natural Sciences and Engineering Research Council of Canada) and
Dr
Grey, that the patch of well-preserved fossils was discovered
beneath an
overlying rock.
The fossils were handed over to the Western Australian Museum by
Dr
David Blight and are now on display at the Museum's Discovery
Centre.
A website based on the story of the stromatolites and print
quality
photographs of their removal can be viewed at
www.dme.wa.gov.au/ancientfossils
Background of the fossil recovery mission
The new stromatolite locality was originally discovered in 1984
in
Western Australia's Pilbara, by Dr Alec Trendall, former Director
of the
Geological Survey Division (GSD) of the Department of Minerals
and
Energy in Western Australia.
Dr Kath Grey visited the outcrop later that year, but unable to
find the
exact site, was not convinced that the structures she saw were
fossils
and consequently, interest in the outcrop declined.
The stromatolite site was visited again by Drs Trendall and
Hickman,
together with Dr Ralph Thorpe from the Geological Survey of
Canada, in
1990, when photographs were taken of one metre high conical
stromatolites embedded in the rock surfaces.
Dr Thorpe later showed these photographs to Professor Hans
Hofmann of
the University of Montreal and a few samples of the conical
structures
were made into thin sections.
The photos and material convinced Prof. Hofmann that the
structures
might be biogenic.
Between 1992 and 1995 several papers were published questioning
the
biogenicity of previously discovered 3.4 billion year old
'fossils' from
the Pilbara and the whole question of early Archaean
stromatolites was
thrown into doubt.
Prof. Hofmann recognised that the Trendall locality, as the area
became
known, would be significant in resolving the controversy about
the
biogenicity of early Archaean stromatolites and referred to the
conical
structures in a draft publication reviewing the oldest known
fossils.
This led to extended discussions between Prof. Hofmann and Dr
Grey,
until a new GSD mapping program in the area finally provided an
opportunity in 1997 for both of them to examine the structures in
the
field, accompanied by Dr Hickman.
Once at the outcrop, it didn't take long for Drs Hofmann[1] and
Grey to
agree that the cones (missed by Dr Grey in 1984) were probably
biogenic,
or for them to discover other complex structures associated with
the
cones.
While working in the area, the three scientists noticed a tiny
patch of
well-formed cones poking out beneath an overlying rock. Upon
removal
of the overlying slab, the 'egg-carton' surface (a series of
small cones
preserved three dimensionally) was revealed.
Field study was followed by laboratory examination carried out by
Professor Hofmann at the University of Montreal, culminating in
the
publication, in August 1999, of a scientific paper (authored by
Hofmann,
Grey, Hickman and Thorpe) describing the find.
The Trendall locality is of particular significance because of
the
exceptional preservation and because it exhibits complex shapes
consistent with biologic activity at beginning of the fossil
record.
The structures are of great interest to the new field of
exobiology
(life on other planets), because NASA's Mars Lander will search
for
similar structures as part of its mission to the red planet,
leaving
Earth in 2003, to look for evidence of life on other worlds.
After assessing the risk of losing the fossils through theft or
erosion
if they were left at the locality and mindful that the structures
needed
to be studied in context, GSD decided to organise an excursion
for
specialists so they could examine the structures before they were
removed.
The 1999 visitors (including five associates of NASA's
Astrobiology
Institute) reacted in much the same way as Drs Grey, Hofmann and
Hickman
towards the coniform structures.
Most agree that the evidence for biogenicity is very strong based
on the
shape of the fossils, however, they will now try to find other
evidence
(such as chemical signatures) that support the claim that the
structures
were built by living organisms.
Because these structures are so significant and because removing
them
from the locality to protect them was a contentious scientific
decision,
GSD invited the ABC television science program Quantum to
document the
removal of the slab to the Western Australian Museum for
safekeeping.
Footnote:
[1] Prof. Hofmann was funded by the Natural Sciences and
Engineering
Research Council of Canada
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