PLEASE NOTE:
*
CCNet 60/2002 - 17 May 2002
---------------------------
"Not everyone finds Bland's work convincing. "I don't
believe it,"
says cratering expert Christian Koeberl (University of Vienna).
Koeberl
says the glassy melt found within the depressions is,
isotopically,
"practically identical" to the surrounding soil, and
its age (as
determined by two different methods) is only 4,000 years - a far
cry from a
half million. Moreover, Schultz says he's now found four
meteorites in
the Rio Cuarto craters, and they're all the same class of
chondritic
stone."
--J. Kelly Beatty, Sky & Telescope, 14 May 2002
"Peter McGauran is optimistic to the point of ignoring the
fossil
record. You don't see many dinosaurs living or voting in
Austrialia? Why
not? Because they took Mr McGauran's view. The chances of an
other impact
which could wipe out, say, 70% of life on earth, are 100%. If the
Austrialian Government knows better, they need to get into
fortune-telling,
BIG TIME."
--Lembit Opik, MP, The Guardian online, 14 May 2002
"While the latest Star Wars sci-fi saga makes its way to a
cinema
near you, a true-to-life space drama is unfolding as a new breed
of
weaponry may soon populate the heavens. Military planners paint a
picture of inevitability concerning space weapons. Certain
experts foresee
a proliferation of anti-satellites and space mines. Others
suggest urgent
need for totally secure, jam-proof satellite links along with a
squadron of quick-reaction space bombers."
--Leonard David, Space.com, 15 May 2002
(1) DID BLAND RUSH TO CONCLUSIONS? CONTROVERSY BREWING OVER RIO
CUARTO
CRATERS
Sky & Telescope, 14 May 2002
(2) "IMPROBABILITY" OF OBLIQUE-ANGLE IMPACTS
Duncan Steel <D.I.Steel@salford.ac.uk>
(3) COSMIC IMPACTS IMPLICATED IN BOTH THE RISE AND FALL OF
DINOSAURS
Andrew Yee <ayee@nova.astro.utoronto.ca>
(4) ASCENT OF DINOSAURS LINKED TO AN IRIDIUM ANOMALY AT THE
TRIASSIC-JURASSIC BOUNDARY
Science, 17 May 2002
(5) ASTEROID IMPACT TIED TO RISE OF DINOSAURS
Space.com, 16 May 2002
(6) ASTEROID LET DINOSAURS RULE
Andrew Yee <ayee@nova.astro.utoronto.ca>
(7) 11 MORE MOONS FOUND AROUND JUPITER
CNN, 16 May 2002
(8) MERCURY METEORITE PUZZLE
BBC News Online, 16 May 2002
(9) SPACE WEAPONS FOR EARTH WARS
Space.com, 15 May 2002
(10) MICROSATELLITE CONSTELLATION TO WATCH OVER DISASTERS FORGES
AHEAD
Space Daily, 15 May 2002
(11) IMPACT ODDS
Michael Paine <mpaine@tpgi.com.au>
(12) YOU DON'T SEE MANY DINOSAURS VOTING IN AUSTRALIA, DO YOU?
The Guardian on-line, 14 May 2002
(13) AND FINALLY: SPACE INDUSTRY FACES A GRAYING WORKFORCE
Denver Post, 15 May 2002
==================
(1) DID BLAND RUSH TO CONCLUSIONS? CONTROVERSY BREWING OVER RIO
CUARTO
CRATERS
>From Sky & Telescope, 14 May 2002
http://skyandtelescope.com/news/current/article_602_1.asp
By J. Kelly Beatty
May 14, 2002 | A controversy is brewing over the origin of
several unusual
depressions in the Pampean plain of northern Argentina. For the
last decade
planetary scientists have considered a cluster of large,
elongated pits near
Rio Cuarto to be unique impact craters, gouged by a chunk of
asteroid that
glanced obliquely through the atmosphere and broke into pieces
just before
striking the Earth.
The idea for such an impact swarm arose in 1991, when an
expedition led by
Peter Schultz (Brown University) and Argentine air-force pilot
Ruben Lianza
discovered samples of fused soil and even intact meteorites
within the
teardrop-shaped depressions. Subsequent laboratory work suggested
that the
Rio Cuarto event must have occurred within the past several
thousand years.
The impact hypothesis recently received its most serious
challenge from a
team led by Phil A. Bland (Open University, London). In the May
10th issue
of Science, they detail a pair of meteorites found within the
putative
craters that not only have different makeups but also appear to
have arrived
on Earth 36,000 and 52,000 years ago - far longer than the age of
the
depressions in which they were found. Bland's team also contends
that the
strange depressions, up to 4½ kilometers long and 1 km wide,
look much like
hundreds of other smaller features scattered throughout the
region - a
situation far too unlikely to be caused by a single collisional
event.
This would suggest that the Rio Cuarto craters are not craters at
all but
rather long hollows carved and shaped over thousands of years by
prevailing
winds. In the process, the gradual removal of material exhumed
meteorites
that had fallen to Earth long ago. "I'd love them to be
low-angle impacts,"
Bland told Sky & Telescope, "but I just don't think the
evidence is there."
But what of the fused-glass nuggets found by Schultz and Lianza?
Bland says
more of these have turned up at a site 400 km farther south,
which suggests
to him that they all came from a much bigger impact about 480,000
years ago.
Such a catastrophic event would have splashed glassy droplets
(known as
tektites) over a very wide area and left behind a crater roughly
5 km
across, which presumably lies hidden beneath the Pampas or
offshore in the
Atlantic. As terrifying as the oblique impacts might have been,
observes H.
Jay Melosh in the same issue of Science, "[Bland's] view of
a shower of hot
glass over a region as large as Texas suggests a far more lethal
event half
a million years ago."
Not everyone finds Bland's work convincing. "I don't believe
it," says
cratering expert Christian Koeberl (University of Vienna).
Koeberl says the
glassy melt found within the depressions is, isotopically,
"practically
identical" to the surrounding soil, and its age (as
determined by two
different methods) is only 4,000 years - a far cry from a half
million.
Moreover, Schultz says he's now found four meteorites in the Rio
Cuarto
craters, and they're all the same class of chondritic stone.
Resolving the origin of these controversial features may take
years of
careful field work and laboaratory analyses. Schultz contends,
for example,
that the Rio Cuarto craters have charateristics unlike those of
the region's
wind-deflation structures. But Bland counters, "I don't know
what criteria
he's basing that on. We couldn't detect any differences."
Copyright 2002, Sky & Telescope
===================
(2) "IMPROBABILITY" OF OBLIQUE-ANGLE IMPACTS
>From Duncan Steel <D.I.Steel@salford.ac.uk>
Dear Benny,
Regarding the report on the Rio Cuarto structures carried in
CCNet today, I
am a little puzzled as to why people think that oblique-angle
impacts are
"improbable." While they are not the majority of cases,
they are not as
unlikely as one might imagine.
The distribution of impact angles for cosmic impacts varies as
[sin theta
cos theta], where theta is the elevation angle above the
horizontal. This
happens to be the angular distribution both before and after
gravitational
focussing (meteor watchers will be familiar with the concept of
"zenith
attraction", this being the same thing, with the
zenith angle being [90 deg
- theta]). This is also be the distribution of impact angles on
the solid
Earth (or oceans), provided that the atmosphere does not cause
any
significant deceleration of the impactor; this will be the case
for
impactors in the size range under consideration here.
The most likely impact angle is therefore 45 degrees (forget all
those
pictures with asteroids descending vertically). An impact
elevation angle of
7 degrees was mentioned in the discussion of the Rio Cuarto
structures; an
impact at precisely this angle occurs with about one-quarter the
likelihood
of the most-probable angle of 45 degrees (i.e. [sin theta cos
theta] is 0.5
if theta=45 deg, and 0.121 if theta=7 deg).
The item did state, though, that the impact angle would have been
"less than
7 degrees." Integrating the distribution over all angles
below 7 degrees and
normalising against the complete range of impact angles (0 to 90
degrees)
one finds a 1.5% probability of such an oblique impact angle
(i.e. one in
67). That's a small value, but not wildly unlikely.
Regards,
Duncan Steel
===============
(3) COSMIC IMPACTS IMPLICATED IN BOTH THE RISE AND FALL OF
DINOSAURS
>From Andrew Yee <ayee@nova.astro.utoronto.ca>
Media Relations
Rutgers
Contact:
Bill Haduch, 732/932-7084, extension 633
E-mail: bhaduch@ur.rutgers.edu
May 16, 2002
Cosmic impacts implicated in both the rise and fall of dinosaurs
NEW BRUNSWICK/PISCATAWAY, N.J. -- New abilities to detect layers
of "space
dust" in the earth's crust are building geological evidence
that comets or
asteroids colliding with earth not only helped wipe out the
dinosaurs, but
may have originally helped bring them to prominence about 200
million years
ago.
Dennis V. Kent, Rutgers geology professor, was among a team of
geologists
who analyzed footprints, bones and plant spores in more than 70
locations in
eastern North America, as well as iridium dust and magnetic
fields in four
corresponding sediment layers in the Newark Basin. The team
published its
findings, "Ascent of Dinosaurs Linked to an Iridium Anomaly
at the
Triassic-Jurassic Boundary," in the May 17 edition of the
journal Science.
"Finding the element iridium, which is common in space
objects, creates a
time marker for comet or asteroid impacts." said Kent.
"Correlating the
finds with evidence of plant and animal life helps to tell us
what
happened."
Using high-resolution spectrometry technology provided by
Christian Koeberl
of the University of Vienna in Austria, the scientists were able
to make
unprecedented comparisons of iridium levels in the
parts-per-trillion range.
Kent said another important find was a thin zone in the sediment,
just below
the Triassic-Jurassic boundary, where the magnetic field is
reversed. This
reverse zone can now serve as a marker to help identify the
boundary
location in the geological record.
"Our research adds to the speculation that there was a comet
or asteroid
impact about 200 million years ago, followed relatively quickly
by the
rising dominance of dinosaur populations of the
Jurassic period," said Kent. He suggested that the effects
of the impact
killed off or reduced many competitive species, clearing the way
for
dinosaurs to adapt and flourish.
"Dinosaurs went on to dominate for the next 135 million
years," he said,
noting that their extinction is now commonly attributed to the
ecological
effects of yet another comet or asteroid impact -- this one about
65 million
years ago.
Besides his work at Rutgers, Kent is associated with the
Lamont-Doherty
Earth Observatory of Columbia University, as are his co-authors
E.C.
Rainforth and P.E. Olsen. Olsen's earlier research about
Triassic-Jurassic
transitions inspired the project. Other co-authors include
Koeberl and H.
Huber of the University of Vienna, H.-D. Sues of the Royal
Ontario Museum,
A. Montanari of the Osservatorio Geologio do Coldigiocom in
Italy, S.J.
Fowell of the University of Alaska-Fairbanks, and M.J. Szajna and
B.W.
Hartline, fossil collectors of Reading, Pa.
EDITOR'S NOTE: Professor Kent may be contacted by phone at (732)
445-2044 or
by e-mail at dvk@rci.rutgers.edu
.
=============
(4) ASCENT OF DINOSAURS LINKED TO AN IRIDIUM ANOMALY AT THE
TRIASSIC-JURASSIC BOUNDARY
>From Science, 17 May 2002
http://www.sciencemag.org/cgi/content/abstract/296/5571/1305
(login required)
P. E. Olsen, D. V. Kent, H.-D. Sues, C. Koeberl, H. Huber, A.
Montanari, E.
C. Rainforth, S. J. Fowell, M. J. Szajna, B. W. Hartline
Analysis of tetrapod footprints and skeletal material from more
than 70
localities in eastern North America shows that large
theropod dinosaurs
appeared less than 10,000 years after the Triassic-Jurassic
boundary and
less than 30,000 years after the last Triassic taxa, synchronous
with a terrestrial mass extinction. This extraordinary turnover
is
associated with an iridium anomaly (up to 285 parts per trillion,
with an
average maximum of 141 parts per trillion) and a fern spore
spike,
suggesting that a bolide impact was the cause. Eastern North
American
dinosaurian diversity reached a stable maximum less than 100,000
years after
the boundary, marking the establishment of dinosaur-dominated
communities
that prevailed for the next 135 million years.
Volume 296, Number 5571, Issue of 17 May 2002, pp. 1305-1307.
Copyright © 2002 by The American Association for the Advancement
of
Science. All rights reserved.
================
(5) ASTEROID IMPACT TIED TO RISE OF DINOSAURS
>From Space.com, 16 May 2002
http://www.space.com/scienceastronomy/planetearth/jersey_dinosaurs_020516-1.html
By Robert Roy Britt
Senior Science Writer
The history of dinosaurs and asteroids became further entwined
today with
the announcement that an impact from a space rock 200 million
years ago may
have eliminated some competition and helped the giant reptiles
flourish and
eventually dominate the planet.
Scientists have long suspected that an asteroid led to the demise
of
dinosaurs' 65 million years ago. Research last year suggested
that an
earlier impact 251 million years ago might have allowed dinosaurs
to evolve
in the first place.
Now a new study of more than 70 sites in North America finds
evidence that
the well-documented mass extinction 200 million years ago was
also caused
when an asteroid or possibly a comet hit Earth. Within 100,000
years of the
event -- an evolutionary eyeblink -- dinosaurs radiated and
multiplied
swiftly, reaching their historical maximum diversity in the
region.
They went on to dominate the planet for 135 million years.
The findings are based on footprints, bones, fern spores, and the
discovery
of elevated levels of iridium -- a rare element on Earth but one
common
among space objects. The results help build a sometimes
controversial case
that in the grand scheme of terrestrial time, space rocks
frequently snuff
out entire species while simultaneously breathing fresh life into
the
evolutionary process.
The results, which need to be validated by further research, will
be
published in the May 17 issue of the journal Science.
Rocky times
Researchers have thought for more than a decade, and with growing
certainty,
that an impact played a critical role in the ultimate death of
dinosaurs.
Other species perished, too, in an event that allowed mammals to
prosper in
a world where there were fewer large creatures to step on them or
swallow
them whole.
However only in recent years has evidence turned up linking
earlier mass
extinctions to impacts.
The new research documents a widespread die-off that occurred at
the
boundary of the Triassic and Jurassic periods in time, when
dinosaurs had
begun to gain a foothold in what is now North America. The study
found
iridium in layers of rock in Earth's crust at several sites that
have been
traced back to the same point in time.
The element is prevalent in asteroids and comets and can be left
behind as a
global signature when an incoming object vaporizes on impact and
kicks up a
dust storm that circles the planet.
Though there is no evidence of a crater, the iridium
"creates a time marker
for comet or asteroid impacts," said Dennis V. Kent, a
Rutgers University
geologist and part of the research team. "Correlating the
finds with
evidence of plant and animal life helps to tell us what
happened."
Paul E. Olsen of the Lamont-Doherty Earth Observatory of Columbia
University
led the study.
Asteroid or volcanism?
An asteroid could certainly do the trick, experts say, creating
years of
winter-like conditions caused by tons of dust that blots out the
Sun.
Yet, other researchers have speculated that the extinction 200
million years
ago was instead a result of increased volcanic activity, which
would have
pumped choking chemicals into the atmosphere. Some experts say a
combination
of an impact and increased volcanism might provide a one-two
punch necessary
to cause extinctions of many species.
Either way, the case is not firm.
"Considerably more geochemistry is needed to rule out a
volcanic origin,"
Olsen told SPACE.com. "And much more sampling over a broader
temporal and
geographic range is needed to confirm that what we found is
really a global
event tied to an impact."
Olsen said, however, that the team found iridium at levels two
and three
times higher than normal "background" levels found in
sedimentary rock. This
anomaly, or difference in levels, is not as high as has been
documented for
the so-called K-T impact that occurred 65 million years ago (and
for which a
crater exists).
"The magnitude of our anomaly is small compared with that at
the K-T
boundary, but it is similar to anomalies at other known
impacts," Olsen
said.
The iridium spike was found to be coincident with a spike in fern
spores,
thought to be a signal of recovery from an impact.
Paul Sereno, the noted dinosaur hunter from the University of
Chicago, said
the study provides "critical new data on the origins and
early evolution of
dinosaurs that support a sharp break in the fossil record between
the early
and rarer dinosaurs of the Triassic period, and the larger
dominant
dinosaurs of the early Jurassic."
The number and extent of the Triassic-Jurassic extinctions have
been much
debated.
"Which is why this well-dated, well-supported find of
iridium and a fern
pollen spike in association with footprints is such key new
information,"
Sereno told SPACE.com. "Doubtless it will spark new research
into the
question of how and when dinosaurs rose to dominance on land -- a
question
that may ultimately become as resolved as the events at the end
to the
dinosaur era."
Other possible impacts
A study last June, also reported in Science, found
extraterrestrial gases
trapped inside special molecules, known as fullerenes, in rock
layers
corresponding to an earlier and greater mass extinction, which
occurred 251
million years ago. This event wiped out 75 percent of all species
and was
likely a first step in allowing dinosaurs to enter the scene.
One of the researchers involved with that study, Robert Poreda of
the
University of Rochester, said the newer results need to be
interpreted with
caution.
"Iridium can be an important tracer for studying impacts,
but in some ways
the overwhelming signal observed at the K-T site has caused some
to view it
as a sort of 'key' signal," Poreda said. "At two to
three times the
background signal [as in Olsen's study] the case can be made for
a
non-impact scenario."
The elevated iridium, Poreda said, might reflect changes in
sedimentation or
accumulation rates where no impact occurred. He said several
indicators need
to coincide, from iridium results to fullerenes, shocked quartz
structures
and more.
Nevertheless, Poreda said the new research "represents one
of the first
steps" in showing that the Triassic-Jurassic extinction was
caused by a
space rock. His own feeling, he said, is that a few years of
study will show
that to be the case.
How it was done
The new iridium study used a special technique called iridium
coincidence
spectrometry, which finds the element based on the ejection of
two gamma-ray
particles per atom after they have been irradiated in a nuclear
reactor, to
make fine comparisons of iridium in the sediment layer compared
to older and
newer layers.
Christian Koeberl of the University of Vienna performed the work.
Earlier attempts to find an iridium "spike" in the
Triassic-Jurassic
boundary did not succeed because the spectrometry equipment was
not
sensitive enough, the researchers said.
The work is painstaking. Earth was an entirely different place
200 million
years ago, with all the continents crowded into a single land
mass called
Pangea. Researchers must first locate exposed sedimentary layers,
which may
have been folded under and back out to the surface over the eons,
and then
properly date and sample them.
Much of the evidence was collected in what are now parts of New
Jersey and
Pennsylvania, along with other archeological sites dotting the
eastern
United States.
Copyright 2002, Space.com
===============
(6) ASTEROID LET DINOSAURS RULE
>From Andrew Yee <ayee@nova.astro.utoronto.ca>
[ http://www.nature.com/nsu/020513/020513-11.html
]
Friday, 17 May 2002
Asteroid let dinosaurs rule
Impact may have caused mass extinction that let hardy giants
thrive
By HELEN PEARSON
A huge asteroid smashing into Earth may have let dinosaurs take
over the
Earth 135 million years before another one wiped them out, a
controversial
new study suggests.
Dinosaurs flourished in the wake of a mass extinction 200 million
years ago.
But no one is sure what made so many plants and animals
disappear.
"The simplest scenario is that a very large asteroid struck
our planet,"
says Paul Olsen of Columbia University in New York. Olsen's
international
research team have new evidence that an earlier impact could be
to blame.
Levels of the metal iridium -- which doesn't occur naturally on
Earth and
only arrives on extraterrestrial objects -- shoot up in rocks
from the time
when many species died out. Simultaneously, spores of ferns, the
first
plants to colonize devastated areas, also rise
dramatically [1].
Similar evidence from sites worldwide supports the final
extinction of
dinosaurs by an impact 65 million years ago. Olsen has
investigated only one
site, the Newark rift basin in eastern North America.
Until more evidence is accumulated, some palaeontologists remain
cautious.
"I tend not to believe it yet," says palaeontologist
Mike Benton of the
University of Bristol. If people find iridium and spores in other
places
around the world, "it will become more convincing", he
says.
Before and after
Around 200 million years ago, large plant-eating dinosaurs grazed
the Earth
alongside primitive meat-eaters as large as ostriches. After the
mysterious
event that marked the Triassic-Jurassic boundary, herbivores
dwindled and
large carnivores flourished. The precursors to Tyrannosaurus rex
were born.
Any explanation for the boundary has to explain why some animals
lived when
so many others perished. Olsen thinks that only the hardiest
creatures would
have survived the extreme conditions following an asteroid
strike. Dust
clouds masking the Sun would have plunged the Earth into cold
gloom,
followed by intense warming as clouds of greenhouse gases built
up.
Warm-blooded dinosaurs that could withstand the cold or those
that scavenged
many food types would have fared best, Olsen suggests.
Big feet
An alternative explanation is that massive eruptions of volcanic
lava, whose
ancient remnants have been found, could have caused the mass
extinction. For
example, gases pumped out with the lava could have cooled the
Earth and
gradual climate change killed off certain species.
Olsen admits he cannot rule this out. But his team does offer
additional
evidence that the mass extinction at the Triassic- Jurassic
boundary was
sudden and extreme. This is more consistent
with the impact hypothesis.
Olsen and his colleagues sifted through sedimentary rocks in
several sites
in the Newark basin for dinosaur and reptile footprints to find
out which
animals wandered around when. Previous timing for the extinction
was based
on sparse fossil finds from around the world.
In lakes that were rapidly filling with sediment, a thick layer
of rock was
laid down in a short period of time. This means that more precise
times can
be pinned on the disappearance and reappearance of animals. Rocks
are dated
on the basis of the types of pollen they contain.
Half of the animal footprints vanish within as little as 50,000
years, the
researchers found, while dinosaur footprints suddenly appear that
are up to
a fifth larger than before. This time period "is
instantaneous on the
geological timescale", says geologist Walter Alvarez of the
University of
California at Berkeley.
Alvarez agrees that the weight of evidence now points to an
impact as the
likely cause of this extinction -- and possibly others too. The
rise and
demise of dinosaurs are only two of five massive extinctions in
world
history. "It becomes more likely that they could be impacts
too," says
Alvarez.
References
[1] Olsen, P. E. et al. Ascent of dinosaurs linked to iridium
anomaly at the Triassic-Jurassic boundary.
Science, 296,
1305 - 1307, (2002).
© Nature News Service / Macmillan Magazines Ltd 2002
===============
(7) 11 MORE MOONS FOUND AROUND JUPITER
>From CNN, 16 May 2002
http://www.cnn.com/2002/TECH/space/05/16/jupiter.moons/index.html
By Richard Stenger
CNN
(CNN) -- Eleven more satellites have been found orbiting Jupiter,
raising
the total of its identified moons to 39, the most for any planet
in the
solar system, astronomers announced Thursday.
The discovery continues an unprecedented series of satellite
sightings. Last
year, the same group of researchers spotted 10 more moons around
Jupiter.
In recent years, the official tally of moons in the solar system
has more
than doubled. Saturn previously held the title of moon king with
30 known
satellites, a dozen of which scientists first identified in 2000.
The latest satellites to be identified hardly resemble Jupiter's
better-known Galilean moons, the planet-sized Io, Europa,
Ganymede and
Callisto.
They are much smaller, with estimated diameters between 1.2 and
2.4 miles (2
and 4 kilometers). They are much farther out, roughly 12 million
miles (20
million kilometers) from Jupiter.
And they travel in highly eccentric orbits in a retrograde
fashion, that is,
opposite the direction that Jupiter rotates.
Jupiter could have captured the moons during its infancy, the
University of
Hawaii-led research team speculated.
One theory holds that the planet's atmosphere slowed passing
asteroids
enough to keep them around for good. Another suggests that the
young Jupiter
grew so rapidly it trapped nearby objects.
"Both processes would have operated in the first million
years of the solar
system," they said in an announcement.
The moons travel in clusters and are likely pieces of larger
objects that
shattered, possibly in collisions with passing comets, the
researchers said.
The new satellites were first spotted with the
Canada-France-Hawaii
telescope atop Mauna Kea, a dormant volcano on the island of
Hawaii. A
University of Hawaii observatory was used to verify their orbital
paths.
Copyright 2002, CNN
==========
(8) MERCURY METEORITE PUZZLE
>From BBC News Online, 16 May 2002
http://news.bbc.co.uk/hi/english/sci/tech/newsid_1991000/1991394.stm
By Dr David Whitehouse
BBC News Online science editor
The first meteorite that may have come from Mercury has been
identified.
NWA 011 was found in the Moroccan Sahara in December 1999 and was
immediately regarded as something unusual.
It clearly had a molten past and was formed from lighter
materials than most
meteorites. This implied it had once been part of a much larger
body.
It was originally classified as a eucrite, a group of meteorites
thought to
be from the asteroid Vesta. But a detailed analysis of NWA 011
showed it to
be different.
Now, researchers speculate that it is the first known meteorite
from our
Solar System's innermost planet, Mercury.
Rocks blasted off Mercury by a large impactor would have a
difficult journey
to reach the Earth, say the researchers - but not impossible.
Nevertheless,
the calculations show such rocks would be an extremely rare find
on Earth.
NWA 011 has an oxygen isotope ratio that indicates it came from a
body
larger than a big asteroid.
Japanese researchers say the basalt in NWA 011 suggests the body
from which
it did originate had a core of molten iron with an outer covering
of silicon
and aluminium that formed a basaltic crust.
And that means a planet-sized body. Could it really be Mercury?
Copyright 2002, BBC
============
(9) SPACE WEAPONS FOR EARTH WARS
>From Space.com, 15 May 2002
http://www.space.com/businesstechnology/technology/space_war_020515-1.html
By Leonard David
Senior Space Writer
While the latest Star Wars sci-fi saga makes its way to a cinema
near you, a
true-to-life space drama is unfolding as a new breed of weaponry
may soon
populate the heavens.
Military planners paint a picture of inevitability concerning
space weapons.
Certain experts foresee a proliferation of anti-satellites and
space mines.
Others suggest urgent need for totally secure, jam-proof
satellite links
along with a squadron of quick-reaction space bombers.
Perhaps more "out there", but openly discussed by
military space
strategists, are orbiting laser and particle beam weapons that
focus killer
rays of energy to zap satellites, enemy warheads in flight, or
even blast
targets on Earth.
Then there are the thunder rods. Tossed down from orbit, these
long and
slender kinetic-energy devices use their own mass and very high
velocity to
create a destructive effect.
Lastly, for those looking for a celestial "big whopper"
of a weapon, how
about using natural meteoroids? Good-sized fireballs of metal
could be sent
to Earth, aimed at targets of choice. These impactors leave a
nice crater.
Better yet, they leave no radioactive debris.
Space-based weapons are the topic of a new report: Space Weapons
- Earth
Wars. Authored by think-tank experts at RAND -- dedicated to help
improve
policy and decisionmaking through research and analysis -- the
just released
study was prepared for the U.S. Air Force.
What's possible and sensible?
Space weapons have been hotly debated for decades. At present,
the Bush
administration's interest in ballistic missile defense has
brought the
question of their use once again to the forefront.
The RAND study does not argue for or against space weapons said
Bob Preston
who led the effort. Rather, the intent was to sort through
realities and
myths surrounding space weapons.
"We wanted to provide an objective basis for grounding
discussion in
physical realities and historical context," Preston told
SPACE.com. His
observation after finishing the task is that the subject of
weapons in space
"is both highly polarized with people violently for and
against the idea,"
he said.
Furthermore, those opposing views are complicated by imprecision
in
definition, "and by rather loose understanding of what's
possible and what's
sensible," Preston added.
Arguably, just about all use of space from the beginning has been
about
national security, Preston said.
"Even civilian scientific uses were undertaken in large part
for security
reasons in the context of the Cold War. There's a pretty good
point of view
that says that almost everything we've ever done in space has
been
predominately motivated by a security perspective," the RAND
analyst said.
Classic classes
RAND reviewed several distinct classes of weapons:
Directed-energy weapons, such as space lasers. They use millions
of
watts of power and large optics to deliver a speed-of-light
knockout punch
as a missile arcs over Earth. Depending on the wavelength of the
energy
beamed out and atmospheric conditions, an energy beam can destroy
a target
on Earth's surface;
Kinetic-energy weapons against missile targets. This hardware can
ram headlong into a target in space or an object still within the
upper
reaches of Earth's atmosphere;
Space-based kinetic energy weapons that slam into targets on the
ground, such as large ships, tall buildings, and fuel tanks.
Sleek and
meteoroid-like in speed, these weapons attack targets at steep,
nearly
vertical trajectories; and
Space-based conventional weapons capable of maneuvering to hit
terrestrial targets. These can carry and dispense rather exotic
packages of
destruction, such as radio-frequency or high-power-microwave
munitions.
Pros and cons
Taken together, RAND analysts found space weapons having a number
of
distinct advantages and disadvantages.
In the advantage column, space weapons can take out targets that
may be
inaccessible to other weapons. While ships and aircraft can take
days to
weeks to reach a far-flung battleground, space-based weapons can
respond in
minutes to several hours. Also, space-based weapons are less
vulnerable to
attack.
On the other hand, there are shortcomings.
For one, an opponent can saturate a space weapon, overwhelming
the weapon's
ability to fully thwart an attack. In addition, the positions of
space-based
weapons are predictable. In this regard, a weapon destroyed on
orbit would
leave a persistent cloud of debris, posing a hazard to other
satellites.
Lastly, large numbers of weapons are required to ensure that one
of them is
in the right place at the right time.
Asteroid weapons
Even the notion of purposely diverting an asteroid toward Earth
as a weapon
was examined by RAND specialists. "For nations that already
have nuclear
arsenals, asteroid weapons might be of only academic
interest," the study
notes.
There is no doubt, the study explains, that asteroids have acted
as big
bruisers in the past. The Earth has the scars to prove the point.
However,
to use asteroids as natural bombs, the scale of the undertaking
would be
grander than that required to build the first A-bomb via the
Manhattan
Project in World War II, the RAND report points out.
"Aside from the limited range of possible effects and the
great uncertainty
about the precision of an effect, one clear argument against
asteroids as
weapons is that smaller, cheaper means of acquiring an equivalent
to a
nuclear deterrent are available," the study explains.
Asteroids as a space weapon of mass destruction "is likely
to remain safely
in the realm of science fiction."
Waiting game
RAND's Preston emphasized that the opportunity to acquire space
weapons is
not limited to the United States. While many countries have only
modest
spacefaring capabilities, each nation knows how space can benefit
their
security.
"There's probably nobody that's involved in space that
doesn't understand
its security uses and isn't motivated to some degree by its
security uses,"
Preston said. Space-based weapons could be a high-leverage,
asymmetric
response to U.S. military strengths, he said.
In the report's summary, there is this observation:
"Before deciding to acquire or forgo space weapons for
terrestrial conflict,
the United States should fully discuss what such weapons can do,
what they
will cost, and the likely consequences of acquiring them. The
discussion
should also address whether other countries might acquire them,
which ones
would be most likely to do so, and how the United States could
discern these
developments and respond effectively."
For Preston, a personal view is that it's not obvious now there's
urgent
need for the United States to defend itself in space from things
in space.
"But it's not unreasonable to expect that you may have to
before long," he
said.
Peacetime uses
The prospect of space weapons and the growing military space
agenda
engenders a wide variety of viewpoints.
Such is the case for America's first woman in Earth orbit, Sally
Ride. She
recently underscored the fact that space has been used for
military purposes
for decades. (Ride is the former president of SPACE.com.)
Last month, Ride presented the annual Drell Lecture at Stanford
University,
sponsored by the on-campus Center for International Security and
Cooperation
(CISAC). After her NASA tour-of-duty, Ride worked in the late
1980s as a
CISAC science fellow, serving alongside Sidney Drell, noted
physicist and
arms control expert.
"Space is a real priority for national security," Ride
said. She is
presently a physics professor at the University of California-San
Diego and
director of the University of California's Space Institute in La
Jolla.
Today, U.S. intelligence agencies and the military count on some
100
satellites as part of the country's national security. These
space-based
assets snap detailed images day and night, keeping an eye on
global
hotspots, even pinpointing missile launchings around the globe
for early
warning purposes. A satellite that in peacetime uses the global
positioning
system (GPS) constellation of spacecraft for navigation purposes,
may in
wartime utilize that same capability to target bombs or remotely
piloted
vehicles, Ride said.
"The current landscape is that the United States has an
absolutely huge
advantage over every other country in space capabilities,"
Ride said. "It's
hard getting to space. It's hard developing things that work in
space, and
it's really, really hard to get things to work reliably over long
periods of
time in space," she added.
Ante up: Anti-satellites
The policy question going forward, Ride explained, might be
simplistically
stated as: Does it make sense for the U.S. to place weapons into
space? One
issue in this regard, she said, is developing and placing in
space
anti-satellite weapons, or ASATs for short.
Unless appropriate constraints are put on testing of ASATs, there
could be a
problem, Ride suggested. High-speed run-ins with space debris
resulting from
any ASAT testing could cripple or destroy numbers of satellites
in Earth
orbit.
Ride recalled an encounter with space debris on her first space
shuttle
voyage. A small but visible gouge in one of the space plane's
window
appeared about halfway through the flight. Later analysis showed
that an
orbiting fleck of paint caused the pit, she said.
"A fleck of paint is not the same as a small piece of metal
traveling at
that same speed. So, as soon as you start increasing the amount
of junk in
low-Earth orbit, you have an unintended byproduct that starts
putting some
of your own quite valuable satellites at possible risk,"
Ride stressed
Preserve by prohibiting
One lawmaker is already pitching legislation before the U.S.
Congress that
bans the weaponization of space. Congressman Dennis Kucinich, a
Democrat
from Cleveland, Ohio, introduced early this year The Space
Preservation Act
of 2002.
The bill is crafted "to preserve the cooperative, peaceful
uses of space for
the benefit of all humankind by prohibiting the basing of weapons
in space
and the use of weapons to destroy or damage objects in space that
are in
orbit, and for other purposes."
In bill language, the terms "space-based weapon" and
"space-based system"
mean a device capable of damaging or destroying an object or
person --
whether in outer space, in atmosphere, or on Earth -- by (A)
firing one or
more projectiles to collide with that object or person; (B)
detonating one
or more explosive devices in close proximity to that object or
person; (C)
directing a source of energy against that object or person; or
(D) any other
undeveloped means.
Kucinich is shopping the bill through the halls of Congress
trying to gain
support for the legislation, which also calls for an
international treaty to
preserve space and prevent an arms race in outer space.
Complicated distinction
Prying out differences between weaponization and militarization
of space is
not easy.
"It's an important distinction," said Bruce Gagnon,
head of the Global
Network Against Weapons & Nuclear Power in Space in
Gainesville, Florida.
"Weaponization I think is clear. Our position is no weapons
in space, at any
level, period. Militarization is more complicated," he told
SPACE.com.
Gagnon took part in last week's 10th Annual International Space
Organizing
Conference and Protest, held at the University of California in
Berkeley.
During the gathering of peace movement leaders from 12 nations,
various
strategies were discussed to block the nuclear arms race from
ascending into
the heavens.
"While we accept some aspects of the militarization of space
for treaty
verification, confidence building measures, etc., we are firmly
against
military space technologies that are used for conventional war
fighting,"
Gagnon said. "Satellite systems that identify and direct war
on Earth, which
essentially allow for 'full spectrum dominance' are not
acceptable in our
view," he said.
"We want a de-escalation of all military systems for
fighting war on Earth
or in space. We'd like to see the stabilizing, treaty verifying
satellite
technologies commonly shared globally. And, of course, no nuclear
power in
space for any reason," Gagnon concluded.
Copyright 2002, Space.com
===============
(10) MICROSATELLITE CONSTELLATION TO WATCH OVER DISASTERS FORGES
AHEAD
>From Space Daily, 15 May 2002
http://www.spacedaily.com/news/microsat-02h.html
Guildford - May 15, 2002
In a remarkable example of international collaboration in space,
seven
organisations from Africa, Asia and Europe have formed a
consortium and
agreed to contribute microsatellites into the first dedicated
Disaster
Monitoring Constellation (DMC). The DMC will comprise seven Earth
observation microsatellites launched into low Earth orbit to
provide daily
imaging revisit anywhere in the world.
The DMC Consortium comprises a partnership between organisations
in Algeria,
China, Nigeria, Thailand, Turkey, Vietnam and the United Kingdom.
Each
organisation is building an advanced yet low-cost Earth
observation
microsatellite to form the first ever constellation specifically
designed
and dedicated to monitoring natural and man-made disasters. The
first DMC
microsatellite is scheduled to be launched for Algeria in
September 2002 and
subsequent microsatellites into the same orbit in 2003 &
2004.
The objective of the Consortium is to derive the maximum mutual
benefit from
the constellation through collaboration and cooperation between
the DMC
Partners. The partners in the DMC Consortium agreed to exchange
their DMC
satellite resources and data to achieve a daily Earth observation
imaging
capability for disaster monitoring and other dynamic phenomena.
The second meeting of the DMC partners was held during 22-23
April 2002. The
meeting was hosted by Centre National des Techniques Spatiales in
Algiers,
and was formally opened by Algeria's Secretary-General of Higher
Education
and Scientific Research and attended by the UN Office for Outer
Space
Affairs.
The DMC partner organisations are: Centre National Techniques
Spatiales (Algeria)
Ministry of Science & Technology (PR China)
National Space Research & Development Agency (Nigeria)
TUBITAK-ODTU (Turkey)
Mahanakorn University of Technology, Bangkok (Thailand)
National Centre for Science & Technology (Vietnam)
British National Space Centre (UK)
Surrey Satellite Technology Ltd (UK)
The DMC will enable the monitoring of any rapidly-changing
phenomena by
providing daily revisit multispectral imaging worldwide at
resolutions from
32-metres multispectral down to 4-metres panchromatic. Current
Earth
observation satellites offer only infrequent image revisits and
the delivery
of critical information may take months due to periodic cloud
cover and
tasking conflicts. Images of disaster-stricken areas are often
made
available too late to be of real use to relief co-ordination
agencies on the
ground. The processed images from the DMC will be distributed to
relief
teams by the Reuters AlterNet Foundation. The Reuters Foundation
launched
AlertNet in 1997 to help the work of relief professionals around
the world.
Each year natural and man-made disasters around the world cause
devastation,
loss of life, widespread human suffering and huge economic
losses. The DMC
will provide a service that will greatly aid the response,
management and
mitigation of disasters whenever, and wherever, they occur The
DMC is an
international project proposed and led by SSTL at the Surrey
Space Centre,
which has developed highly capable microsatellites that provide
high quality
multispectral imaging at a small fraction of the cost of a
conventional
satellite, thus making the constellation and this humanitarian
service both
practicable and affordable.
Six of the seven microsatellites for the DMC are being
constructed at SSTL
in the UK. The first satellite of the constellation, AlSAT-1 for
Algeria,
has been manufactured and is currently undergoing tests in
preparation for a
planned launch in September 2002. Construction of BILSAT-1
(Turkey) is also
underway at SSTL, along with the UK-DMC microsatellite funded
through the
BNSC.
NigeriaSat-1 will commence assembly in May. The satellites for
Algeria,
Turkey and Nigeria are being built under a Know-How Transfer and
Training
(KHTT) programme at Surrey. The seventh microsatellite
(Thai-Paht2) is being
built at the Mahanakorn University of Technology (MUT) in
Bangkok, Thailand.
This follows MUT's successful KHTT programme with Surrey and the
launch of
their first microsatellite (Thai-Paht-1) in 1998. The Chinese and
Vietnamese
satellites are in the final stages of contract negotiation with
SSTL and
both are planned to be built at Surrey
Copyright 2002, Space Daily
============================
* LETTERS TO THE MODERATOR *
============================
(11) IMPACT ODDS
>From Michael Paine <mpaine@tpgi.com.au>
Dear Benny
Andy Smith points out that the odds of Tunguska type impact are
about 1 in
100 in the next year. The chances are however that it would
happen over
ocean or uninhabited land. Based on the one million simulation
that I
carried out early in 2000, there is roughly a 1 in 300 chance
each
year of an impact that causes more than 100 fatalities (see table
below).
The royal flush comparison refers to a major hit by an asteroid
perhaps
1.5km across (OK 1 mile) that would cause severe global climate
disruption
and perhaps a billion fatalities, mostly from crop failures.
Somewhere between the two are events that would cause global
trauma through
the loss of a "significant" city or region, as raised
by Jens Kieffer-Olsen in the same
CCNet posting. I have reanalysed my one million year simulation
to estimate
the frequency of fatal events of certain magnitudes. The results
are set out
below. Note that program was run in 10,000 year
increments so it seriously underestimates the number of smaller
events.
The results, however, a still quite sobering:
FATALITIES COUNT P(ANNUAL) RISK
>0 3708 0.003708 1 in 269
>100 3221 0.003221 1 in 310
>1000 2800 0.002800 1 in 357
>10,000 1705 0.001705 1 in 586
>100,000 621 0.000621 1 in 1610
>1 Million 180 0.000180 1 in 5555
>10 Million 65 0.000065 1 in 15384
>100 million11 0.000011 1 in 90909
I would expect an event causing 1 million or more fatalities
would be quite
traumatic for our society, irrespective of where it hit. The
annual risk is
1 in 5555 - that's the same as drawing four of a kind in poker!
I have added a new graph to my simulation web page at
http://www4.tpg.com.au/users/tps-seti/sta1046.htm#fatal_freq
On a slightly related matter, in the Budget speech tonight the
Australian
Treasurer said the government would be spending at least AU$500
million
(~200m pounds) "protecting" Australia's borders from
asylum seekers (a few
hundred boat people in dire circumstances). Now that's what I
call a
"fruitless, unnecessary, self-indulgent exercise", to
use the words of our
notorious Science Minister (although "self-indulgent"
could be replaced with
"selfish").
regards
Michael Paine
==============
(12) YOU DON'T SEE MANY DINOSAURS VOTING IN AUSTRALIA, DO YOU?
from the Guardian on-line chat:
http://talk.guardian.co.uk/WebX?50@@.eecb40c
simonreesX - 04:12pm May 13, 2002: What would you say to
Australian science
minister Peter McGauran who describes the search for near earth
asteroids as
a "fruitless, unnecessary, self-indulgent exercise.".
http://www.space.com/scienceastronomy/solarsystem/asteroids_australia_020319
.html. This means most of the effort going into tracking near
earth
asteroids only covers the northern skies. A smaller impact would
only have
regional effects (which is Australia's own problem) but a larger
asteroid would affect
everyone one earth. Should there be an internationally funded
effort to track near earth
asteroids through for example the United Nations rather than
relying on national
contributions as at present?
Reply by Lembit Opik - 02:51pm May 14, 2002
Peter McGauran is optimistic to the point of ignoring the fossil
record. You
don't see many dinosaurs living or voting in Austrialia? Why not?
Because
they took Mr McGauran's view. The chances of an other impact
which could
wipe out, say, 70% of life on earth, are 100%. If the Austrialian
Government
knows better, they need to get into fortune-telling, BIG TIME.
===========
(13) AND FINALLY: SPACE INDUSTRY FACES A GRAYING WORKFORCE
>From Denver Post, 15 May 2002
http://www.denverpost.com/Stories/0,1918,36%257E53%257E612208%257E,00.html
Space industry faces a graying workforce
Aerospace careers not inspiring youth
By Bill McAllister
Denver Post Washington Bureau
Wednesday, May 15, 2002 - WASHINGTON - The people who put
Americans on the
moon and challenged the Soviet Union in space are retiring,
creating a void
that few youngsters seem eager to fill, a national commission was
told
Tuesday.
To many American youths, space no longer spells a glamorous
future, and that
raises the specter of a serious shortage of scientists to create
the next
generation of space vehicles, experts told the Commission on the
Future of
the U.S. Aerospace Industry.
The panel, charged with recommending how to bolster a depressed
and
overbuilt space industry, heard bold suggestions of what the
federal
government ought to make its priorities in space. Land on
asteroids, explore
Mars and build much faster spacecraft, some urged.
All those grand ideas could go begging for a lack of scientists,
several
experts said.
What makes the problem urgent, said Sean O'Keefe, administrator
of the
National Aeronautics and Space Administration, is the
"extremely mature
workforce" in his agency and private industry. "Almost
one-third of NASA's
workforce will be eligible to retire within the next three to
five years,"
he said.
In the 1960s, President Kennedy ignited the American public's
imagination
about space. Four decades later, even Gen. Ralph E.
"Ed" Eberhart, commander
of the U.S. Space Command in Colorado Springs, conceded:
"Somehow we've lost
that excitement."
Elliot G. Pulham, president the Colorado-based Space Foundation,
said few
students seem interested in the industry. "A generation
raised with the
expectation that humans should "boldly go where no one has
gone before' is
bored with the same old airplanes, same old rockets, the same old
low-Earth-orbit stuff," he said.
The space shuttle was orbiting Earth before today's college
students were
born, he said. "And they've seen nothing new from NASA or
industry in their
lifetime."
Pulham, whose nonprofit foundation promotes the space industry,
also warned
that industry employers may be too selective in their hiring.
"As long as
conservative government contracting teams prefer to hire
gray-bearded,
pin-striped, brown-shoed baby boomers instead of blue-haired,
tattooed,
nose-ringed youth of Generation X, the same old conservative
ideas will
prevail and the space and aerospace workforce will continue to
age," he
said.
The commission, whose report to President Bush and Congress is
due in
November, did not indicate what it would recommend.
In addition to the concerns about a lack of new scientists, the
panel got a
dose of practical advice from Sen. Bill Nelson, D-Fla. The
senator, a former
astronaut, said NASA needs more than the "pitiful" $15
billion a year the
Bush administration has budgeted for space.
He called on the commission to urge the Pentagon's space spending
be merged
with NASA's budget for various projects that are supposed to
follow the
space shuttle program.
A number of other experts agreed that space spending must
increase. "You
cannot build a first-class space program on the cheap," said
Tidal McCoy,
chairman of the Space Transportation Association.
Eberhart, who was recently nominated to head the new U.S.
Northern Command
for homeland security, was perhaps the most optimistic of those
who spoke to
the commission. "The last century was the century of
flight," he said. "This
century will be the century of space. It's incumbent on us that
we write
that history."
Copyright 2002, Denver Post
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