PLEASE NOTE:


*

CCNet, 31/2000 - 13 March 2000
------------------------------


     POEM OF THE DAY

     An old night-ravager,
     that one which, burning,
     seeks a burial mound,
     the smooth dragon of malice
     who flies by night
     encompassed in fire,
     found the hoard
     standing open.
     Earth dwellers fear him much. [...]
                              
     The beginning was fearful
     to people in the land,
     as was the ending:
     death for their king.
     The fiend spouted fire,
     burned bright houses--
     the glow of fire stood out,
     a horror to the people.
     That terrible sky-flier
     wished to leave
     nothing alive.

     Near and far was seen
     the dragon's violence,
     how that destroyer
     hated and humbled the Geat
     people. The people of the land
     were enveloped in fire. [...]

     Beowulf learned the terror
     quickly, in truth:
     the surging fires
     burned his house,
     the mead hall of the Geats. [...]
     The flame-dragon had burned
     the fortress of the people.
     The war-king studied revenge.

         -- from BEOWULF
           (Anglo-Saxon epic, ~8th century AD)


(1) IMPACT EFFECTS COULD BE WORSE THAN PREDICTED
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(2) ANTARCTIC SEA ICE SCRUBS CO2 DURING GLACIAL PERIODS
    SpaceDaily, 13 March 200

(3) METEORIC BOMBARDMENT AND BIOLOGICAL EVOLUTION
    Andrew Glikson <geospectral@spirit.com.au>

(4) 1998 KY26 NOT FASTEST-SPINNING ASTEROID
    Daniel Fischer <dfischer@astro.uni-bonn.de>

(5) LARGE ROCKETS FOR PLANETARY DEFENSE
    Michael Paine <mpaine@tpgi.com.au>

(6) BEOWULF, OR MOVING HEAVEN AND EARTH
    Bev M Ewen-Smith <coaa@mail.telepac.pt>

(7) VOLCANOES & GLOBAL COOLING
    Joel Gunn <jdgunn3@mindspring.com>

(8) AND, FINALLY: TECHNO-SCARE OF THE DAY
    INTELLIGENT ROBOTS MAY SOON WIPE OUT HUMANS
    Washington Post, 12 March 2000


=========================
(1) IMPACT EFFECTS COULD BE WORSE THAN PREDICTED

From Andrew Yee <ayee@nova.astro.utoronto.ca>

Oregon State University

SOURCES:
Andrew Blaustein, 541-737-5356
Charles Cockell, (international) 44-1223-221560

03-09-00

Asteroid devastation could even be worse than feared
By David Stauth, 541-737-0787

CORVALLIS, Ore. -- Researchers say in a new report that if a huge
asteroid were to hit the Earth, the catastrophic destruction it
causes, and even the "impact winter" that follows, might only be a
prelude to a different, but very deadly phase that starts later on.

They're calling it, "ultraviolet spring."

In an analysis of the secondary ecological repercussions of a major
asteroid impact, scientists from Oregon State University and the
British Antarctic Survey have outlined some of the residual effects
of ozone depletion, acid rain and increased levels of harmful
ultraviolet radiation. The results were just published in the journal
Ecology Letters.

The findings are frightening. As a number of popular movies have
illustrated in recent years, a big asteroid or comet impact would in
fact produce enormous devastation, huge tidal waves, and a global
dust cloud that would block the sun and choke the planet in icy,
winter-like conditions for months. Many experts believe such
conditions existed on Earth following an impact around the
Cretaceous-Tertiary, or K-T boundary, when there was a massive
extinction of many animals, including the dinosaurs.

That's pretty bad. But according to Andrew Blaustein, a professor of
zoology at Oregon State University, there's more to the story.

"Scientists have pretty well documented the immediate destruction of
an asteroid impact and even the impact winter which its dust cloud
would create," Blaustein said. "But our study suggests that's just
the beginning of the ecological disaster, not the end of it."

Blaustein and colleague Charles Cockell examined an asteroid impact
of a magnitude similar to the one that occurred around the K-T
boundary, which is believed to have hit off the Yucatan Peninsula
with a force of almost one trillion megatons.

The immediate results would be catastrophic destruction and an impact
winter, with widespread death of plants and the large terrestrial
animals -- including humans -- that most directly depend on those
plants for food. That's the beginning of an ugly scenario, the
researchers say.

As a result of the impact, the atmosphere would become loaded with
nitric oxide, causing massive amounts of acid rain. As they become
acidified, the lakes and rivers would have reduced amounts of
dissolved organic carbons, which would allow much greater penetration
of ultraviolet light.

At first, of course, the ultraviolet rays would be blocked by the
dust cloud, which sets the stage for a greater disaster later on.
Many animals depend on some exposure to ultraviolet light to keep
operational their biological protective mechanisms against it --
without any such light, those protective mechanisms would be eroded
or lost.

During the extended winter, animals across the biological spectrum
would become weaker, starved and more vulnerable. Many would die.
Then comes ultraviolet spring, shining down on surviving plants and
animals that have lost their resistance to ultraviolet radiation and
penetrating more deeply, with greater intensity, into shallow waters
than it ever has before.

"By our calculations, the dust cloud would shield the Earth from
ultraviolet light for an extended period, with it taking about 390
days after impact before enough dust settled that there would be an
ultraviolet level equal to before the impact. After that, the ozone
depletion would cause levels of ultraviolet radiation to at least
double, about 600 days after impact."

According to their study, these factors would lead to
ultraviolet-related DNA damage about 1,000 times higher than normal,
and general ultraviolet damage to plants about 500 times higher than
normal. Ultraviolet radiation can cause mutations, cancer, and
cataracts. It can kill plants or slow their growth, suppressing the
photosynthesis which forms the base of the world's food chain.

Smaller asteroid impacts, which have happened far more frequently in
Earth's history, theoretically might cause similar or even worse
problems with ultraviolet exposure, the researchers say. The ozone
depletion would be less, but there would also be less of a protective
dust cloud.

"Part of what we're trying to stress here is that with an asteroid
collision, there will be many synergistic effects on the environment
that go far beyond the initial impact," said Cockell, a researcher
with the British Antarctic Survey who did some of this analysis while
formerly working with NASA. "Effects such as acid rain, fires, the
dust clouds, cold temperatures, ozone depletion and ultraviolet
radiation could all build upon each other."

During the K-T event, the scientists said, many of the animals may
actually have been spared most of the ultraviolet spring they
envision. That impact, oddly enough, hit a portion of the Earth's
crust that was rich in anhydrite rocks. This produced a 12-year
sulfate haze that blocked much of the ultraviolet radiation. But it
was a lucky shot -- that type of rock covers less than 1 percent of
the Earth's surface.

So when the next "big one" comes, the scientists said, the ecological
repercussions may be more savage than any of those known in Earth's
long history. The collision will be devastating, the "impact winter"
deadly. 

But it will be the ultraviolet spring that helps finish off the
survivors. 

==================
(2) ANTARCTIC SEA ICE SCRUBS CO2 DURING GLACIAL PERIODS

From SpaceDaily, 13 March 200
http://www.spacedaily.com/spacecast/news/iceage-00b.html

Antarctic Sea Ice Scrubs Carbon Dioxide During Glacial Periods

San Diego - March 13, 2000 - A new study indicates that variations in
Antarctic sea ice may have played a significant role in lowering
atmospheric carbon dioxide (CO2) concentrations during the last ice
age. This study makes progress towards unraveling the mysteries of the
past climate changes, a necessary step for predicting future climate.

The study by Britton Stephens, a University of Colorado researcher at
the National Oceanic and Atmospheric Administration's Climate
Monitoring and Diagnostics Laboratory in Boulder, Colo., (formerly of
Scripps), and Ralph Keeling of Scripps Institution of Oceanography at
the University of California, San Diego, appears in the March 9 issue
of Nature and presents a new theory to explain why low carbon dioxide
concentrations in the atmosphere are found during glacial periods.

According to ice core records, every hundred thousand years or so, the
earth cycles between warm periods and cold glacial periods, with
Antarctic temperatures varying by about 20 degrees Fahrenheit.

Records also indicate that during the glacial periods there was 30
percent less CO2 in the atmosphere. This study attempts to solve the
mystery of the connection between global atmospheric CO2 concentrations
and Antarctic temperatures, which seem to rise and fall together.

FULL STORY at
http://www.spacedaily.com/spacecast/news/iceage-00b.html

=============================
* LETTERS TO THE MODERATOR *
=============================

(3) METEORIC BOMBARDMENT AND BIOLOGICAL EVOLUTION

From Andrew Glikson <geospectral@spirit.com.au>

Dear Benny,

I refer to news items (1) and (2) on CCNet of 10 March, 00.  Paul
Rennes and his colleagues are to be commended on their progress in
deciphering the impact history of the moon. Some of the following
queries/comments are likely resolved in the full Science paper, which
has not reached this part of the world as yet.

1. The remarkable isotopic resolution of 40/39Ar laser ultraviolet
spot analyses is only matched by the prospect that a single gram of
lunar regolith (Fra Mauro formation, Apollo 14) contains a mixture of
impact spherule condensates representative of a  >4*10^9 years-long
history of lunar bombardment. 40/39Ar analysis of a larger number of
lunar surface samples is required before statistically meaningful
conclusions can be drawn.

2. Due to the Moon-Earth gravity section of 1:1.4, Earth was more
heavily bombarded and no 1:1 correlation can be drawn between lunar
and terrestrial impact history.

3. The suggested apparent decrease in frequency of impact events on
Earth back with time is likely to be as much the consequence of
destruction of craters by subduction, uplift/erosion and
subsidence/burial.  Exposed/preserved pre-Cambrian (pre-540 Myr)
terrains form less than 10 percent of the Earth Surface, and have
mostly been re-cycled to the obliteration of original impact
features. Increasingly, however, the pre-Cambrian impact record is
being deciphered in relic crustal segments, including multi-ring
craters such as Vredefort (2023+/4 Myr; D=300 km) and Sudbury
(1850+/-3; D=250 km), and fallout deposits of oceanic impacts at 2.49
Gyr, 2.56 Gyr, 2.63 Gyr (Simonson and Hassler, 1997, Aust. J. Earth
Sci, 44, 37-38), 3.24 Gyr (Lowe et al., 1989, Science, 245, 959-962),
and 3.46 Gyr (Lowe and Byerly, 1986, Geology, 14, 83-86). In
particular, the 3.24 Gyr spherule units correspond to a mega-impact
cluster which, from calculations based on geochemical mass balance
and spherule dimensions, represent oceanic terrestrial
mare-equivalents several hundred kilometre in diameter (Byerly and
Lowe, 1994, Geochim. Cosmochim. Acta, 58, 3469-3486).

4. That the more extensive evidence of the pre-Cambrian impact record
has not as yet been uncovered is likely to represent the combined
consequence of (1) crustal destruction/recycling, and (2) the fact
that geologists - traditionally oriented towards endogenic solutions
- have not been long searching for impact fallout deposits. 
Consequently, the quoted suggestion by R.A. Mueller of a "reversion
from a benign to a violent solar system about 500 million years ago"
is surprising - I will look forward to read the evidence in detail.

5. It is a mute question whether the pre-Cambrian craters of
diameters several hundred km-large represent (1) the tail-end of
early bombardment in the inner solar system, or alternatively (2)
remnants of distinct impact episodes, such as the 4.2-3.8 Gyr Late
Heavy Bombardment (LHB) was considered to be.

6. There is no reason to suggest that 3.45 Gyr stromatolites,
confirmed recently in the Pilbara Craton, Western Australia (Hoffman
et al., 1999, Geol. Soc. Am. Bull., 111, 1256-1262), represent the
oldest life on Earth.  Rather, they represent the oldest life
DISCOVERED to date on Earth. Traces of isotopically light 13/12C
ratios in graphite in c.3.8 Gyr Greenland gneisses hint, although do
not confirm, existence of yet older life.

7. Potential connections between impact-triggered extinctions and
post-impact radiations have been observed in more than one case, the
classic example being the mammals. The possibility that the "Cambrian
Explosion" represents biogenetic radiation in the wake of an impact
cluster has circumstantial support related to oceanic splitting and
extensive alkaline igneous intrusion - we are still searching for the
craters.

8.  There is no need to resort to extra-terrestrial "seeding" or
enrichment in terrestrial amino-acids as a factor in terrestrial
biological evolution, for examdple since: (1) as indicated earlier
(CCNet 11.12.98) amino isobutaric acid (CH3)2CNH2COOH) and racemic
isovaline (CH3CH2(CH3)CNH2COOH), which form major amino acids in
carbonaceous chondrites, are exceedingly rare on Earth (Zhao and
Bada,1989; Nature, 339:463-464), with exceptions such as at the K-T
impact boundary at Stevns Klint, Denmark; (2) the volumes of amino
acids inherently associated with terrestrial volcanic environments
are orders of magntiude larger than those introduced by cosmic dust
and by impactors. The latter factor would be minimized by
dissociation of amino acids upon impact-explosion.

9. Whether an impact periodicity, variably suggested in the range of
26-35 * 10^6 years (Rampino and Stothers, 1984, Nature, 308, 709-712;
Rampino, 1998, Celestial Mechanics and Dynamical Astronomy, Kluwer
Academic Publ., 49-58), is confirmed or otherwise, this in itself does
not resolve the question of the origin of such periodicity,
alternatively interpreted in terms of (1) a "Nemesis" twin star
(Muller, 1988, Nemesis - The Death Star, Weidenfeld and Nicolson, New
York), and (2) Z-shaped solar system oscillations across the galactic
plane with consequent disturbance of the cometary Oort cloud (Bachal

and Bachal, 1985, Nature, 316, 706-708; Napier, 1998, Celestial
Mechanics and Dynamical Astronomy, Kluwer Academic Publ., 59-76).

Further extensive studies of lunar and terrestrial impact spherules
are needed in order to shed light on the impact history of the Moon
and Earth. Paul Rennes and colleagues are congratulated on their
studies of these fundamental questions in the history of the Solar
system.

Andrew Glikson
11.3.00

Research School of Earth Science, Institute of Advanced Studies,
Australian National University,
Canberra, ACT 0200

================
(4) 1998 KY26 NOT FASTEST-SPINNING ASTEROID

From Daniel Fischer <dfischer@astro.uni-bonn.de>

Hi,

just to get the record straight re. the first item in the March 8
CCNet: 1998 KY26 ist not the fastest-spinning asteroid anymore.
Already last year it was announced that the light curve of 1999 TY2
indicates a rotation period of 7 minutes which was roughly confirmed
by the line-broadening of radar echoes - see
http://sunkl.asu.cas.cz/~ppravec/99ty2.htm and
http://www.geocities.com/skyweek/mirror/152.html (story #7).
There are also rumors that an asteroid with a 'day length' of just 4
minutes has been found.

Regards, Daniel

=============
(5) LARGE ROCKETS FOR PLANETARY DEFENSE

From Michael Paine <mpaine@tpgi.com.au>

Dear Benny,

In my Space.com article (CCNet 17 Feb 2000) I discussed the lack of
large rockets for delivering payloads to threatening asteroids and
comets. It turns out NASA has tentative plans for a rocket to (almost)
rival the Saturn V:
NASA Draws Up Big Booster for Mars By Todd Halvorson
http://www.space.com/space/technology/nasa_mars_booster.html

The Magnum rocket would be able to deliver a payload of about 80t to
Low Earth Orbit, compared with about 20t for the Space Shuttle and
100t for the Saturn V. This is also covered in the March 2000 issue
of Scientific American.
http://www.sciam.com/2000/0300issue/0300quicksummary.html

regards
Michael Paine

=============
(6) BEOWULF, OR MOVING HEAVEN AND EARTH

From Bev M Ewen-Smith <coaa@mail.telepac.pt>

Dear Benny,

With your interest in (and the gradually increasing respectability
of) possible impact events in historical time, you might like to
consult an expert on the Anglo Saxon epic poem Beowulf.

After the hero Beowulf deals with the monster Grendal and then
Grendal's mother, the poem ends with an unpleasant encounter with a
dragon which contains some very suggestive imagery - fire from the
sky etc etc.

I read it 30 years ago when I tried to learn Anglo Saxon but it was
serialised on the BBC World Service last week.

On a somewhat orthogonal topic....

In the context of avoiding a space-miss (well, an airborne collision
that is not quite, is an 'air-miss'), nobody ever suggests shifting
the Earth instead.  After all the infrastructure can be built,
installed, powered, tested, maintained right here without -a priori-
knowing anything about the target. It seems obvious to me. OK there
are a few digits in the exponent that make it a tad difficult - but
think big!

Regards

Bev

===========
(7) VOLCANOES & GLOBAL COOLING

From Joel Gunn <jdgunn3@mindspring.com>

Relative to volcanic cooling of the earth, Richardson Gill has a book
just published that examines the impact of global cooling on the size
and location of the Bermuda-Azores Subtropical High and its impact on
Maya civilization. Global cooling in most instances can be traced to
volcanic eruptions. 

Joel Gunn

Gill, R. B. The Great Maya Droughts: Water, Life, and Death. 
University of New Mexico Press, 2000, Albuquerque

===============
(8) AND, FINALLY: TECHNO-SCARE OF THE DAY -
    INTELLIGENT ROBOTS MAY SOON WIPE OUT HUMANS

From Washington Post, 12 March 2000
http://search.washingtonpost.com/wp-srv/WPlate/2000-03/12/215l-031200-idx.html

Sunday, March 12, 2000; Page A15

From Internet Scientist, a Preview of Extinction
By Joel Garreau, Washington Post Staff Writer

A respected creator of the Information Age has written an
extraordinary critique of accelerating technological change in which
he suggests that new technologies could cause "something like
extinction" of humankind within the next two generations.

The alarming prediction, intended to be provocative, is striking
because it comes not from a critic of technology but rather from a
man who invented much of it: Bill Joy, chief scientist and co-founder
of Sun Microsystems Inc., the leading Web technology manufacturer.

Joy was an original co-chairman of a presidential commission on the
future of information technology. His warning, he said in a telephone
interview, is meant to be reminiscent of Albert Einstein's famous
1939 letter to President Franklin Delano Roosevelt alerting him to
the possibility of an atomic bomb.

In a 24-page article in the Wired magazine that will appear on the
Web Tuesday, Joy says he finds himself essentially agreeing, to his
horror, with a core argument of the Unabomber, Theodore Kaczynski --
that advanced technology poses a threat to the human species. "I have
always believed that making software more reliable, given its many
uses, will make the world a safer and better place," Joy wrote in the
article, which he worked on for six months. "If I were to come to
believe the opposite, then I would be morally obligated to stop this
work. I can now imagine that such a day may come." [...]

Joy is disturbed by a suite of advances . He views as credible the
prediction that by 2030, computers will be a million times more
powerful than they are today. He respects the possibility that robots
may exceed humans in intelligence, while being able to replicate
themselves.

He points to nanotechnology -- the emerging science that seeks to
create any desired object on an atom-by-atom basis -- and agrees that
it has the potential to allow inexpensive production of smart
machines so small they could fit inside a blood vessel. Genetic
technology, meanwhile, is inexorably generating the power to create
new forms of life that could reproduce.

What deeply worries him is that these technologies collectively
create the ability to unleash self-replicating, mutating, mechanical
or biological plagues. These would be "a replication attack in the
physical world" comparable to the replication attack in the virtual
world that recently caused the shutdowns of major commercial Web
sites. [...]

What further concerns him is the huge profits from any single advance
that may seem beneficial in itself. "It is always hard to see the
bigger impact while you are in the vortex of a change," Joy wrote.
"We have long been driven by the overarching desire to know that is
the nature of science's quest, not stopping to notice that the
progress to newer and more powerful technologies can take on
a life of its own."

Finally, he argues, this threat to humanity is much greater than that
of nuclear weapons because those are hard to build. By contrast, he
says, these new technologies are not hard to come by. Therefore, he
reasons, the problem will not be "rogue states, but rogue
individuals."

FULL STORY at
http://search.washingtonpost.com/wp-srv/WPlate/2000-03/12/215l-031200-idx.html

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*

CCNet-Essay, 13 March 2000
--------------------------

THE VIOLENT HABITAT OF EARLY TERRESTRIAL LIFE

By Andrew Glikson <geospectral@spirit.com.au>

Research School of Earth Science, Institute of Advanced Studies,
Australian National University, Canberra, A.C.T. 0200

Confirmation of the biological nature of 3.45 billion years-old
stromatolites in the Pilbara, Western Australia, tells a story of
survival amid volcanic and meteoritic impact events
. . . [continued]



CCCMENU CCC for 2000

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