PLEASE NOTE:
*
CCNet 04/2000 - 11 January 2000
-------------------------------
QUOTES OF THE DAY
"No matter how remote, the danger
from celestial objects is
gradually prompting an international
response, unlocking resources
and setting the basis for a coordinated
planetary defence against
a faceless enemy... Governments are
allocating more and more
funds, equipment and personnel to
monitor the skies”.
-- Agence
France-Presse, 10 January 2000
"But the current odds are that a
large NEO will strike with little
or no warning because the world-wide
search for NEOs is grossly
under-funded and under-staffed".
-- Michael Paine, 10
January 2000
(1) SPIN DOCTORING THE IMPACT HAZARD
Andrew Yee <ayee@nova.astro.utoronto.ca>
(2) SIMULATING ARMAGEDDON ON YOUR PC: ASTEROID IMPACTS
WITH EARTH
Explorezone, 10 January 2000
(3) HOW MANY COSMIC IMPACTS HAVE PUNCTUATED EARTH
DURING THE LAST 10,000 YEARS?
Benny J Peiser
(4) STRANGE ICE FLAVOURS ON PLUTO'S MOON
Andrew Yee <ayee@nova.astro.utoronto.ca>
(5) 1999 LEONIDS
Marc Gyssens <gyssens@charlie.luc.ac.be>
(6) COULD MARTIAN LIFE SURVIVE A BLAST THROUGH THE ATMOSPHERE?
Larry Klaes <lklaes@bbn.com>
(7) DESERT WETNESS CHANGES CURRENT CLIMATE IDEAS
Bob Kobres <bkobres@arches.uga.edu>
==========
(1) SPIN DOCTORING THE IMPACT HAZARD
From Andrew Yee <ayee@nova.astro.utoronto.ca>
[http://asia.dailynews.yahoo.com/headlines/technology/afp/article.html?s=asia/headlines/000109/technology/afp/Asteroid_menace_moves_out_of_the_pages_of_sci-fi.html]
Sunday, January 9, 2000, 11:07 AM EST
Asteroid menace moves out of the pages of sci-fi
PARIS (AFP) -- In the 1950s, the idea of the Earth being hit by
an
asteroid, wiping out civilisation at a stroke, was the stuff of
pulp
science fiction.
Today, space rocks are being taken seriously.
No matter how remote, the danger from celestial objects is
gradually
prompting an international response, unlocking resources and
setting
the basis for a coordinated planetary defence against a faceless
enemy.
Dozens of observatories around the world now scour the skies
nightly
for any threat from space. The United States has a dedicated
deep-space
telescope on asteroid duty, and Japan is building one. The
British
government last week set up a three-man task force to evaluate
any
peril from the skies.
Each day, several thousand tonnes of cosmic debris fall to Earth,
says
Jean-Eudes Arlot, director of the Institute of Celestial
Mechanics at
the Paris Observatory.
Most of it consists of minute specks of dust released from
passing
comets, or fragments of asteroids that smashed into each other
millions
of years ago.
Objects of this size are harmless. Larger ones, about the size of
a
pebble, provide an entertaining "shooting star,"
burning up from
friction with the Earth's atmosphere.
What worries space watchers are the bigger celestial wanderers --
brutes that measure several metres (yards) or more and race
through the
heavens at up to 30 kilometers (20 miles) per second.
As was shown in 1994, when the tail of the comet Shoemaker-Levy 9
rammed dramatically into Jupiter, these release catastrophic
energy on
impact.
An asteroid or comet measuring at least a kilometer (half a mile)
[sic] that slammed into Mexico's Yucatan peninsula around 65
million
years ago is believed to have caused the dinosaurs to die out.
It unleashed a firestorm and kicked up such huge volumes of dust
that
vegetation could no longer get adequate light from the Sun.
Plants
withered, and the impact resounded up the food chain.
Scientists agree that the risk of doomsday is very remote.
Yet every 100 years or so an object measuring 50 metres (165
feet)
smacks into the Earth, inflicting local devastation, according to
NASA's Jet Propulsion Laboratory (JPL).
A comet about 60 metres (200 feet) wide exploded over Siberia in
1908
with a force the equivalent of 600 times the Hiroshima bomb,
reducing a
40-kilometer (25-mile wide) patch of forest to matchwood.
Cities the size of London or New York would be reduced to cinders
by
such an impact. If the object hit the sea, it could trigger a
giant
tidal wave, swamping low-lying areas.
The good news is that resources, ideas and organisation are
quickly
improving mankind's knowledge of the threat.
Governments are allocating more and more funds, equipment and
personnel
[sic] to monitor the skies. Data and watch duties are being
shared
among astronomers and space agencies through a loose cooperative
effort, Spaceguard Foundation.
An international measurement of risk assessment, called the
Torino
Scale, was agreed last year. The International Astronomical Union
(IAU), based in Paris, has been placed in charge of vetting any
warning
to ensure the size of the danger and avoid any false alarm.
Big technical strides are also being made.
In less than two years, a deep space telescope operating at the
White
Sands Missile Range in New Mexico has discovered more than 200 of
the
700 or so known Near-Earth Objects (NEO), as these dangerous
itinerants
are called.
A second large telescope is scheduled to start operating at the
same
site.
"It'll be another 10 or 15 years before we've detected most
objects
more than a kilometer across," says Hans Rickman, the IAU's
deputy
secretary-general.
"Enormous progress has been made in plotting the
trajectories of NEOs,"
says Arlot.
"Ten years ago, the margin of error would have been in the
thousands of
kilometers, up to 10,000 kilometers (6,000 miles).
"Today, that margin is several dozen kilometers (miles),
mainly thanks
to satellite technology that uses the stars as a measuring point
when
the asteroid passes near by."
That sort of finessing is vital.
It helped to tone down a scare about the the most dangerous
identified
NEO -- a kilometer- (half-mile) -sized asteroid, 1999 AN10, which
is
due to skim past the Earth on August 7, 2027.
The latest arithmetic says 1999 AN10 could run as close as 37,000
kms
(19,000 miles) -- but no closer -- to the Earth.
"The probability of a collision in 2027 is essentially
zero," JPL's NEO
Program says.
But, it adds, there is "about one chance in 10 million"
that the
asteroid will hit the Earth when it returns on its orbit around
the Sun
in 2039.
Such observations could give the Earth years of warning about
impending
danger.
Yet what could be done if the alarm sounded?
Experts caution against Hollywood heroics of blasting the
asteroid into
smithereens with nuclear bombs, as this could merely cause it to
split
into chunks that could rain down over a larger area.
"It could be possible to land a probe on to it and use solar
power to
nudge it out of its orbit," said Arlot.
"But the interception would have to be done over a great
distance and
the operation would have to be unfold over several months or
years. In
theory, it's possible, but at the moment, despite the progress,
that
remains in the realm of science fiction."
Copyright © 2000 Agence France-Presse. All rights reserved.
============
(2) SIMULATING ARMAGEDDON ON YOUR PC: ASTEROID IMPACTS
WITH EARTH
From Explorezone, 10 January 2000
http://explorezone.com/columns/space/2000/neo_jan_simulate.htm
Simulating armageddon ON YOUR PC: Asteroid Impacts with Earth
By Michael Paine for explorezone.com
Millions of uncatalogued space rocks careen through
interplanetary
space, and Earth is one of the many sitting ducks in the cosmic
shooting gallery. Although centuries can pass on Earth without a
catastrophic strike, waiting impassively to be hit is seen by
many
experts as a clear and possibly deadly gamble.. But what are the
odds? And what would happen under different types of impacts?
As with almost anything that can be simulated, the odds and
consequences of an asteroid strike have been programmed into a
computer
software package.
I ran some scenarios on the new software, created by
planetary
scientist John Lewis from the University of Arizona. The results,
described below, are not official predictions, but they do lay
out some
frightening possibilities that put the threat of rocks from space
into
tangible terms, while at the same time pointing to the need to
search
for the uncharted asteroids and comets (known as Near Earth
Objects or
NEOs) that threaten our civilisation.
Lewis' software uses a Monte Carlo analysis to calculate the
human
fatalities resulting from impacts. This works by generating
random
numbers for the size and type of NEO and the human population
density
at the impact site. The process is based on the actual
distribution of
these factors. It includes fatalities from "airbursts,"
where the NEO
explodes in a devastating fireball several miles from the ground.
The consequences are similar to those from a nuclear bomb and
estimates
of fatalities are based mainly on research with nuclear weapons.
Another danger modelled by the program is the risk of tsunami
swamping
coastal cities hundreds or thousands of miles from the site of an
ocean
impact.
A million years of bombardment
In one run I simulated a total of one million years, looking at
the
worst event in each of 10,000 centuries.
I want to stress that these are not predictions and that no known
NEOs
are on a collision course with Earth.
Although one million years seems a very long time, bear in mind
that
impacts do not run like clockwork -- they could occur at any
time. An
event which happens once in one million years of the simulation
has a
one-in-a-million chance of happening in the next twelve months.
This
should not be dismissed as unimportant, particularly if it could
involve billions of deaths and the end of civilisation. After
all, many
optimistic people around the world regularly buy lottery tickets
where
the chance of winning first prize is one in 30 million or worse.
The chance of getting dealt a royal flush in 5 card poker is
about one
in half a million.
In my simulation the total death toll during one million years
was 7.5
billion. This represents an average of 7,500 fatalities per year
and is
higher than the 3,000 fatalities per year generally quoted by
scientists. However, nearly half of these fatalities occurred in
one
devastating event that wiped out half of the world's population
-- a
possible outcome in the real-life gamble with rocks from space.
To put the NEO death toll in perspective, it lies somewhere
between
that of airline crashes (700 per year) and earthquakes (10,000
per
year).
Looking at the results
Fatalities topped 1 million in 2% of the centuries. Nearly
two-thirds
of centuries had no fatalities.
In a further 5 percent of centuries the worst event happened in a
remote location and caused less than one thousand fatalities.
Such
events would probably not been blamed on NEOs, for lack of being
spotted. Another of 5 percent centuries had only had tsunami
fatalities, with an average of 100,000 fatalities per tsunami
event.
Many of these tsunami events would not have been linked to a NEO
since the ocean impact happened well away from eyewitnesses.
Overall, some 70 percent of centuries may have had no reported
fatalities from NEOs. This may help to explain the general lack
of
awareness of the NEO threat by the public and politicians.
Surprisingly, 1,207 fatal impacts involved NEOs with a diameter
less
than 50 yards. Most did their damage in an airburst of around 10
megatons -- like that of a "small" H-bomb.
There were several sobering impact events in the simulation. They
are
described below. Geographic names are arbitrary and are intended
to
give an indication of the population density and landforms of the
impact site (as well as dramatic effect).
Big blasts
First the really big ones -- asteroids or comets a mile or more
across.
These are civilisation-destroying events that leave little
opportunity
for disaster recovery. Estimates of the NEO population suggest
that,
over a period of one million years, about 5 such impacts can be
expected. By chance, this is the number produced in the
simulation.
During the 133rd Millennium a 1.3-mile-wide comet hits the
American
Midwest at a speed of 100,000 mph. The blast, equivalent to 3
million
megatons of TNT or 60,000 H-bombs, kills 7 million instantly and
makes
a crater 20 miles across. Within days the skies around the globe
darken
from the dust injected into the atmosphere. Sunlight is blocked.
Crops
fail and, over the next year, half of the Earth's human
population
dies, mainly from starvation.
In the 621st Millennium a mile-wide comet slams into Mongolia.
"Only"
300,000 people die instantly, but the dust from a crater 13 miles
across darkens the skies around the globe. Some 900 million die
from
starvation.
In the 952nd Millennium a 1.2-mile-wide comet hits central
Africa.
About 3 million people are killed instantly. An 11-mile-wide
crater is
formed. Later, 500 million starve to death around the globe.
During the 11th Millennium a 1.2-mile asteroid hits the southern
Atlantic Ocean 400 miles off the coast of southern Argentina. A
tsunami
250 yards high sweeps 50 miles inland and kills 300,000. The
climatic
effects are less severe than with a land impact, but 400 million
still
die from starvation due to these effects.
An almost identical event, this time off the northern coast of
Russia,
occurs in the 699th Millennium.
Quirky blasts
There were several events that were unusually deadly -- a matter
of
bad luck for 54 million people:
136th Millennium: A 200-yard-wide asteroid hits the South China
Sea
just 300 miles from Hong Kong. A 40-yard-high tsunami sweeps the
coast
and kills 18 million people.
20th Millennium: An asteroid just 70 yards across explodes in the
skies
14 miles above London. 10 million are killed in the 80-megaton
blast
and firestorm.
273rd Millennium: A 50-yard-wide comet travelling at an unusually
fast
150,000 mph explodes in the atmosphere 25 miles above Mexico
City. 14
million are killed by the 110-megaton blast and firestorm.
721st Millennium: An almost identical event occurs over Manila,
killing
12 million.
The lessons from the simulation
Comets accounted three-quarters of the fatalities, due mainly to
the
Midwest event in the United States. That event was caused by a
long-period comet that spent tens of thousands of years out
beyond
the orbit of Neptune before diving into the inner solar system.
The simulations show that unusual events can be killers. In his
book,
Lewis points out that the simulations generally produce a greater
number of casualties from small NEOs than would be expected from
calculations involving "typical" values. Unfortunately,
it would be
extremely difficult for current technology to reliably detect
such
small, but deadly, objects.
The situation is very different for the civilisation-destroying
giants
because most can be easily spotted from Earth using existing
technology. Given decades of warning, we can develop the space
technology to nudge them into a non-threatening orbit. But the
current
odds are that a large NEO will strike with little or no warning
because
the world-wide search for NEOs is grossly under-funded and
under-staffed (as one frustrated scientist put it -- less than
the
number of staff at a typical McDonalds restaurant).
Lewis sums up the situation succinctly: "Of all the natural
hazards
facing Earth, impacts are the most dangerous. Unlike native
hazards of
the Earth's surface, impacts know no size limit. Their effects
can be
devastating over the entire surface of the planet. They are the
only
credible natural threat to human civilisation. But impacts,
especially
those of large bodies, are both predictable and avoidable.
"The Near Earth Object (NEO) population constitutes both an
unprecedented hazard and an unparalleled opportunity," Lewis
says.
"It is sometimes said that there is a fine line that
separates a threat
from an opportunity. The near-Earth asteroids present us with
just this
dilemma. They present us with an intelligence test of the highest
order,
with the highest possible stakes for the human race."
Copyright 2000, Explorezone
============
(3) HOW MANY COSMIC IMPACTS HAVE PUNCTUATED EARTH
DURING THE LAST 10,000 YEARS?
ANNUAL MEETING OF THE
AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE
SCIENCE IN AN UNCERTAIN MILLENNIUM
17-22 February 2000 - Washington DC
Symposium: Unpredictable Natural Events of Extra-Terrestrial
Origin:
Their Impacts on Humanity (Organised by Rolf M. Sinclair)
How many Cosmic Impacts have punctuated Earth during the last
10,000
Years? BENNY J PEISER, Liverpool John Moores University, School
of
Human Sciences, Liverpool L3 3AF, UK, b.j.peiser@livjm.ac.uk
Cosmic impacts have punctuated life on Earth repeatedly. Such
extraterrestrial perturbations, depending on the size, physical
nature
and hence the cohesive strength of the impactor/s, can have
catastrophic effects on the ecological system in a variety of
ways: i)
low or high level multimegaton explosions of fireballs which
destroy
natural and cultural features on the surface of the Earth by
means of
floods, blasts and seismic damage, ii) massive high level influx
of
cosmic dust high above the stratosphere which causes a dramatic
drop of
global temperature and which can lead to the suspension of
agriculture,
iii) massive high level influx of cosmic chemicals (associated
with
dust) with, as yet, incalculable biochemical potentials which may
be
harmful to DNA. Whilst a dozen Holocene impact craters have been
confirmed to date, the majority of impacts that occurred during
the
last 10,000 years have not been detected yet. This is due to a
limited
focus on crater producing events. Tunguska-like impacts or
"Super-Tunguskas" are thereby taken out of the
equation. Due to their
catastrophic detonation above ground (or in the oceans), they
often
leave no obvious fingerprints behind. Tunguska-like impacts occur
every
100 years or so. Occasionally, massive high level multimegaton
explosions and widespread atmospheric and/or oceanic impacts
triggering
ecological crises on a hemispheric, continental or even global
scale.
Current risk assessment is based on the statistical analysis of
the
number of known impact structures in addition to the current
asteroidal
flux. However, there are other sources of cosmic input capable of
triggering ecological crises without producing impact craters:
cosmic
dust veils, atmospheric impacts and oceanic impacts. I will
present
different sources of proxy data for paleocatastrophic
reconstruction
which are relevant for the search of yet undiscovered Holocene
impacts.
For more information see: www.aaas.org/meetings
MODERATOR'S NOTE: I will be visiting North America in mid
February and would be available for lectures at request.
==============
(4) STRANGE ICE FLAVOURS ON PLUTO'S MOON
From Andrew Yee <ayee@nova.astro.utoronto.ca>
[http://www.academicpress.com/inscight/01072000/graphb.htm]
7 January 2000, 5 pm PST
Strange Ice Flavors on Pluto's Moon
By Robert Irion
Astronomers have taken their first detailed look at Pluto's
companion
Charon, the most distant known moon in the solar system. This
dark body
appears to be covered with a mixture of water ice and ammonia
ice, a
chilly brew quite different from the frosts of methane, carbon
monoxide, and nitrogen ices that sheath the surface of Pluto. The
marked contrast is surprising, for many astronomers have regarded
Pluto
and Charon as a "double planet."
Pluto and Charon orbit each other every 6.4 days at a distance of
just
20,000 kilometers -- about 20 times less than the separation
between
Earth and its moon. This tight pirouette makes Charon exceedingly
difficult to study and obscured its very presence until 1978.
Images of
the two objects usually blur together even in powerful
telescopes. A
rare night of spectacular atmospheric conditions at the W. M.
Keck
Observatory in Hawaii last May allowed planetary scientist
Michael
Brown of the California Institute of Technology in Pasadena to
distinguish the light from Pluto and Charon more clearly than
ever
before.
Brown teamed with Wendy Calvin, a spectroscopy expert at the
University
of Nevada, Reno, to analyze the outer skin of Charon based on the
spectrum of infrared light reflected from the moon. They saw a
surface
dominated by crystalline water ice, commonly seen on other moons
in the
outer solar system. But a curious dip in part of the spectrum
demanded
further explanation, the team reports in today's Science. Using
models
of the light reflected from a variety of ices and minerals, Brown
and
Calvin deduced that the most likely cause is ammonia ice, which
until
now astronomers had seen only in comets.
Early in the solar system's history, a large object probably
struck
Pluto; the debris later coalesced into Charon, astronomers
believe.
Volcanoes driven by the heat of the impact may have coated the
moon's
surface with a slushy ammonia-water mixture. Then, after the heat
faded
away, Charon would have frozen solid. Pluto, nearly five times
more
massive than Charon, retains a shroud of methane, carbon
monoxide, and
nitrogen in a thin atmosphere and as surface frosts, Brown says.
In
contrast, Charon's gravitational pull is too feeble to hold on to
those
volatile gases.
Planetary scientist Eliot Young of the Southwestern Research
Institute
in Boulder, Colorado, isn't yet sold on Charon's ammonia ice.
"It's
worth following up, but it's hard to check an exhaustive list of
compounds when you are trying to match a small depression in a
spectrum," he says. Even so, Young is excited by the
prospect of
learning more about Charon's composition. "If you're
interested in what
the early solar system was made of, Pluto, Charon, and comets
are among your best bets."
© 1999 The American Association for the Advancement of Science
[Extracted from INSCiGHT, Academic Press.]
===============
(5) 1999 LEONIDS
From Marc Gyssens <gyssens@charlie.luc.ac.be>
A preliminary analysis of visual data on over 1/4 million meteors
seen
during the 1999 Leonid display, to appear shortly in the December
1999
issue of WGN, the Bimonthly Journal of the International Meteor
Organization, is already available on the Organization's Web site
(http://www.imo.net), and we
invite you to consult it!
Marc Gyssens
WGN, Editor-in-chief
===============
(6) COULD MARTIAN LIFE SURVIVE A BLAST THROUGH THE ATMOSPHERE?
From Larry Klaes <lklaes@bbn.com>
Although they know that bacteria can survive a tremendous amount
of
time in the cold of space, astrobiologists aren't sure how they
can
handle atmospheric re-entry on a meteorite. To test their
theories,
they've strapped artificial meteorites filled with bacteria onto
a
Russian space probe which will be launched into space and then
returned to Earth.
http://www.kayser-threde.de/news/FOTON-12-Landing-e.htm
http://news.bbc.co.uk/hi/english/sci/tech/newsid_570000/570429.stm
=============
(7) DESERT WETNESS CHANGES CURRENT CLIMATE IDEAS
From Bob Kobres <bkobres@arches.uga.edu>
http://unisci.com/stories/20001/0110002.htm
Desert Wetness Changes Challenge Current Climate Ideas
Where does one go to find information about tropical rainfall
patterns
since the last major glaciation? Try the driest desert of South
America. That's the approach taken by University of Arizona
geoscientists Julio Betancourt and Jay Quade.
With assistance from several UA students, they are combing the
Atacama
Desert in northern Chile for clues on regional climate changes
over the
past 40,000 years. Their findings may force the scientific
community to
rethink the accepted views on the timing of wet and dry periods
in the
region -- and the importance of the tropics during times of
climate
change.
FULL STORY at http://unisci.com/stories/20001/0110002.htm
----------------------------------------
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*
LETTERS TO THE MODERATOR, 11 January 2000
-----------------------------------------
(1) MR SPOCK & PEPPER CAT
Alain Maury <Alain.Maury@obs-azur.fr>
(2) TSUNAMIS AND HOUSE INSURANCE
Duncan Steel <D.I.Steel@salford.ac.uk>
(3) A FEW CITY-BUSTERS BETTER THAN ONE DINO-KILLER?
Victor Noto <vnn2@kua.net>
(4) WARNING TIMES & PLANETARY DEFENSE
Jon Richfield <jonr@iafrica.com>
==========
(1) MR SPOCK & PEPPER CAT
From Alain Maury <Alain.Maury@obs-azur.fr>
Dear Benny,
I doubt that Jim Gibson, who named an asteroid after his beloved
cat,
is a reader of the CCNet, so let me tell the underlying story
behind
the naming of asteroid Mr Spock as Jim Gibson told it to me:
One of the possible conditions for naming a minor planet for a
person
is that he/she (it?) must have contributed in solar system
research. Mr
Spock (the cat) was very often spending nights with Jim and his
wife
observing, and by doing this, Jim felt it had contributed to
solar
system research much more than many observatory directors... ;-)
In more recent times, Jean Mueller who is the senior observer at
the
Palomar/Oshin Schmidt, had wanted to name one of her asteroids
after
her beloved "Pepper Cat" who had just passed away.
This, however, was
refused by the naming committee, and a compromise was found by
naming
it 4257 Ubasti, the Egyptian god with a cat's face. Nevertheless,
Schmadel's "Minor Planet Name Dictionary" has a mention
of Pepper Cat in
the citation for asteroid Ubasti.
Alain
===========
(2) TSUNAMIS AND HOUSE INSURANCE
From Duncan Steel <D.I.Steel@salford.ac.uk>
Dear Benny,
In CCNet of 2000/1/6 you carried a discussion from Michael Paine
in
which he quite correctly emphasized that the people of Australia
- the
vast majority of whom live on coastal plains facing onto vast
oceans -
face an unappreciated but large risk from tsunamis. He wrote:
"Four potential sources of tsunami are described:
earthquakes,
undersea volcanoes, submarine landslides and asteroid/comet
impacts."
Whilst I was resident in Australia, I once took out my household
insurance policy to look at the small print. Therein I found that
tsunamis were *defined* as being large waves caused by any of the
*first three* causes which Michael mentioned. That is,
"asteroid/
comet impacts" were *not* included in the insurers
definition of
"tsunamis".
From this it would appear that not only are Australians at risk
from
impact-generated large waves, but also their insurers would not
cover
them against losses sustained through such a source. Provided the
insured parties (and indeed the insurance companies) actually
survive,
of course.
My note is whimsical, if one can joke about such things, but it
has a
point at the end. Say we all started writing to our insurers
asking
whether we *are* actually covered against losses caused by
asteroid/
comet impact, through tsunamis or otherwise. At first the
insurance
companies would just say "Yes, of course." After a
dozen letters they'd
decide they should look into it. Then when they discovered the
facts
for themselves, they'd get upset, and the proverbial would really
hit
the fan. Because the annual expectation of loss due to such
catastrophes for houses in Sydney, say, is of the same order as
the
house insurance premiums currently charged. The insurance
companies
would thus have two choices: (a) Greatly increase the premiums;
or
(b) Write into their smallprint terms which specifically exclude
impact-related damage.
Now, wouldn't that get things moving?
Cheers,
Duncan Steel
==============
(3) A FEW CITY-BUSTERS BETTER THAN ONE DINO-KILLER?
From Victor Noto <vnn2@kua.net>
Hi Jon,
Nice article in CCNET on Jan 7, 2000 entitled A FEW CITY-BUSTERS
BETTER
THAN ONE DINO-KILLER? which sums up my feelings on the subject
pretty
well. Although a five year warning is considered too short a time
by
many experts, I think every effort will be made to do something
about
diverting such an dino killing object from space.
Actually five years is a optimistic scenario and a more realistic
time
interval according to Dr. Duncan Steel, Dr. David Morrison and
others
is a few seconds. But even a comet would probably only give a few
years
warning at best since they come out of the Oort cloud rather
suddenly.
So you see as bad as you made our threat from near earth objects,
the
human condition is actually worse.
Ultimately the only solution to the problem of NEO's civilization
destroying impacts is to be out there as a permanent inhabitant
of
inter solar space to either divert such objects when and if
detected or
to survive if earth is greatly impacted.
We need time and no one knows for sure if we have time and the
will to
do it. Perhaps we will need to genetically engineer a new race of
humans to survive the rigors of space. All will eventually
be possible
if the will and time is there to do it. I personally think
there is
not the will or time and man will go the way of the dinosaur.
Victor
My take on threat: http://www.phoenixat.com/~vnn2/mytake.htm
Victor D. Noto - Kissimmee, FL 34747
Lat 28.283 Long, -81.417
Email: vnn2@phoenixat.com
http://www.phoenixat.com/~vnn2/bigrock..htm
Website theme quote: "Life really is a Rock and the Big Rock
giveth and
taketh away all life!!"
--------------
MODERATOR'S NOTE
Dear Victor
May I briefly respond to your comment. While Jon has raised a
hypothetical question which may have to be addressed at some
unknown
time in the future, I regret to say that I find your response
somewhat
fatalistic.
In some rare cases, a five year warning period to prevent a
potential
impact might indeed be too short given our *present* technology.
But in
50 or 100 years time, a 5 year warning period may be more than
enough.
Who knows what advances will be made during the 21st century -
and the
odds of a 10km dino-killer (or even a 500-1000m object) hitting
earth
during the next 100 years are extremely small.
In view of the fact that - during the last 20 years or so - we
have
begun to realise this cosmic threat, and are beginning to develop
a
defensive capability, the human condition is actually much better
than
at any stage of our long evolutionary history (during which we
were
unable to do anything but to pray).
Yet neither prayers, nor space migration or genetical engineering
are
effective messures to protect the world's population against the
potential impact threat. Instead, there are realistic and
technologically viable methods which should - given some time -
be enough
to safeguard life and civilisation on our planet.
The fatalistic assumption that "there is not the will or
time and man
will go the way of the dinosaur" is, I regret to say, mainly
based
on rather pessimistic feelings. And these, I am sure you will
agree,
should not blur our future potential for self-protection.
With best wishes,
Benny
===============
(4) WARNING TIMES & PLANETARY DEFENSE
From Jon Richfield <jonr@iafrica.com>
Hello Benny,
My note has elicited comments from Victor Noto among other
correspondents, and indirectly from you. To all of you thanks. A
few
further comments from me:
First an extract from my reply to anonymous correspondents whose
time
is too much at a premium at present, to participate fully:
(Jon)>I notice in retrospect that I made a booboo of an order
of
magnitude in the diameter of the dino-killer size. No
matter, it does
not affect the principle. <
(Correspondent) You have questioned the view that it is better to
leave
the object intact than to smash it into an unmanageable swarm of
particles. I too distrust that view because in the first place
letting
events take their course will certainly lead to total
disaster.
Smashing the object would leave large and small fragments and the
small
ones will be relatively harmless, while the chances are fair that
some
of the large masses might miss the planet altogether.
(Jon) Just so. My main reservation is that for certain size
ranges this
would mean that say a country-buster would be replaced by a
gaggle of
city-busters. Now, if the city-busters all land in the
country which
would have been wiped out anyway, that would be an obvious profit
to
many and a loss to none. However, that would be a most
unlikely
scenario. Very likely someone would get the chop who otherwise
would
have got off scot free and such victims would have a legitimate
gripe,
even if the human population as a whole profited. In fact, it
might
even be that two neighbouring countries were at each other's
throats and
as a result of the tinkering one that had been the predicted
impact zone
would no longer be destroyed, while the other would now be, not
actually
destroyed, but severely and murderously peppered, even ruined.
Serbia
and Albania would be examples, or India and China or Pakistan.
Even
within one country there could be difficulties; Would Quebec be
willing
to sacrifice Montreal just to save Alberta? There are precedents
for
this kind of thing; in WWII there were difficulties about fooling
the
Germans to deflect the V1s from London to the rural southern
counties.<
(Correspondent) This does however leave us with a situation which
is
altogether uncontrollable and that is the basis of the concerns
of the
anti-smashing brigade...
(Jon) Well, not absolutely uncontrollable; the assumption is that
the
upper limit of the consequences of the intervention be lower than
the
lower limit of the unmitigated impact, given reasonable levels of
confidence. Mind you, given the assumptions of a marginal time
scale
and of far greater than marginally self-interested, probably
self-aggrandising committees making the decisions, I would have
precious little faith in the wisdom and good faith of their
decisions,
but then I am a cynic, so surely I am putting the whole matter in
too
bleak a light.
One correspondent also expressed understandable reservations on
the
hazards associated with the necessary testing and deployment of
nukes
on the necessary scale. Though I share his concerns in principle,
I
was more optimistic and replied in part as follows:
...The threats from the large impactors dwarf even direct nuclear
threats, let alone tests, pretty decisively. Secondly we have a
lot of
bombs that don't really need testing, though I understand that
there is
some wailing about the need to test them from time to time to
prove
that they are still in good enough nick to take out any notional
enemy
on demand. Thirdly, if it were decided on good grounds that
such bombs
as we still had were OK for frying nasties, but not well designed
for
surgical engineering or steering of asteroids and comets, then
they
could be tested underground under international scrutiny without
much
pollution, certainly with negligible effects compared to those of
the
threats they were intended to avert. Again, given that we
had a
reasonable idea of the effects of the bombs, we could (should, in
fact)
send up a few to divert the orbits of a disposible rock or two to
confirm that our engineering is competent and effeective. These
things
always sound so simple, but in practice something always happens
that
had no business on the agenda. There should be no
difficulty in
finding a disposible target in an orbit safe for the study.
Victor responded kindly, though rather pessimistically and you
replied.
My reactions are as follows:
> In some rare cases, a five year warning period to prevent a
potential
> impact might indeed be too short given our *present*
technology. But
> in 50 or 100 years time, a 5 year warning period may be more
than
> enough.
I am hesitant to rely on new magic from the treasure chest of
future
technology, which often exceeds our expectations, but hardly ever
in the
form we expect. However, even given simple extensions of our
current
technology, I can imagine a pretty good improvement in our
reaction
times at a modest cost. Suppose for instance that we park in
lunar
Trojan orbit, a number of craft bearing whatever deflection
engines our
engineers decide have the best prospects of success, whether
bombs or
nuclear powered thrusters or anything else desirable. They could
be
deployed at very short notice and with their greatest problem
already
overcome: getting close to Earth's escape velocity. There may
also be a
case for deploying other parcels at other strategic points
throughout
the Solar system so that we could intercept any serious threat
within a
year or two.
It is not as though this would be a major extravagance; deploying
and
maintaining such stations would be of incalculable scientific
value,
both "pure" and "applied". They could
logically be observation stations
for all kinds of effects, solar, astronomical, NEO tracking,
cosmological; you name it.
> In view of the fact that - during the last 20 years or so -
we have
> begun to realise this cosmic threat, and are beginning to
develop a
> defensive capability, the human condition is actually much
better
> than at any stage of our long evolutionary history (during
which we
> were unable to do anything but to pray).
Any practical reaction is better than none and our soundest basis
for
hope is that the more probable the impact, the smaller it is, and
near
misses are more frequent than actual impacts, so we are likely to
have a
few practice runs before the Big One comes along.
Also, I don't understand Victor's sources' remarks on our having
only
seconds of warning. That could happen with dog killers, but even
a
modest space watch should give us a good probabiity of timely
warning of
city busters.
> Yet neither prayers, nor space migration or genetical
engineering are
> effective messures to protect the world's population against
the
> potential impact threat. Instead, there are realistic and
> technologically viable methods which will - given some time
- be
> enough to safeguard life and civilisation on our planet.
As I see it, this needs a bit of qualification. I constructed a
scale
of classes of impact scales some time ago and if you no longer
have it
to hand, I can exhume it. We can in principle handle anything up
to
dino-killers, given sufficient warning, but by the time we are
looking
at planet busters we have no foreseeable prospect of deflecting
them, no
matter how much warning we get. For those we would like a few
centuries
of warning, not to safeguard life on the planet, but to establish
a
colony(ies) in space or on other planet(s). Yes, we could at best
rescue a viable genetic and technological nucleus, but consider
the
alternative!
>...pessimistic feelings... should not blur our future
potential for
> self-protection.
This is the crux of the matter. If we curl up and die, we really
must
die. If we take a sufficiently positive view of the matter, the
spur of
the perpetual NEO threat could be just what humanity needs, to
break out
of our sterile and eventually doomed existence on this planet. To
be
sure, a few billion years or so is a long way to look ahead to
certain
destruction, but there is no reason to pre-empt it by falling
prey to
disastrous little rocks or climate shifts or eruptions every few
thousand years or so.
On a global scale the expenditure would be trivial and the
incidental
benefits considerable.
Them's my sentiments anyway.
Cheers,
Jon