PLEASE NOTE:
*
CCNet 59/2003 - 22 August 2003
------------------------------
* Yes, I'm back from glorious and refreshing summer holidays.
Hope you all had a nice break too!
--Benny Peiser
"As the search [for NEOs] expands, at least one group is
recommending a practice deflection. The B612 Foundation, which
takes its name from the asteroid in Antoine de Saint-Exupéry's
The Little Prince, is designing a mission to alter an asteroid's
orbit using a low-thrust, possibly nuclear-electric spacecraft.
The Houston-based organization, a group of scientists and
astronauts that includes space station crewmember Ed Lu, won't be
able to fund the mission on its own, so B612 plans to present the
plan to NASA and other space agencies, and push for a test by
2015. Clark Chapman of B612 won't name an exact price for the
mission, but he estimates it will fall somewhere between the cost
of a typical interplanetary probe mission and NASA's
several-billion-dollar Jupiter Icy Moons Orbiter project."
--Gregory Mone, Popular Science,
September 2003
"Over 200,000 objects in space that could be described as
space garbage are in near Earth orbits. Asteroids are also
dangerous. A network of telescopes and radars needs to be created
to monitor and tackle these problems. The equipment available in
Europe is not sufficient. Therefore a new project involving
Europe's means of surveillance and the optical facilities and
radars of former Soviet republics has been launched."
--Igor Molotov, Russian Academy of
Sciences, --Interfax News Agency, 17 August 2003
(1) INCOMING: PLANNING THE NEXT STEPS OF THE SPACEGUARD PROJECT
Popular Science, September 2003
(2) WORLD'S LARGEST ROBOTIC TELESCOPE READY TO TRACK NEAS
NEO Information Centre, 18 August 2003
(3) RUSSIAN RESEARCHERS PROPOSE TRANS-EUROPEAN SPACEGUARD AND
SPACE GARBAGE PROJECT
Interfax News Agency, 17 August 2003
(4) BOILING SEAS LINKED TO MASS EXTINCTION (AND BIBLICAL FLOOD)
Nature Science Update, 22 August 2003
(5) DEFENSES DOWN, GALACTIC DUST STORM HITS SOALR SYSTEM
Space.com, 14 August 2003
(6) TSUNAMIS: THE NEXT BIG WAVE
The Economist, 14 August 2003
(7) CONFRONTING CATASTROPHE IN THE ANCIENT WORLD
Erhan Altunel <ealtunel@ogu.edu.tr>
(8) "... OTHERS, SUCH AS OUR SUN, ARE METEL-RICH, OFTEN
CONTIANING AN IRON CORE."
Oliver Manuel <oess@umr.edu>
(9) SUPERLAKES, MEGAFLOODS AND ABRUPT CLIMATE CHANGE
Michael Paine <mpaine@tpg.com.au>
(10) CATASTROPHES IN EARTH HISTORY
Rolf Sinclair <rolf@santafe.edu>
================
(1) INCOMING: PLANNING THE NEXT STEPS OF THE SPACEGUARD PROJECT
Popular Science, September 2003
http://www.popsci.com/popsci/aviation/article/0,12543,473545-1,00.html
Its name is 1950DA, it's the size of a small mountain, and it's
headed for Earth. According to one grim scenario, 1950DA will hit
its target-most likely water, since there is more water than land
on our planet-and plunge to the seabed in a fraction of a second.
When the asteroid meets the ocean floor, it will explode,
excavating a crater 11 miles wide. A column of water and debris
will shoot a few miles into the sky-to the height of a low-flying
jetliner. Then skyscraper-high walls of water will head for
shore, eventually breaking in the shallows and flooding the
coast. The rest you know, if you saw the weepy 1998 asteroid
movie Deep Impact.
Worse things may already have happened: One theory credits an
11-kilometer-wide asteroid with roasting dinosaurs alive 65
million years ago. The enormous impact sent debris flying back
into space-some of it halfway to the Moon. When the asteroid bits
reentered the atmosphere, the heat that was generated flash-baked
plant and animal life. (Had that not happened, mind you, we
probably wouldn't be here today.) 1950DA is minuscule by
comparison, though even a still smaller asteroid could take out
an entire city with a direct hit. And make no mistake, there are
plenty of space rocks out there; one missed Earth by only 75,000
miles in June 2002-and wasn't spotted until after it had whizzed
by.
Now for the good news. First, 1950DA is 877 years away and a
300-to-1 long shot for actually striking the planet and doing the
damage in the scenario above, which is part of a simulation
recently created by planetary scientists Steven Ward and Erik
Asphaug of the University of California, Santa Cruz. And although
there are more 1950DAs out there-maybe bigger, maybe due to
arrive much sooner-the search for potential killer asteroids is
at least under way, though sorely underfunded. Furthermore, a
small band of scientists, many of them fueled more by passion
than by actual government grants, is working on novel methods to
deal with asteroids before they get too close to be diverted or
destroyed. (The time spans involved give a new definition to
advance thinking: As the foldout on the previous pages shows,
some diversion operations would require centuries to work.)
NASA is more than halfway through a search for asteroids and
comets that come within striking distance of Earth-called
"near Earth objects," or NEOs-and are wider than a
kilometer. Experts calculate that the chance of an object that
size hitting Earth in the next century is only one in several
thousand, but the result would be global havoc.
After astronomers spot an asteroid in their telescopes, they use
radar tracking to get a more precise picture of where it's
headed, how fast it's moving, and whether its orbit around the
Sun will intersect with Earth's orbit. Before 1950DA's predicted
encounter with Earth in 2880, the asteroid will swing around the
Sun almost 400 times, while Earth will complete 876 orbits.
Of the 600-plus large NEOs tracked thus far, only 1950DA poses
any threat at all. But at this stage of the search, there are an
estimated 400 potential global killers left to find, not to
mention over a million hard-to-spot smaller asteroids capable of
regional destruction. (A rock that exploded over Tunguska,
Siberia, in 1908 leveled a thousand square miles of remote
forest; it was a mere 60 meters wide.) Making the tallying work
more tricky are a few long-period comets, which only swing by
every few hundred years and are much more difficult to track.
The search is only the beginning, and as Jay Melosh, a planetary
scientist at the University of Arizona points out, "The
question is, If we find one with our name on it, can we do
anything?"
NASA's search effort receives a paltry $3 million per year, just
a fraction of the $25 million that NASA earmarked last year to
fix the doors on the Kennedy Space Center's vehicle-assembly
building. "I'd like to see more money spent," says
David Morrison of NASA's Ames Research Center. But as yet,
there's no official program either to build or to test
asteroid-deflection technologies. If Earth gets whacked by a
significant asteroid within the next few centuries, survivors
might find themselves marveling that their ancestors, with tools
in hand, did little to prevent a cataclysm.
The asteroid interception and diversion experts are mostly
hobbyists-planetary scientists, astronomers and engineers who
think up these strategies on their own time. But the ideas are
plentiful: As our gatefold shows, the path from detection to
mitigation could include low-thrust engines, solar sails,
standoff nuclear explosions and more.
Melosh, for example, has been focusing on the use of solar
collectors, which could concentrate sunlight on an asteroid,
vaporizing enough material to gradually nudge the rock off
course. Until recently, this idea amounted to little more than a
series of conceptual sketches bolstered by calculations. Then
Melosh learned of L'Garde, a California company that makes
smaller versions of the exact collectors he needs. With a few
adjustments, he says, his strategy could be put to work tomorrow.
It would take years for sunlight to redirect an asteroid,
however, so advance notice is absolutely critical. Ditto for
tactics that would involve painting an incoming asteroid or
covering its surface with white glass beads-both approaches would
make the asteroid more reflective, increasing the tiny reaction
forces produced when sunlight is radiated back into space. Over
several centuries, the cumulative effect of these slight forces
would alter the asteroid's velocity and cause a miss. "You
let the Sun do the work," says Jon Giorgini of NASA's Jet
Propulsion Laboratory (JPL), one of the scientists who projected
1950DA's orbit out to 2880.
"The key," says Donald Yeomans, who heads the NEO
Program Office at JPL, "is you've got to find them early. If
they're on an approach trajectory and you've [only] got a few
months, there's not much you can do."
Given ample time, an effective defense strategy might require
that a probe be launched to study the structure of the incoming
body. Not all asteroids are the solid objects familiar from
museum meteorite displays. Some are porous, others are
collections of rubble loosely held together by gravity. Exploding
a nuclear bomb nearby might nudge a dense asteroid off track, but
it could break a brittle one into pieces, effectively multiplying
the threat by creating smaller but still lethal rocks.
Each threat, in other words, requires an adjustment of strategy.
"You need to find out [the asteroid's] density, find out its
mass, its porosity, its composition, because all these things are
important if you want to effect some kind of mitigation or
deflection," says Yeomans. One approach uses so-called
kinetic kill vehicles-numerous small spacecraft placed in an
asteroid's path. Hit by hit, they slow it down enough that Earth
will pass through the projected collision point before the
asteroid does.
Also possible is a dock-and-push approach, in which a spacecraft
parks on the asteroid's surface, fires its thrusters, and alters
the trajectory. Robert Gold of the Applied Physics Laboratory at
Johns Hopkins University says the probe he designed for NASA's
Near Earth Asteroid Rendezvous mission-the first to land on an
asteroid-could divert a hundred-meter-wide object, which is large
enough to wipe out the Washington Beltway. "If you found
[the asteroid] 30 years in advance, that little 6-foot by 6-foot
spacecraft could provide enough impulse to make it miss
Earth," he says.
Still, as Yeomans warns, none of this will work without advance
notice. Currently, NASA expects to find only about 90 percent of
the NEOs large enough to cause global catastrophes. The remaining
10 percent are too dark for today's telescopes, or too difficult
to distinguish from the many asteroids that orbit harmlessly in
the solar system's main asteroid belt between Mars and Jupiter.
Andrea Milani, of the Space Mechanics group at the University of
Pisa in Italy, wants to find the hidden large NEOs and extend the
survey down to objects as small as 300 meters across. Both goals
require a new generation of ground-based telescopes capable of
detecting fainter objects, and possibly space-based observatories
to peer into obscure areas of the solar system. The ground-based,
8.4-meter Large-aperture Synoptic Survey Telescope is one
possibility, but its $120 million price is the equivalent of 40
years of the current search budget.
As the search expands, at least one group is recommending a
practice deflection. The B612 Foundation, which takes its name
from the asteroid in Antoine de Saint-Exupéry's The Little
Prince, is designing a mission to alter an asteroid's orbit using
a low-thrust, possibly nuclear-electric spacecraft. The
Houston-based organization, a group of scientists and astronauts
that includes space station crewmember Ed Lu, won't be able to
fund the mission on its own, so B612 plans to present the plan to
NASA and other space agencies, and push for a test by 2015. Clark
Chapman of B612 won't name an exact price for the mission, but he
estimates it will fall somewhere between the cost of a typical
interplanetary probe mission and NASA's several-billion-dollar
Jupiter Icy Moons Orbiter project.
Morrison applauds the civilian effort, but also calls for more
from NASA. "We need an actual program, even if it's a modest
beginning, to demonstrate that we can do some of this," he
says. Morrison doubts that any concerted effort will be made
until a specific threat is discovered-something like 1950DA but
closer to home. In the meantime, he and fellow asteroid spotters
will keep at it.
"It's one of the few areas where astronomy can actually have
a practical impact on us, on Earth," he says. "Saving
the world, that's not such a bad idea."
Gregory Mone, a PopSci assistant editor, is the author of The
Wages of Genius.
Copyright 2003, Popular Science
===============
(2) WORLD'S LARGEST ROBOTIC TELESCOPE READY TO TRACK NEAS
NEO Information Centre, 18 August 2003
http://www.nearearthobjects.co.uk/news_display.cfm?code=news_intro&itemID=195
The telescope designed, constructed and commissioned by Telescope
Technologies Ltd., a subsidiary company of [Liverpool John Moores
University], observes autonomously from its site on La Palma in
the Canary Islands. The Liverpool Telescope's unique capabilities
of flexible scheduling and rapid response will put the UK at the
forefront of exciting new fields of research in time dependant
astrophysics. "This enables us to study such phenomena as
supernovae and Gamma Ray Bursts, the biggest explosions in
space," said Professor David Carter of the ARI.
The telescope's other great strength is its ability to make
regular observations of objects that vary over periods from
seconds to years. With current astronomical facilities this is
very difficult, whereas the new telescope will track newly
discovered objects such as comets or Near Earth Asteroids (NEAs),
allowing accurate calculations of their paths and potential
hazards.
The telescope is supported by the Particle Physics and Astronomy
Research Council (PPARC), making 40% of the observing time
available to astronomers throughout the UK. A further 5% of the
time has been donated by JMU to the National Schools' Observatory
(NSO) programme. "School children can now work on their own
projects alongside professional astronomers," said Dr. Andy
Newsam (NSO astronomer). This is the first time regular access
has been granted to schools for world-class research telescopes.
The telescope is sited at the Observatorio del Roque de los
Muchachos which is operated on the island of La Palma by the
Instituto de Astrofísica de Canarias.
More info: The Liverpool Telescope http://telescope.livjm.ac.uk/
=============
(3) RUSSIAN RESEARCHERS PROPOSE TRANS-EUROPEAN SPACEGUARD AND
SPACE GARBAGE PROJECT
Interfax News Agency, 17 August 2003
MOSCOW. Aug 17 (Interfax) - Russian researchers have proposed
establishing a Trans-European monitoring system to prevent
satellite collisions with asteroids and space garbage.
"Over 200,000 objects in space that could be described as
space garbage are in near Earth orbits. Asteroids are also
dangerous. A network of telescopes and radars needs to be created
to monitor and tackle these problems," Igor Molotov, an
expert form the Russian Academy of Sciences' Pulkovo Observatory,
has told Interfax.
"The equipment available in Europe is not sufficient.
Therefore a new project involving Europe's means of surveillance
and the optical facilities and radars of former Soviet republics
has been launched," he said.
"The new system will be able to warn of small pieces of
space garbage and monitor them round-the-clock in any weather.
There are telescopes and radars located from Spain to the Far
East, covering several time zones," Molotov said.
"The system will be capable of finding new asteroids and
measuring their orbits and determining their physical properties,
which will help make long-term forecasts on dangerous space
collisions and evaluate the consequences of possible
impacts," he said.
Copyright 2003 Interfax News Agency.
=============
(4) BOILING SEAS LINKED TO MASS EXTINCTION (AND BIBLICAL FLOOD)
Nature Science Update, 22 August 2003
http://www.nature.com/nsu/030818/030818-16.html
Methane belches may have catastrophic consequences.
TOM CLARKE
A massive methane explosion frothing out of the world's oceans
250 million years ago caused the Earth's worst mass extinction,
claims a US geologist.
Similar, smaller-scale events could have happened since, which
might explain the Biblical flood, for example, suggests Gregory
Ryskin of Northwestern University in Evanston, Illinois1. And
they could happen again: "It's a very conjectural idea but
it's too important to ignore," says Ryskin.
Up to 95% of Earth's marine species disapeared at the end of the
Permian period. Some 70% of land species, including plants,
insects and vertebrates, also perished. "It's arguably the
single most important event in biology but there's no consensus
as to what happened," says palaeontologist Andrew Knoll of
Harvard University in Cambridge, Massacheusetts.
Ryskin contends that methane from bacterial decay or from frozen
methane hydrates in deep oceans began to be released. Under the
enormous pressure from water above, the gas dissolved in the
water at the bottom of the ocean and was trapped there as its
concentration grew.
Just one disturbance - a small meteorite impact or even a fast
moving mammal - could then have brought the gas-saturated water
closer to the surface. Here it would have bubbled out of solution
under the reduced pressure. Thereafter the process would have
been unstoppable: a huge overturning of the water layers would
have released a vast belch of methane.
The oceans could easily have contained enough methane to explode
with a force about 10,000 times greater than the world's entire
nuclear-weapons stockpile, Ryskin argues. "There would be
mortality on a massive scale," he says.
"It's a wacky idea," says geologist Paul Wignall of the
University of Leeds, UK, "but not so wild that it shouldn't
be taken seriously." There is evidence that the oceans
stagnated at the end of the Permian period. And the chemical
signature in fossils of the time hints there was a massive change
in the amount of atmospheric carbon dioxide. Carbon dioxide would
have been produced as methane broke down or exploded in the
atmosphere.
After all, belches of trapped methane from lakes and oceans are
"a rare but well-known maritime hazard", Wignall adds.
Flood warning
The same phenomenon could explain more recent events, such as the
Biblical flood, Ryskin also argues. An eruption from Europe's
stagnant Black Sea would fit the bill. There is even some
geological evidence that such an event took place 7,000-8,000
years ago.
Other sluggish seas might still be accumulating methane at their
depths and could represent a future hazard, Ryskin adds.
"Even if there's only a small probability that I am right,
we should start looking for areas of the ocean where this might
be happening," he argues.
References
1. Ryskin, G. Methane driven oceanic eruptions and mass
extinctions. Geology, 31, 737 - 740, (2003).
(c) Nature News Service / Macmillan Magazines Ltd 2003
=============
(5) DEFENSES DOWN, GALACTIC DUST STORM HITS SOALR SYSTEM
Space.com, 14 August 2003
http://www.space.com/scienceastronomy/dust_storm_030814.html
By Robert Roy Britt
Our solar system's natural defenses are down and a vigorous
cosmic dust storm is blowing through, according to a new study.
The forecast calls for a prolonged and increasing blizzard of
small interstellar bits.
While no serious consequences are expected, the extra dust could
slightly alter our night sky and might pose an increased risk to
spacecraft, which are vulnerable to high-speed impacts from the
tiny particles.
The whole scenario is also a vivid reminder that there is no such
thing as empty space.
The number of incoming particles recently tripled and the pace is
expected to grow over the next decade. Terrestrial weather and
climate will not likely be affected, but more shooting stars
could grace the night sky, said the study's leader, Markus
Landgraf of the European Space Agency (ESA).
The fresh influx is related to a periodic weakening of the Sun's
magnetic field.
The discovery was made using data from ESA's Ulysses spacecraft,
which orbits the Sun on a noncircular path between Earth and
Jupiter and his been monitoring the situation since 1992. The
probe detects small particles and, based on direction, mass and
speed, figures out which ones came from outside the solar system.
Threefold increase
The number of interstellar dust grains increased from four per
day, per meter in 1997 to 12 per day in 2000, Landgraf said. The
results were announced earlier this month. He expects the rate to
stay constant until 2005, and then increase by another factor of
3 prior to 2013.
The potential effects are not well known, according to Landgraf
and his colleagues at the Max-Planck-Institute.
"Generally interstellar dust is not considered a problem, as
it does not penetrate typical spacecraft structures,"
Landgraf explained in an e-mail interview. "However, due to
the high impact velocity, sensitive high-voltage instruments can
suffer a short circuit after an exceptionally big impact. Also,
sensitive optical instruments have to worry about the erosion of
polished surfaces."
Most interstellar grains are just one-hundredth the diameter of a
human hair. But they move fast, roughly 58,160 mph (26 kilometers
per second) relative to the Sun.
Secondary effects
Any notable effects on Earth will likely involve secondary
processes. When interstellar dust hits comets and asteroids, it's
like shooting a tiny bullet at a rock, and more dust is kicked
up, and the follow-on dust tends to be bigger.
More interstellar dust means more dust generated in-house.
"This has a number of potential effects," Landgraf
said, cautioning that they haven't been observed yet, however.
One possibility is an increased number of sporadic meteors, those
not associated with known showers like the summer Perseids or the
November Leonids. Meteors are created when something vaporizes in
Earth's atmosphere. Space rocks as big as peas and baseballs
crash through now and then, but most shooting stars are made of
mere dust.
It's also possible, Landgraf said, that the eerie Zodiacal Light
-- a "false dawn" caused by sunlight reflecting off
space dust -- will be enhanced.
And in general, more material might rain down to Earth from space
every year.
Astronomers armed with huge telescopes will be interested to see
if increased secondary dust brightens the Kuiper Belt, a region
of frozen rocks and dust beyond Neptune. "With the brighter
dust, especially infrared space telescopes will have a harder
time to see faint objects behind the dust," Landgraf said.
Among other tasks, infrared telescopes on the ground and in space
are used to study dust around other stars.
More to come
The solar system is always plowing through interstellar material.
The Sun's giant magnetic field thwarts much of the dust from
entering the solar system. But the magnetic field weakens
periodically, on a cycle that lasts roughly 22-years. The cycle
is related to an 11-year cycle of sunspot activity.
This is the first of the related dust storms that has been
seriously monitored by a spacecraft.
Some day, the influx could get worse. The solar system is plowing
toward the fringes of a galactic cloud known as the G-cloud.
"The time of the entry into the G-cloud is unknown, but is
expected to occur any time in the next 10,000 years,"
Landgraf said. "There will be a constant increase [in dust
rates], because the G-cloud is more dense than the local
interstellar cloud that is now surrounding our Sun."
The study will be published in the Journal of Geophysical
Research.
Copyright 2003, Space.com
=============
(6) TSUNAMIS: THE NEXT BIG WAVE
The Economist, 14 August 2003
http://www.economist.com/science/displayStory.cfm?story_id=1989485
New ways of tracking these killer waves may help save lives
FOR many inhabitants of the Pacific coast, powerful waves caused
by earthquakes or underwater landslides-generally known by their
Japanese name, tsunamis-are an ominous threat. When a wave 15
metres (50 feet) high pounded the northern shores of Papua New
Guinea in July 1998, the inhabitants were taken by surprise. This
tsunami killed more than 2,200 villagers, making it one of the
most destructive in recent years. But it was just one of a string
of killer waves that have struck the western Pacific over the
past few years. Since 1990, ten big tsunamis have claimed more
than 4,000 lives. So it would be nice to be able to detect such
tsunamis far enough in advance for people to be evacuated. But
that is not easy.
Seismometers and coastal tidal gauges-instruments already
deployed for other purposes-can provide some warning.
Seismometers measure earthquakes that might cause tsunamis, but
they cannot detect the waves themselves. Nor can they normally
detect landslides triggered by earthquakes, since the energy
released in a landslide is small compared with that released by
an earthquake. Yet landslides are often the cause of the most
destructive tsunamis. (The New Guinea tsunami mentioned above is
believed to have been amplified in this way.) The result is error
on the side of caution: since the 1950s, 75% of tsunami warnings
that led to evacuations have turned out to be false alarms. Such
evacuations are not cost-free. A false alarm that triggered the
evacuation of Honolulu, in May 1986, resulted in losses of more
than $30m.
The environment
The NOAA's Tsunami Research Programme is developing detection
systems. Teruyuki Kato is researching tsunamis at the Earthquake
Research Institute in Tokyo. Emile Okal is doing likewise at
Northwestern University.
Tidal gauges, by contrast, can spot tsunamis reliably from their
effect on the sea level, at least when they are close to shore.
But since a tsunami may travel at more than 700kph (450mph), that
does not give much warning. Tidal gauges cannot measure tsunamis
in the deep ocean.
Waving, not drowning
What is needed are specific detectors that take advantage of the
fact that tsunamis are felt throughout the ocean's depths, unlike
wind-generated waves, which affect only its surface. One approach
is to put pressure detectors on the seabed. When a tsunami passes
by, the detector records the increased pressure caused by its
passage.
Japan was the first country to deploy such detectors. It now has
14 of them. But they are connected to the mainland by submarine
cables. That means, in practice, that they can be deployed only
some 50km from land, which is better than tidal gauges, but not
ideal. The network can give local warnings. But the only way to
be sure whether a dangerous wave is headed towards a distant
coastline is to track it across the open ocean.
America's National Oceanic and Atmospheric Administration (NOAA)
hopes to do just that. Its "tsunameters", as they are
dubbed by Eddie Bernard, the director of the agency's Pacific
Marine Environmental Laboratory, have cut the umbilical cord with
the land. Instead, they transmit warnings to buoys on the
surface, and these, in turn, relay the information to NOAA via
satellite. Besides allowing the detectors to be deployed almost
anywhere, this system is cheaper than using cables. Each detector
costs about $200,000 to set up. The Japanese versions cost more
than $5m each.
According to Frank Gonzalez, who heads NOAA's tsunami research
programme, five tsunameters have been deployed in the North
Pacific and one in the South Pacific, with the actual detectors
located at depths of up to 4km. A seventh will be set up near
Chile in November this year, to intercept tsunamis generated off
South America. Although the system has yet to detect a big
tsunami (none has occurred since it began operations), it has
successfully identified small ones.
The Japanese, meanwhile, are trying an alternative approach to
the job of cutting the cable. A group of researchers at Tokyo
University's Earthquake Research Institute are developing a
warning system that relies on global positioning system (GPS)
navigation satellites to monitor the motion of buoys moored in
the open ocean. By placing GPS antennae on shore and on the
buoys, the researchers are able to compare a buoy's
"altitude" with that of a stable location on land.
According to Teruyuki Kato, the project's leader, this
arrangement can measure a buoy's vertical motion with an accuracy
of a few centimetres, which will pick up dangerous tsunamis in
the open ocean where they are mere ripples on the surface (they
rear up into killer waves only when they reach the shallows). Dr
Kato's team has already tested the system successfully in the sea
off Ofunato, in the east of the country, and a new system will be
placed off Muroto promontory, in the west, early next year.
Another line of research that holds promise is the analysis of a
type of sound wave known as a T-phase wave. Rocks rumbling
downhill produce T-phase waves that are carried by the ocean to
both nearby and distant coastlines. Emile Okal of Northwestern
University in Evanston, Illinois has observed that T-phase waves
produced by landslides can be heard by hydrophones (underwater
microphones) of the sort used to detect submarines. Dr Okal has
used this technology to identify tsunamis caused by landslides
(ie, the sort most likely to be dangerous, and thus require
evacuations to be organised). He has also been able to process
seismograms and identify differences between the seismic signals
from earthquakes that produce tsunamis directly and those that
trigger tsunami-producing landslides.
Merely detecting tsunamis, though, is not enough. Tsunamis must
be classified to predict the level of danger. One way of doing
that is by computer modelling. Models developed by Vasily Titov,
at NOAA, and Costas Synolakis, at the University of Southern
California, can predict the size and shape of the waves that will
be generated by a particular tsunami, as well as the resulting
coastal inundation. Knowing how far inland a tsunami will
penetrate should help the authorities to evacuate the right
areas.
Technology, though, can do only so much. The best protection,
according to Dr Synolakis, is common sense. Coastal dwellers must
be able to recognise the signs of a possible tsunami-such as
strong, prolonged ground shaking-and seek higher ground at once.
As with any hazard, the more informed the public are, the better
their chances of survival. For instance, after the Papua New
Guinea tsunami, an international team was dispatched to Vanuatu,
a group of islands in the Pacific, where they showed videos of
tsunamis to the villagers. When a tsunami struck Vanuatu in 1999,
only five people died in it. The message is clear enough. There
is no way to stop a tsunami once set in motion, but there is
certainly a way to avoid getting killed by one. Run like hell.
Copyright © The Economist Newspaper Limited 2003.
============
(7) CONFRONTING CATASTROPHE IN THE ANCIENT WORLD
ANCIEN-L@LISTSERV.LOUISVILLE.EDU
Dear Colleagues,
We wish to draw your attention to the following scientific
workshop that will be held at Osmangazi University, Eskesehir, in
western Turkey, on 20-22 June 2004.
CONFRONTING CATASTROPHE IN THE ANCIENT WORLD
Human development over the last 11,500 years (the Holocene) is
set against an environmental backdrop of climatic and geological
instability. The natural actions of sudden and dramatic climatic
shifts and of extreme geophysical events ensure that nature in
the ancient world was in flux, not balance. But what are the
cultural resonances of rapid environmental change? How did past
human communities adapt to and recover from a constantly moving
and frequently harmful natural world? And, most critically, how
can we disentangle the cultural consequences of natural change
from those of human action?
This 3-day workshop seeks to bring together an interdisciplinary
forum of geologists, archaeologists, historians, anthropologists,
climate scientists, and ecologists to critically examine human
responses to past rapid environmental change. The convenors
encourage submission of
research presentations that are seeking to elucidate the cultural
history of major environmental downturns or reconstruct the
environmental history of dramatic cultural transitions.
Contributions with an emphasis on establishing high-resolution
chronologies of cultural and environmental change are
particularly welcome.
Abstract deadline: 15 January 2004
The workshop is the joint initiative of two current international
research projects: (1) International Council for Science (ICSU) -
'Dark Nature - Rapid Natural Change And Human Responses', and (2)
International Geological Correlation Programme Project 490 - 'The
Role Of Holocene Environmental Catastrophes In Human History'.
An associated fieldtrip around key cultural and geological sites
in western Turkey will take place immediately following the
workshop (24-30 June 2004).
A first circular with further details of the scientific
programme, the fieldtrip and the local and international
scientific committee is currently in preparation. However, those
interested in participating are encouraged to contact the main
lead convenors as early as possible:
Dr Erhan Altunel,
Osmangazi University, Eskesehir,
ealtunel@ogu.edu.tr
Dr Iain Stewart
University of Glasgow,
Glasgow G12 8QQ,
UK.
E-mail: istewart@geog.gla.ac.uk
=========== LETTERS ==============
(8) "... OTHERS, SUCH AS OUR SUN, ARE METEL-RICH, OFTEN
CONTIANING AN IRON CORE."
Oliver Manuel <oess@umr.edu>
Dear Benny,
The above quote from Tom Clarke's report on the International
Astronomical Union meeting in Sydney, Australia illustrates how
opinions are changing in the astronomical community.
Twenty years ago Meteoritics 18, 209-222 (1983) showed the Sun is
iron-rich. Subsequent measurements confirmed this [See "Why
the model of a hydrogen-filled Sun is obsolete" in
Meteoritics & Planetary Sci. 37, A92 (2002)].
The Sun consists mostly of the same elements Harkins reported in
1917 to comprise 99% of ordinary meteorites: Fe, O, Ni, Si, S, Mg
and Ca [J. Am. Chem. Soc. 39, 856-879]. They have even
atomic numbers and high nuclear stability.
This is important to the scientific community because:
a) Over 99% of the mass of the solar system is in
the Sun, and
b) The Sun serves as a model for other stars in the
cosmos.
With kind regards,
Oliver
Professor of Nuclear Chemistry
University of Missouri
Rolla, MO 65401 USA
Phone: 573-341-4420 or -4344
Fax: 573-341-6033
E-mail: oess@umr.edu or om@umr.edu
http://www.umr.edu/~om/
http://www.ballofiron.com
=============
(9) SUPERLAKES, MEGAFLOODS AND ABRUPT CLIMATE CHANGE
Michael Paine <mpaine@tpg.com.au>
Dear Benny
Hope you enjoyed your August break. The following is from
Science, 301: 922-923
The timing (6200 BC) is interesting!
Mike
Superlakes, Megafloods, and Abrupt Climate Change
Garry Clarke, David Leverington, James Teller, Arthur Dyke
About 8200 years ago, the climate of much of the Northern
Hemisphere cooled abruptly for a period of about 200 years. In
their Perspective, Clarke et al. examine the most likely culprit
for this cooling: an outburst of fresh water from a vast,
ice-dammed glacial lake in North America. The superlake had
formed when the kilometers-thick ice sheet covering much of North
America disintegrated. When the ice dam became unstable, fresh
water flooded from the lake into the North Atlantic. It remains
unclear how this fresh water affected ocean circulation or
whether the outburst occurred in more than one stage, but the
timing points strongly to the outburst flood as the trigger of
the 8200-year climate event.
G. Clarke is in the Department of Earth and Ocean Sciences,
University of British Columbia, Vancouver, British Columbia V6T
1Z4, Canada. E-mail: clarke@eos.ubc.ca
D. Leverington is at the Center for Earth and Planetary Studies,
National Air and Space Museum, Smithsonian Institution,
Washington, DC 20560, USA. J. Teller is in the Department of
Geological Sciences, University of Manitoba, Winnipeg, Manitoba
R3T 2N2, Canada. A. Dyke is in the Terrain Sciences Division,
Geological Survey of Canada, Ottawa, Ontario K1A 0E8, Canada.
============
(10) CATASTROPHES IN EARTH HISTORY
Rolf Sinclair <rolf@santafe.edu>
Hi Benny --
The readers of CCNet may be interested in the 32nd International
Geological Congress (Florence, Italy, August 20-28, 2004). There
will be topical symposia on "Catastrophes in Earth
History" and "Myth and Geology" (as well as on
"Geology and Wine").
Full information at http://www.32igc.org/home.htm
and http://www.32igc.org/circular-gen01.htm.
Rolf Sinclair
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