PLEASE NOTE:
*
CCNet 110/2002 - 24 September 2002
----------------------------------
"An interesting sight Thursday night took many people in the
Bay
area by surprise. It was a mysterious light streaking across the
sky,
leaving a trail of vapor. From South San Jose to Willow Glen,
people
out enjoying the warm late summer evening speculated about what
they saw
in the night sky. Was it an airplane, terrorist attack, falling
star?
Nobody knew it was an unarmed Minuteman III intercontinental
ballistic
missile launched from Vandenberg Air Force Base until it was long
gone."
--Newsnet5.com, 20 September 2002
"Scientists are not certain how or when Iturralde Crater
formed
(despite its name that alludes to an impact). General speculation
and
circumstantial evidence point to the collision of a meteor -
either an
asteroid or comet -- about 5,000 to 30,000 years ago. This would
make it
one of the youngest impact craters known, although some
scientists argue
it is much older. If the crater is young, it may correlate to
climatological
events in Earth's history or to a known extinction event. It may
even
be included in the folklore of some South American native
tribes."
--Diana Jong, Space.com, 24 September 2002
(1) THE SEARCH FOR THE MISSING AMAZON METEOR
Space.com, 24 September 2002
(2) DISPATCHES FROM THE ITURRALDE CRATER
Blue Ice Online
(3) MISSILE MISTAKEN FOR METEOR
Newsnet5.com, 20 September 2002
(4) GENERAL CALLS FOR METEOR WARNING SYSTEM
Discovery.com, 23 September 2002
(5) SCIENTISTS, GOVERNMENTS STEP UP SURVEY OF NEAR EARTH OBJECTS
MSNBC, 21 September 2002
(6) CHICKEN LITTLE OR PLANETARY SAVIOURS?
Popular Science, September 2002
(7) NEW CLUES IN THE CONTINUING DETECTIVE STORY OF J002E3
Ron Baalke <baalke@jpl.nasa.gov>
(8) STUDY CAST DOUBT ON EARTHQUAKE-PREDICTION MODEL
Andrew Yee <ayee@nova.astro.utoronto.ca>
(9) IMPACT INDUCED MELTING
Michael Paine <mpaine@tpg.com.au>
(10) THE THINGS YOU LEARM FROM TRIVIAL PURSUIT...
James Oberg <joberg@houston.rr.com>
(11) AND FINALLY: FORGET SIZE, WE'RE TALKING LONGEVITY
Reuters, 13 September 2002
===============
(1) THE SEARCH FOR THE MISSING AMAZON METEOR
>From Space.com, 24 September 2002
http://www.space.com/scienceastronomy/planetearth/crater_expedition_020924-1.html
By Diana Jong
The Araona people wanted $1 million before they would let the
NASA
scientists pass through their territory in the remote Bolivian
Amazon. Given
a budget of $20,000 for their entire expedition, the scientists
resorted to
negotiating, and the indigenous people eventually agreed to a
payment of
$500, plus 500 rounds of .22 ammunition and 200 D-cell batteries.
"They couldn't be Eveready; they had to be Rayovac,"
recalls Compton Tucker,
an earth scientist from NASA's Goddard Space Flight Center.
Unfortunately, the discussions stalled the group a week and by
the time they
reached the Iturralde Crater in October 1998, the rainy season
had started
and flooding prevented them from completing their research.
Four years later, Tucker and his colleagues have returned to the
site to
finish their work. This time, he says, "we know what to
expect."
In an interview in early September before he left for Bolivia,
Tucker said
email reports from the pre-expedition negotiations with the
Araona indicate
that they want a motorized canoe, two extra motors and an office,
rent paid,
in the nearby town of Riberalta.
The price is worth it to Tucker and the other researchers on the
expedition,
in full swing this week, because of the significance of the
questions they
could answer.
Unknown cause
Scientists are not certain how or when Iturralde Crater formed
(despite its
name that alludes to an impact). General speculation and
circumstantial
evidence point to the collision of a meteor - either an asteroid
or comet --
about 5,000 to 30,000 years ago. This would make it one of the
youngest
impact craters known, although some scientists argue it is much
older.
If the crater is young, it may correlate to climatological events
in Earth's
history or to a known extinction event. It may even be included
in the
folklore of some South American native tribes.
"Or it's just an odd, perfect round hole on the face of the
Earth and you
have to start thinking about extraterrestrials or
something," jokes Tim
Killeen, a conservation biologist who will lead the trek.
Killeen, a research fellow with Conservation International, has
been living
in Bolivia and working with the Noel Kempff Mercado Natural
History Museum
in Santa Cruz for about the last 18 years. He first met Tucker
when, he
says, "about seven or eight years ago, these guys from NASA
started coming
down and bothering me to help them interpret their satellite
imagery."
Despite Killeen's familiarity with Bolivia, the expedition team
needs the
assistance of the Araona to reach the Iturralde Crater, not just
to pass
through their land, but to serve as guides. The locals will also
help blaze
the 9-mile (15-kilometer) trail to the crater, which caps a trip
involving
rides in a jet, a motorboat, a dugout canoe and a helicopter
(courtesy of
the Drug Enforcement Agency).
But it isn't the crater's remote location that contributed to
scientists'
late identification of Iturralde as a possible impact site in
1985. Rather,
its features are very subtle.
Unlike Meteor Crater, a gaping hole 550 feet (170 meters) deep in
the
Arizona bedrock, the elevation at Iturralde changes by no more
than the
height of a small child. It is difficult to spot in an area that
spans 5
miles (10 kilometers). Yet a nearly perfectly circular pattern,
due to
differences in vegetation, stands out in Landsat images taken
from space.
Washing away evidence
Iturralde's subtle features may be due to its location. Erosion
is quick in
the wet, rainforest environment.
If the crater is still visible, some scientists say, it cannot be
much older
30,000 years; otherwise it would have completely eroded away.
The challenges in identifying the crater are many. The soil in
rainforests
is very deep. There is about 2 miles (3 kilometers) of it
covering the
bedrock that's under Bolivia. An impact would have ejected that
material
into the atmosphere, but some of it would have slumped back into
the
temporarily gaping hole over time.
"It was more like a big splat," Tucker says, in
reference to other impacts
that expend most of their energy blowing up bedrock.
All this makes the researchers' job more difficult. They will
still search
for the usual, expected rocks and glass particles (called shocked
quartz)
associated with impacts, but this material may have eroded away.
The
scientists will take soil core samples to analyze for increased
levels of
elements that are found in more abundance in meteors than on
Earth. One of
these, iridium, can help distinguish whether a space rock was a
comet or
asteroid.
Canoe science
There are other subtle clues to look for. The impact might have
displaced
ancient, extremely deep layers of soil, or paleo-soils, and
placed them at a
higher level than normal.
"If there was this big explosion," Killeen explains,
"there would have been
a big splash, so that splash should have slopped over a lot of
soil to the
areas adjacent to the crater."
Three or four meters of newer soil that was formed since the
impact would
then cover the displaced paleo-soils. Scientists will float the
river in
motorized canoes searching for areas where water cuts into the
riverbanks
and the paleo-soils might be revealed. Dating the paleo-soils and
the soil
levels that sandwich them can also narrow down when the impact
occurred.
Killeen will also participate in the biologists' efforts to
collect samples
of the flora and fauna in and around the crater. Besides
contributing to
their understanding of the region's biodiversity (which is
Killeen's primary
work for Conservation International) they are trying to
characterize the
subtle differences in vegetation detected by Landsat.
But perhaps what would be the most compelling evidence of an
impact is not
in rocks or shocked quartz or flora, but in data showing changes
in the
magnetic field.
Big as a bus
To make a crater the size of Iturralde, the impacting object
would be
roughly the size of a bus and the event would release energy
equivalent to
thousands of megatons of dynamite, according to James Garvin, an
impact
crater expert at NASA. In comparison, the largest hydrogen bomb
ever
detonated had the power of one megaton of dynamite.
"The global impact would have been equivalent to that of a
large volcanic
eruption, like Pinatubo," Garvin says.
Dust could have been carried through the atmosphere and deposited
in places
as far away as Greenland, the Andes mountains, or even
Antarctica. Any data
gathered at Iturralde can then be correlated with ice cores taken
at these
frozen locations.
But on a local level around the blast, the energy released would
heat the
surrounding dust and material to a plasma-like state. As the
material cools,
the magnetic field realigns differently from the original
direction and can
form a conspicuous pattern distinct from the underlying magnetic
field of
the Earth.
"It's like if you drop a pebble in the water and you see the
waves coming
out, with rings that define different magnetic
measurements," says Patrick
Coronado, a senior engineer at Goddard.
Miniature Cessna
Coronado led the team that developed the MagPlane, or
Magnetometer Plane, a
one-third-scale Cessna with a 12-foot wingspan, fitted with a
highly
sensitive hand-made magnetometer. "The same quality and
sensitivity as
spacecraft magnetometers," Coronado says. It runs on a
modified weed-whacker
engine that should power the 44-pound plane for three hours on a
half-gallon
of standard gasoline. "Trying to get special fuel down there
is not trivial
so we had to use the regular stuff."
Each MagPlane cost about $50,000 to make. The first one went from
concept to
finished product in six months. "Even if we had all the
money in the world
it wouldn't really have helped because a lot of it was new,"
Coronado says.
The MagPlane was born when Tucker and the expedition organizer,
Peter
Wasilewski, a Goddard astrophysicist, were consulting with
Goddard's Office
of University Programs, which provided most of their funding
through the
director's discretionary fund, about maximizing their magnetic
field
measurements.
"The [University Programs] office is just down the hall from
me," Coronado
says. They told Tucker and Wasilewski about "this guy down
the hallway who
has little planes for remote sensing, so they perked their ears
and opened
their eyes and came down and talked to me," Coronado
recounts. "This was six
months ago, and we started working the next day. We were behind
schedule the
day after we started."
Coronado says the project was similar to the Skunkworks,
"like the old days
at Lockheed when you crammed a bunch of engineers in a room and
you put food
and water under the door and they worked until they
dropped."
When Coronado spoke with SPACE.com, he and his team were still
constructing
the magnetometer for a backup MagPlane. "My engineer
is taking it down with
him to install on the second plane in case the first one goes
down.
Otherwise all there is is a pretty plane flying around taking
pictures."
Because of the tight schedule, however, the MagPlane has not been
fully
tested. "A lot of the testing will occur as it's doing
its job."
Still, the MagPlane is more than was originally planned. The trek
was
supposed to start last fall but was postponed because of the
terror attacks
last year.
The expedition officially started this year on Sept. 10, and the
MagPlane
flight is scheduled for Wednesday, Sept. 25. In case it doesn't
work out,
the scientists have also brought along ground-based
magnetometers.
On Sept. 26, the expedition team will hold their third and last
live
webcast, accessible through their web site (http://www.blueiceonline.org).
Reaching out
One of the main functions of the website, besides entertaining
interested
Web surfers, is to link the scientists in Bolivia with teachers
participating in an educational outreach. Called "Teacher as
Scientist," the
program involves educators at home in the scientific process,
working
alongside the researchers to determine what kind of data will be
gathered in
the field. There is even one teacher-scientist on the expedition
team.
Students can follow the expedition through the live webcasts and
daily
updates. A worksheet has also been posted as a classroom
resource.
The educational component of the expedition is a result of the
funding
provided by the Office of University Programs. But there are also
those not
financially invested in the expedition who are very interested in
the
results.
Legends of fire
Last month, scientists at the "Environmental Catastrophes
and Recovery in
the Holocene" conference in London discussed the high
incidence of disaster
and fireball legends in the areas of South America, including
Bolivia.
The Iturralde Crater, if it was made by an impact, could be an
explanation,
says Benny Peiser, a social anthropologist from Liverpool John
Moores
University.
"If there was an impact in the last 10,000 years, then the
logic would be
that the survivors would be talking about it and including it in
their
traditions and legends," Peiser says. "If this proves
to be an impact crater
of a very young age, then this could have enormous consequences
for our view
of societal evolution and potentially might answer a lot of
questions in the
history of South America."
Garvin has studied impact craters, including Iturralde, while at
Goddard,
but he is now NASA's lead Mars scientist. There are no plans to
send an
expedition to study impact craters on Mars, so the Bolivian trek
is as close
as Garvin will get. Even though the environments on the two
planets are very
different, the soft, dusty soils may be similar.
"There are a lot of these real subtle impact features that
look like
Iturralde, with no trees, on Mars," Garvin says.
"Studying craters on Earth,
we can get up close and personal with them; it's the only way
we're going to
understand what we have on a planet like Mars."
Garvin, who has traveled to exotic places including Kazakhstan to
study
impact craters, is not a part of the expedition and so awaits the
data from
the comfort of his office in Washington D.C.
"I'll be frank," he said. "I've been to many
impact sites on this planet and
I find that my talents are better in the cold, dry environments.
That's part
of the reason why I work on Mars. Compton is the type of guy who
does real
well in the jungle."
This trip will be Compton Tucker's seventh or eighth Amazonian
voyage. They
seem almost natural to him as he calmly describes the jungle
lifestyle he
will lead. The team members eat two meals a day, prepared by a
cook they
hire, of rice and beans supplemented with fish they catch and
things they've
brought from home. The menu ranges from piranha to beef jerky.
Social bugs
The team's base camp consists of tents pitched along a river in
Puerto
Araona, the main village of the Araona people, population: 110.
"And it'll be hot and humid and there will be a lot of
insects," Tucker
says. "One of the big problems which most people don't
realize, in all the
tropical forests I've been in, there isn't much salt because it
rains so
much it would tend to wash it away. The social insects view
sweating people
like us as a great salt lick, so the social insects will
communicate to
other social insects where you are and so after two or three
days, there
will just be, as soon as the Sun comes up, hundreds if not
thousands of bees
and wasps who want to just land on you to get the salt. And of
course there
are a lot of mosquitoes."
But Tucker is not intimidated.
"Some people freak out but that's just one of the things you
have to
endure...You just have to keep moving and every day you have to
bathe, so
you just get in the river and wash and you also wash your clothes
because
you want to get the salt out."
Killeen, who has led at least 15 Amazonian expeditions, has an
equally
optimistic outlook. "I think it's going to be a great
time," he says. "I'm
looking forward to swinging a machete instead of thinking about
traffic."
For others, though, it's not the fear of insects or the primitive
living
conditions or even sometimes-stubborn indigenous people that keep
them from
the Iturralde Crater.
"I'd like to go," says Coronado, the Goddard engineer,
"but my wife wouldn't
let me."
Copyright 2002, Space.com
===========
(2) DISPATCHES FROM THE ITURRALDE CRATER
>From Blue Ice Online
http://www.blueiceonline.org/blueweb/dispatch10.html
19 SEPT: INTO THE CRATER
Today at 10AM EST the advance team of Dr Tim Kileen, Peter Hardy,
David
Beverly Sr, Gunther Kletetschka and Peter Wasilewski breached the
rim of the
crater. Coming in low and fast on board HU-1 helicopters out of
Puerto
Araona the team had a few tense moments due to the dense thickets
of foliage
on the ground which impeded landing. After several harrowing
tries the
pilots were finally able to squeeze through, past the snarl of
tree limbs,
and touch down. The conditions on the ground are quite extreme
with very
high heat and humidity.
The main body of the ICE2002 team had reached Palmasola last
night after a
12 hour odyssey on the Manupare River. Due to extremely low water
levels the
trip downriver from Puerto Araona became an arduous stop and go
ordeal
composed of intermittent paddling and carrying. One of the
propellers on a
motorized cargo boat was shattered by rocks in the shallow
riverbed further
delaying the group. The weary team finally arrived after
nightfall in
Palmasola. A bright spot of the journey was the discovery of some
interesting rocks that could aid in uncovering the mystery of the
crater.
This morning, after a brief rest, this part of the team will hike
into the
crater and link up with the advance team.
The ICE 2002 team will be sending back pictures and info this
evening so
stay tuned and check back tonight or tomorrow morning for
updates.
20 SEPT: CRATER RESEARCH BEGINS
After arriving in the crater, Gunther Kletetschka and Dr. Peter
Wasilewski
took some preliminary fluxgate magnetonometer readings (image of
measurement
points) and established the teams exact GPS coordinates. You can
find the
magnetometer data uploads in the 'Science Stuff' area.
Peter Hardy has continued his soil analysis and produced a series
of 3
videos to explain the process.
The conditions on the ground are intense - David Beverly reports,
"We're all
hot, sweaty, dirty and tick infested - we haven't eaten much in
two days -
and I'm loving every minute of it!" While administering
todays webcast David
was besieged by a raging swarm of sweat bees and wasps. These
pests are a
constant and painful presence.
21-22 SEPT: ICE2002 HUNKERS DOWN AND WEATHERS STORM
On Saturday a drenching storm descended on the ICE2002 camp.
Confined to
tents for most of the day - field work was limited. Having gone
nearly a
week without bathing some members of the team took advantage of
the natural
shower provided by the clouds and washed off a bit of the grime.
The rest of
the time was spent preping gear and later that night David
Beverly treated
the weary team to an impromptu guitar concert.
On Sunday the team split up into three parts with distinct
mission
objectives. Peter Wasilewski, Peter Hardy, David Beverly and
Allen Lunsford
headed back to Puerto Araona (compliments of the Red Devil Task
Force
helicopters) to prepare the MAGPLANE for its first flight later
in the week
and to set up tomorrows webcast. Holly Offerman, Tim Killeen and
Compton
Tucker set out on foot to Palmasola continuing their botanical
research.
Last, Gunther Kletetschka stayed behind at the crater basecamp (
dubbed LA
JUNTA DE GENIOS Y DAVE ) to get further magnetometer readings.
The standing
protocol for ICE2002 is that no one ventures out alone - there
must always
be a guide present. This prevents anyone from getting lost in the
maze of
the rainforest.
23 SEPT: TEAM PREPARES MAGPLANE FOR LAUNCH
The team has begun preparing the area around Puerto Araona and
the MAGPLANE
itself for launch on Wednesday. This morning a large chunk of
timber was
dragged across the landing strip to smooth the surface and the
labor
continued well into the evening as members of the team got down
on their
hands and knees to pull out small tufts of grass that were
peppered
throughout the runway. If the small plane got snagged on some of
this grass
the MAGPLANE mission could end before it ever got into the air.
===========
(3) MISSILE MISTAKEN FOR METEOR
>From Newsnet5.com, 20 September 2002
http://www.newsnet5.com/news/1679316/detail.html
Streak In Sky Visible Throughout Western U.S.
SAN JOSE, Calif. -- An interesting sight Thursday night took many
people in
the Bay area by surprise. It was a mysterious light streaking
across the
sky, leaving a trail of vapor.
>From South San Jose to Willow Glen, people out enjoying the
warm late summer
evening speculated about what they saw in the night sky. Was it
an airplane,
terrorist attack, falling star?
Nobody knew it was an unarmed Minuteman III intercontinental
ballistic
missile launched from Vandenberg Air Force Base until it was long
gone. The
test missile was headed for the Kwajalein Missile Range in the
western chain
of the Marshall Islands in the Pacific Ocean. It traveled 4,200
miles in 30
minutes.
The military says it was a perfect launch
"We do this two or three times a year, but because the
weather was so
perfect we decided to launch it early," said Vandenberg
spokeswoman Kelly
Gabel.
As a result, people were still awake to see it, and although the
sun had set
over the western United States, sunset was recent enough that
sunlight below
the horizon glinted off unspent fuel particles and water
droplets.
The next unclassified missile launch, according the Vandenberg
Air Force
Base Web site, is in December, when two Defense Department
payloads will be
sent into orbit.
Copyright 2002 by NewsNet5.com. All rights reserved
=========
(4) GENERAL CALLS FOR METEOR WARNING SYSTEM
>From Discovery.com, 23 September 2002
http://dsc.discovery.com/news/briefs/20020916/meteor.html
By Larry O'Hanlon, Discovery News
Sep. 20 - A general with the U.S. Space Command is calling for a
global
early warning system for meteor explosions so that nuclear wars
aren't
started by mistake.
Brigadier Gen. Simon P. Worden, U.S. Space Command's deputy
director for
operations at Peterson Air Force Base in Colorado, said an
exploding meteor
came close to triggering a nuclear war this summer.
On June 6, U.S. satellites detected a 12-kiloton explosion in the
atmosphere, equivalent to the bomb that leveled Hiroshima. It was
a meteor
vaporizing over the Mediterranean Sea, but had it hit the Earth's
atmosphere
a few hours earlier, it would have been seen as a bright flash
and felt as a
distant boom by Indian and Pakistani soldiers in the disputed
Kashmir
region.
At the height of tensions between the two nations, the blast
could have been
mistaken for a nuclear blast and started a nuclear war, said
Worden.
"In the Cold War you just had us and the Soviet Union, and
we had hot lines
set up" to communicate in emergencies, Worden told Discovery
News. "Now you
have the problem of a dozen countries with weapons of mass
destruction and
delivery systems" and no hotlines.
There isn't even an early warning system to inform governments
and
militaries that the flash was a harmless meteor and not your
nuclear enemy
lobbing a bomb at you, he said.
The United States is currently the only country with infrared
satellite
technology deployed that can detect and distinguish between
exploding
meteors and bombs, said Worden. He wants about ten more officers
at Space
Command's center of operations to help set up and operate the
global early
warning system.
Monitoring meteors is also important for verifying compliance
with the
Comprehensive Test Ban Treaty. Seismologists can already detect
underground
tests and separate them from earthquakes, said forensic
seismologist Terry
Wallace at the University of Arizona. But there is still a need
to set up a
global system to monitor atmospheric explosions, and Worden's
satellites do
just that.
Every year there are about 30 meteors that explode in the
atmosphere with
power greater than a kiloton - the equivalent of a thousands tons
of TNT -
Worden said.
"The (satellite) signature for a meteor is different than a
nuclear
detonation," Worden noted. But right now there is no quick
way to get that
information to nations who are ready to retaliate and have
nuclear
capabilities, he said.
Because meteors travel through space at tens of thousands of
miles per hour,
even a refrigerator-sized rock hits the Earth's atmosphere with
ferocious,
kiloton power.
Copyright © 2002 Discovery Communications Inc.
=============
(5) SCIENTISTS, GOVERNMENTS STEP UP SURVEY OF NEAR EARTH OBJECTS
>From MSNBC, 21 September 2002
http://www.msnbc.com/news/810486.asp
Scientists, governments step up survey of 'near earth objects'
By Antonio Regalado
THE WALL STREET JOURNAL
Sept. 20 - Scientists never saw it coming. In June, an asteroid
the size of
a football field had a near-brush with Earth, coming within
71,000 miles, or
roughly one-third the distance to the moon.
BUT NO ONE KNEW about it until three days after the fact.
Astronomers
snapping telescopic pictures at New Mexico's White Sands Missile
Range
detected the 600,000-ton boulder, hurtling through space at a
relative speed
of 24,000 miles per hour. Had it collided with Earth, the
asteroid,
designated "2002 MN," would have generated an explosive
force equal to that
of a hydrogen bomb.
Now, some scientists are calling for more-aggressive measures to
assess and
counter the threat posed by nearby comets and asteroids, known as
"near-Earth objects," or NEOs. Late last month, more
than 60 astronomers and
space engineers met in a Virginia hotel to consider ideas for
preventing a
NEO from hitting Earth, including comet-penetrating bombs and
tugboat-like
craft that could drag dangerous asteroids off a collision
course.
Governments, too, have begun taking the asteroid risk seriously.
In the
mid-1990s, the U.S. Congress ordered the National Aeronautics and
Space
Administration to start searching for threatening NEOs.
The mile-wide Barringer Crater in Arizona was caused by the
impact of a
small asteroid approximately 50,000 years ago.
The agency is spending $4 million a year to survey dangerous NEOs
and says
by 2008 it will catalog 90% of those larger than 1 kilometer
across. These
giant NEOs probably number about 1,200. But scientists agree a
collision
with just one could be a civilization-ending event - excavating a
citysize
crater and throwing up so much dust and debris that the sun could
be blotted
out for a year.
Smaller NEOs also pose a real threat, and some astronomers say
NASA should
be doing more to monitor them. "Three thousand people died
in 9/11, but
similar damage could be caused by a very small asteroid,"
says Clark
Chapman, an astronomer with the Southwest Research Institute, a
Boulder,
Colo., independent engineering research organization.
The tens of thousands of NEOs in our solar system approach Earth
only every
few years, as they orbit the sun. Many have never been identified
or even
seen before. "If one hits us in the next few decades, we are
likely to see
it when it enters the atmosphere," says Mike Belton, a
private consultant to
NASA.
News media have jumped on dangerous-asteroid stories. But many
times, rocks
that look as if they might hit, based on initial calculations,
turn out to
be no threat at all. "Such media scares may have helped
sensitize the public
to the impact hazard," says David Morrison, of NASA's
Astrobiology
Institute. Still, he says, "they have also demeaned the
credibility of
astronomers."
Scientists deny exaggerating the NEO threat in order to win more
funding. In
fact, NASA initially siphoned off funds from its basic science
budget to
fund the NEO surveys, prompting an outcry from astronomers. The
search for
smaller NEOs has become feasible only during the past decade,
with the
development of more-sensitive instruments. Far smaller than
planets and
dimmer than the dimmest star, asteroids can be detected only when
close to
Earth.
More than 46 comets and nearly 2,008 asteroids have been
discovered since
the NASA survey began. None poses an immediate danger. But many
astronomers
agree with Dr. Morrison, who says if a NEO is found on a
collision course,
"society is in uncharted territory."
Several projects are under way to land robotic equipment on a
comet or
asteroid. In January 2004, NASA expects to launch its Deep Impact
probe,
which will venture millions of miles into space to fire a
816-pound copper
projectile into the nose of comet Tempel-1, creating a crater 100
feet deep
and 300 feet across. Cameras will bring scientists their first
glimpse into
a comet's interior.
Such scientific missions - a long way from Hollywood's "Deep
Impact," the
1998 movie about a last-second diversion of a comet - are
essential to the
technological goal of deflecting them. "If you want to move
an asteroid, you
have to understand what it is made of," says Dr. Belton, who
is deputy
principal investigator for NASA's Deep Impact. Scientists
"have a
realization that we have the tools to do something about
this."
Still, NASA has no plans for deflecting an asteroid, says Tom
Morgan,
minor-planets program scientist at the agency. But the path of an
asteroid
can be calculated many centuries into the future, ruling it out
as a danger.
The surveys, he says, are a way of "retiring risk."
A 1997 Air Force report estimates a "mitigation
mission" to move an asteroid
off a collision course with Earth would take 15 years and cost
$1.2 billion.
The most likely means would be to land something on it and, using
thrusters,
slowly turn it away. "With a decade advance notice, you
could possibly have
a go at it," says Alan Harris, a researcher at NASA's Jet
Propulsion
Laboratory. "But with the future of Earth in the balance, I
would like a
little more time."
NEOs are an extreme example of a low-probability risk. But
because a big one
could wipe out humankind, the chances of dying from an asteroid
impact are
actually considered roughly equal to those of dying in a plane
crash. Yet
far less money is spent addressing asteroid risk.
Geological records leave little doubt about the dangers. An
impact 65
million years ago in Mexico's Yucatan Peninsula, by an object
estimated at 6
miles across, is believed to have led to the extinction of the
dinosaurs. A
250-foot asteroid that exploded in 1908 in the air over Tunguska,
in
Siberia, flattened or burned 1,000 square miles of forest.
Such an explosion could be mistaken for a nuclear attack,
according to the
U.S. Space Command, the Defense Department unit in Colorado
Springs, Colo.
In June, near the height of the India-Pakistan military crisis,
Space
Command satellites watched as an asteroid exploded in the
atmosphere high
over the Mediterranean, releasing three kilotons of energy, Brig.
Gen. Pete
Worden says. "If it had gone off over a city, it would have
looked like a
warning nuclear burst," says the officer, an astronomer by
training.
The most dangerous asteroid astronomers have found is still a
long way off.
According to published orbital calculations, an asteroid a
half-mile wide,
known as "1950 DA" has about a 1-in-300 chance of
hitting the Earth - in
A.D. 2880.
Copyright © 2002 Dow Jones & Company, Inc.
All Rights Reserved.
============
(6) CHICKEN LITTLE OR PLANETARY SAVIOURS?
>From Popular Science, September 2002
http://www.popsci.com/popsci/science/article/0,12543,353821,00.html
Astronomy: Timothy Ferris eyes the amateur asteroid-watchers.
by Robin Nelson
The discovery of asteroid 2002 NT7, the space rock that
astronomers believe
could collide with Earth on February 1, 2019, wasn't the worst
cosmic news
of the summer. More unsettling was the announcement on June 17
that a
football-field-size asteroid had whizzed by Earth three days
before. It
missed us by 750,000 miles-less than a third of the distance to
the moon-and
had the destructive pop of a nuclear weapon.
Then this rev-elation: Of the 50 such asteroids that cross
Earth's path each
year, only a few fall under the watchful gaze of institutional
observatories. That, explains author Timothy Ferris in his new
book Seeing
in the Dark (Simon & Schuster), is where you come in. Thanks
to
high-resolution CCD cameras and Dobsonian telescopes, backyard
stargazers
are probing deeper into space than ever before, and guarding
Earth from
interplanetary peril while they're at it. Consider: A hunk of
rock just 1
kilometer wide could do catastrophic damage.
Amateurs, Ferris explains, have always been important. Steve
O'Meara, for
example, used the old-fashioned method of sketching at his
telescope to
produce drawings of spoke-like patterns in Saturn's rings in the
mid-1970s.
Scientists discounted them until Voyager confirmed their
existence in 1979.
More recently, amateurs have been linking up on the Internet to
discover
everything from exploding stars to new asteroids.
Ferris also sums up the latest news, explaining the mysteries
behind the
Ring Nebula, Silver Coin galaxy, and Virgo supercluster. Best of
all, he
writes in a language accessible to laymen and scientists alike.
ASTEROID-WATCHING 101
There's a space rock out there with your name on it. Here's how
to find it.
Step 1: Buy the Right Equipment
Find yourself a good CCD telescope-reflection or refraction will
do-and a
star chart (free at www.fourmilab.to/yoursky).
Step 2: Go Star-Watching
The Near Earth Object page
(http://cfa-www.harvard.edu/iau/NEO/TheNEOPage.html)
offers good advice on
where to search.
Step 3: Report Your Find
You can do that here
(http://cfa-www.harvard.edu/iau/MPEph/NewObjEphems.html).
Astronomers will
respond within 24 hours.
Step 4: Name Your Discovery
Send your proposed name to the Committee for Small Body
Nomenclature
(mpc@cfa.harvard.edu).
Approval takes two months.
Copyright 2002, Popular Science
=============
(7) NEW CLUES IN THE CONTINUING DETECTIVE STORY OF J002E3
>From Ron Baalke <baalke@jpl.nasa.gov>
New Clues in the Continuing Detective Story of J002E3
Paul Chodas and Steve Chesley
NASA's Near-Earth Object Program Office
September 19, 2002
The precision of our orbit solution for the unusual
Earth-orbiting object
J002E3 has improved considerably since last week, as astronomers
around the
world have continued to track this interesting body and provide
measurements
of its position. Even though the object has been tracked for only
15 days and
traveled only about one sixth of the way around its orbit since
discovery, it is now
possible to draw more precise conclusions about its origin and
future destinations.
While it was strongly suspected a week ago that J002E3 had been
captured by
the Earth in April of this year, it was not known how long the
object had
been orbiting the Sun prior to capture. Additional observations
have now
confirmed that the object was indeed captured from a solar orbit
earlier
this year, and they have also made clear that it escaped the
Earth-Moon
system in March 1971. The mechanics of the escape are much
like those of
the capture in reverse: in both cases, the object passes slowly
through a
portal separating the regions of space controlled by the Earth
and Sun. The
portal is located at the L1 Lagrange point, about 1.5 million
kilometers
from Earth on a line towards the Sun.
The timing of the object's escape is consistent with our theory
that this
object is the Apollo 12 S-IVB third stage, which was left in a
distant Earth
orbit after it was launched on November 14, 1969 and passed the
Moon four
days later. We theorize that the spent rocket orbited the
Earth chaotically
for 15 months before finding the exit pathway through the L1
portal. The
excellent match between the intrinsic brightness of J002E3 and
that expected
for a rocket stage of the S-IVB's size also supports this
theory. The other
four S-IVB stages still flying (those from Apollos 8 through 11)
have been
dismissed as suspects because they entered solar orbit much
earlier than
March 1971.
Other possibilities for the true identity of J002E3 have been
suggested.
The object could be one of the Spacecraft-Lunar Module Adapter
panels which
enclosed the Lunar Module during Apollo launches. Or, the
object might be a
rocket stage from an unmanned lunar probe from that era.
None of these,
however, were launched at the right time or are known to have
entered the
sort of distant orbit from which escape is possible. Furthermore,
these
alternative candidates seem too small to explain the
current brightness of
J002E3. We conclude that the Apollo 12 S-IVB stage is the
most likely
identity of the object.
Our improved orbital knowledge for J002E3 is also allowing more
precise
predictions for its future motion. The likelihood that the object
will
impact the Moon next year has decreased to less than one percent.
This new
conclusion follows from the fact that the range of possible
motion in 2003
is now more tightly constrained and barely intersects the Moon.
The
possibility of collision with the Earth has also decreased, down
to well
less than one percent. (Even if it should hit our planet, the
object is too
small to be considered hazardous.) It now appears likely that the
object
will escape back into solar orbit in June 2003 after its brief
six-orbit
visit to our planet. In 30 years time the Earth may once again
capture
J002E3 for another brief tour around its home planet.
=============
(8) STUDY CAST DOUBT ON EARTHQUAKE-PREDICTION MODEL
>From Andrew Yee <ayee@nova.astro.utoronto.ca>
Stanford University
Stanford, California
CONTACT:
Mark Shwartz, News Service
(650) 723-9296; e-mail: mshwartz@stanford.edu
9/17/02
Study casts doubt on validity of standard earthquake-prediction
model
By Mark Shwartz
A new study by Stanford University geophysicists is raising
serious
questions about a fundamental technique for making long-range
earthquake
predictions.
Writing in the journal Nature, geophysicists Jessica Murray and
Paul Segall
show how a widely used earthquake model failed to predict when a
long-anticipated magnitude 6 quake would strike the San Andreas
Fault in
Central California.
In their Sept. 19 Nature study, Murray and Segall analyzed the
"time-predictable recurrence model" -- a method
scientists use to calculate
the probability of future earthquakes. Developed
by Japanese geophysicists K. Shimazaki and T. Nakata in 1980, the
time-predictable model has become a standard tool for hazard
prediction in
many earthquake-prone regions -- including the United States,
Japan and New
Zealand.
For example, the U.S. Geological Survey (USGS) relied on the
time-predictable model and two other models in its widely
publicized 1999 report projecting a 70-percent probability
of a large quake striking the San Francisco Bay Area by 2030.
Strain build-up
The time-predictable model is based on the theory that
earthquakes in fault
zones are caused by the constant build-up and release of strain
in the
Earth's crust.
"With a plate boundary like the San Andreas, you have the
North American
plate on one side and the Pacific plate on the other,"
explained Segall, a
professor of geophysics. "The two plates are moving at a
very steady rate
with respect to one another, so strain is being put into the
system at an essentially constant rate."
When an earthquake occurs on the fault, a certain amount of
accumulated
strain is released, added Murray, a geophysics graduate student.
"Following the quake, strain builds up again because of the
continuous
grinding of the tectonic plates," she noted. "According
to the
time-predictable model, if you know the size of the most recent
earthquake
and the rate of strain accumulation afterward, you should be able
to
forecast the time that the next event will happen simply by
dividing the
strain released by the strain-accumulation rate."
Parkfield, Calif.
Although the model makes sense on paper, Murray and Segall wanted
to put it
to the test using long-term data collected from an ideal setting.
Their
choice was Parkfield -- a tiny town in Central California midway
between San
Francisco and Los Angeles.
Perched along the San Andreas Fault, Parkfield has been rocked by
a
magnitude 6 earthquake every 22 years on average since 1857. The
last one
struck in 1966, and geologists have been collecting earthquake
data there
ever since.
"Parkfield is a good place to test the model because we have
measurements of
surface ground motion during the 1966 earthquake and of the
strain that's
been accumulating ever since," Murray noted. "It's also
located in a fairly
simple part of the San Andreas system because it's on the main
strand of the
fault and doesn't have other parallel faults running
nearby."
When Murray and Segall applied the time-predictable model to the
Parkfield
data, they came up with a forecast of when the next earthquake
would occur.
"According to the model, a magnitude 6 earthquake should
have taken place
between 1973 and 1987 -- but it didn't," Murray said.
"In fact, 15 years
have gone by. Our results show, with 95 percent confidence, that
it should
definitely have happened before now, and it hasn't, so
that shows that the model doesn't work -- at least in this
location."
Could the time-predictable method work in other parts of the
fault,
including the densely populated metropolitan areas of Northern
and Southern
California? The researchers have their doubts.
"We used the model at Parkfield, where things are fairly
simple," Murray
observed, "but when you come to the Bay Area or Los Angeles,
there are a lot
more fault interactions there, so it's probably even less likely
to work in
those places."
Segall agreed: "I have to say, in my heart, I believe this
model is too
simplistic. It's really not likely to work elsewhere, either, but
we still
should test it at other sites. Lots of people do these kinds of
calculations. What Jessica has done, however, is to be extremely
careful.
She really bent over backward to try to understand what the
uncertainties of
these kinds of calculations are -- consulting with our colleagues
in the
Stanford Statistics Department just to make sure that this was
done as
carefully and precisely as anybody knows how to do. So we feel
quite
confident that there's no way to fudge out of this by saying
there are
uncertainties in the data or in the method."
Use with caution
Segall pointed out that scientists in the United States and other
Pacific
Rim countries routinely use this technique for long-range hazard
assessments.
"We're in a tough situation, because agencies like the USGS
-- which has the
responsibility for issuing forecasts so that city planners and
builders can
use the best available knowledge -- have to do the best they can
with what
information they have," Segall observed. "The message
I would send to my geophysical colleagues about this model is,
'Use with
caution.' "
Technological advances in earthquake science could make
long-range
forecasting a reality one day, added Murray, pointing to a
recently launched
San Andreas Fault drilling experiment in Parkfield under the
aegis of USGS
and Stanford.
"I always tell people to prepare," Segall concluded.
"We know big
earthquakes have happened in the past; we know they will happen
again. We
just don't know when."
Funding for the Nature study was provided by Stanford Graduate
Fellowships
and the USGS Earthquake Hazards Reduction Program.
-30-
EDITORS: Photos of Murray and Segall are available at
http://newsphotos.stanford.edu
(slug: "Murray" & "Segall"). Their
study, "Testing time-predictable earthquake recurrence by
direct measurement
of strain accumulation and release," will be published in
the Sept. 19 issue
of Nature.
Relevant Web URLs:
* http://kilauea.stanford.edu/paul/
* http://kilauea.stanford.edu/jrmurray/
* http://quake.wr.usgs.gov/research/parkfield/index.html
* http://geopubs.wr.usgs.gov/open-file/of99-517/
==============
(9) IMPACT INDUCED MELTING
>From Michael Paine <mpaine@tpg.com.au>
Dear Benny
See the following abstracts frtom http://www.sciencedirect.com/
regards
Michael Paine
---------------
Impact induced melting and the development of large igneous
provinces
a Department of Geological Sciences, University College London,
Gower
Street, London WC1E 6BT, UK
b SRI International, Menlo Park, CA 94025, USA
c Century Dynamics Ltd., Dynamics House, Hurst Road, Horsham,
West
Sussex RH12 2DT, UK
Earth and Planetary Science Letters
Volume 202, Issues 3-4, 30 September 2002, Pages 551-561
Abstract
We use hydrodynamic modelling combined with known data on mantle
melting
behaviour to examine the potential for decompression melting of
lithosphere
beneath a large terrestrial impact crater. This mechanism may
generate
sufficient quantity of melt to auto-obliterate the crater.
Melting would
initiate almost instantaneously, but the effects of such massive
mantle melting may
trigger long-lived mantle up-welling that could potentially
resemble a
mantle hotspot. Decompression melting is well understood; it is
the main
method advocated by geophysicists for melting on Earth, whether
caused by
thinned lithosphere or hot rising mantle plumes. The energy
released is
largely derived from gravitational energy and is outside (but
additive to)
the conventional calculations of impact modelling, where energy
is derived
solely from the kinetic energy of the impacting projectile, be it
comet or
asteroid. The empirical correlation between total melt volume and
crater
size will no longer apply, but instead there will be a
discontinuity above
some threshold size, depending primarily on the thermal structure
of the
lithosphere. We estimate that the volume of melt produced by a 20
km
diameter iron impactor travelling at 10 km/s may be comparable to
the volume
of melt characteristic of terrestrial large igneous provinces
(~106 km3);
similar melting of the mantle beneath an oceanic impact was also
modelled by
Roddy et al. [Int. J. Impact Eng. 5 (1987) 525]. The mantle melts
will have
plume-like geochemical signatures, and rapid mixing of melts from
sub-horizontal sub-crater reservoirs is likely. Direct coupling
between
impacts and volcanism is therefore a real possibility that should
be
considered with respect to global stratigraphic events in the
geological
record. We suggest that the end-Permian Siberian Traps should be
reconsidered as the result of a major impact at ~250 Ma.
Auto-obliteration
by volcanism of all craters larger than ~200 km would explain
their
anomalous absence on Earth compared with other terrestrial
planets in the
solar system.
Corresponding author. Tel.: +44-207-679-7083; Fax:
+44-207-387-1612;
email: adrian.jones@ucl.ac.uk
----------------
Shallow-marine impact origin of the Wetumpka structure (Alabama,
USA)
David T. King, Jr. , , a, Thornton L. Neatheryb, Lucille W.
Petrunyc,
Christian Koeberld and Willis E. Hamesa
a Department of Geology, Auburn University, Auburn, AL
36849-5305, USA
b Neathery and Associates, 1212-H 15th Street East, Tuscaloosa,
AL
35404, USA
c Astra-Terra Research, Auburn, AL 36831-3323, USA
d Institute of Geochemistry, University of Vienna, Althanstrasse
14,
1090, Vienna, Austria
Received 11 December 2001; revised 27 March 2002;
accepted 28 June
2002. Available online 11 September 2002.
Earth and Planetary Science Letters
Volume 202, Issues 3-4, 30 September 2002, Pages 541-549
Abstract
The Wetumpka structure, an arcuate, 7.6 km diameter, rimmed
feature of the
inner Coastal Plain, Alabama, is a Late Cretaceous shallow-marine
impact
crater. In this paper, we show unequivocal evidence of Wetumpka's
impact
origin. Within and about this structure, pre-existing Upper
Cretaceous
stratigraphy was resedimented and(or) deformed, thus creating
distinctive
intra-structure and extra-structure terrains. These terrains are
located,
respectively, within Wetumpka's crystalline-rim terrain and
adjacent to the
structure on the southern side. Core drilling near the
structure's
geographic center revealed that Wetumpka's basin-filling sequence
has two
distinctive units, suggestive of a two-stage filling process
consisting of
(1) fall-back plus resurge followed by (2) a later secondary
seawater
resurge event. Wetumpka's lower subsurface unit includes polymict
impact
breccias, which contain quartz grains displaying
shock-characteristic
multiple sets of planar deformation features. Selected subsurface
samples of
this breccia also contain elevated Ir, Co, Ni and Cr
concentrations
indicative of a minor extraterrestrial component.
Corresponding author. Tel.: +1-334-844-4882; Fax:
+1-334-844-4486;
email: kingdat@auburn.edu
============
(10) THE THINGS YOU LEARM FROM TRIVIAL PURSUIT...
>From James Oberg <joberg@houston.rr.com>
You might be interested in this exchange...
From: "Russell Stewart" <nospam@nospam.com>
Subject: The things you learn from Trivial Pursuit...
Date: Thursday, September 19, 2002 12:35 PM
Last night my wife and I were playing Trivial Pursuit (Genus 5
edition), and
the following question came up:
"What object exploded in Ireland in 1997, creating a
mile-wide crater that
was initially blamed on an IRA bomb until it was identified by
astronomers?"
The answer, as you might have guessed, is "an
asteroid".
I found this rather shocking, as it seemed to me that such an
event would
have been all over the news, and I would have *some* memory of
it. I don't
recall slipping into any comas in 1997, and I don't remember any
headlines
about an asteroid hitting Ireland and making a mile-wide (!)
crater. Has
anyone heard of this incident?
Keep in mind that this is the same edition of Trivial Pursuit
that
identified one of the training sites for Apollo astronauts as
"Meteor
Crater, New Mexico", so I'm not inclined to take what it
says at face value
(unless there are now *two* asteroid impacts that I've never
heard of!)
--
Russell Stewart |
E-Mail: check my web page
UNM Physics Department | http://www.russell-stewart.net
alt.atheism #343
"If knowledge is dangerous, the solution cannot
be ignorance. The solution has to be wisdom."
--Isaac Asimov
From: "Dave Michelson" <dmichelson@ieee.org>
Subject: Re: The things you learn from Trivial Pursuit...
Date: Thursday, September 19, 2002 12:55 PM
There was a crater, but it was only a couple of feet in diameter.
It was the
sight and sound of entry that attracted attention.
Afterward, there was speculation that it was caused by a small
chunk of a
larger meteorite that impacted the Greenland icecap on the same
day.
--
Dave Michelson
dmichelson@ieee.org
===============
(11) AND FINALLY: FORGET SIZE, WE'RE TALKING LONGEVITY
>From Reuters, 13 September 2002
http://story.news.yahoo.com/news?tmpl=story&u=/nm/20020913/sc_nm/science_penis_dc_1
Oldest Known Penis Is 100 Million Years Old
LEICESTER, England (Reuters) - Sex was first recognized in the
fossil
records more than 500 million years ago and the oldest known
penis is about
100 million years old, a conference heard on Friday.
It belongs to an ostracod, an early crustacean related to crabs,
shrimps and
water fleas, and was found in a fossil sample unearthed in
Brazil.
"To my knowledge it is the oldest penis. I don't know of any
older,"
Professor David Siveter, of the University of Leicester, told the
British
Association science conference.....
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