PLEASE NOTE:


*

CCNet 48/2002 - 16 April 2002
----------------------------


"In a recent study published by the Iowa Law Review, Policy Analyst
Evan R. Seamone has addressed the duty to mitigate asteroid and comet
impacts from the perspective of international law. The report argues
that the nature of the dangers posed by asteroids and comets place the
threat in the category of certain types of disasters for which the
international community is unprepared."
-- Elizabeth Davis, Iowa Law Review


(1) NEW COMET DETECTED BY SOHO - VISIBLE THE REST OF THE WEEK
    Paal Brekke <pbrekke@esa.nascom.nasa.gov>

(2) LEGAL DUTY TO "MITIGATE" ASTEROID OR COMET COLLISIONS WITH THE EARTH
INVOLVES MUCH MORE THAN  
    STARGAZING, SAYS POLICY ANALYST
    Elizabeth Davis, http://www.uiowa.edu/~ialawrev/

(3) CRASH COURSE: SCIENTISTS STEP UP EFFORTS TO TRACK ASTEROIDS
    The Dallas Morning News, 15 April 2002

(4) EUROPEAN SPACE AGENCY TO PROBE ASTEROID BLIND SPOT
    Karen O'Flaherty <Karen.O'Flaherty@esa.int>

(5) MISSIONS TO PLUTO, EUROPA CANCELED
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(6) MECHANISM THAT CREATES NEAR-EARTH BINARY ASTEROIDS
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(7) RADAR REVEALS FIVE DOUBLE ASTEROID SYSTEMS ORBITING EACH OTHER NEAR
EARTH
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(8) A LAST WAVE GOODBYE
    The Guardian, 11 April 2002

(9) DAVE RODDY, 1932 - 2002
    U.S. Geological Survey

(10) THE REAL THREAT TO THE PLANET
     Tech Central Station, 9 April 2002

(11) ROCKET FRAGMENT, NOT METEORITE, LANDED IN UGANDA
     Ron Baalke <baalke@jpl.nasa.gov>

(12) AND FINALLY: CHINA METEOR MAY (OR MAY NOT) SOLVE MYTHICAL DEATH OF
MYTHICAL EMPEROR
     Ron Baalke <baalke@jpl.nasa.gov>


=================
(1) NEW COMET DETECTED BY SOHO - VISIBLE THE REST OF THE WEEK

>From Paal Brekke <pbrekke@esa.nascom.nasa.gov>

The comet SOHO-422 was first reported on Friday, April 12, by XingMing Zhou
of China, who discovered the comet while watching SOHO real-time images on
the Internet.  The comet is a new comet, not belonging to any known group of
comets. It will be visible in LASCO C3 images until
Saturday, April 20. The comet was first visible late in the day on Thursday,
April 11.  It enters the FOV at the bottom edge, almost directly under the
Sun.  It is moving upwards, first to the left. It will eventually move back
towards the right, exiting from the LASCO C3 field of view at the top edge,
to the right of the Sun.

It will reach perihelion on April 17 at about 6:30 UT, at a distance of 17.7
solar radii.  At this time, the apparent distance in LASCO will be about 13
solar radii.  As the week goes on, the comet will move through the field of
view more quickly.

It's officially designated as C/2002 G3 (SOHO) in MPEC 2002 G51.

Updating mpegs where people can follow the comet across the LASCO field of
view:
http://sohowww.nascom.nasa.gov/data/LATEST/current_c3.mpg
http://sohowww.nascom.nasa.gov/data/LATEST/current_c2.mpg

Stills:
http://sohowww.nascom.nasa.gov/data/realtime-images.html

In all these images the shaded disk is a mask in the instrument that blots
out direct sunlight.  The white circle added within the disk shows the size
and position of the visible Sun.

NOTE: AROUND 08:18 UT TODAY the comet went behind the pylon (the metal rod
holding the occulting disk in front of the Sun). It will reappear around
15:18 UT.

SOHO has discovered more than 420 comets in just under 6 years which makes
SOHO the most prolific comet finder in the history of astronomy. Most of the
comets were first spotted by amateurs around the world downloading our real
time images to their home computers. All the SOHO images are freely
available on the SOHO web site:  http://sohowww.nascom.nasa.gov/

THUS, ANYONE WITH INTERNET ACCESS CAN TAKE PART IN THE HUNT FOR NEW COMETS
AND BE A COMET DISCOVERER. To read more about sungrazing comets and how to
spot new ones visit: http://sungrazer.nascom.nasa.gov/

Solar radiation heats the comet which in turn causes the outgassing of the
water molecules and dust. The dust scatters sunlight at visible wavelengths,
making the comet bright in LASCO images.  The water molecules break down
into oxygen and hydrogen atoms, and the hydrogen atoms interact with the
coronal plasma.

IMAGE CREDITS:  SOHO (ESA/NASA)

Launched almost 6 years ago as a project of international cooperation
between the European Space Agency and NASA, the Solar and Heliospheric
Observatory has revolutionized the science of the Sun.

Webstories on:
http://sohowww.nascom.nasa.gov/hotshots/

----------------------------------------------------------------------------
-
Paal Brekke,
SOHO Deputy Project Scientist  (European Space Agency - ESA)

NASA Goddard Space Flight Center,      Email: pbrekke@esa.nascom.nasa.gov
Mail Code 682.3, Bld. 26,  Room 001,   Tel.:  1-301-286-6983 /301 996 9028
(cell)
Greenbelt, Maryland 20771, USA.        Fax:   1-301-286-0264
----------------------------------------------------------------------------
-
SOHO WEB: http://soho.nascom.nasa.gov/
----------------------------------------------------------------------------
-

=====================
(2) LEGAL DUTY TO "MITIGATE" ASTEROID OR COMET COLLISIONS WITH THE EARTH
INVOLVES MUCH MORE THAN STARGAZING, SAYS POLICY ANALYST

Dateline:       April 13, 2002 ... Iowa City, Iowa
Contact Name:   Elizabeth Davis
Contact Phone:  319-335-9132
Web Address:    http://www.uiowa.edu/~ialawrev/

Iowa City, Iowa - April 13, 2002 - In the 1960's, a period that many called
the "Golden Age of Space," the public began to doubt the writings of lawyers
who addressed space-related topics. Too many had "jumped on board the ship,"
so to speak. Today, one area where the attention of lawyers is desperately
needed relates to the mitigation of threats posed by asteroid or comet
collisions with the Earth.

Aside from the efforts of nations to conduct sky searches and catalogue
potential threats, there exist few, if any, plans to evacuate nations,
educate the public about the nature of a significant impact, or deal with
the rationing of scarce resources, in the event that scientists or military
personnel are unable to destroy or deflect an oncoming space body of
significant mass.

In a recent study published by the Iowa Law Review, Policy Analyst Evan R.
Seamone has addressed the duty to mitigate asteroid and comet impacts from
the perspective of international law. The report argues that the nature of
the dangers posed by asteroids and comets place the threat in the category
of certain types of disasters for which the international community is
unprepared. Similar threats include the mutation of the Acquired Immune
Deficiency Syndrome into an airborne virus or the collapse of the Cumbre
Vieja volcano in the Canary Islands, which would devastate multiple nations
simultaneously.

Seamone argues that mitigating asteroid or comet threats necessarily
involves preventive measures including the commitment of resources and
personnel. He first explains the three major obstacles that must be overcome
before mitigation efforts will succeed. First, the public must be educated
to treat the threat seriously, an objective attainable by developing
international protocols, especially involving warning mechanisms and the
verification of actual threats. Second, the dangers posed by these unique
threats must be situated in policies that extend beyond traditional disaster
response measures at the international level, which often suffer from a lack
of coordination.

Third, duties to commit resources preventively must rest on principles other
than the allocation of blame, which characterizes much of the corpus of law
dealing with international responsibilities to mitigate transboundary harm.

Next, recognizing the danger posed to governments in the absence of serious
preventive coordination, the report associates the duty to mitigate asteroid
and comet impacts with General Principles of International Law, as
recognized by the Statute of the International Court of Justice. The legal
precedents supporting international cooperation hinge on the duty to
self-preserve as articulated by philosophers such as Vattel and Hobbes and
in numerous State Constitutions guaranteeing essential necessities such as
air, food, and water, and the extension of that duty, which would require
nations to cooperate in order to secure the survival of their own populaces,
as indicated in legal opinions such as the Island of Palmas case.

After pointing out manifestations of nations' adherence to the principle of
"cooperative preservation," through duties to warn other nations of
impending danger, such as Article 28 of the International Law Commission's
Draft Articles on the Law of Non-Navigational Uses of International Water
Courses, and duties to mitigate impending danger, such as Principle VII of
Principles Relevant to the Use of Nuclear Power Sources in Outer Space,
Seamone recommends international collaboration similar to the Scientific
Committee on Antarctic Research (SCAR), which deals with issues facing the
Antarctic region, endowed with certain unique powers to influence
legislation and the allocation of resources.
 
IF INTERESTED in receiving an offprint of Evan R. Seamone's "When Wishing on
a Star Just Won't Do: The Legal Basis for International Cooperation in the
Mitigation of Asteroid Impacts and Similar Transboundary Disasters," the
author has reserved 100 complementary copies for interested individuals. The
Iowa Law Review can facilitate such orders. The author may be contacted
directly at (319) 358-6422 or eseamone@blue.weeg.uiowa.edu

====================
(3) CRASH COURSE: SCIENTISTS STEP UP EFFORTS TO TRACK ASTEROIDS

>From The Dallas Morning News, 15 April 2002
http://www.dallasnews.com/health/stories/041502dnlivasteroid.a8e99.html

By ALEXANDRA WITZE / The Dallas Morning News

Like a clay pigeon, Earth serves as the moving target in a cosmic shooting
gallery.

Flying chunks of rock and ice - asteroids and comets - constantly wallop the
planet. The small ones burn up or explode in the atmosphere. But someday,
scientists worry, a really big one could hit with the force that killed the
dinosaurs 65 million years ago.

The last few months have brought some scary reminders.In January, an
asteroid the size of a football field zoomed by a month after it was
discovered. In March, a smaller rock made headlines when it was spotted four
days after passing Earth. This month, astronomers announced an up to
1-in-300 chance that another big asteroid could hit in the year 2880.

The good news is that this asteroid, called 1950 DA, is helping scientists
better understand the risk of collision - and what to do if a big rock is
discovered heading for Earth.

"I was hoping this case would move the discussion to a higher level," says
Jon Giorgini, leader of the team that announced the possible future impact.
"In the past it's all been about primal fear issues: Is it going to hit, is
it not going to hit?"

Researchers now know more about 1950 DA's path than they do about any other
near-Earth asteroid.

"The exciting thing is the science coming out of this," says Steven Chesley,
an asteroid expert at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

For instance, scientists are learning about the subtle physical forces that
can nudge asteroids onto a path toward, or away from, Earth. Dangerous
asteroids can also come in pairs, other new work has shown - doubling the
trouble for scientists trying to save the planet.

Not all asteroids are bad. Most of the 40,000 identified so far orbit the
sun between Mars and Jupiter, in the asteroid "main belt." But sometimes
gravitational tugs from planets or other celestial bodies send main-belt
asteroids closer to the Earth. The same thing can happen to comets, icy
bodies from farther out in the solar system.

The Earth is pockmarked with scars - impact craters - from previous meetings
with asteroids and comets. And every year, scientists monitor dozens of
explosions in the atmosphere caused by rocks several feet across.

Meanwhile, a rock on the order of several hundred feet across might hit
every few centuries to 100,000 years, scientists estimate. A really big
asteroid, measuring two-thirds of a mile across or more, might hit about
once every million years - possibly causing global devastation by
enshrouding the planet in dust.

Researchers are most worried about the biggest objects, like the estimated
1,000 Earth-threatening asteroids that are two-thirds of a mile across or
more.

Congress has asked NASA to find 90 percent of those objects before the end
of 2008, says Don Yeomans, manager of the near-Earth object program office
at the Pasadena lab. Five U.S.-led search teams, along with some now-defunct
programs, have identified just under 600 of those asteroids.

"That looks pretty good on paper, but it's like the old Easter egg problem,"
says Dr. Yeomans. "The first ones are a lot easier to find than the
subsequent ones."

Also of concern are smaller asteroids, which could still wipe out a city if
they hit.

"Those are bullets out there that can really ping us, too, and we can't
overlook those," says longtime asteroid hunter Eleanor Helin of the Jet
Propulsion lab.

The closest known near-miss was a small asteroid, about the size of a flying
couch, that zoomed by in 1994 at a distance of about 70,000 miles, or
three-tenths of the way to the moon. In contrast, the asteroid that got so
much attention in March, known as 2002 EM7, passed at about 290,000 miles
away, farther than the moon.

"Objects like that pass around those distances on the order of every single
week of every single year," says Dr. Chesley.

The sun's glare obscures objects coming toward Earth from the direction of
the sun, so scientists often won't spot an asteroid until after it's passed,
he says.

More intriguing - not just because it was immortalized in a column by
humorist Dave Barry - was the football-field-sized asteroid 2001 YB5.
Discovered in December by Dr. Helin's team, 2001 YB5 whizzed within 520,000
miles on Jan. 7.

Now, scientists are most worried about an object called 2002 CU11, which has
a small chance of hitting Earth in August 2049. That risk that will probably
disappear as astronomers get more observations to pin down the asteroid's
path, says Dr. Yeomans.

Unlike many other near-Earth asteroids, 2002 CU11 has a stable orbit that
doesn't get perturbed by other planets. "It avoids all the planets except
Earth," Dr. Yeomans notes.

As of last week, 2002 CU11 was the only object rated a "1" on the Torino
scale, which was devised to communicate asteroid risk to the public. The
scale runs from 0 (which includes all other asteroids) to 10 (indicating a
certain collision with global consequences).

But on another risk scale, 2002 CU11 has been rated as less threatening than
the general, or background, risk of any other impact; as of last week, it
had a value of minus 1.28 on the Palermo scale.

Last summer, scientists introduced the Palermo scale to help prioritize the
many asteroids that were showing up as 0 on the Torino scale.

With only the Torino scale, "we don't have a way of categorizing these
hundreds of potential impact events," says Dr. Chesley. The Palermo scale
uses 0 to represent the background risk of impact; numbers can range below
or above 0 depending on relative risk.

The only object to receive a positive Palermo rating so far - meaning its
risk is above the background - is 1950 DA, with a rating of plus 0.17.

Like other asteroids, 1950 DA will probably be marked as safe once it
reappears and astronomers can observe it, says Dr. Chesley. But just in
case, asteroid experts are busy dreaming up Armageddon-like schemes for
deflecting a rock heading for Earth.

Strategies might include blowing up the asteroid with a nuclear or
conventional explosive; blasting off enough small pieces to change the
asteroid's trajectory; or exploiting a little-known effect caused by the
sun's heat.

The "Yarkovsky effect" describes how, as the afternoon side of an asteroid
rotates into darkness, it reradiates heat from its warmed surface and pushes
slightly in the opposite direction. It is this effect that serves as the
greatest uncertainty about where 1950 DA might be in 2880, says Mr.
Giorgini, of the Pasadena lab.

The Yarkovsky effect may be responsible for making some asteroids dangerous
in the first place; the subtle radiation may help nudge asteroids from the
main belt into Earth-crossing orbits, some scientists think.

Other researchers believe that harnessing the effect might be the best way
to save Earth. Some astronomers, including Andrea Milani of the University
of Pisa in Italy and Joseph Spitale of the University of Arizona, have
independently suggested methods for altering an asteroid's heat-absorbing
properties. This might involve changing the asteroid's color - by painting
or covering it in black or white substances.

"There are obviously engineering problems with taking so much talcum powder
out into space," Dr. Chesley notes.

Saving the planet might be twice as hard if the incoming asteroid were
actually in two pieces.

One in six near-Earth asteroids is probably a binary, which means two rocks
travel together, says a new paper published last week in the online version
of Science magazine. The scientists, led by Jean-Luc Margot of the
California Institute of Technology, say that five such pairs have been found
so far. Twinned rocks have hit Earth before; several of the impact craters
on Earth are double craters formed by two asteroids at the same time.

Whether one or two asteroids is approaching, astronomers want as much lead
time as possible to prepare for any impact. At least several decades would
be needed to plan a strategy, says Benny Peiser, a social scientist at
Liverpool John Moores University in England who studies impact risks.

Dr. Peiser says that the public may have to learn to live with uncertainty.
Even with the best predictions, he says, "we could have this prolonged
period of anxiety and uncertainty when we don't know what is going to
happen."

Fortunately, scientists are working hard now so that they won't be too
surprised in the future.

"The problem is being handled, at least at some level," says Dr. Yeomans.
"Whereas 10 years ago, people didn't even know there was a problem."

E-mail awitze@dallasnews.com

Copyright 2002, Dallas Morning News

===============
(4) EUROPEAN SPACE AGENCY TO PROBE ASTEROID BLIND SPOT

>From Karen O'Flaherty <Karen.O'Flaherty@esa.int>

In the past five weeks two asteroids have passed close by Earth, at
distances of 1.2 and 3 times the distance to the Moon. Another asteroid has
recently been shown to be on course for a collision with Earth in 2880.
Monitoring known asteroids allows astronomers to predict which may collide
with Earth. But that is only true for the asteroids we know of. What about those
that lie in the asteroid blind spot between the Sun and Earth? The European Space
Agency is studying ways in which its missions can assist in monitoring these
unseen but potentially hazardous asteroids.

It is difficult to estimate the danger posed by asteroids. This is, in part,
because astronomers do not yet know how many asteroids there are. A recent
discovery, made using data from ESA's Infrared Space Observatory (ISO),
showed that there could be nearly two million asteroids larger than one
kilometre in the main asteroid belt, between Mars and Jupiter.  That is more
than twice as many as previously thought.

In addition, even when an asteroid is identified many observations must be
made before it is known whether or not it will come close to, or even
collide with, Earth.

If the asteroids remained in the main-belt, they would pose no danger to
Earth. However, they can be thrown into different orbits by collisions with
other asteroids or by the influence of Jupiter's gravitational field. If
their new orbits cross the Earth's orbit, they could one day collide with
our planet, inflicting unprecedented devastation.

A number of ground-based searches are already underway to find as many
potentially hazardous asteroids (PHAs) as possible but there is a notorious
'blind spot' that telescopes on Earth can never peer into. It is the region
of space inside Earth's orbit, towards the Sun. From Earth,
astronomical observations close to the Sun are almost impossible because it
means observing during the daytime when only the brightest celestial objects
stand out from the blue sky. That means asteroids lurking in this region of
space can 'sneak up' on the Earth undetected. Asteroid 2002 EM7, which
passed close by the Earth on 8 March this year, was one such object and was
only detected after it crossed Earth's orbit to appear briefly in the night
sky, before it crossed back into the glare of the Sun.

About 550 similar asteroids are known. They are called the Atens and spend
most of their time inside Earth's orbit, close to the Sun. Traditional
estimates suggest there may be several thousand in total and tracking them
from Earth is next to impossible.  However, a study performed for ESA has
shown that the Gaia spacecraft will be able to see clearly into this
'blind spot' and keep precise track of the Aten population.

François Mignard of Observatoire de la Côtes d'Azur, France, conducted the
study. He found that Gaia would be ideal because it is designed to measure
the position of celestial objects with unprecedented accuracy. In addition,
since there is no atmosphere in space to scatter the Sun's rays and create a
blinding blue sky, Gaia can see close to the Sun without disturbance.

Gaia is expected to be launched around 2010. Even if ground-based searches
have spotted more Atens by that time, the mission still has an essential
role to play because it will reveal their orbits to a precision 30 times
better than any observation from the ground, thus identifying whether any
pose a danger to Earth.

"To know how close these objects will come to Earth is very dependent on how
accurately one can measure their orbits.  That's the main contribution that
Gaia can be expected to make," says Michael Perryman, project scientist for
Gaia, at ESA's European Space Research and Technology Centre in the
Netherlands.

Gaia's data will also provide astronomers with a first estimate of these
objects' composition.  This knowledge could help to determine methods to
divert or destroy asteroids that are set on a collision course with Earth.

Several ESA missions are contributing, or will contribute, to our
understanding of minor bodies of the Solar System: these include ISO, Gaia
and Rosetta, which will study asteroids Siwa and Otawara. ESA is also
considering the addition of an asteroid spotting telescope to its
BepiColombo mission.

================
(5) MISSIONS TO PLUTO, EUROPA CANCELED

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

[ http://www.latimes.com/news/nationworld/nation/la-000026460apr13.story ]

Saturday, April 13 2002

Missions to Pluto, Europa Canceled
By USHA LEE McFARLING, LOS ANGELES TIMES STAFF WRITER

NASA's on-again, off-again mission to Pluto appears to be off, at least for
now. And a JPL mission to Jupiter's watery moon Europa -- considered the
most likely spot for extraterrestrial life -- also has been canceled for
budget reasons.

Top NASA officials said Friday it was highly unlikely that a mission to
Pluto would launch by 2006 -- the final date set by scientists to be able to
reach the planet in time to study its atmosphere before it becomes
inaccessible for a century. The Europa mission was canceled
after its projected cost more than doubled.

Though a darling of schoolchildren and a long-elusive target of scientists,
a Pluto expedition is not favored by the White House. For the second year in
a row, the administration budget has included no money to explore the
distant world. Last year, Congress added $30 million to NASA's budget to
develop plans for a Pluto mission after a flood of letters and calls from
distraught children and concerned citizens. But this year, scientists at the
Applied Physics Laboratory
at Johns Hopkins University in Baltimore were refused the $122 million they
say is necessary to continue developing a $500-million mission.

Even if Congress again restores funding at the last minute, the unmanned
mission faces two significant hurdles, said Chris Scolese, NASA's deputy
associate administrator for space science.

It has yet to be proved, he said, that the distant mission is feasible. In
addition, the use of plutonium in the spacecraft, to power its instruments,
remains controversial.

In other spacecraft, including Cassini, which is bound for Saturn, it has
generally taken about eight years to receive permission to use plutonium,
Scolese said. Opponents of using the radioactive material fear contamination
from a spacecraft accidentally returning to Earth; NASA says the plutonium
is well shielded, minimizing any risk.

Finally, the mission is scheduled to leave Earth aboard a new rocket --
either a Boeing Delta IV or a Lockheed Martin Atlas V. Both rockets have yet
to take their maiden voyage; NASA officials would want the rockets to be
well proved before using them to launch spacecraft.

Life on Europa Thought Possible

The mission to Europa was canceled after its $650-million budget swelled to
$1.4 billion. The mission could compete for funding in the new NASA budget
if its cost is trimmed back to $650 million. But scientists think it is
unlikely that they could conduct an effective mission to probe the icy
moon's subsurface oceans for traces of life for less than $1 billion.

Most of the staff working on the Europa mission at the Jet Propulsion
Laboratory -- 80 to 90 people -- are continuing to work on a new generation
of faster, smaller radiation-hardened electronics that were part of the
project and will now be used to improve future missions. Others have been
redeployed to work on a Mars rover project. Lab officials said the move
resulted in no layoffs.

Planetary scientists and those in favor of exploration are angered by NASA's
move. Reaching Pluto and Europa is among the top priorities for solar system
exploration. Pluto was considered especially urgent because it is entering a
distant, colder part of its elliptical orbit. This means the atmosphere will
freeze completely and could be unavailable for study for roughly 100 years.

Lou Friedman, executive director of the Planetary Society, called the
decisions shortsighted and called them the equivalent of "recalling the
fleet."

Colleen Hartman, who directs solar system exploration for NASA, said it may
still be possible to reach Pluto and Europa in the near future as
technologies such as nuclear propulsion evolve. "We're doing things now that
seemed impossible five years ago," she said.

Hartman was also awaiting a survey, done once a decade by the National
Academy of Sciences and due out in August, that will set priorities among
scientific goals for planetary exploration. A strong push to get to Pluto or
Europa from the respected organization could resurrect funding for the
projects.

==============
(6) MECHANISM THAT CREATES NEAR-EARTH BINARY ASTEROIDS

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

Media relations
Caltech

Contact:
Robert Tindol, (626) 395-3631

4/11/2002

Researchers find evidence for mechanism that creates near-Earth binary
asteroids

About one in six of all near-Earth asteroids are binaries -- in other words,
two bodies that travel in close companionship as they orbit the sun. A new
study reveals that binaries most likely form when a single asteroid swings
close to Earth, is ripped apart by the planet's tidal
attraction, and eventually reforms into separate bodies.

In a refereed article to be released Thursday, April 11 on the Science
Express Web site of the journal Science, California Institute of Technology
astronomer Jean-Luc Margot and his co-authors report detailed information on
the near-Earth asteroid currently assigned the rather unpoetic name 2000
DP107, and also on four other binary asteroids. 2000 DP107 comprises two
bodies that are about three kilometers apart, the larger of the two being
about 800 meters in diameter and the other about 300 meters. Using
particularly detailed radar data, the study is a description of the system
and explains how both these particular bodies and near-Earth binaries in
general can be formed.

Near-Earth asteroids were formed between Mars and Jupiter, like all other
asteroids, but are kicked into elliptical orbits by the gravitational
influence of Jupiter and occasionally pass near Earth. An Earth-crossing
orbit is one in which the asteroid actually crosses
the path that Earth follows around the sun, which means the two bodies could
eventually collide.

Margot, a postdoctoral researcher in the Division of Geology and Planetary
Science at Caltech, led the observations in October 2000 that uncovered 2000
DP107's binary nature, just months after the asteroid was first discovered
by MIT researchers. The current study, of which Margot is lead author,
employs data obtained from the 70-meter Goldstone NASA tracking telescope
and the Arecibo Observatory's radio telescope in Puerto Rico, which is funded by the
National Science Foundation with additional support from NASA and operated
by Cornell University, to yield a much more detailed picture of the two
orbiting bodies and their dynamics.

Other details from the radar data show that the two bodies are probably in a
tidal lock, which means that a person standing on the larger body would
always see the same face of the smaller body, but a person on the smaller
body would see the larger body spinning. This is exactly like the tidal lock
of the Earth-moon system.

Further, the research suggests that the tidal force applied to an asteroid
by a larger planet can be the cause of its breaking apart. The process,
known as "spin and fission," means that a body approaching Earth is made to
change its spin rate. Specifically, the tidal force tends to make an
asteroid passing nearby spin at the orbital rate, which can increase rather
substantially in a close approach to a planet. This increase in spin rate,
coupled with the tidal pull itself, can cause a loosely-bound, gravel-like
accumulation such as the near-Earth asteroids, to sling off material. Later,
the weak gravitational attraction of the particles allows the material to
reform in a second body.

But the most important issue raised by the paper is that near-Earth binaries
are so common, says Jet Propulsion Laboratory researcher Steve Ostro, one of
the authors. "The discovery of the existence and substantial abundance of
binary asteroids in Earth-crossing orbits is a major one," says Ostro, an
expert on the radar characterization of asteroids. "Presumably, binary
asteroids have hit Earth in the past, and will do so in the future."

"Of course, the most important thing to know about any (potentially
hazardous asteroid) is whether it is two objects or one, and this is why we
want to observe these binaries with radar whenever possible."

"The use of radar allows precise measurements of asteroid densities, a very
important indicator of their composition and internal structure," says
Margot.

"Getting (near-Earth asteroid) densities from radar is dirt-cheap compared
with getting a density with a spacecraft," Ostro explains.

In addition to Margot and Ostro, the other authors are Michael Nolan of the
Arecibo Observatory; Lance Benner, Raymond Jurgens, Jon Giorgini, and Martin
Slade, all of JPL; and Donald Campbell of Cornell University.

The article will be available Thursday on the Science Express Web site at
http://www.sciencemag.org/cgi/content/abstract/1072094v1

Related Links

* More on Binary Asteroids
  http://www.gps.Caltech.edu/~margot/2000DP107
* Science Express
  http://www.scienceexpress.org

=============
(7) RADAR REVEALS FIVE DOUBLE ASTEROID SYSTEMS ORBITING EACH OTHER NEAR
EARTH

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

News Service
Cornell University

Contact: David Brand
Office: 607-255-3651
E-Mail: deb27@cornell.edu

EMBARGOED FOR RELEASE: 2 p.m. Eastern Time, April 11, 2002

Radar reveals five double asteroid systems orbiting each other near Earth,
likely formed in close encounters with planet

ITHACA, N.Y. -- Binary asteroids -- two rocky objects orbiting about one
another -- appear to be common in Earth-crossing orbits, astronomers using
the world's two most powerful astronomical radar telescopes report. And it
is probable, they say, that these double asteroid systems have been formed
as a result of gravitational effects during close encounters with at least
two of the inner planets, including Earth.

Writing in a report published by the journalScience on its Science Express
web site (April 11, 2002), the researchers estimate that about 16 percent of
so-called near-Earth asteroids (NEAs) larger than 200 meters (219 yards) in
diameter are likely to be binary systems, with about a three-to-one relative
size of the two encircling bodies. To date, five such binary systems have
been identified by radar, says lead researcher Jean-Luc Margot, an O.K. Earl
postdoctoral fellow in the Division of Geological and Planetary Sciences at
the California Institute of Technology.

Margot, who at the time of the observations was a research associate in the
planetary studies/radar group at the National Science Foundation's (NSF)
Arecibo Observatory in Puerto Rico (managed at Cornell University), says
that theoretical and modeling results show the binary asteroids appear to be
formed extremely close to Earth -- within a distance equal to a few times
the planet's radius (6,378 kilometers or 3,963 miles). "The fact that one
out of every six large NEAs is a binary and that they typically survive on the order
of 10 million years, implies that these close encounters must happen frequently compared
to the lifetime of the binary asteroids," says Margot.

The Science article, "Binary Asteroids in the Near-Earth Object Population,"
is coauthored by Michael Nolan, research associate at Arecibo; Lance Benner,
Steven Ostro, Raymond Jurgens, Jon Giorgini and Martin Slade at the Jet
Propulsion Laboratory (JPL); and Donald Campbell, professor of astronomy at
Cornell. The observations were made at the 70-meter Goldstone NASA tracking
telescope in California and at Arecibo Observatory.

NEAs are formed in the asteroid belt, between the orbits of Mars and
Jupiter, and nudged by the gravitational attraction of nearby planets,
largely Jupiter, into orbits that allow them to enter the Earth's
neighborhood. Most of the asteroids are the remnants of the initial
agglomeration of the inner planets.

Astronomers have long speculated about the existence of binary NEAs, based
in part on impact craters on Earth. Of about 28 known terrestrial impact
craters with diameters greater than 20 kilometers, at least three are double
craters formed by impacts of objects about the same size as the newly
discovered binaries. Astronomers also have noted the changes in brightness
of reflected sunlight for some NEAs, indicating a double system was causing
an eclipse or occultation of
one by the other.

In 2000, Margot and his co-researchers, using measurements from the
Goldstone radar, found that a small, roughly 800-meter-diameter
(half-a-mile) asteroid, 2000 DP107 (discovered only months before by a team
from the Massachusetts Institute of Technology), was a binary system.
Observations over eight days last October with the much more sensitive
Arecibo telescope clearly established the physical characteristics of
DP107's two asteroids as well as their orbit
about each other. The smaller object called the secondary, it was found, is
about 300 meters (1,000 feet) in diameter and is orbiting the larger
asteroid, the primary, every 42 hours at a distance of 2.6 kilometers (1.6
miles). The two asteroids appear to be locked in synchronous rotation, with
the smaller always with the same face oriented to the larger.

Since that observation, says Margot, four more binary NEAs have been
discovered, all in Earth-crossing orbits and each with a main asteroid
significantly larger than the smaller body. "The primary is rotating much
faster than most NEAs in all five binaries that have been discovered," says
Cornell's Campbell. The Science Express article speculates that the most
likely way the binaries are created is by close encounters of asteroids with
the inner planets Earth or Mars. Of the five binary NEAs discovered to date,
none has an orbit that brings it as close to the sun as Venus or Mercury.

NEAs, basically piles of rubble held together by gravity, are on
trajectories that bring them within a few thousand miles of the planets,
where tidal forces -- essentially the pull of gravity -- can increase the
spin rate of the asteroid, causing it to fly apart. The ejected rubble then
reforms in orbit around the larger asteroid.

"The asteroid is already rotating very quickly as it approaches the planet.
A little extra boost from tidal forces can be enough to exceed its breakup
limits, and it sheds mass. This mass can end up forming another object in
orbit around the asteroid. Right now this seems the most likely
explanation," says Margot.

There is an important reason for studying binary asteroids, says JPL's
Ostro: their potential for colliding with Earth. Knowing the density of
so-called PHAs (for potentially hazardous asteroids), he observes, "is an
extremely important input to any mitigation plans." He says, "Getting NEA
densities from radar is dirt cheap compared with getting a density with a
spacecraft. Of course, the most important thing to know about any PHA is
whether it is two objects or one, and this is why we want to observe these
binaries with radar whenever possible."

Margot notes, "Radar gives us very precise measurements of the size of the
objects and their shape. The radar measurements of the distance and velocity
of each component allows us to obtain precise information on their orbits.
>From this we can obtain the mass of each of the objects allowing, for the
Þrst time, measurements of NEA densities, a very important indicator of
their composition and internal structure."

Arecibo Observatory is operated by the National Astronomy and Ionosphere
Center at Cornell under a cooperative agreement with the NSF. The research
was supported by the NSF, with NASA providing
additional support for the planetary radar program at Arecibo.

Related World Wide Web sites:

The following sites provide additional information on this news release.
Some might not be part of the Cornell University community, and Cornell has
no control over their content or availability.

* Science Express
  http://www.sciencemag.org/cgi/content/abstract/1072094v1
* Images of binary asteroid 2000 DP107
  http://www.gps.caltech.edu/~margot/2000DP107

-30-

IMAGE CAPTION:
[ http://www.news.cornell.edu/photos/DP107.sum6.300.gif (698KB)] A montage of
radar images, captured with the Arecibo Observatory radar telescope, of
binary asteroid 2000 DP107, showing the smaller body (about 300 meters in
diameter) circling the larger body (about 800 meters) at a distance of 2.6
kilometers every 42 hours. Jean-Luc Margot, Caltech.

===============
(8) A LAST WAVE GOODBYE

>From The Guardian, 11 April 2002
http://www.guardian.co.uk/Archive/Article/0,4273,4391088,00.html

An asteroid landing in the ocean would produce the tsunami to end them all,
says Duncan Steel

Throw a stone into a pond and the ripples take just seconds to spread to the
banks. Drop an asteroid into the Atlantic and you get much the same effect,
but on a grander scale. Hours later, the coastlines are deluged.

When the possible consequences of cosmic impacts on our planet are
discussed, people take comfort from the fact that 70% of the Earth's surface
is ocean. In reality, we would not want a small asteroid to land in the open
sea: it would cause more damage and kill more people.

Consider a lump of space rock 200 metres in diameter, colliding with our
planet at 12 miles per second, a typical speed. As it is brought to an
abrupt halt, it releases its kinetic energy in an explosion equivalent to
600 megatons of TNT, 10 times the yield of the most powerful nuclear weapon
tested (underground). The asteroid vaporises, and the rapidly expanding
shock wave carries away its energy. For a land impact, the area devastated
would be about 10,000 square miles: everything within a 60-mile radius would
be obliterated. Beyond that, the destruction would still be substantial.

However, the implications for humanity would likely be worse if the open
ocean were struck instead. An asteroid landing in an ocean produces a
phenomenal tsunami (often mistakenly called a "tidal wave"). Even though
only about 10% of the energy of the impactor would be transferred to the
tsunami, such waves are effective at carrying that energy over the large
distances to the coastlines. They therefore cause destruction over a much
wider area than is the case for a land impact. In the latter, the
interaction between the blast wave and the irregularities of the ground
(hills, buildings, trees) limits the area damaged, but on the ocean, the
wave propagates until it runs into something.

Paradoxically, ships at sea are little affected by tsunamis. They simply
ride the waves that move outward from the epicentre at well over 100mph. On
the open ocean, a major tsunami may be only 10 to 50cms high; it is the
run-up that occurs as the wave reaches the continental shelf that causes the
wave height to increase markedly, and they can penetrate miles inland.

During the past century, several significant tsunamis have swept across the
Pacific, provoked by undersea landslips, earthquakes or volcanic eruptions.
A major rumble off the coast of Chile in 1960 induced a series of waves that
killed more than a thousand people on the mainland. The waves reached Hawaii
15 hours later, drowning more than 60 people. As the main wave smacked Hilo
harbour it was over 10 metres high. Seven hours later, it killed hundreds in
Japan. In July 1998, an earthquake-generated tsunami in Papua New Guinea
swept more than 2,000 coastal dwellers to their deaths.

Dr Steven Ward, who works in the Institute of Geophysics and Planetary
Physics at the University of California at Santa Cruz, modelled a 200-metre
asteroid slamming into the Atlantic about 700 miles west of the tip of
Cornwall. The transient crater formed in the three-mile deep ocean is about
four miles wide and a mile-and-a-half deep. It's like throwing a big rock
into a vast pond, although at hypervelocity. One hour later, the outermost
edge of the wave has spread about 300 miles from the epicentre. The greatest
wave amplitude is further back, because the tsunami continues to be boosted
by the water oscillating up and down at the epicentre. To see what happens,
over a much shorter time scale, drop a sugar cube into a cup of coffee.

After two hours, the tsunami is just reaching the south-western tip of
Ireland. The distortion of the wave from circularity is clear, due to the
crossing of the continental shelf, where the water is much shallower. This
slows the wave, but considerations of conservation of momentum say that it
must get taller. This is called "shallow water shoaling". Three hours
post-impact, the west coast of Ireland is inundated: goodbye Galway and
Donegal, although Limerick and Cork may survive, shielded by their natural
harbours. In this scenario, Ireland provides a singular service to the rest
of the British Isles, bearing the brunt of the tsunami. Five to six hours
after the strike, Cornwall, Devon and south Wales are hit, as are the
Western Isles of Scotland, but the ports lining the Irish Sea escape the
worst.

Further south, the news is not so good. The shallow waters of the English
Channel cause the wave to elevate, and seaside resorts to Brighton and
beyond would be swept away. One must hope that eight hours - the time the
tsunami would take to reach the Isle of Wight - are enough to organise an
evacuation. Shortly after, the wave would penetrate between Dover and
Calais, and the dykes of the Netherlands would provide little resistance.
With no offshore shield, the coasts of France, Spain and Portugal are
pummelled by the tsunami.

The shadowing effect provided by islands is most obvious in the case of the
Azores. When a tsunami hits a coast, it ramps up in height by a factor that
depends upon the profile of that coastline and, in particular, the gradient
of the sea bottom. That factor may be only two or three, but it may be more
than 10. The latter would mean that waves 10 metres in amplitude on the open
sea would attain a height of 100 metres as they hit land. We are not talking
of a simple flood, then. We are talking about a coastline swept clean.

How often does such an event occur? Asteroids around 200 metres in size
strike the Earth about once every couple of thousand years. The Atlantic has
about a one-in-10 chance of being the next target.

A parting thought. Last time I checked my house insurance, I was covered for
tsunami damage. Trouble is, tsunamis were defined in the small print as
being large sea-waves produced by sub-oceanic volcanoes, landslips or
earthquakes. Asteroid impacts don't count, it seems.

· Duncan Steel conducts research on asteroids at the University of Salford.
 
Guardian Unlimited © Guardian Newspapers Limited 2002 

================
(9) DAVE RODDY, 1932 - 2002

http://astrogeology.usgs.gov/About/People/DaveRoddy/

U.S. Geological Survey, Astrogeology Team Emeritus David John Roddy passed
away at 9:40 in the morning, March 21 at St. Louis hospital while on a short
trip. He had gone into the hospital complaining of chest pains and ruptured
an aorta while undergoing a heart scan. He died immediately.

Dave was a world-renowned scientist at the forefront of investigators
studying impact and explosion craters. His field mapping of Flynn Creek was
the first mapping detailed enough to demonstrate the impact origin of an
ancient structure in North America. David was an authority on the Meteor
Crater impact structure, east of Flagstaff. Dave's work has assisted in the
recognition of large-body impact as an important geologic process on Earth.
His study of explosion craters led to longtime involvement with the
Department of Defense and was of critical value in strategic military
planning. His specialties were the mechanics of hypervelocity impacts,
nuclear- and explosion-cratering processes, and high-pressure shock-wave
deformation of natural materials, and the geologic and geophysical
applications of the science to terrestrial and planetary research. He was
also a U.S. Air Force flight navigator and instructor, and a qualified
private and commercial pilot for most of his life.

David was born in Springville, Ohio, in 1932 to Jack and Nellie Roddy. He
attended the U.S. Air Force School in Harlington, Texas, from 1957 to 1958.
Dave got his A.B. and M.S. degrees from Miami University in Ohio in 1955 and
1957, respectively. He was a distinguished graduate of the U.S. Air Force
ROTC program at Miami University. From 1957-1960, he was in active service
as an Air Force navigator. He attended California Institute of Technology in
southern California from 1960 to 1966, receiving a Ph.D. on the dissertation
topic of "Impact-cratering mechanics of Flynn Creek, Tennessee" working
under Dr. Gene Shoemaker. In 1962, he was induced by Gene to work in an
interim capacity at the USGS in the newly-formed Branch of Astrogeology. He
joined the Astro Team full time in 1965. Dave was Associate Branch Chief of
the Astrogeology Team from 1983-1984. He retired from the USGS in 1992, but
remained with the Team as an Emeritus and was extremely active in Science to
the very end. David was a member of Sigma Gamma Epsilon, the Geological
Society of America, the Mineralogical Society of America, Sigma Xi, American
Geophysical Union, and the American Society of Industrial Security.

He was the recipient of the U.S. Department of Interior Unit award for
Pacific Enewetak Atoll Crater Explosion Program. He received several letters
of appreciation and commendation from Generals at the Department of Defense
and from the Secretary of the Air Force for his work with Desert Storm. He
was cited by the Secretary of the Interior for a Meritorious Service Award.
The prestigious Barringer Award was presented to David Roddy at the
International Meteoritic Society Meeting in Prague, Czechoslovakia, on
August 3, 1994, in recognition of his outstanding scientific contributions
and lifetime work in the field of impact crater mechanics.

Co-workers at the USGS remember a caring, kind, loyal friend with a sharp
sense of humor. Dave was a good listener, who could always be trusted to
keep confidences. Extremely honest and ethical, he was always willing to
help someone in need. Throughout the 1980s and early 1990s his constant
companion was a small white terrier named Michelle. Clad in sunglasses and
leather pilot jacket with Michelle trotting at his side, Dave was a driven
scientist with a Colonel Flag persona, who aspired to the highest of
standards, but usually had time for lunch with friends.

Most of his life Dave was a vital man with a passion for running and staying
fit. Although the last ten years of his life were marked by a battle with
Parkinson's disease, he fought it every inch of the way. In 2000, he ran 2.5
miles in the annual Flagstaff 4th of July 10K/fun run. Last year, he walked
the entire 10K. It was hot as hell and Dave came in last, receiving the red
caboose award and another for being the oldest participant, but he still had
enough energy to walk over and view the 2-hour parade, eat lots of my
daughter's candy, and then beg us to join him for lunch. Lunches with Dave
were always memorable, a meal rarely ended without his ordering one dessert,
that we all had to share. David was a practical joker. He probably pulled
his last one on me, a week before his death, in Houston at the Lunar and
Planetary Science Conference. We were going out to lunch in a group of 5:
Bevan French and Wylie Poag in a small car and David, John McHone, and I
were to use the LPI van service. Inside the van, Dave wasn't happy with the
lax schedule of the driver. He pointed out an open-door car across the
parking lot and asked me to jump out and run over there, to see if we could
all squeeze in Wylie Poag's car. I sprinted across the lot, glanced at the
empty back seat, and asked if we could join them, only to find that the two
men in the front seat were not French or Poag. Bill Casidy, on the passenger
side, wanted to know what my companions looked like. Mortified, I apologized
and walked back to the van to find Dave and John laughing their heads off.
Dave said, "I knew it wasn't them all the time, you should have seen the
looks on their faces, but don't worry - you made their day."

Dave was married twice. First to Andrea Biehler of Riverside, California,
with whom he had 3 sons. His second marriage was to Jeannie Swan Roddy of
Halifax, Nova Scotia. His mother Nellie, 3 sons: David M., Mark R., and
Matthew J. Roddy, as well as stepsons, Glen and Kevin Swan and 3
grandchildren survive Dave. He was active in his community and is sorely
missed by numerous friends, co-workers, and peers.

A memorial service will be held 11:00 a.m. on Saturday, May 18 in Wettaw
auditorium (building #88, room #130) on the Northern Arizona University
campus in Flagstaff, Arizona. The Wettaw building is the new
biology-biochemistry building near the corner of DuPont and Beaver. The
entrance is on the west side, and parking is available in lot P-1 northwest
of the building. The family has asked that in lieu of flowers, donations may
be made to the Parkinson's Foundation, 1250 Hylan Blvd., Suite 4B, Staten
Island, NY 10305, or to an animal care organization of the donor's choice.

By Mary G. Chapman
26 March 2002

Selected Publications

Roddy, D.J., Boyce, J.M., Colton, G.W., and Dial, A.L., Jr., 1975, Meteor
Crater, Arizona, rim drilling with thickness, structural uplift, diameter,
depth, volume, and mass-balance calculations: Lunar Science Conference, 6th,
Proceedings, New York, Pergamon Press, p. 2621-2644.

Roddy, D.J., 1976, Impact cratering and its record on the planets and Moon,
in Greeley, R., and Schultz, P. eds., Planetary Geology Short Course, April
1976, p. 100-157.

Roddy, D.J., 1977, Tabular comparisons of the Flynn Creek impact crater,
United States, Steinheim impact crater, Germany, and Snowball explosion
crater, Canada, in Impact and explosion cratering: Planetary and terrestrial
implications, Roddy, D.J., Pepin, R.O., and Merrill, R.B., eds., New York,
Pergamon Press, p. 125-162.

Roddy, D.J., 1977, Large scale impact and explosion craters: Comparisons of
morphological and structural analogs, in Roddy, D.J., Pepin, R.O., and
Merrill, R.B., eds., Impact and explosion craterering: Planetary and
terrestrial implications: New York, Pergamon Press, p. 185-246.

Roddy, D.J., 1977, Pre-impact conditions and cratering processes at the
Flynn Creek crater, Tennessee, in Roddy, D.J., Pepin, R.O., and Merrill,
R.B., eds., Impact and explosion cratering: Planetary and terrestrial
implications: New York, Pergamon Press, p. 277-308.

Roddy, D.J., and Davis, L.K., 1977, Shatter cones formed in large scale
experimental explosion craters, in Roddy, D.J., Pepin, R.O., and Merrill,
R.B., eds., Impact and explosion cratering: Planetary and terrestrial
implications: New York, Pergamon Press, p. 715-750.

Roddy, D.J., and Pepin, R.O. 1977, Introduction, in Roddy, D.J., Pepin,
R.O., and Merrill, R.B., eds., Impact and explosion cratering: Planetary and
terrestrial implications: New York, Pergamon Press, p. xi-ix.

Roddy, D.J., Pepin, R.O., Merrill, R.B., eds., 1977, Impact and explosion
cratering: Planetary and terrestrial implications: New York, Pergamon Press,
1301 p.

Ullrich, G.W., Roddy, D.J., and Simmons, G., 1977, Numerical simulations of
a 20-ton TNT detonation on the Earth's surface and implications concerning
the mechanics of central uplift formation, in Roddy, D.J., Pepin, R.O., and
Merrill, R.B., eds., Impact and explosion cratering: Planetary and
terrestrial implications: New York, Pergamon Press, p. 959-982.

Roddy, D.J., 1978, Pre-impact geologic conditions, physical properties,
energy calculations, meteorite and initial crater dimensions and
orientations of joints, faults and walls at Meteor Crater, Arizonz: Lunar
and Planetary Science Conference, 9th, Proceedings, Houston, Geochimica et
Cosmochimica Acta, v. 3, Supplement 10, p. 3891-3930.

Roddy, D.J., 1979, Structural deformation at the Flynn Creek impact crater,
Tennessee: A preliminary report on deep drilling: Lunar and Planetary
Science Conference, 10th, Proceedings, p. 2519-2534.

Roddy, D.J., Watson, R.D., and Theisen, A.F., 1980, Shock-induced
luminescence at Meteor Crater, Arizona, measured by laboratory and airborne
Fraunhofer line discriminator systems: Meteoritics, v. 15, no. 4, p.
356-357.

Roddy, D.J., Schuster, S.H., Kreyenhagen, K.N., and Orphal, D.L., 1980,
Computer code simulations of the formation of Meteor Crater, Arizona:
Calculations MC-1 and MC-2: Lunar and Planetary Science Conference, 11th,
Proceeding, p. 2275-2308.

Roddy, D.J., Schuster, S.H., Rosenblatt, M., Grant, L.B., Hassig, P.J., and
Kreyenhagen, K.N., 1987, Computer simulations of large asteroid impacts into
oceanic and continental sites--Preliminary results on atmospheric, cratering
and ejecta dynamics: International Journal of Impact Engineering, v. 5, nos.
1-4, in Hypervelocity Impact, Proceedings of the 1986 Symposium, Anderson,
C.E., ed., Pergamon Press, p. 525-541.

===============
(10) THE REAL THREAT TO THE PLANET

>From Tech Central Station, 9 April 2002
http://www.techcentralstation.com/1051/envirowrapper.jsp?PID=1051-450&CID=1051-040902B

By Sallie Baliunas 04/09/2002 
 
"...[G]lobal warming [is] the most serious threat that we have ever
faced..." (Al Gore, Earth in the Balance, p. 40)

"...[A large asteroid striking the earth is a] serious and surprising danger
posed to our global civilization from outer space." (Carl Sagan)

Two global threats - one supposedly human-made, the other natural. How much
worry should be parceled to each? Calamitous global warming from human
activities like fossil-fuel burning finds little support in reliable
measurements of the temperature of the earth - either at the surface or in
the sensitive lower atmosphere. On the other hand, an eventual asteroid
strike is a dead certainty.

Just discovered is the threat of asteroid 1950 DA, which might endanger the
earth in 878 years. The risk of comet or asteroid strike is not unusual - it
is ever present. However, for the first time in the history of life on
earth, science may allow Homo sapiens to see and deflect a cosmic destroyer.

Natural catastrophes have always pounded the earth and its precious life. As
the plates of the crust of the earth ride the underlying molten flow of
magma, land masses smash together only to tear apart. Crumpled ridges jut
into high mountain ranges, and crushes of volcanoes emit choking dust and
gases, plus waves of lava that blanket continent-sized regions.

Today the lever of science helps to measure, classify and comprehend past
calamities. But the action of continental drift, winds, seas and volcanoes
blurs the evidence, making scientists' detective work hard. Still,
geologists gaze, for example, at the Himalayas and see the 1,800-mile long
wrinkling of land produced by the enormous force of the collision between
the roughly 75-mile thick Eurasian and Indian tectonic plates around 50
million years ago.

Through the 4.5 billion years of the earth's existence, internal actions
have jostled, jolted, smoothed and havocked the earth, with life and its
Darwinian process forced to respond.

And then there is the moon.

Thoughts of the moon run first to its strangeness compared to the earth. A
verdant, sapphire-blue, cloud-dappled and dynamic planet brimming with life,
orbited by a satellite starched in gradations of unrelenting gray, arid,
airless, lifeless - and anciently cratered. The craters attest to the early
phase of intense bombardment as the planets nearer the sun grew out of the
amalgamation of rocky bits built in turn from the sticky collisions of dust
motes over eons. How can two bodies so seemingly disparate end up orbiting
each other?

By accident! About 4.5 billion years ago, two planets that had formed -- the
earth and a planet about the size of Mars - collided. The debris of the
disintegrated smaller body collected in a nearby gaseous ring whose
particles collided, stuck together and grew to form another planetesimal -
this time the moon in orbit around the earth.

Just north of Los Angeles sits Mount Wilson Observatory with its
deliberately time-frozen exhibits in the Astronomical Museum. Built in 1936,
the Museum displays splendid backlit glass photographs of astronomical
objects, many taken with the Observatory's 100-inch Hooker Telescope, then
the largest in the world. The early captions describe the 1930's state of
astronomical knowledge. Accompanying a glorious close-up of the pocked
lunarscape is the best science of that period: "Lunar craters are probably
of volcanic origin, although some of the smaller ones may have been caused
by impacts from meteors."

Thanks to science, that notion has been revised. Lunar craters reveal the
chaos to which both the earth and the moon must have been subjected in the
inner solar system during the first billion years or so. Lacking the great
erosive forces of wind, ocean, vulcanism and plate tectonics, the moon's
surface preserves a record of early solar system history. On earth, that
record has been all but obliterated.

Fossil evidence on earth from about 3.5 billion years ago suggests that life
persisted and flourished soon after the early pummeling by asteroids and
comets ceased. On the arid, airless moon, life must not have even begun -
there is no hint of evidence favoring lunar life.

The scarred lunar regolith warns of exo-terrestrial hazards that have
endangered the earth and its life. While the early chaos has long since
calmed, asteroids and comets continue to strike the planets, including the
earth. One line of evidence is the remnants of recent craters on the earth,
like Barringer Meteor Crater in Arizona, an awful sight near Interstate 40.
There, an exo-terrestrial projectile about 150 feet across exploded and
disintegrated upon impact with the ground about 50,000 years ago, leaving a
crater three-fourths of a mile across.

More evidence of strikes comes from recent impact sightings, some
historically described. NASA researcher John S. Lewis speculates in Rain of
Fire and Ice that the Bible's Joshua (Chapter 10) may tell of a deadly
asteroid strike ca. 1400 B.C.E., when a rain of "great stones out of the
heavens" killed Joshua's battlefield enemies. Just a few verses later sits
the astonishing line, "and the sun standeth in the midst of the heavens, and
hath not hasted to go in - as a perfect day." Rather than the rotation of
the earth temporarily stalling, the exploded debris of an asteroid or comet
that decimated the men must also have lit the sky with long-burning glows
that would have seemed like sunlight and full moonlight persisting long
beyond sunset. To the ancient mind, bright, nighttime light from the debris'
disintegration equaled the sun's standing still - and the timing and
consequence of the asteroid strike would have seemed a miracle.

Television history was made with the broadcast of the 1994 collision of
Jupiter with the Comet Shoemaker-Levy. Because Jupiter is the largest planet
in the solar system, its strong gravitational attraction will tend to draw
asteroids toward it. However, the Sun is also tugging at them, and some
near-earth objects (NEO's) may end up on trajectories intercepting earth's
orbit. The evidence is irrefutable: exo-terrestrial objects have struck the
earth, and will do so in the future. The laws of celestial mechanics say
that earth is not immune to exo-catastrophe.

The impact of an NEO larger than about one-half mile in size could produce
severe environmental damage. The only way to avoid the destruction and death
from a large NEO is to detect and then deflect it. Several groups around the
world, and especially in the United States and Britain, search the skies for
NEO's, and then determine their orbits. That process allows the probability
of a future collision with earth to be estimated. To date, about half of
approximately 1,000 destructive asteroids that may cross the earth's orbit
have been catalogued, and their orbits give assurance that there would be
years of warning before a strike. But the unknown objects foment anxiety:
there would be no warning that an undetected NEO is on a collision course
with the earth, because the existence of that NEO would not yet be
suspected.

The NASA Spaceguard Survey will improve the odds by attempting to detect
about 90% of the NEO's by 2008. The idea is to locate, track and deflect
these true exo-terrestrial hazards. On rough average, an asteroid a bit
larger than a mile across strikes the earth every million years or so, and
would present a major global catastrophe.

The detection and tracking technology is relatively straightforward and
inexpensive, but requires constant vigilance. However, deflection capability
is still in its infancy. Rockets fast enough to reach an asteroid on
intercept course with earth would have to be deployed, with energetic means
of shoving the asteroid onto a non-perilous orbit. That might require
advanced nuclear devices that are detonated beside the asteroid, to shove it
into another orbit, while avoiding shattering the asteroid into
uncontrollable pieces.

Deflection technology remains rudimentary, and no one yet knows how quickly
it may be needed. But it will eventually be needed. As an aside, if we
assume that the astronomers' estimates of an enormous number of habitable
planets in the universe are correct, the cosmos may harbor trillions of
intelligent species. On more than one of those planets, odds are that a
putative intelligent species or two was cratered to oblivion - perhaps just
before its technology dawned to avert a low-probability but certain
exo-catastrophe.

The cosmic environment streams with hazards for earth and earthlings.
Asteroid and comet strikes truly endanger life on earth. Until the science
says otherwise, human-made global warming winds up low on the list of
anxieties.


Copyright 2002, Tech Central Station

==============
(11) ROCKET FRAGMENT, NOT METEORITE, LANDED IN UGANDA

>From Ron Baalke <baalke@jpl.nasa.gov>

http://allafrica.com/stories/200204100271.html

Mubende Hit By Rocket Fragment, Says Police
Frederick Kiwanuka
New Vision (Kampala)
April 10, 2002

POLICE yesterday said the alien spherical object that landed in Kasambya,
Kikandwa sub-county in Mubende district last month was not a meteorite but a
suspected rocket fragment from outer space.

Police spokesman Asuman Mugenyi, whose personnel collected the object for
scrutiny, said yesterday that they were still scrutinising the object whose
whereabouts he did not disclose.

Full story here:
http://allafrica.com/stories/200204100271.html

==============
(12) AND FINALLY: CHINA METEOR MAY (OR MAY NOT) SOLVE MYTHICAL DEATH OF
MYTHICAL EMPEROR

>From Ron Baalke <baalke@jpl.nasa.gov>

http://asia.cnn.com/2002/WORLD/asiapcf/east/04/09/china.emperor.reut/index.html

China meteor may solve death of mythic emperor
Reuters
April 9, 2002

BEIJING, China (Reuters) -- A 5,000-year-old meteorite unearthed in
northwestern China may explain the legendary death of the man celebrated as
the nation's earliest ancestor, the Yellow Emperor, state media said.

The meteorite, found near a mausoleum for the Yellow Emperor in the Shaanxi
province county of Huangling, may lie behind the cataclysmic shattering of
land that historical records say killed China's enigmatic first emperor, the
official China Daily said Tuesday.

The discovery also sheds light on a local legend that nine dragons broke up
the ancient town of Huangling, the newspaper said, quoting Li Yanjun, a
long-time Yellow Emperor researcher and one of those who found the
meteorite.

Full story here:
http://asia.cnn.com/2002/WORLD/asiapcf/east/04/09/china.emperor.reut/index.html

--------------------------------------------------------------------
CCNet is a scholarly electronic network. To subscribe/unsubscribe, please
contact the moderator Benny J Peiser < b.j.peiser@livjm.ac.uk >. Information
circulated on this network is for scholarly and educational use only. The
attached information may not be copied or reproduced for
any other purposes without prior permission of the copyright holders. The
fully indexed archive of the CCNet, from February 1997 on, can be found at
http://abob.libs.uga.edu/bobk/cccmenu.html. DISCLAIMER: The opinions,
beliefs and viewpoints expressed in the articles and texts and in other
CCNet contributions do not necessarily reflect the opinions, beliefs and
viewpoints of the moderator of this network.



CCCMENU CCC for 2002

The content and opinions expressed on this Web page do not necessarily reflect the views of nor are they endorsed by the University of

The content and opinions expressed on this Web page do not necessarily reflect the views of nor are they endorsed by the University of Georgia or the University System of Georgia.