CCNet 84/2002 - 17 July  2002

   "There was a great storm and hail and flashes of lightning in the
   darkened, blackened sky and a great and crashing 'thunder-noise'
   everywhere. ... There were also a great shaking, jumping and trembling
   of the earth beneath and a rolling-up of the great waters."
     --Hoh Indians from the Forks area of Washington's Olympic Peninsula

   "Thus by my count for the 20th century we have one confirmed 60-m
   impactor (Tunguska) and no evidence of anything else approaching this
   size (although of course we would miss most impacts since they would
   occur in the ocean; absence of evidence in this case is not evidence
   of absence). For comparison, the latest estimated frequency of impact
   of 60-meter projectiles is only about once per millennium, rather
   lower than the older estimates of once every couple of hundred years."
         --David Morrison, 15 July 2002

    The Seattle Times, 14 July 2002

    Andrew Yee <>

    Space Daily, 16 July 2002

    Die Welt, 17 Juli 2002

    David Morrison <>


    Drake A. Mitchell <PlanetaryDefence@Netscape.Net>

    John Michael Williams <>

    Andy Smith <>

     Mike Baillie <>

     Bob Kobres <>


>From The Seattle Times, 14 July 2002

By Elizabeth Murtaugh
The Associated Press

When scientists figured out that seawater drowned groves of tall trees
up and down the coast of Washington state the same year a tsunami hit
Japan, they theorized that a massive earthquake in the Pacific most
likely triggered both events.

Based on Japanese records, scientists were able to pinpoint a date -
Jan. 26, 1700 - and estimate that the rupture of a long stretch of
seafloor had caused a magnitude 9 quake, which would be the largest
known temblor to strike what is now the contiguous United States.

But Ruth Ludwin, a University of Washington geophysics professor, wanted
to know more.

There appeared to be no accounts of cataclysmic earth-shaking in the
stories and legends of the only North Americans who would have witnessed
the quake: Indians.

"When you talk about a very large earthquake in 1700, for that to be
really convincing to me, I really need to have evidence from people who
were there," Ludwin said. "I was looking for a more comprehensive

Ludwin began to search obscure volumes of tribal folklore, where she
found that for centuries, Indians from British Columbia's Vancouver
Island to the coast of Northern California had been telling strikingly
similar tales of mudslides, of plains that suddenly became oceans and
other stories that strongly suggest tribes bore witness to tsunamis like
the one in 1700.

Many of the legends involve a mythic battle between a thunderbird and a

One tale told by generations of Hoh Indians from the Forks area of
Washington's Olympic Peninsula contains what Ludwin considers the
clearest description of a concurrent earthquake and tsunami yet
discovered in tribal legend.

As the story goes, "There was a great storm and hail and flashes of
lightning in the darkened, blackened sky and a great and crashing
'thunder-noise' everywhere. ... There were also a great shaking, jumping
and trembling of the earth beneath and a rolling-up of the great

The Makah Indians, whose reservation at Neah Bay sits at the northwest
tip of Washington state, also have a version - one that ends with a
thunderbird delivering a whale inland to the mouth of a river, giving
the giant beast to a tribe that had been starving during a winter
thousands of years ago.

Although it's unclear exactly how long the story has been told, it
formed the basis of the tribe's centuries-old whale hunt and could be
linked to one of the seven "megathrust" quakes scientists believe have
occurred during the past 3,500 years.

Many legends contain no time elements. Others that were never written
down have been lost entirely, so Ludwin's work can seem like trying to
solve a puzzle with most of the pieces missing. But she says it's worth

"The work that I've done is not extremely important from a scientific
point of view, but it's important from the point of view of
understanding and believing," Ludwin said. "It's another piece of the

The megathrust quake believed to have occurred in 1700 ruptured the
Cascadia subduction zone, where two of the tectonic plates that form the
Earth's crust - the Juan de Fuca and the North America plates - overlap.

From its northern end, off the western coast of Vancouver Island, the
subduction zone stretches about 600 miles south to Cape Mendocino in
Northern California, then runs into the San Andreas fault.

The Japanese first theorized that an enormous earthquake in the Pacific
caused what they called their "orphan tsunami," so named because there
was no local temblor that accompanied the torrent of 6-foot-high waves
that crashed along 500 miles of coastline.

When they learned that groves of red cedars and Sitka spruces along
Washington's coast had dropped several feet, drowning in saltwater
sometime in the late 1600s or early 1700s, they theorized that one huge
quake must have been responsible for both the Japanese tsunami and this
state's "ghost forests."

Radiocarbon dating of spruce stumps narrowed the timeline of the tree
drownings to somewhere between 1680 and 1720, said Brian Atwater, a U.S.
Geological Survey scientist in Seattle.

That was too big of a window, so scientists went back to one of the
estuaries where roots of red cedars had survived and could be dated by
their rings.

At that grove, near the Copalis River in Grays Harbor County, tree-ring
dating showed the red cedars died sometime between August 1699 and May

"If we had found that those red cedars died in 1697 or 1703, we would
say, 'Well, we're not sure your tsunami came from our earthquake,' "
Atwater said. "We knew there was an earthquake or a series of
earthquakes. The question was how big and exactly when."

Although the geological evidence of the 1700 megathrust seemed solid,
there were still some skeptics before Ludwin started finding Indian
tales that supported the science.

"People understandably want human evidence as well as physical
evidence,"Atwater said.

Copyright © 2002 The Seattle Times Company


>From Andrew Yee <>

European Space Agency
Press Release No. 51-2002
Paris, France 15 July 2002

ESA and the European Commission launch a consultation forum on
satellite-based Global Monitoring for Environment and Security

Satellites can help the EU monitor climate change, address
international crises and contain natural disasters. Today in
Brussels EU Research Commissioner Philippe Busquin and Mr Antonio
Rodotà,  the Director General of the European Space Agency (ESA),
officially opened a large stakeholder consultation forum aiming
at the definition of European needs to enhance global monitoring
for environment and security (GMES). 250 participants,
representing users, suppliers and researchers, addressed policy
options to upgrade Europe's capability for global monitoring by

Combining spaceborne, land-based and airborne technologies, GMES
will pool Europe's activities in satellite observation and remote
sensing. GMES seeks to make better use of Europe's existing
and planned capabilities and infrastructures and to develop
mechanisms for improved collection and distribution of information.

Data from Envisat and other spaceborne and terrestrial
observation systems will improve the ability of European
researchers, private companies and public authorities to track
environmental pollution, react to emergencies, improve cross-
border response to catastrophic events, follow movements of
refugees, facilitate the distribution of aid, and support
peacekeeping troops outside Europe.
Commissioner Busquin said: "GMES is both a technological and an
organisational challenge for Europe. It is a good example of how
Europe, by working together in research, can develop technologies
that contribute to improving the quality of life and meeting
security needs. For instance, GMES will support implementation
of the EU fisheries policy through more accurate monitoring of
the evolution and migration of fish stocks."

Mr Rodotà referred to the dedicated efforts by ESA in the
framework of GMES. As a new step, ESA will start implementing
operational services than can now meet some priority users'
requirements, based on current Earth observation capacities.
"Concrete implementation of the GMES initiative is thus
underway. Furthermore, ESA is now fully engaged with the
European Commission in discussing the most appropriate
arrangements for ensuring the long-term sustainability of the
GMES initiative" .

Today's meeting is the first in a series that will foster
dialogue between decision-makers and the many organisations
involved in monitoring and in providing information for
environmental and security purposes. The forum will lead to
publication of a report at the end of 2003, to provide policy-
makers with recommendations for future action.

GMES will enhance Europe's ability to retrieve and process
information obtained from space-borne and terrestrial
observation systems with other geographical or socio-economic
data.  It will respond to growing concerns among policy-makers
for timely, free and independent access to information on the
environment and security at global, regional and local levels.
GMES will support EU policies in areas such as sustainable
development, global climate change and the common foreign and
security policy.

At the global level, GMES will provide new verification tools
to contribute to the precise monitoring of compliance with
international agreements, such as the Kyoto protocol on
climate change, as well as security and international aid
agreements. At the same time, GMES will help local authorities
pinpoint problems (e.g. shoreline erosion, environmental
stress) and react more effectively to catastrophic events (e.g.
floods, mudslides, avalanches, and forest fires). At EU level
GMES will provide new objective data to support a broad range
of EU policies, including regional development, transport,
agriculture, enlargement, development, and foreign policy.

GMES is a key element of the European Space Strategy developed
by the Commission and the European Space Agency. Along with
the Galileo global satellite navigation system, GMES will be
a major pillar of the European Space Policy emerging from the
ever-closer partnership between the two organisations.

In November 2000, both the EU and ESA Ministerial Councils
endorsed the GMES initiative and identified GMES and Galileo
as top priorities and test cases for implementation of the
European Strategy for Space.

GMES was also presented in the Commission Communication to the
Gothenburg Council in June 2001, with the goal to create the
system by 2008. The idea was further developed in the
Communication "Outline GMES EU Action Plan (Initial Period:
2001-2003)", which elaborates on the objectives, general
implementation principles, organisation and first priorities.

On the ESA side, GMES is at the core of a new 5-year programmatic
element (the "GMES Services element"), fully subscribed by the
ESA Council at ministerial level in November 2001. It will allow
for the delivery of operational information, based on current
European observation capacities, for the thematic priorities
already identified in the GMES framework. A first invitation to
tender for those services will be issued in September 2002.

GMES is also a key element of the "Aeronautics & Space" priority
of the 6th EU Research Framework Programme and will feature in
calls for proposals to be published at the end of 2002.

The GMES initiative will also be presented at the World Summit
for Sustainable Development  taking place in Johannesburg, South
Africa, in September 2002, as a follow-up to the 1997 Kyoto
conference on global climate change.

For further information on European space policy and GMES please

For more information, please contact:

Michel Verbauwhede
Tel. :+32(0)2.743.30.93
Fax : +32(0)2.743.30.71


>From Space Daily, 16 July 2002

by Louis Varricchio
Middlebury - Jul 16, 2002

The Moon is not the geologically dead world that most astronomy
textbooks claim, according to Hal Povenmire, a Florida Institute of
Technology astronomer, long-time meteorite hunter and former NASA
Project Apollo engineer.

In February, NASA officials announced new evidence that the Moon has an
active, molten core. Povenmire concurs with NASA and believes that there
are signs of geologically recent lunar volcanism right here on Earth.

The most recent eruption on the Moon, he claims, showered a portion of
Asia and Australia with many tons of volcanic glass. This so-called
Australasian event occurred within the past million years.

Povenmire's interest in tektites was aroused long before he discovered
both the Upsilon Pegasid meteor shower and a new asteroid, officially
named 12753 Povenmire.

In 1970, realizing that 34.5 million year-old tektite stones found in
Georgia were extremely rare and that their strewn field had never been
mapped, he undertook a monumental effort to learn more about them.

To date, thanks to Povenmire's fieldwork, the size of the Georgia
tektite zone has been expanded from 500 square miles to over 7,000
square miles. The number of Georgia tektites he discovered increased
from 200 to over 1,300.

Povenmire said thousands of tektites might have fallen on prehistoric
Georgia in a single day or night.

Povenmire believes that these natural glass stones are volcanic material
blown off the Moon by eruptions, an idea first proposed by a European
geologist around 1900.

Many scientists disagree with Povenmire's theory, but the Florida
researcher is now convinced that the Moon belches and hurls tons of
obsidian-like debris into Earth's gravity well every few million years.

Tektite falls may also cause climate change and extinctions on Earth, he

Armed with his Georgia fieldwork data, Povenmire refutes the current
theory that tektites were formed when asteroids or comets hit the Earth
and melted sediments and rocks. Tektites, a dry homogeneous natural
glass, he noted, do not resemble wet inhomogeneous impact glass found
around many meteor craters.

Povenmire notes that the slow way tektite glass formed, and the volcanic
features some researchers have observed within chunky, layered tektites,
can't be explained by the widely accepted terrestrial-impact theory.

Ablation studies also prove that the infall velocities of tektites
reached 6 km per second or greater­an unlikely speed for terrestrial
ejecta to attain going up through the atmosphere.

Povenmire likes to point out that cosmic-ray traces inside tektites show
they couldn't come from beyond the Earth-Moon system implying that they
didn't spend a long time in space.

Based on still more circumstantial evidence­such as the fact that
Apollos 12 and 14 astronauts found several lunar highland and subcrustal
rocks with tektite-like chemistry­Povenmire believes the space-science
community needs to drastically rethink what mechanisms caused the
ancient stones to fall to Earth.

Louis Varricchio is a science writer living in Vermont and can be
contacted via (

Copyright 2002, SpaceDaily


>From Die Welt, 17 Juli 2002

Platzende Asteroiden im All täuschen nukleare Angriffe vor

In einer Konferenz in der US-Hauptstadt Washington haben Wissenschaftler
und Militärangehörige nun beraten, wie mit dem Phänomen, das
kriegerische Handlungen vortäuscht, umzugehen ist
Washington - Neben Tausenden von Sternschnuppen, die täglich in der
Atmosphäre verglühen, gehen jedes Jahr auch rund 30 kosmische Objekte
mit einem Durchmesser von einigen Metern auf die Erde nieder. Wenn sie
mit mehreren Zehntausend Stundenkilometern in die höhere Atmosphäre
eintauchen und zerplatzen, setzen sie dort eine Energie frei, die jener
einer Atombombe entspricht. Aufgrund der großen Höhe verursachen sie
aber keinen unmittelbaren Schaden. Wissenschaftler und Militärs haben
jedoch auf eine mittelbare Gefahr der Himmelsobjekte aufmerksam gemacht:
Die Asteroiden könnten zufällig einen Krieg auslösen.

Hintergrund ist die Tatsache, dass die berstenden Gesteinsbrocken
Leuchterscheinungen verursachen, die jenen bei der Detonation von
Boden-Luft-Raketen oder gar von Atomsprengköpfen gleichen. Erst Anfang
dieses Monats berichtete der Pilot eines israelischer Passagierflugzeugs
von einer derartigen Erscheinung über der Ukraine. Doch die dortige
Behörden wussten nichts von Raketenangriffen oder -manövern.

In einer Konferenz in der US-Hauptstadt Washington haben Wissenschaftler
und Militärangehörige nun beraten, wie mit dem Phänomen, das
kriegerische Handlungen vortäuscht, umzugehen ist. Was würde passieren,
wenn etwa ein derartiger Asteroid über der von Pakistan und Indien
umkämpften Kaschmir-Region explodieren würde? "Keine dieser Staaten hat
die ausgeklügelten Geräte, die den Unterschied zwischen einem kosmischen
Objekt und einer nuklearen Explosion erkennen", sagte US-General Simon
Worden dem Fachmagazin "Aerospace Daily". Die daraus resultierende Panik
könne in der sensiblen und hoch gerüsteten Region zum Auslöser für einen
Atomkrieg werden.

Die Experten in Washington plädierten deshalb dafür, ein Warnzentrum zu
errichten, das Informationen über Asteroidenexplosionen sammelt und
diese sofort an alle Regierungen weiterreicht. wom

Copyright 2002, Die Welt

see also


>From David Morrison <>

NEO News (07/15/02) LSST, Worden, & Warnings

Dear Friends and Students of NEOs:

This edition of NEO News expands on issues raised by the U.S. Senate
NEO Roundtable discussion reported in NEO News for (07/11/02). But
first, I report briefly on the new recommendation by the Planetary
Exploration panel of the U.S. National Academy of Sciences - National
Research Council that endorses construction of the LSST telescope in
order to extend the survey of potentially threatening NEAs to smaller
sizes -- presumably down to diameters of 200 - 300 m. Second, I
enclose the complete written text of the remarks given at the
Roundtable by Pete Worden, a text that Pete hopes will clear up some
misunderstandings or misattributions to him. My thanks to Pete for
sending me this text. Third, I briefly comment on two issues raised
at the NEO Roundtable dealing with the frequency of 100-m asteroid
hits and the requirements for a warning system in case a NEA is
discovered on an impact trajectory.

David Morrison



On July 11 the United States National Research Council released its
eagerly awaited recommendations for an Integrated NASA Solar System
Exploration Strategy for the next decade. Among its Crosscutting
Themes and Key Questions is:

10. What hazards do solar system objects present to Earth's biosphere?

To deal with this issue, the NRC recommends that NASA partner equally
with the National Science Foundation (NSF) to build and operate a
survey facility, such as the Large-Aperture Synoptic Survey Telescope
(LSST) previously described in the NRC's recommendations for
astronomy and astrophysics. Thus the LSST with its objective of
extending the Spaceguard Survey down to 300 m objects has now been
recommended by two separate NRC panels for high priority at both NASA
and the NSF.

Following are some quotes on LSST from the earlier NRC Astronomy &
Astrophysics Survey Committee (2001):

The Large-aperture Synoptic Survey Telescope (LSST) is a
6.5-meter-class optical telescope designed to survey the visible sky
every week down to a much fainter level than that reached by existing
surveys. It will catalog 90 percent of the Near-Earth Objects larger
than 300 meters and assess the threat they pose to life on Earth. It
will find some 10,000 primitive objects in the Kuiper Belt, which
contains a fossil record of the formation of the solar system. It
will also contribute to the study of the structure of the universe by
observing thousands of supernovae, both nearby and at large redshift,
and by measuring the distribution of dark matter through
gravitational lensing. All the data will be available through the
[proposed] National Virtual Observatory, providing access for
astronomers and the public to very deep images of the changing night
sky. [The estimated cost] of the LSST is $170 million. (p 10-11)

By surveying the visible sky every week to a much fainter level than
can be achieved with existing optical surveys, LSST will open a new
frontier in addressing time-variable phenomena in astronomy. This
6.5-m-class optical telescope will detect 90 percent of the
Near-Earth Objects larger than 300 meters within a decade, and will
enable assessment of the potential hazard each poses to Earth. . . (p

With its huge array of detectors, LSST will collect more than a
trillion bits of data per day, and the rapid data reduction,
classification, archiving, and distribution of these data will
require considerable effort. The resulting database and data-mining
tools will likely form the largest non-proprietary data set in the
world and could provide a cornerstone for the National Virtual
Observatory. (p 108)

Study of the history of collisions of asteroids and comets with Earth
provide the framework for understanding cataclysmic climate changes
over geological time scales. While far rarer now than during the
first billion years of the solar system's history, collisions of
comets and asteroids with planets still take place. On Earth, such
collisions can produce dramatic environmental events, from giant
tidal waves to Earth-girdling dust clouds that can alter climate for
centuries and in some cases lead to mass extinctions of species.
Astronomers now have the tools to detect comets and Earth-crossing
asteroids of size sufficient to threaten human civilization and to
assess the threat of such a collision. (p 154)



Deputy Director for Operations
United States Space Command
Peterson AFB, CO
July 10, 2002

The opinions and concepts expressed are those of the author and do
not necessarily represent the position of the Department of Defense
or the United States Space Command


A few weeks ago the world almost saw a nuclear war.  Pakistan and
India were at full alert and poised for a large-scale war - which
both sides appeared ready to escalate into nuclear war.  The
situation was defused - for now!  Most of the world knew about this
situation and watched and worried.  But few know of an event over the
Mediterranean in early June of this year that could have had a
serious bearing on that outcome.  U.S. early warning satellites
detected a flash that indicated an energy release comparable to the
Hiroshima burst.  We see about 30 such bursts per year, but this one
was one of the largest we've ever seen.  The event was caused by the
impact of a small asteroid - probably about 5-10 meters in diameter
on the earth's atmosphere.  Had you been situated on a vessel
directly underneath the intensely bright flash would have been
followed by a shock wave that would have rattled the entire ship and
possibly caused minor damage.

The event of this June caused little or no notice as far as we can
tell.  But had it occurred at the same latitude, but a few hours
earlier, the result on human affairs might have been much worse.
Imagine that the bright flash accompanied by a damaging shock wave
had occurred over Delhi, India or Islamabad, Pakistan?  Neither of
those nations have the sophisticated sensors we do that can determine
the difference between a natural NEO impact and a nuclear detonation.
The resulting panic in the nuclear-armed and hair-trigger militaries
there could have been the spark that would have ignited the nuclear
horror we'd avoided for over a half-century.  This situation alone
should be sufficient to get the world to take notice of the threat of
asteroid impact.

The Threat

I've just relayed the aspect of the near-earth objects (NEO) that
should worry us all.  As more and more nations acquire nuclear
weapons - nations without the sophisticated controls and capabilities
build up by the United States over the 40 years of Cold War - we must
first and foremost ensure that the 30-odd impacts on the upper
atmosphere are well understood by all to be just what they are.

A few years ago those of us charged with protecting this nations
vital space system, such as the Global Positioning System (GPS)
became aware of another aspect of the NEO problem.  This was the
Leonid meteor storm.  This particular storm occurs every 33 years.
It is caused by the debris from a different type of NEO - a comet.
When the earth passes through the path of a comet, it can encounter
the dust thrown off by that comet through its progressive passes by
the Sun.  This dust is visible on the Earth as a spectacular meteor
storm.  But our satellites in space can experience the storm as a
series of intensely damaging micrometeorite strikes.  We know about
many of these storms and we've figured out their parent comet
sources.  But there are some storms arising from comets that are too
dim or spent for us to have seen that can produce "surprise" events.
One of these meteor storms has the potential of knocking out some or
even most of our earth-orbiting systems.  If just one random
satellite failure in a pager communications satellite a few years ago
seriously disrupted our lives, imagine what losing dozens of
satellites could do!

Most people know of the Tunguska NEO strike in Siberia in 1908.  An
object probably less than 100 meters in diameter struck over Siberia
releasing the equivalent energy of up to 10 megatons.  It leveled a
forest 50 miles across.  But most people don't know that we have
evidence of two other strikes during last Century.  One occurred over
the Amazon in the 1930s and another over central Asia in the 1940s.
Had any of these struck over a populated area, thousands and perhaps
hundreds of thousands might have perished.  Experts now tell us that
an even worse catastrophe that a land impact of a Tunguska-size event
would be an ocean impact near a heavily populated shore.  The
resulting tidal wave could inundate shorelines for hundreds of miles
and potentially kill millions.  There are hundreds of thousands of
objects the size of the Tunguska NEO that come near the earth.  We
know the orbits of but a handful.

Finally, just about everyone knows of the "dinosaur killer"
asteroids.  These are those objects a few kilometers across that
strike on timescales of tens of millions of years.  While the
prospect of such strikes grab people's attention - and make great
catastrophe movies - too much focus on these events has in my opinion
been counterproductive.  In my organization, the Department of
Defense, I have tried to raise our concern and interest in addressing
the very real threats outlined above.  However I get the predictable
response. "General, if this threat only hits every 50 million years,
I think we can focus our attention of more immediate threats!"  In
short the "giggle factor" in the professional scientific and national
security community has meant that we have gotten little done on this

What Should We Do?

First and foremost we must know when an objects strikes the earth
exactly what it is and where it hit.  Fortunately our early warning
satellites already do a good job of this task.  And our next
generation system, the Space-Based Infrared System (SBIRS) will be
even better.  The primary difficulty here is that this data is also
used for vital early warning purposes and its detailed performance is
classified.  However, in recent years the U.S. DoD has been working
to provide extracts of this data to nations potentially under missile
attack with cooperative programs known as "Shared Early Warning."
Some data about asteroid strikes has also been released to the
scientific community.  Unfortunately this data takes several weeks to
get released.  Thus my first recommendation is that the United States
DoD make provision to assess and release this data a soon as possible
to all interested parties - exercising proper cautions of course to
ensure that sensitive performance data is safeguarded.

We have begun to scope what an NEO warning center might look like.
We believe adding a modest number of people, probably less than 10
all told, to current early warning centers and supporting staffs
within Cheyenne Mountain could accomplish this.   A Natural Impact
Warning Clearinghouse has been scoped to do this job.

Perhaps the most urgent mid-term task has already been begun.  This
is the systematic observation and cataloguing of close to all
potentially threatening NEOS.  We are probably about halfway through
cataloging "large" NEOS (greater than a kilometer in diameter).  It's
interesting to note that the most effective sensor has been the MIT
Lincoln Lab LINEAR facility in New Mexico.  This is a test bed for
the next generation of military ground-based space surveillance
sensors.  But this ground-based system, however effective, can only
really address the "large", highly unlikely threats.  We find out
every few weeks about "modest" asteroids a few hundred meters in
diameter.  These are often caught as they sail by the earth, often
closer than the Moon, unnoticed until they have nearly passed.  Most
recently the object 2002MN had just this sort of near miss - this
time only a few tens of thousands of kilometers from the earth!
Moreover, ground-based systems such as LINEAR are unable to detect
one of the potentially most damaging classes of objects, those such
as comets that come at us from the direction of the sun.  New
space-surveillance systems capable of scanning the entire sky every
few days are what's needed.

New technologies for both space-based and ground based surveys of the
entire space near the earth are available.  These technologies could
enable us to completely catalog and warn of objects as small as the
Tunguska meteor (less than 100 meters in diameter).  The LINEAR
system is limited primarily by the size of its main optics - about 1
meter in diameter.  By building a set of three-meter diameter
telescopes equipped with new large-format CCD-devices, the entire sky
could be scanned every few weeks.  But more important the follow-up
observations necessary to accurately define orbits, particularly for
small objects could be done.

The most promising systems for wide-area survey - particularly to
observe close to the sun to see objects coming at up from that
direction - are space-based surveillance systems.  Today the only
space-based space surveillance system is the DoD's "MSX" Satellite.
This was a late 1990s missile defense test satellite and most of its
sensors have now failed.  However one small package weighing about 20
kg and called the "SBV" sensor is able to search and track satellites
in Geosynchronous orbit using visible light.  This has been a
phenomenally successful mission having lowered the number of "lost"
objects in GEO orbit by over a factor of two.  MSX is not used for
imaging asteroids, but a similar sensor could be.  The Canadian Space
Agency, in concert with the Canadian Department of National Defense
is considering a "microsatellite" experiment with the entire
satellite and payload weighing just kg.  This Near-Earth Surveillance
System (NESS) would track satellites in GEO orbit, as MSX does today.
However, it would also be able to search the critical region near the
sun for NEOs that would be missed by conventional surveys.

The U.S. DoD is planning a constellation of somewhat larger
satellites to perform our basic satellite-tracking mission.  Today
our ground-based radars and telescopes, and even MSX only track
objects that we already know about.  These systems are not true
outer-space search instruments as the LINEAR system is.  However, the
future military space surveillance system would be able to search the
entire sky.  As an almost "free" byproduct it could also perform the
NEO search mission.  Corresponding, larger aperture ground based
systems could then be used to follow up to get accurate orbits for
the NEOs discovered by the space-based search satellites.  Again, I
believe there is considerable synergy between national security
requirements related to man-made satellites and global security
related to NEO impacts.

Regardless of how well we know NEO orbits and how well we can predict
their impacts the fact remains that today we have insufficient
information to contemplate mitigating an impact.  We do not know the
internal structure of these objects.  Indeed, we have reason to
believe that many, if not most are more in the nature of  "rubble
piles" than coherent objects.  This structure suggests that any
effort to "push" or divert a NEO might simply fragment it - and
perhaps turn a single dangerous asteroid into hundreds of objects
that could damage a much larger area.

What are needed are in-situ measurements across the many classes of
NEOs, including both asteroids and comets.  This is particularly the
case of small (100meter) class objects of the type we would most
likely be called upon to divert.  Until recently missions to gather
these data would have taken up to a decade to develop and launch and
cost 100s of millions of dollars.  However, with the rise of
so-called "microsatellites" weighing between 50-200 kg and which are
launchable as almost "free" auxiliary payloads on large commercial
and other flights to GEO orbit, the situation looks much better.
These missions can be prepared in one-two years for about $5-10M and
launched for a few million dollars as an auxiliary payload.  Such
auxiliary accommodation is a standard feature on the European Ariane
launched and should be, with proper attention, here in the United
States on our new EELV launcher systems.

With a capable microsatellite with several kilometers per second
"delta-V" (maneuver capacity) launched into a GEO transfer orbit (the
standard initial launch orbit for placing systems into GEO) the
satellite could easily reach some NEOs and perform in-situ research.
This could include sample return and direct impact to determine the
internal structure and potential to physically move a small object.
Indeed, NASA is planning several small satellite missions.  The key
point here, however, is that with missions costing $10M each, we can
sample many types of objects in the next decade or so to gain a full
understanding of the type of objects we face.

There is an interesting concept to consider.   If we can find the
right small object in the right orbit we might be able to nudge it
into an orbit "captured" by the earth.  This would make a NEO a
second natural satellite of earth.  Indeed, there is at least one NEO
that is close to being trapped by the Earth now, 2002 AA29.  If such
an object were more permanently in earth orbit it could not only be
more closely studied but might form the basis for long-term
commercial exploitation of space.  Moreover, a very interesting next
manned space flight mission after the Space Station would be to an
asteroid, maybe even one we put into earth's gravity sphere.

The key of each of these proposed actions on developing the ability
to mitigate NEO impacts is that they are all items our national
security community and we in the United States are likely to do for
other reasons.  If these efforts can be adapted to the NEO threat
problem, this would add minimal additional expense.

One of the most important aspects of NEO mitigation is often
overlooked.  Most experts prefer to focus on the glamorous
"mitigation" technologies - diverting or destroying objects.  In
fact, as the military well knows the much harder part is what we call
"command and control."  Who will determine if a threat exists?  Who
will decide on the course of action?  Who will direct the mission and
determine when mission changes are to be made?  Who will determine if
the mission was successful?  And there are hosts more.

  These command and control issues are those that the military has
long struggled with.  The NEO community has not faced this essential
issue.  Indeed, the United States Space Command has just completed a
concept of operations for the first step in NEO mitigation - a
Natural Impact Warning Clearinghouse.  This operation is a command
and control function.  It would be able to catalog and provide
credible warning information on future NEO impact problems as well as
rapidly provide information on the nature of an impact.

International Issues

Much discussion has been expended suggesting that any NEO impact
mitigation should be an international operation.  I would
respectfully disagree.  International space programs such as the
International Space Station fill many functions.  An NEO mitigation
program would have only one objective.  In the latter case a single
responsible nation and organization would have the best chance of a
successful mission.  Moreover, the nation responsible would not need
to worry about giving up national security sensitive information and
technology as it would build and control the entire mission itself.
For as pointed out the means to identify threats and mitigate them
overlap considerably with other national security objectives.

It does, however make considerable sense that the data gathered from
surveys and in-situ measurements be fully shared among all.  This
will maximize the possibility that the nation best positioned to
perform a mitigation mission would come forward.  One of the first
tasks of the Natural Impact Warning Clearinghouse noted above would
be to collect and provide a distribution point for such data.


NEO Mitigation is a topic whose time has come.  Various aspects
related to NEO impacts, including the possibility than an impact
would be misidentified as a nuclear attack, are critical national and
international security issues.  The focus of NEO mitigation efforts -
both in finding and tracking them and in exploring and moving some
should shift to smaller objects.  Not only are the near-term threats
much more likely to come from these "small" objects (100 meters in
diameter or so), but we might also be able to divert such objects
without recourse to nuclear devices.

After a suitable class of NEOs are found, microsatellite missions to
fully explore and perhaps perform test divert operations should
commence.  The technologies for low-cost NEO missions exist today.

The necessary command and control, sensor and space operations
technologies and equipment are all "dual use" to the military.  We
have similar, and in some cases almost identical requirements.  It
thus stands to reason that strong military involvement and even lead
in the decades ahead on NEO mitigation is in order.   As the U.S.
Government considers how to proceed on this critical issue, the major
role that the military and the technologies it controls should be
carefully integrated into our overall national work.



David Morrison

Impact Frequency

In his written statement (above) Pete Worden mentions three large
impacts during the 20th century, and in his oral testimony he called
all three of these 100-m class impacts. He wrote: "Most people know
of the Tunguska NEO strike in Siberia in 1908. An object probably
less than 100 meters in diameter struck over Siberia releasing the
equivalent energy of up to 10 megatons. It leveled a forest 50 miles
across. But most people don't know that we have evidence of two other
strikes during last Century. One occurred over the Amazon in the
1930s and another over central Asia in the 1940s. Had any of these
struck over a populated area, thousands and perhaps hundreds of
thousands might have perished". Others have made similar comments,
sometimes also including the dramatic Sikhote-Alin iron meteorite
fall of February 12, 1947.

Of these four events, the Tunguska impact (June 30, 1908) of an
asteroidal object nominally 60 m in diameter was by far the most
dangerous, producing an airburst releasing 5-15 megatons energy.
Sikhote-Alin was well observed and studied, and more than 40 tons of
iron were recovered from multiple craters, but the estimated diameter
of the projectile was no more than 3 meters. The Amazon impact in the
1930s has been discussed but is based on scattered human reports with
no supporting physical evidence, and most researchers suspect that
this impact is spurious. I have not heard anything about the
Kazakastan impact of the 1940s, and I suspect that is spurious also.

Thus by my count for the 20th century we have one confirmed 60-m
impactor (Tunguska) and no evidence of anything else approaching this
size (although of course we would miss most impacts since they would
occur in the ocean; absence of evidence in this case is not evidence
of absence). For comparison, the latest estimated frequency of impact
of 60-meter projectiles is only about once per millennium, rather
lower than the older estimates of once every couple of hundred years.

Call for an NEO Warning Center

Several participants in the NEO Roundtable called for establishing a
NEO coordination and warning center. In the summaries by the
panelists this was a nearly unanimous recommendation. Worden wrote
above that "We [USAF Space Command] have begun to scope what an NEO
warning center might look like. We believe adding a modest number of
people, probably less than 10 all told, to current early warning
centers and supporting staffs within Cheyenne Mountain could
accomplish this. A Natural Impact Warning Clearinghouse has been
scoped to do this job."

It would be interesting to me to understand better what is meant by
such a warning center. I think everyone can share Worden's concern
about misidientification of meteors that hit the atmosphere and
explode with kiloton-scale energies. I certainly support his proposal
that this information be disseminated more widely and quickly.
However, these are not what I call "warnings" -- they are timely
reports on events that have already happened and been observed from

The only warnings I know of would concern asteroids or comets
discovered to be on possible impact trajectores. Over the past 6
years there have been several short-lived "warnings" of possible
future impacts that were quickly withdrawn as new data and/or better
orbital calculations became available. Today with multiple
international centers for calculating orbits and improved data
sharing, it is likely that there will be fewer such public warnings.
In fact, the only legitimate warning (if you want to call it that) on
the books today is NEA 1950DA, with a nominal chance of 1 in 300 of
an impact in March 2880.

As the NEA surveys increase in power, there will almost certainly be
additional cases of newly-discovered NEAs that appear for a short
time to have a possibility of colliding with the Earth. These will
all be predictions for far in the future, probably at least several
decades. Some will be reported in the press, but most will be quietly
checked out and their orbits refined without the glare of publicity.
Astronomers in several countries today have this computational
capability. I therefore wonder what is the purpose of the proposed
warning center, and just what sort of warnings it anticipates issuing?

Perhaps it is worth repeating that none of the proposed surveys is
designed to look for any NEA on its final plunge to collision with
the Earth. Indeed, it would be very difficult and non-cost-effective
to try to design such a "last minute warning" system. The approach
first articulated a decade ago is to survey the sky, discover NEAs,
determine their orbits, and predict their future paths. Any potential
impactor should be picked up decades (or more) in advance. We can do
this because orbital dynamics is an exact science, and asteroids do
not change orbits capriciously. This approach will apply as well to
the smaller NEAs that are discovered in the future as it does to
those being found today. "Warning" is a word that conveys the wrong
impression: In my opinion, what we should be talking about are
long-term predictions, based on a comprehensive survey of NEAs.


NEO News is an informal compilation of news and opinion dealing with
Near Earth Objects (NEOs) and their impacts.  These opinions are the
responsibility of the individual authors and do not represent the
positions of NASA, the International Astronomical Union, or any other
organization.  To subscribe (or unsubscribe) contact  For additional information, please see the
website:  If anyone wishes to copy or
redistribute original material from these notes, fully or in part,
please include this disclaimer.

MODERATOR'S NOTE: It is interesting to see just how unhappy Dave is about
the recent U.S. Senate Space Roundtable. He has been trying hard to minimise
the threat of smaller impacts with the Earth for much of the
last two decades. It does not come as much of a surprise that he also
tries to rubbish the research of others into small impacts reported
during the 20th century. According to Dave's "count for the 20th century
we have one confirmed 60-m impactor (Tunguska) and no evidence of
anything else approaching this size." He even claims that Tunguska-size
objects (50-60m) hit the Earth's atmosphere on average only once in 1000
years. These claims seem untenable to me given that we are *frequently*
bombarded by small asteroids close in size to the Tunguska object. In
fact, in the last 10 years alone, two asteroids between 30 and 40 metres
across have been detected after exploding in the Earth's atmopshere. It's
time for Dave to wake up and smell the smoke of these recent impacts. BJP



>From Drake A. Mitchell <PlanetaryDefence@Netscape.Net>

Dear Benny,

As I was under the impression that this is a "scholarly network", I have
tried to be diligent with references to the literature, especially with
references that are links to such documents and other information freely
available on the Web. It is sad to me that such "web links" and even
the many search engines still seem to be a novelty for a Conference in an
electronic millennium, but then I suppose allowances have to be made -
even for the fact that indispensable volumes in our field, some that are
already many years old, seem to be rarely read in their entirety even

Anyway, although the text appended below is more than six months old, it
does represent some of the latest understanding in the unclassified
literature of the smaller sized impactors, per 15Jul02's topical
inquiry. Regarding non-terrestrial empirical verifications of such impact
modeling efforts, with a dedicated program we could actually begin smaller
deflection-based impact experiments on Mars within a decade (sooner for
the Moon). Contrary to widespread misconception, this would be entirely
economically justified by an approach to the NEO hazard that finally
dispensed with our currently interminable "adhocracy."

If Russia's proposal two weeks ago [1] for a $20B human mission to Mars
by 2015 was enhanced, say by a) including their improved particle-bed
reactor rockets using twisted-ribbon mixed-carbide fuel [2] for much
faster travel times, and b)their giving up on NASA and accepting a more
gung-ho China as the third partner to Russia and Europe, we might even
have humans in Mars orbit [3] in time to witness these first impact
events (incidentally, it might also be prudent to test deflections into
Mars-orbit before we try to deflect NEAs into Earth-orbit for proposed
resource harvesting).

Regardless, more encouraging are the recent proposals for increased
instrumentation infrastructure on this planetary body:

"Advocated by the SSES is establishment of a Mars Long-Lived Lander
Network. This grid of Mars science stations would run for at least one
Martian year from spots around the planet. The armada of stations would
complement a suite of planned French NetLander packages, a system
limited in number and spaced across Mars's equatorial region.
Additionally, a Mars upper Atmosphere Orbiter is promoted by the SSES.
This small, dedicated mission can help reconstruct the evolution of the
Red Planet's atmosphere" [4].

It may be rather hard to believe, especially for those in our field that
still live and breathe in a ground-based telescopic paradigm, but the
most recent cost estimate for X2 to detect all the Potentially Hazardous

Asteroids (PHAs) down to 110m is less than $300M, including launches and
seven years of operation. Perhaps even harder to believe is that
detecting the more monstrous number of PHAs down to 10m, which include
the still hazardous ~3% of Iron PHAs, represents an additional
incremental cost on the  order of only ~$70M. These estimates do assume
an adequate telemetry infrastructure.

This text below [5] was reference "[33]" in the most recent CCNet Essay;
I hope it is helpful to Mr. Ebisch and others.

DPS 2001 meeting, November 2001
[41.05] The Role of Asteroid Strength in Impact Damage
J.G. Hills, M.P. Goda (Los Alamos National Lab)

The fragmentation and dispersal of an asteroid in the atmosphere help
determine the damage it can cause (Hills and Goda, 1993, Astronomical J.
105, 1114-1144). Large asteroids are suspected to be rubble piles with
little overall strength. This lack of strength causes them to break up
higher in the atmosphere than would be the case if they had the same
material strength as normal meteorites. The higher elevation breakup
causes them to spread apart more at a given elevation in the atmosphere,
so less of their energy is available for ground impact.

We made computer simulations of such dispersal using asteroids of normal
strength and those with much reduced strength to see if the more
fragmented asteroids produce less damage. We find that these differences
are much greater for irons than for stones, which is not surprising
given the greater material strength of the irons. Irons with radii less than
about 20 meters lose most of their energy before they reach sea level if
they are of normal strength. If they are rubble piles, they produce
little ground impact damage unless their radii exceed 70 meters. Iron
asteroids have to have radii above these critical values to allow them
to produce significant craters on land and tsunami in water. If the radius
of an iron asteroids exceeds 200 meters, the size of the crater it
produces is nearly independent of its material strength. Solid-stone
asteroids with radii greater than about 100 meters produce significant
craters. This critical limit is only about 20% larger for rubble-pile
stone asteroids.

Blast damage from stony asteroids is not very sensitive to their
strength. Small iron asteroids, with radii less than about 20 meters,
produce more blast damage if they are solid, because their energy is
dissipated lower in the atmosphere. If their radii exceed this value,
the weaker asteroid produces more blast damage than the stronger one because
the stronger one loses less of its energy in the atmosphere and more of
it on ground impact.
[2] Gehrels et al, 1994, "Hazards...", pp. 1097-1098


>From John Michael Williams <>

Hi Benny.

> >From Press Association, 14 July 2002
> A SMALL asteroid exploding in the Earth's atmosphere could
> accidentally cause a nuclear war if "trigger-happy" nations mistook it
> for a first strike attack, experts have warned. This has led to
> scientists and military chiefs calling for a new warning centre that
> would make asteroid detections available to governments around the
> world....

This will never work, anonymous scientists and military chiefs
notwithstanding. The temptation to lie, or to interpret negative ("not a
bomb") obervations as lies, will be too strong.

Consider India and Pakistan, ten years from now, with high-speed,
unstoppable antiballistic missiles rearmed with nuclear warheads. If
there was a nuclear war, several hundred MILLION lives would be lost.
Now suppose someone launched a nuclear missile, perhaps by accident
or by the malicious act of an individual, crazed scientist or military
chief.  Or, suppose a comet fragment exploded in the lower atmosphere
over one of these countries:

What would the new warning center report? If it reported NOT an
asteroid, hundreds of millions would die. Investments of dozens of
scientists and military chiefs would be vaporized. If it reported an
asteroid, deaths, damage, and destruction would be limited.  Why should
such a center EVER report that an unexpected explosion in the atmosphere
was not an asteroid?

What MIGHT work, would be a system of sharing openly the technology so
that each nuclear nation could build its own asteroid detection system,
under its own, sovereign control.  There then would be no good reason
for any country to lie to itself--any more than there would be in the
absence of such a system, of course.

As a case in point, the article you circulated ends by saying,

> In the case of the El Al jet, the Ukrainian authorities insisted that
> no missiles had been fired near the plane and suggested the flash might
> have been a meteor explosion. This now seems the most likely
> explanation.

However, as I recall, the cause of the jet explosion WAS an Ukrainian
missile, as reported at the time by the very US defense systems the
article advocates. Several Ukrainian  officials were fired for denying
responsibility (as they would have done, were they manning an asteroid
observation system). At the time, both Russia and the United States
confirmed that that explosion was a Ukrainian antiaircraft missile.

So much for the veracity of scientists and military chiefs of another

                     John Michael Williams


>From Andy Smith <>

Hello Benny and CCNet,

It is a pleasure to contemplate the sunrise, on the eighth anniversary
of our great wake-up call.....the impact of Shoemaker-Levy 9 on Jupiter,
which started on the 16th of July 1994. Many of us, who had become
concerned about the asteroid/comet impact danger, as a result of the
near-miss of asteroid 1989 FC and as a result of the many important
international conferences held in the early 1990's,  were beginning to
wish and to pray for a harmless demonstration of this danger.....and
Gene Shoemaker was certainly in that group.

We could not have had a more impressive and safe demonstration and
Galileo could not have been better positioned to help us see it.  That
demonstration and all of the things we have learned have added a special
new appreciation for every day of bright sunshine. Many of us have also
developed an increased dedication to doing all we can to inform others
(especially our policy makers) of the dangers, the need for meaningful
and adequately funded NEO early-warning, defense and civil emergency
preparedness programs (which should be international, in scope).

On this day, each year, we salute all of you and all of the earlier
pioneers,in this important quest (over the last century). We thought it
especially appropriate that the presentations were made to the U.S.
Senate, this week and that some of our old friends and supporters from
the House of Representatives, we able to participate. We also salute the
many friends and supporters of planetary protection around the World and
especially the CCNet, the Spaceguard and Space Shield Foundations, the
Planetary Society, the Space Frontier Organization and many other
organizations and individuals,  for helping us to continually
communicate and cooperate.

We will toast the future and effective planetary protection, tomorrow
and we will give thanks for the  progress which has been made. We thank
you all for your contributions.


Andy Smith and the International Planetary Protection Alliance


>From Mike Baillie <>


Oliver Morton's update on electrophonic sounds from fireballs
left out the fact that Colin Keay, from Australia, has been publishing
papers on the subject for decades. A few examples are given below. 

cheers  Mike

Keay, C.S.L. 1980 Anomalous Sounds from the Entry of Meteor Fireballs.
Science 210, 11-15

Keay, C.S.L. 1993, Progress in Explaining the Mysterious Sounds Produced
by Very Large Meteor Fireballs, Journal of Scientific Exploration 7 (4),

Keay, C.S.L. 1995, Continued Progress in Electrophonic Fireball
Investigations, Earth, Moon and Planets 68, 361-8


>From Bob Kobres <>

More books encoded in the DjVu format that may be of interest to

Among them:

. . .

It is a singular coincidence that evidence of a prehistoric
torrent-fire exists certainly in Ireland, where bog-buried
forests have been unearthed exhibiting all the signs of a
flowing torrent of molten fire or lava. According to the
author of Bogs and Ancient Forests, when the Bog of Allen
in Kildare was cut through, oak, fir, yew, and other trees
were found buried 20 or 30 feet below the surface, and
these trees generally lie prostrated in a horizontal position,
and have the appearance of being burned at the bottom of
their trunks and roots, fire having been found far more
powerful in prostrating those forests than cutting them
down with an axe; and the great depth at which these
trees are found in bogs, shows that they must have lain
there for many ages.

No ordinary or casual forest fire is capable of prostrating
an oak or fir tree, and the implement which accomplished
such terrific devastation must have been something volcanic
and torrential in its character.

I am, however, not enamoured of the Atlantean or any
other theory. My purpose is rather to collate facts, and as
all theorising ends in an appeal to self-evidence, it is better
to allow my material, for much of which I have physically
descended into the deeps of the earth, to speak for itself:
-we must believe the evidence of our senses rather than
arguments, and believe arguments if they agree with the
. . .
+ banner

svastika, Bird of Fire, etc.:


and the Fight between Bel and the Dragon,
as told by Assyrian Tablets from Nineveh, 1921

Bob Kobres
Main Library
University of Georgia
Athens, GA  30602

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