CCNet 18/2002 - 1 February 2002
* Please note that I will be abroad for most of next week, BJP *
(1) WORLD'S ASTEROID HUNTERS MAKE POLITICAL PLEA TO SAVE EARTH
Space.com, 1 February 2002
(2) COLLIDING STORMS ON JUPITER AND A FLARING COMET
SpaceWeather.com, 31 January 2002
(3) EUVE SPACECRAFT RE-ENTERS EARTH'S ATMOSPHERE
Ron Baalke baalke@ZAGAMI.JPL.NASA.GOV>
(4) CLOSE APPROACHES OF PHAS DURING TWO CENTURIES
JH Ji & L Liu
(5) RE: "ASTEROID IMPACT MAY HAVE ADDED TO AUSTRALIAN WEALTH"
Franco Pirajno <email@example.com>
(6) POPE'S DUST-FREE K/T IMPACT STIRS UP LOTS OF DUST
Jan Smit <firstname.lastname@example.org>
(7) ON NUCLEAR & COSMIC WINTERS
S. Fred Singer <email@example.com>
(8) ABOUT THE CAUSE OF THE K/T EXTINCTIONS
Tom Van Flandern <firstname.lastname@example.org>
(9) 1680 COMET
Duncan A. Lunan <email@example.com >
(10) JOSHUA IMPACT
Brian Moore <bmoore.freeserve.co.uk>
(11) AND FINALLY: ASTEROID IMPACT HAZARDS "GREATLY OVERSTATED"
New Scientist, 30 January 2002
(1) WORLD'S ASTEROID HUNTERS MAKE POLITICAL PLEA TO SAVE EARTH
>From Space.com, 1 February 2002
By Robert Roy Britt
Senior Science Writer
Prompted by a close brush between Earth and an asteroid in early January,
scores of top researchers who often don't see eye-to-eye have made a joint
political plea for help in saving the planet.
The fear: a cosmic sucker punch from southern skies that could destroy
The remedy: a new multi-million dollar telescope in Australia.
While a coordinated asteroid search program is underway in the Northern
Hemisphere, none exists south of the equator, creating a blind spot that
equals nearly a third of the heavens. So 91 international astronomers and
prominent space activists -- including a who's who of asteroid experts --
sent a letter asking the Australian government to rejoin the asteroid search
seven years after the country dropped out.
The letter, provided to SPACE.com before it was mailed Tuesday, commends the
Australians for a recent official comment that the government would look
into renewed funding for Spaceguard, an international group that promotes
asteroid detection programs.
The letter prods Australia to action, suggesting the country build a
telescope. It makes no bones about the stakes involved.
"A major global Spaceguard effort could provide decades of warning prior to
an impact," the letter states. "This would be sufficient time to refine the
space technology needed to nudge a threatening asteroid into a harmless
orbit, or to evacuate the predicted impact area. Without Spaceguard there
would be too little warning to prevent a disaster."
The signatories include scientists from NASA and several universities and
institutions in America, Europe, Russia and Australia. The voices range
widely, from renowned asteroid hunter Carolyn Shoemaker, of the Lowell
Observatory, to Ann Druyan, wife of the late Carl Sagan.
Several of the scientists who signed the letter have, from time-to-time,
argued over how to conduct the asteroid hunt -- both scientifically and
politically. One camp favors focusing on the largest asteroids, which could
cause global destruction. Another prefers plans that include smaller rocks
that might wipe out a city and, due to sheer numbers, present a greater
statistical risk of impact.
The scientists also sometimes disagree over how their findings should be
presented, or not presented, to the public. Some have called for full
disclosure at times. Others have suggested a more guarded release of
information only after public risk, or lack of it, has been well
One thing they all agree on, however, is that the threat is real.
The odds of an asteroid larger than 1 kilometer (0.6 miles) hitting Earth
sometime in the next century are typically put at 1-in-5,000. Such an impact
could destroy a country, would likely cause some species to go extinct, and
might blot out the Sun long enough to ruin farming and send humans into a
Dark Ages existence, analysts say. Past impacts are recorded in a handful of
craters that have not fully eroded.
Smaller events occur as often as once every 100 years and can cause local or
regional damage. A comet or asteroid exploded just above the surface of
Siberia in 1908, leveling thousands of acres of unpopulated forest.
Don Yeomans of NASA's Jet Propulsion Laboratory is among four scientists
there who signed the letter. JPL oversees NASA's asteroid search efforts. In
a telephone interview, Yeomans agreed it is unusual for so many of his
colleagues to band together on a single political statement.
He added, though, that it was not the first time scientists have tried to
arm-twist governments into recognizing the dangers of asteroids and taking
action. A similar letter, signed by far fewer researchers, was once sent to
the Canadian government, he said.
And scientists have regularly prodded the British government to get
involved, leading to a recent announcement to create a UK center for
Yeomans explained why Australia is the preferred location, rather than some
other country south of the equator.
"Australia already has a nucleus of [research] groups that could easily be
put online," Yeomans said. "They are already there, they have the equipment
available, they have the interest."
In fact, a minor search program does exist in Australia, funded by U.S.
institutions, but it is seen as inadequate.
The letter, mailed from Spaceguard UK, points out that the United States
bears the brunt of the burden in looking for asteroids. NASA has a
congressional mandate to catalogue all asteroids that roam in the vicinity
of Earth's orbit and are at least 0.6 miles (1 kilometer) wide.
While no asteroid is known to be on a collision course with Earth, it is
these large Near Earth Objects, or NEOs, that generate the most concern
among some researchers because, they say, an impact by one could have global
consequences. Over time, their orbits are altered by the gravity of the Sun
Only about half of these large NEOs have been found, according to the most
widely accepted estimates. Some 500 or so are thought to await detection.
Meanwhile, about 30 percent of the sky has never been surveyed, Yeomans
said. Pointing to an additional need for a southern telescope, he said, is
that when asteroids are discovered in northern skies, they often need to be
studied later from the south before their exact paths can be determined.
"It's not that we'll miss them forever, it's just that it will take a lot
longer," he said. He said a full-fledged search program Down Under "would
definitely help" achieve NASA's goal for 2008.
Large asteroids could be found with an existing, 1-meter (3-foot) Australian
telescope that was used for the purpose through 1996. This solution would
require no initial investment. Less than $1 million would be needed annually
to operate the telescope and pay astronomers, researchers say.
But the thrust of the letter is to encourage the Australians to build a new,
larger telescope that would also find small asteroids.
Yeomans notes, however, that larger telescopes, while they can spot small
asteroids, cover a smaller region of the sky and so are less effective in
finding bigger asteroids.
Construction of a new telescope would run about $7 million for a 2-meter
telescope and roughly $21 million for a 3-meter telescope, the ultimate
Spaceguard goal, according to Benny Peiser, a researcher at Liverpool John
Moores University who is one of the initial authors of the letter.
"This is a highly cost effective investment in the prevention of loss of
life and severe economic damage from asteroid impacts," the letter states.
NASA or other U.S. institutions might cover some of the costs, researchers
said. Other funding might materialize.
"If Australia were to rejoin Spaceguard, there potentially is a good chance
that the UK and other European partners might become interested in a joint
project," Peiser said.
The story behind the letter
The original idea for the plea dates back several years, said Michael Paine,
a volunteer with Planetary Society in Australia and a Spaceguard proponent
who helped draft the letter.
But a natural impetus came on Jan. 7, when an asteroid the size of three
football fields (300 meters wide) passed relatively close to Earth, just
twice the distance to the Moon. The rock, named 2001 YB5, was first seen in
December -- nowhere near enough time to mount a space mission to deflect it.
"Had it been on a collision course, there is little that could have been
done to prevent possibly millions of casualties when an area the size of
Tasmania would have been devastated," the signatories agree. Tasmania is
about the size of Ohio.
A similar asteroid flyby occurred last October, when a rock thought to be
between 50 and 100 meters in diameter zoomed by Earth at a similar distance.
The object, big enough to destroy a city, was first detected just two days
The more recent flyby of 2001 YB5 got wide coverage in Australia, however,
and a spokesperson for Science Minister Peter McGuaran said the Government
would look into renewing the funding of a dedicated Australian Spaceguard
program. (McGuaran made a similar statement in 1997, according to press
reports from the time.)
Three researchers -- Paine, Peiser, and Australian author and physicist Paul
Davies -- jumped on the recent comment and drafted the letter beginning Jan.
10, then sought the signatures
Copyright 2002, Space.com
(2) COLLIDING STORMS ON JUPITER AND A FLARING COMET
>From SpaceWeather.com, 31 January 2002
Space Weather News for January 31, 2002
Something extraordinary is happening on the planet Jupiter in full view of
amateur astronomers: Two gigantic storms are interacting. One is a "white
oval" -- a 70-year old hurricane nearly the size of Earth. The other is the
famous Great Red Spot -- a centuries-old tempest twice as wide as our
planet. Sky watchers with 6" to 10" telescopes can view the action on clear
nights with good atmospheric seeing.
Meanwhile, southern-hemisphere sky watchers can follow another dynamic show:
Comet LINEAR (C/2000 WM1) is flaring. Only a few days ago, the comet was
barely visible to the unaided eye (6th magnitude), but now it is relatively
eye-catching (3rd magnitude). Comet LINEAR passed close to the Sun in late
January, an encounter that might have disrupted its icy nucleus and
triggered the ongoing show.
Visit SpaceWeather.com for details and updates.
(3) EUVE SPACECRAFT RE-ENTERS EARTH'S ATMOSPHERE
>From Ron Baalke baalke@ZAGAMI.JPL.NASA.GOV>
Headquarters, Washington Jan. 31, 2002
Goddard Space Flight Center, Greenbelt, Md.
EUVE SPACECRAFT RE-ENTERS EARTH'S ATMOSPHERE
NASA's Extreme Ultraviolet Explorer (EUVE) re-entered the Earth's atmosphere
at approximately 11:15 p.m. EST Wednesday. According to calculations made by
the United States Space Command Space Control Center, EUVE re-entered the
atmosphere over central Egypt.
"The actual location of EUVE's re-entry was within the predicted orbit
track," said Scott Hull, spacecraft engineering lead for space science
mission operations, at NASA Goddard Space Flight Center, Greenbelt, Md. "We
expected EUVE could come in at a number of points along the ground
EUVE did not have an on-board propulsion system to allow engineers to
control the spacecraft's re-entry. Using U.S. Space Command data, engineers
calculated EUVE's orbit track and predicted where it could re-enter the
atmosphere. EUVE was in a 28.5-degree orbit and could re-enter in any
location within this orbit range. This range included areas as far north as
Orlando, Fla., and as far south as Brisbane, Australia.
The object was not designed to survive re-entry intact and was expected to
break apart and mostly burn up in the atmosphere. U.S. Space Command cannot
confirm if any pieces survived re-entry.
EUVE was launched on July 7, 1992. Science operations ended in December
2000. During its eight years in orbit, EUVE was the first astrophysics
mission to explore the extreme ultraviolet-and helped to bridge the gap in
our understanding of this previously unknown spectrum. EUVE observed more
than 1,000 nearby sources, including more than three dozen objects outside
Additional background information about EUVE is available at
(4) CLOSE APPROACHES OF PHAS DURING TWO CENTURIES
Ji JH, Liu L: Close approaches of potentially hazardous asteroids during two
CHINESE JOURNAL OF ASTRONOMY AND ASTROPHYSICS 1 (6): 549-554 DEC 2001
Asteroids are the most important small bodies in the solar system and the
near-earth asteroids (NEAs) are of especial concern to the world. The reason
is that they will make close approaches to the earth in the near future. We
use a reasonable dynamical model and an efficient computing method to
calculate the orbits of over 160 Potentially Hazardous Asteroids (PHAs) for
Ji JH, Chinese Acad Sci, Purple Mt Observ, Nanjing 210008, Peoples R China
Chinese Acad Sci, Purple Mt Observ, Nanjing 210008, Peoples R China
Nanjing Univ, Dept Astron, Nanjing 210093, Peoples R China
Chinese Acad Sci, Natl Astron Observ, Beijing 100012, Peoples R China
Copyright © 2002 Institute for Scientific Information
* LETTERS TO THE MODERATOR *
(5) RE: "ASTEROID IMPACT MAY HAVE ADDED TO AUSTRALIAN WEALTH"
>From Franco Pirajno <firstname.lastname@example.org>
I refer to the short article that appeared in New Scientist on the Woodleigh
impact structure and reported in CCNet on January 25th, and wish to add my
voice to the clarification communicated earlier by Andrew Glikson of ANU.
The short article is somewhat sensationalistic and perhaps misleading. The
"valuable" elements found in the central uplift granite are in the parts per
million abundances, although somewhat anomalous with respect to average
granite. Every impactologist would be well aware of this, but the public at
large may have taken the statement at face value. Our work on the
geochemistry of the central uplift of Woodleigh is documented in Mory et
al., 2000, EPSL, v. 177, 119-128 and Mory et al, GSWA Record 2001/6; and
more recently by Koeberl et al., 2001, 64th Ann. Met. Soc. Meeting. In
addition, another paper by Glikson et al. (in which I am one of the
co-authors) on the topic has recently been submitted to Meteoritics. That
the heat energy caused by the impact could well have set up hydrothermal
circulation cells in the surrounding region and below the crater, resulting
in the genesis of hydrothermal mineral deposits is a distinct possibility,
and one which I endeavoured to explain to the New Scientist journalist.
Therefore, whether or not the Woodleigh impact site contains hydrothermal
mineral deposits is to be taken in the proper context; and of course this
can only be established through systematic exploration.
Geological Survey of Western Australia
100, Plain Street, East Perth, WA 6004
(6) POPE'S DUST-FREE K/T IMPACT STIRS UP LOTS OF DUST
>From Jan Smit <email@example.com>
I have some comments to make on the controversial Geology (feb2002) paper by
Kevin Pope, and some of the reactions on it, by pointing at available real
world data rather than models.
I read with interest Kevin Popes paper, and agree with some of his
conclusions, but I don't agree with some of his reasoning behind it. My main
disagreement is that he takes model-derived data (see his figures) rather
than real world data one can obtain from the geological record at K/T.
I think therefore that he underestimates the amount of dust, but agree that
the consequences may have been exaggerated. The blocking of dust was the
first scenario to explain the extinctions behind the impact by the Alvarez
group, and it would be a micracle if this scenario survived for 25 years
without modification. Yet, the collapse of the foodchain by temporary
shutdown of photosynthesis explains almost all of the stratigraphic and
paleontologic data from the oceans on the K/T extinctions.
That sudden collapse is a reality, notwithstanding the incorrect comment by
Gerta Keller on Pope's paper, stating:
".....dust cloud scenario as primary cause for the K/T mass
extinction...... simply does not fit the paleontological data that show
strong declines in populations for at least the last 0.5-1.0 million
years prior to the K/T impact."
Keller's comment can only apply to some rudist and inoceramid species,
occupying rare and presently vacated niches in the Late Cretaceous, while
Keller implies that such decline accounts for all ecologically important
species. That is simply misleading. The extant data on extinction of e.g.
dinosaurs, pollen, shallow carbonate platform biota, and all planktic
calcareous species, nannofossil as well as planktic foraminiferal species
(Kellers own speciality), representing the calcareous surface plankton at
the end of the Cretaceous, do not show such 'strong decline'. On the
contrary, these planktic species thrive - almost unchanged - up to the
global ejecta layer itself. No preceding decline there.
But as Kevin said, the sudden collapse of the foodchain could be achieved
by sulfate aerosol loading as well. The resulting cooling (from sulphate
aerosols), has empirically been supported by
1) evidence for hailstone holes in fossil waterlily leaves at KT, (a bit
flimsy), but more importantly,
2) by migration patterns of dinoflagellates just after the KT boundary when
cold, boreal species move temporarily from Denmark to Tunisia (Brinkhuis,
H., J. P. Bujak, et al,1998).
One of the problems for the impact-extinction theory gaining a wider
acceptance, is the lack of strong, positive, evidence for an impact at the
other major extinction horizons (P/T, Late Devonian etc). Evidence of
extinction at known major impact events, such as Popigai, Chesapeake bay
about 34ma ago, (although this next largest crater after Chicxulub is 10x
less energetic than Chicxulub) is lacking. This leaves the backdoor open for
alternative explanations for the K/T boundary as well, and I think that for
this reason we see a recent (see the last episode of Walking with Dinosaurs
of the BBC!) resurge of volcanic explanations for Dinosaur extinction
(Deccan vs Chicxulub). But the plankton extinction record in the oceans does
not agree at all with these volcanic scenarios.
Therefore, I also agree with Kevin that the effects of lesser impacts on
life may have been overstated in the sense that these do not lead to
As for the K/T dustload, I include here some of my estimates for this, based
on available K/T ejecta-layer data. The maximum amount of dust can be
derived from the pore-space filling between the condensate spherules within
the global K/T ejecta layer. This layer is between 2-3mm thick, >4000km
away from the Chicxulub crater.
Thickness global layer(mm) 2-3mm
Surface area earth(cm2) 5.10E+18 cm2
Volume global layer 3mm thick(cm3) 1.53E+18 cc
Weight 3mm thick layer, assuming density3 (g) 4.59E+18 gram
global number of spherules assuming 200µ diameter,
total weight of these spherules (density3) (g) 2.40362E+18 gram
weight of dust in porespace(g) (dens3) 2.19E+18 gram
The maximum amount of dust may thus be about 2x1018gram, about a factor
100-200 more than estimated by Kevin. These figures are rough numbers, but
this is the amount present in the global ejecta layer. It does not matter
whether it is in the southern of northern hemisphere, the thickness of the
layer and amount/size of spherules remains the same. Remains the question of
course, whether all this material has been accumulated as dust size
particles. The dropoff
below 100µ mentioned by Kevin is based on small scale models and nuclear
explosions, and it remains to be seen if that works with Chicxulub-sized
impacts. Iridium in the ejecta layer is in extremely small, less than
0.1micron particles, because, despite several attempts at locating
particulate matter (nuggets) in the ejecta layer, these have not been found
unequivocally. Recently a study appears to confirm this small size
Although some fraction of iridium resides in spinel-rich condensate
spherules, more than half does not, and it remains likely that also other
parts of the vaporized bolide and vaporized target have the same size
distribution as the iridium particles, and have landed as dust!
Some other points I place question marks. In Pope's fig 1 and in the text he
remarks that the amount of dust in Italy and Walvis ridge is much less than
elsewhere, but he leaves out the simple explanation for that. Both in Italy
and WR the K/T ejecta layer is severely disrupted by bioturbation,
decreasing the amount of dust in the layer itself considerably. But when you
recalculate the numbers of spherules and qz back into a 2-3mm thick layer,
the amount/cm2 is the same as in Spain and republic of Georgia, locations
that straddle Italy, and where the ejecta layer is well preserved. Same for
Walvis ridge at site 524. Woodside Creek in New Zealand and ODP site 465a in
the Pacific show this same 2-3mm thick layer. So from the thickness of the
fireball layer alone, being the same on both hemispheres, one can infer a
ballistic emplacement, not transport by stratospheric winds.
Also, his conclusion that there are clear geographic patterns is based on
postdepositional burrowing and dispersal. His figure 2 is not as clear as he
claims. Coarse shocked quartz is indeed found in and near North America,
(<4000km) then there is a gap in the distribution (larger than shown in his
fig 2 (see Smit, 1999). Further (>7000km) distal the sizes are within error,
the same size. I don't believe the size decrease follows this power decay
law. The shocked quartz is generally believed to be entrailed in the vapor
plume, mostly on the very outside, where the grains tend to slow down
quicker being at the edge, smaller ones being entrailed deeperin the main
cloud, and dispersed worldwide (i.e. >7000km). This size distribution does
not seem to support his stratospheric wind dispersal.
The third argument is the distribution of the amount of iridium. Contary to
the shocked quartz, there is no clear increase in amount towards the crater.
On the contrary, the amount increases to regions antipodal to Chicxulub, the
south Pacific and Woodside Creek being the most enriched (Kyte et al,1996).
Wind dispersal would undoubtly show a higher concentration closer to the
Brinkhuis, H., J. P. Bujak, et al. (1998). "Dinoflagellate-based sea surface
temperature reconstructions across the Cretaceous-Tertiary boundary."
Paleogeogr., Paleoclim., Paleoecol. 141: 67-83.
Smit, J. (1999). "The global stratigraphy of the Cretaceous Tertiary
boundary impact ejecta." Annual Review of Earth and Planetary Sciences 27:
Kyte, F. T., J. A. Bostwick, et al. (1996). The Cretaceous-Tertiary boundary
on the Pacific plate: composition and distribution of impact debris. The
Cretaceous-Tertiary Event and Other Catastrophes in Earth History. G. Ryder,
D. Fastovski and S. Gartner. Boulder, Geol. Soc. of Amer. Sp. Pap. 307:
For more information, see http://www.geo.vu.nl/~smit
Dr. J. Smit
Department of Sedimentology
Faculty of Earth and Life Sciences
de Boelelaan 1085
tel +3120-4447384 /gsm 00316 15123633
(7) ON NUCLEAR & COSMIC WINTERS
>From S. Fred Singer <firstname.lastname@example.org>
I might contribute to the debate on the consequences of an asteroid impact
by pointing to physical factors that have been omitted so far. I don't think
it will settle the issue of what caused the K-T extinction and just why the
dinosaurs disappeared, which is really an immensely complicated problem. But
My work relates to the problem of Nuclear Winter and is fully published in
Meteorology and Atmospheric Physics (Springer Verlag) 1888. You recall that
the idea of Nuclear Winter, first proposed by Birks and Crutzen, and
elaborated by Sagan, Turco, Toon et al, was inspired by the Alvarez
discussion of the climate and ecological consequences of an asteroid impact.
I pointed out that Nuclear Winter won't work as advertised. The smoke layer
created in the fires from nuclear bomb explosions would have to cover the
whole earth and be everywhere of the right thickness: too thin and sunlight
would penetrate; too thick and IR from the earth surface could not escape
into space. Anyway, long before such a smoke layer could form, it would have
been washed out of the atmosphere by rain.
More important even, I calculated that the original nuclear explosions would
create fireballs rising into the stratosphere and carry sufficient moisture
to create cirrus clouds. DIRTY cirrus (as opposed to clean ice crystals)
has a complex refractive index that provides high IR opacity and therefore
creates a strong greenhouse effect. It would create a Nuclear Summer, or
perhaps just a Nuclear Spring. The effect of the smoke in the lower
troposphere would be secondary.
Finally, the stratospheric clouds would contribute to a depletion of ozone,
exacerbated by the increase in water vapor there. One would also need to
factor in the effects of a long-term increase in UV-B at the earth surface.
Overall then, in addition to dust one cannot ignore the effects of water
vapor in all of its ramifications.
(8) ABOUT THE CAUSE OF THE K/T EXTINCTIONS
>From Tom Van Flandern <email@example.com>
The geological K/T boundary event at 65 million years ago was global in
extent and included the southern hemisphere.  Yet a terrestrial impact
event, however major, ought logically to confine most of its damage to one
hemisphere of the Earth. Global damage requires special circumstances. Dust
injected into the atmosphere, for example, would eventually spread around
the Earth, but only within a limited range of latitude. Seismic waves
transmitted through the Earth might produce major earthquakes at the focus
point on the far side, but no plausible model exists to link the giant
impact event at Chicxulub in Central America with, for example, the
geologically simultaneous Deccan Traps giant volcanism episode in India.
Recently, Kevin Pope showed that the impact of a 10-km sized object on the
Earth 65 million years ago could not, as has been widely assumed, trigger a
dust-connected "cosmic winter" with global effects. [2-5] His key finding:
"The global mass and grain-size distribution of the clastic debris indicate
that stratospheric winds spread the debris from North America, over the
Pacific Ocean, to Europe, and little debris reached high southern latitudes.
These findings indicate that the original K-T impact extinction hypothesis -
the shutdown of photosynthesis by sub-micrometer-size dust - is not valid,
because it requires more than two orders of magnitude more fine dust than is
Further, since 1991, U.S. geologist Dewey McLean has been suggesting that a
K/T boundary impact winter would have been "too transitory, or feeble, to be
recorded in the geological record, and not of sufficient magnitude to
trigger global biological catastrophe". [6,7] McLean's and Pope's papers
further the conclusion that the K/T boundary event was not a single impact.
Indeed, any overview of the totality of evidence for the nature of the K/T
event turns up some evidence inconsistent with all hypotheses but one. Let's
briefly examine that evidence.
Ejecta from an impact is generally limited in range by its maximum speed of
about 2.5-3.0 km/s. Anything ejected at higher speeds is vaporized by the
shock wave. [8,9] Calculations show that this maximum speed might be
sufficient to hurl debris up to 1000 km or so from a terrestrial impact
site, but certainly is not enough to spread ejecta globally. For example,
Cretaceous stratigraphy is observed to be disturbed only out to a distance
of roughly 100-200 km from the Chicxulub crater.
Here is a list of the main features already identified at the K/T boundary
· far more iridium than can be explained by terrestrial processes or slow
accretion from space
· other siderophile elements, consistent with one or more major impacts
· microtectites and diamonds in the boundary clay
· a verified global extent and discreteness
· shocked quartz well beyond what volcanism can produce
· abundant carbon ash
· mass extinctions occurring mainly within inches below the boundary layer
· "event beds" around the Caribbean Sea
· inland seas drained
· numerous "hot zones" of radioactivity, especially in Africa
· the Deccan Traps, and the onset of an extended period of unparalleled
· atmospheric and ocean compositional changes
· a single global fire
So we must ask, was all this the result of a single asteroid impact
producing the 200 km-diameter crater at Chicxulub in the Yucatan Peninsula?
Or was something more involved? The answer is clearly the latter. Consider
· A global set of major craters all date (by at least one technique) to the
same 65 Mya epoch: Manson (Iowa), Kara (Western Siberia), Kamensk, Gusev,
and an unnamed impact in the Pacific Ocean. [11-14] The diameter and
abundance of quartz grains are larger in western North America than
elsewhere in the world, suggesting that the single largest impact was the
Chicxulub event. But the other craters clustered near the same time indicate
it was not the only event.
· The K/T boundary mostly consists of two distinct claystone layers. The
upper (soot, iridium) layer is 3-8 mm thick claystone with multiply shocked
quartz. The lower layer is 1-2 cm thick claystone, but lacks shocked grains.
Two contiguous, segregated ejecta layers suggest two different
geologically-simultaneous causes operating.
· Gorceixite (altered tektites, with identical swirl patterns) is segregated
within each layer, suggesting that different impact events formed these
· A single bolide impact cannot simultaneously explain the pattern of major
floral extinctions on land and other extinctions at sea.
· A Central American impact is not a likely cause for draining inland seas
or producing hot spots in Africa or volcanism in India.
· Sediments in Cuba range from 5 to 450 meters thick, probably from a giant
wave. The (upper) ejecta layer is 50 cm thick in nearby Haiti, far more than
at any other site, suggesting a major impact within 1000 km, which would
still be far from the Chicxulub crater in Mexico.
· The K/T boundary layer is apparently absent from the Antarctic regions.
Indeed, studies of this K/T mass extinction event contain many suggestions
of a cause other than a single impact event. For example, Shoemaker and
Izett  suggest two or more impacts from a split comet are needed to form
the double boundary, especially because there is more than one associated
crater. Moreover, plant roots appear in the lower layer (the result of the
global fire?), but not in the upper one, indicating that not enough time
elapsed between the two events for plants to grow again. That makes
coincidental, unrelated impacts very unlikely.
The point about the inland seas may be another telltale clue. Among other
indicators of this, apparently an intra-continental sea covered the middle
of North America during the Cretaceous period, but disappeared near the K/T
boundary.  Evaporation of a large, distant body of water would not be an
expected consequence of an impact event. Neither is a single global fire.
However, both are predicted consequences of heating of the biosphere by a
massive, prolonged, heavy bombardment of meteors, as would follow for
example the explosive break-up of a planet-sized body elsewhere in the solar
The diamond/iridium ratio in the boundary clay layer may constrain the type
of impactors. The observed ratio is close to the value found in type C2
chondritic meteorites, one of the most common meteorite types.  The
diamonds found at the K/T boundary are confirmed to be of extraterrestrial
origin, not shock-generated or terrestrial, based on delta C-13 measures.
 So we are definitely talking about an event of extraterrestrial origin,
not a purely terrestrial one. Any such event that might produce the
requisite meteors would surely have affected the Moon as well. That
implication is apparently confirmed by an analysis of lunar crater formation
dates by Schultz, showing three dating peaks, one at 65 million years ago.
Yet another indicator of an exogenous cause for this event is that, although
it was nearly global in extent, Earth's southern polar region was apparently
largely excluded.  Unfortunately, Earth's northern polar region lacks a
land mass to enable us to determine if it was or was not affected. An
exogenous event would generally exclude one polar region because distant
bodies near the planetary plane spend up to six months of each year
continually below the horizon as seen from each terrestrial polar region. So
the observed global pattern seen for the K/T event is consistent with
multiple impacts and meteors from an exogenous source taking place over of
period of at least one day. The spread in arrival times for multiple
fragments from an explosion several astronomical units away is certain to be
greater than one day, exposing the entire surface of the Earth except one
polar region to meteors and impacts. The following sequence is predicted:
· an initial high-energy blast wave consisting of radiation and plasma,
requiring days to pass
· a break-up debris wave consisting of asteroids and meteors, requiring
weeks to pass
· a high impact period consisting of asteroids and comets, lasting about
· a normal impact period consisting of asteroids and comets, lasting up to
100 million years for asteroids in earth-crossing orbits
Here is David Raup's assessment of Pope's study: "The strong implication is
that the impact explanation of the K/T extinction will fall if the dust
cloud hypothesis falls." This may now be seen as referring only to failure
of the single impact hypothesis. Instead, we see much to support the already
massive body of formally unchallenged evidence for the explosion of at least
one, if not several, former planetary bodies in our solar system over its
lifetime. [22-33] An excellent match of the exploded planet hypothesis to
all the observational evidence in the solar system, not just the K/T-related
points discussed here, strongly supports the conclusion that a planetary
explosion was the catalyst for the terrestrial K/T boundary mass extinction
event, one of the two greatest extinctions since life became abundant on
Earth half-a-billion years ago.
Tom Van Flandern
 Science 294, 1613 & 1700-1702 (2001).
 CCNet 14/2002.
 GSA Release #02-04, 2002/01/23.
 Geology 30#2, 99-102 (2002).
< http://www.gsajournals.org/gsaonline/?request=get-abstract&issn=0091-7613&volume=030&issue=02&page=0099 >.
 D.M. McLean, Global biomass burning: atmospheric, climatic, and
biospheric implications, Levine, J. S., ed., MIT Press, Cambridge, 493-503
< http://filebox.vt.edu/artsci/geology/mclean/Dinosaur_Volcano_Extinction/pages/impwintr.html >.
 Science 271, 1387-1392 (1996).
 CCNet Special, 10 July 2001.
 Thanks to S. Krueger for some items on this list.
 Lunar & Planetary Science XXII, abstracts, 961-962 (1991).
 Nature 363, 670-671 (1993).
 Nature 363, 615-617 (1993).
 Nature 288, 651-656 (1980).
 Science 255, 160-161 (1992).
 Science News 141, 72-75 (1992).
 E. Öpik, Irish Astron. J. 13, 22-39 (1977). In a 1978 colloquium and
subsequent discussions at the U.S. Naval Observatory in Washington, DC, Öpik
acknowledged that evidence for an exploded planet survived his own
falsification test, and agreed that the "nuclear winter" effect of smoke
from the meteors would keep the biosphere cool enough to prevent all life
 Nature 352, 708-709 (1991).
 Nature 357, 119-120 (1992).
 P.H. Schultz and S. Posin, Global Catastrophes in Earth History, LPI
Contrib. No. 673, 168-169 (1988).
 Nature 366, 511-512 (1993).
 T. Van Flandern, Dark Matter, Missing Planets and New Comets, North
Atlantic Books, Berkeley, chapter 11, (1993; 2nd edition 1999) - synthesis
of exploded planet hypothesis (EPH) evidence.
 Icarus 36, 51-74 (1978) - technical justification for the EPH.
 <http://metaresearch.org>. "Solar System" tab, "EPH" sub-tab - recent
updating and distilling of the most telling EPH evidence, and how its
predictions have fared; to be published in 2002.
 Mercury 11, 189-193 (1982) - the EPH as an alternative to the Oort
cloud for the origin of comets.
 Icarus 47, 480-486 (1981) - the EPH's "satellite model" for comets as
an alternative to the "dirty snowball" model.
 Science 203, 903-905 (1979) - asteroid satellite evidence, confirming
an EPH prediction.
 Science 211, 297-298 (1981) - technical comment on previous paper.
 Asteroids, T. Gehrels, ed., U. of Ariz. Press, Tucson, 443-465 (1979) -
theory and observations of asteroid satellites.
 Dynamics of the Solar System, R.L. Duncombe, ed., Reidel, Dordrecht,
257-262 (1979) - short summary of selected EPH evidence.
 Dynamics of Planets and Satellites and Theories of their Motion, V.
Szebehely, ed., Reidel, Dordrecht, 89-99 (1978) -- short summary of selected
 Comets, Asteroids, Meteorites, A.H. Delsemme, ed., U. of Toledo,
475-481 (1977) - short summary of EPH evidence with technical critiques and
 Science Digest 90, 78-82 + 94-95 (1982) - popular exposition of the EPH
and its implications.
(9) 1680 COMET
>From Duncan A. Lunan <firstname.lastname@example.org >
At the beginning of December, ASTRA had an excellent lecture from Martin
Lunn, MBE, on 'The Great Comets'. He brought a range of books with him and
among others I bought Gale B. Christianson's "Edwin Hubble, Mariner of the
Nebulae" (Institute of Physics Publishing, 1995). On page 55 I've just found
"a second comet tracked by Edmond Halley in 1680... it was William Whiston,
a disciple of the great Isaac Newton and his successor as Lucasian Professor
of Mathematics at Cambridge, who believed that the comet of 1680 had
literally grazed the earth after the fall of Eden, triggering the Noachian
Deluge in 2346 BC - 'the year of sin'. As far as Edwin [Hubble] was
concerned, Whiston's theory 'makes as good reading for me as the 'Blue Fairy
Book' does for Emma Jane.'"
Francois Arago, in "Popular Astronomy", reckoned that the 1680 comet had
passed in 1786 BC. It made the closest approach to Earth by any of the
comets whose orbits Halley examined, at about the distance of the Moon. "Mr.
Halley leaves it to philosophers to discuss what consequences would arise
from the appulse, contact or collision of the celestial bodies, which yet is
not altogether impossible". The comet's period was approximately 575 years,
which makes 1786 and 2346 BC look possible, six and seven revolutions
earlier respectively. In the light of growing evidence for an impact around
that time, is a fragment of the comet a candidate for the c.2350 event, or
was Hubble right to dismiss it as a fairy story?
(10) JOSHUA IMPACT
>From Brian Moore < email@example.com >
In CCNet 17/2002 - 30 January 2002 Göran Johansson ruminating about a
"Joshua" event stated:
"No, I don't know about any meteorite shower from the same year. But
from summer, 3rd year of Murshilish II, we have an interesting story. It
is quoted in Younger, Ancient Conquest Accounts, page 208. The king was
marching with his army towards the west when they observed a meteor.
The city Apasa (Ephesus?) was struck by it. The difference in time is just
seven years so I guess the two items were combined in the Bible into one
and the same event."
This reminded me that some years ago (in SIS Review Vol II No 1 1977 to be
precise) B.O'Gheoghan speculated that the Papyrus Ipuwer (one of those
ancient texts which might indicate cosmic bombardment - a view I think
supported by Victor Clube) suggested that radiation damage was one of the
consequences ("Indeed, women are barren and none conceive" etc). This was
supported in the subsequent issue by Ragnar Forshufvud who pointed out that
Ipuwer also states: "Indeed, hair [has fallen out] for everybody, and the
man of rank can no longer be distinguished from him who is nobody."
Forshufvud goes on to say "Epilation, or loss of hair, is one of the
symptoms of exposure to radiation. Back in the forties, when little was
known about long-term effects of radiation, a Swedish scientist who planned
a three-week trip through the United States, being well aware of the lacking
standardisation of U.S. plugs and sockets, decided not to bring his electric
razor. Instead, he exposed his chin to a well calculated dose of radiation
from some radio-active material, and had no shaving problems for the next
few weeks. I would certainly not recommend this method. A dose of 300-400
rem will give temporary epilation, while 700 rem will give permanent
epilation. If the whole body is subjected to a single dose of 450 rem, there
is only a 50 per cent chance of survival. Thus it may be argued that the
margin between an epilation dose and a lethal dose is so narrow that if hair
fell out "for everybody", then few people would have survived. This,
however, is not contradicted by Ipuwer, who says, "Indeed, men are few, and
he who places his brother in the ground is everywhere." (2:13-14)."
I also commented, mentioning the text referred to by Johansson above, which
includes a rather bizarre titbit:-
>From Society for Interdisciplinary Studies II/2 1977:
"Possible support for radiation-induced infertility might be found in a text
quoted in the article "Diana at Ephesus" (SISR I:2, p.13). The annals of
Mursilis II report a fireball which fell at Apashash/Ephesus and go on to
state: "It struck Uhha-zitish himself; he was taken with a terrible disease,
he was struck (?) on the knee." Given the reasonable deduction that the
fireball did not score a direct hit on Uhha-zitish, and that "knee" is a
Hittite euphemism for sexual organs, it would seem justifiable to interpret
the report as referring to a disease affecting the King's generative
(11) AND FINALLY: ASTEROID IMPACT HAZARDS "GREATLY OVERSTATED"
>From New Scientist, 30 January 2002
ASTEROID IMPACT HAZARDS "GREATLY OVERSTATED"
If a collision with an asteroid is going to finish us off, it will have to
be a lot larger than anyone thought, according to a controversial new study
of the impact that wiped out the dinosaurs.
Virtually everyone agrees that the asteroid that hit Chicxulub in Mexico 65
million years ago killed the dinosaurs, but how it did so is unclear. A
long-standing theory is that clouds of dust hung in the upper atmosphere for
months, blocking sunlight and stopping plants growing. But no one is sure
that this is really the reason, and finding out is critical for assessing
the risk asteroids pose to humanity.
Now geologist Kevin Pope of Geo Eco Arc Research in Aquasco, Maryland, is
claiming that dust cannot have been to blame. Only dust grains smaller than
a micrometre across stay suspended in the atmosphere, and Pope says that the
10-kilometre asteroid would not have created enough fine dust to have a
Instead he thinks sulphur from the rocks vaporised by the impact may have
formed sulphate aerosols that blocked out the light. He says earlier
overestimates of dust levels mean that the hazards from an asteroid impact
today have been "greatly overstated".
The Chicxulub impact spread debris across the globe, which settled to form a
layer averaging 3 millimetres thick--that's a few trillion tonnes of
material. But having reviewed previous work on the subject, Pope says that
more than 99 per cent of the layer is made up of spherules--droplets that
condensed from vaporised rock. Only the remaining 1 per cent of the debris
consisted of rock pulverised directly into dust.
It's still uncertain what the size distribution of that dust would have
been, but from studies of volcanic dust, Pope deduces that less that 1 per
cent of it consisted of particles smaller than 1 micrometre. That's only 100
million tonnes--about 10 times as much dust as was released by the 1991
eruption of Mount Pinatubo, which had a barely measurable effect on global
But other researchers aren't convinced that the impact produced so little
dust. Jan Smit of the Free University in Amsterdam points out that volcanic
dust isn't formed in the same way as impact dust, so the particle sizes
wouldn't necessarily be the same. He says his studies of iridium in the
impact layer suggest that at least half of it is in particles smaller than
Even if Pope is right, we can't rest easy just yet. "Other things will get
you," says Brian Toon, an atmospheric scientist from the University of
Colorado in Boulder. He believes the effects of an asteroid impact would be
apocalyptic - filling the entire sky with fiery meteors as the debris rained
back down onto the atmosphere. "Everything on the surface is going to catch
fire," he predicts.
But despite all the debate, much still depends on guesswork. "We know so
little about impacts," says theoretical geophysicist Jay Melosh of the
University of Arizona. "The uncertainties are at least a factor of five."
Journal reference: Geology (vol 30, p 99)
Copyright 2002, New Scientist
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An Open Letter to the Australian Federal Government from
The Hon John Howard, MP, Prime Minister of Australia
The Hon Peter McGauran, MP, Minister for Science
The Hon Dr Brendan Nelson, MP, Minister for Education, Science and Training
Senator the Hon Robert Hill, Minister for Defence
The Hon Dr David Kemp, MP, Minister for the Environment and Heritage
Australia's contribution to Spaceguard
Spaceguard is the name given to an international effort to search the skies
for asteroids that might collide with the Earth. The name was coined by Sir
Arthur C Clarke in a 1973 novel that described how mankind set up an
asteroid detection and defence network after a large asteroid
struck Italy and devastated southern Europe. Since the novel was written the
risks and grave consequences of asteroid impacts have been recognised and
studied. Scientists around the globe are now working to ensure that Clarke's
scenario of a sudden, deadly impact does not occur.
The United States is the main contributor to the search effort, with several
telescopes dedicated to Spaceguard. Japan recently constructed a new
telescope facility for Spaceguard work and Europe is in the process of
setting up search telescopes and the vital support systems to analyse the
data from the searches.
Rob McNaught from Siding Spring in New South Wales runs the only
professional asteroid tracking project in the southern hemisphere. This
operation is funded mostly by the United States and is associated with the
Australian National University. It was set up in recognition of the need for
Spaceguard telescopes in the southern hemisphere. Gordon Garradd, an
astronomer from Loomberah in New South Wales, receives some funds from NASA
for critical southern hemisphere follow-up observations using a home-made
However, a much greater search effort, including a larger telescope, is
needed to detect asteroids that pass through southern skies. It would cost
several million dollars to set up a suitable facility in Australia but some
of this might be covered by contributions of equipment from the USA.
Operational costs should be less than $1 million per year. This is a highly
cost effective investment in the prevention of loss of life and severe
economic damage from asteroid impacts.
McNaught and Garradd were previously in a team of Australian astronomers,
led by Dr Duncan Steel, who searched for asteroids between the late 1980s
and 1996. They found about one third of new threatening asteroids discovered
during this period, demonstrating Australian expertise and the importance of
searching southern skies. Australian government funding for the project was
withdrawn in 1996 and the team disbanded.
The United Nations and the OECD have recognised the potential hazard to our
civilisation from asteroid impacts. This month the OECD is looking at the
issue as part of its Global Science Forum and recently asked developed
nations to indicate their plans to contribute to the Spaceguard effort.
A major global Spaceguard effort could provide decades of warning prior to
an impact. This would be sufficient time to refine the space technology
needed to nudge a threatening asteroid into a harmless orbit, or to evacuate
the predicted impact area. Without Spaceguard there would be too little
warning to prevent a disaster. This is clearly demonstrated by the recent
close approach of a 300m wide asteroid. It was discovered only a few days
before it passed by the Earth and, had it been on a collision course, there
is little that could have been done to prevent possibly millions of
casualties when an area the size of Tasmania would have been devastated.
We note that a spokesperson for Science Minister Peter McGuaran said that
the Government would look into renewing the funding of a dedicated
Australian Spaceguard programme (The Age, 9th January). We welcome this
reassessment of the issue and look forward to Australia rejoining the
international effort to deal with the asteroid threat.
Paul Abell, Rensselaer Polytechnic Institute, USA
Olga T. Aksenova, Blagoveschensk State University, Russia
Gennady V. Andreev, Astronomical Observatory of Tomsk State University, Russia
John Anfinogenov, Tunguska Preserver, Siberia, Russia
Yana Anfinogenova, Siberian State Midical University, Russia
David Asher, Bisei Spaceguard Center, Japan
Mark Bailey, Armagh Observatory, UK
Mike Baillie, Queen's University, Belfast, N. Ireland
Michael J Barlow, University College London, UK
Andrea Boattini, IAS, Area Ricerca CNR Tor Vergata, Italy
Jiri Borovicka, Astronomical Institute, Academy of Sciences, Czech Republic
Mark Boslough, Sandia National Laboratories, USA
Peter Brown, Department of Physics and Astronomy, University of Western Ontario, Canada
Larisa Budaeva, Tomsk State University, Siberia, Russia
Andrea Carusi, IAS, Area Ricerca CNR Tor Vergata, Italy
Silvano Casulli, Colleverde di Guidonia Observatory, Italy
Clark R. Chapman, Southwest Research Institute, USA
Andrew Cheng, Applied Physics Laboratory, USA
Paul Davies, Australian Centre for Astrobiology, Macquarie University, Australia
Ann Druyan, CEO, Cosmos Studios, USA
Alan Fitzsimmons, Queen's University Belfast, UK
Giuseppe Forti, Osservatorio Astrofisico di Arcetri, Firenze, Italy
Luigi Foschini, Istituto di Astrofisica Spaziale e Fisica Cosmica, Italy
Lou Friedman, The Planetary Society, USA
Michael J. Gaffey, Space Studies, University of North Dakota, USA
Jon Giorgini, Jet Propulsion Laboratory, USA
Valentina Gorbatenko, Tomsk Polytechnic University, Russia
Vic Gostin, Dept.Geology & Geophysics, University of Adelaide, Australia
Tom Gehrels, The University of Arizona, USA
Ian Griffin, Space Telescope Science Institute, USA
Valentin Grigore, The Romanian Society for Meteors and Astronomy (SARM), Romania
Christian Gritzner, Dresden University of Technology, Germany
Gerhard J. Hahn, German Aerospace Center (DLR), Germany
Peter Haines, University of Tasmania, Australia
Eleanor Helin, NEAT Program, Jet Propulsion Laboratory, USA
Nigel Holloway, United Kingdom Atomic Energy Authority & Spaceguard UK
Ola Karlsson, UDAS Program, Uppsala Astronomical Observatory, Sweden
Colin Keay, The University of Newcastle, Australia
Bob Kobres, University of Georgia, USA
Natal'ya V.Kolesnikova, Moscow State University, Moscow, Russia
Leif Kahl Kristensen, Institute of Physics and Astronomy, University of Aarhus, Denmark
Karl S. Kruszelnicki, School of Physics, The University of Sydney, Australia
Evgeniy M. Kolesnikov, Moscow State University, Russia
Korado Korlevic, Visnjan Observatory - Spaceguard HR, Croatia
Eugeny Kovrigin, Tomsk State University, Siberia, Russia
Richard Kowalski - Quail Hollow Observatory, USA
Yurij Krugly, Astronomical Observatory of Kharkiv National University, Ukraine
David H. Levy, Jarnac Observatory, USA
Dmitrij Lupishko, Kharkiv National University, Ukraine
Terry Mahoney, Instituto de Astrofisica de Canarias, Spain
Brian Marsden, Harvard-Smithsonian Center for Astrophysics, USA
Bruce Mackenzie, National Space Society, USA
Ilan Manulis, The Israeli Astronomical Association, Israel
Austin Mardon, Antarctic Institute of Canada
Jean-Luc Margot, California Institute of Technology, USA
Gianluca Masi, Bellatrix Observatory, Italy
Alain Maury, CNRS, France
John McFarland, Armagh Observatory, UK
Natalya Minkova, Tomsk State University, Russia
Joe Montani The University of Arizona, USA
Darrel Moon, Oxnard College, California, USA
Thomas G. Mueller, Max-Planck-Institut, Garching, Germany
Bill Napier, Armagh Observatory, UK
Chernykh Nikolaj, Crimean Astrophysical Observatory, Crimea, Ukraine
Steve Ostro, Jet Propulsion Laboratory, USA
Trevor Palmer, Nottingham Trent University, UK
Benny Peiser, Liverpool John Moores University, UK
Joaquin Perez, Universidad de Alcala, Spain
Paul Roche, University of Glamorgan, UK
Maria Eugenia Sansaturio, University of Valladolid, Spain
Lutz D. Schmadel, Astronomisches Rechen-Institut Heidelberg, Germany
Hans Scholl, Observatoire de la Cote d'Azur, France
Vladimir A. Shefer, Astronomical Observatory, Tomsk State University, Russia
Carolyn Shoemaker, Lowell Observatory, USA
Vadim A. Simonenko, Space Shield Foundation, Russia
S Fred Singer, University of Virginia, USA
Giovanni Sostero, Remanzacco observatory, Italy
Reiner M. Stoss, Starkenburg Observatory, Germany
Jay Tate, International Spaceguard Information Centre, UK
Luciano Tesi, Osservatorio di San Marcello Pistoiese, Italy
Jana Ticha, Klet Observatory, Czech Republic
Josep M. Trigo-Rodriguez , University Jaume, Spain
Roy A. Tucker, Goodricke-Pigott Observatory, Arizona, USA
Harry Varvoglis, Department of Physics, Aristotle University of Thessaloniki, Greece
Gerrit L. Verschuur, University of Memphis, USA
Fiona Vincent, University of St.Andrews, Scotland, UK
Dejan Vinkovic, University of Kentucky, USA
Vladimir Vorobyov, Pomor State University n.a. M.V. Lomonosov, Russia
Chandra Wickramasinghe, Cardiff University, Wales, UK
Gareth Williams, Minor Planet Center, Smithsonian Astrophysical Observatory, USA
Don Yeomans, Jet Propulsion Laboratory, USA
Oleg M. Zaporozhets, Kamchatka State University, Russia
Krzysztof Ziolkowski, Space Research Centre, Warsaw, Poland
A PDF copy of the letter and press release can be viewed at
CCCMENU CCC for 2002
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