PLEASE NOTE:
*
CCNet 18/2002 - 1 February 2002
-------------------------------
* Please note that I will be abroad for most of next week, BJP *
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(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 <franco.pirajno@mpr.wa.gov.au>
(6) POPE'S DUST-FREE K/T IMPACT STIRS UP LOTS OF DUST
Jan Smit <smit@geo.vu.nl>
(7) ON NUCLEAR & COSMIC WINTERS
S. Fred Singer <singer@sepp.org>
(8) ABOUT THE CAUSE OF THE K/T EXTINCTIONS
Tom Van Flandern <tomvf@metaresearch.org>
(9) 1680 COMET
Duncan A. Lunan <astra@dlunan.freeserve.co.uk
>
(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
http://www.space.com/scienceastronomy/solarsystem/aussie_asteroid_020201-1.html
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
civilization.
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."
Who's who
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
established.
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.
Arm-twisting
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
asteroid study.
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.
Blind spot
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
and planets.
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.
What's needed
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
prior.
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
http://www.spaceweather.com
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>
Dolores Beasley
Headquarters,
Washington
Jan. 31, 2002
(Phone: 202/358-1753)
Nancy Neal
Goddard Space Flight Center, Greenbelt, Md.
(Phone: 301/286-0039)
RELEASE: 02-19
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
track."
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
our galaxy.
Additional background information about EUVE is available at
http://heasarc.gsfc.nasa.gov/docs/euve/euve.html
========
(4) CLOSE APPROACHES OF PHAS DURING TWO CENTURIES
Ji JH, Liu L: Close approaches of potentially hazardous asteroids
during two
centuries
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
two centuries.
Addresses:
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 <franco.pirajno@mpr.wa.gov.au>
Dear Benny,
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.
Regards
Franco Pirajno,
Geological Survey of Western Australia
100, Plain Street, East Perth, WA 6004
Australia
=============
(6) POPE'S DUST-FREE K/T IMPACT STIRS UP LOTS OF DUST
>From Jan Smit <smit@geo.vu.nl>
Dear Benny,
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
mass-extinctions.
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,
cubic ordening.
1.91274E+23
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
http://www.lpi.usra.edu/meetings/impact2000/pdf/3031.pdf
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
source.
Sincerely
Jan Smit
References
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:
75-91.
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:
389-402.
For more information, see http://www.geo.vu.nl/~smit
Dr. J. Smit
Department of Sedimentology
Faculty of Earth and Life Sciences
Vrije Universiteit
de Boelelaan 1085
1081HV Amsterdam
the Netherlands
tel +3120-4447384 /gsm 00316 15123633
fax +3120-6462457
e-mail: smit@geo.vu.nl
http://www.geo.vu.nl/users/sedimar/staff/personal/smit.html
http://www.vpro.nl/yucatan
http://icdp.gfz-potsdam.de/html/sites/chicxulub/news/news.html
===========
(7) ON NUCLEAR & COSMIC WINTERS
>From S. Fred Singer <singer@sepp.org>
Dear Benny
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
here goes...
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.
Best Fred
=======
(8) ABOUT THE CAUSE OF THE K/T EXTINCTIONS
>From Tom Van Flandern <tomvf@metaresearch.org>
The geological K/T boundary event at 65 million years ago was
global in
extent and included the southern hemisphere. [1] 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
estimated here."
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
[10]:
· 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
global volcanism
· 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
these points:
· 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
glassy beads.
· 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 [15] 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. [16] 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
system. [17]
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.
[18] 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.
[19] 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.
[20]
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. [21] 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
100,000 years
· 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
Meta Research
<tomvf@metaresearch.org>
References
[1] Science 294, 1613 & 1700-1702 (2001).
[2] CCNet 14/2002.
[3] GSA Release #02-04, 2002/01/23.
[4] Geology 30#2, 99-102 (2002).
[5]
< http://www.gsajournals.org/gsaonline/?request=get-abstract&issn=0091-7613&volume=030&issue=02&page=0099
>.
[6] D.M. McLean, Global biomass burning: atmospheric, climatic,
and
biospheric implications, Levine, J. S., ed., MIT Press,
Cambridge, 493-503
(1991).
[7]
< http://filebox.vt.edu/artsci/geology/mclean/Dinosaur_Volcano_Extinction/pages/impwintr.html
>.
[8] Science 271, 1387-1392 (1996).
[9] CCNet Special, 10 July 2001.
[10] Thanks to S. Krueger for some items on this list.
[11] Lunar & Planetary Science XXII, abstracts, 961-962
(1991).
[12] Nature 363, 670-671 (1993).
[13] Nature 363, 615-617 (1993).
[14] Nature 288, 651-656 (1980).
[15] Science 255, 160-161 (1992).
[16] Science News 141, 72-75 (1992).
[17] 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
from perishing.
[18] Nature 352, 708-709 (1991).
[19] Nature 357, 119-120 (1992).
[20] P.H. Schultz and S. Posin, Global Catastrophes in Earth
History, LPI
Contrib. No. 673, 168-169 (1988).
[21] Nature 366, 511-512 (1993).
[22] 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.
[23] Icarus 36, 51-74 (1978) - technical justification for the
EPH.
[24] <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.
[25] Mercury 11, 189-193 (1982) - the EPH as an alternative to
the Oort
cloud for the origin of comets.
[26] Icarus 47, 480-486 (1981) - the EPH's "satellite
model" for comets as
an alternative to the "dirty snowball" model.
[27] Science 203, 903-905 (1979) - asteroid satellite evidence,
confirming
an EPH prediction.
[28] Science 211, 297-298 (1981) - technical comment on previous
paper.
[29] Asteroids, T. Gehrels, ed., U. of Ariz. Press, Tucson,
443-465 (1979) -
theory and observations of asteroid satellites.
[30] Dynamics of the Solar System, R.L. Duncombe, ed., Reidel,
Dordrecht,
257-262 (1979) - short summary of selected EPH evidence.
[31] Dynamics of Planets and Satellites and Theories of their
Motion, V.
Szebehely, ed., Reidel, Dordrecht, 89-99 (1978) -- short summary
of selected
EPH evidence.
[32] Comets, Asteroids, Meteorites, A.H. Delsemme, ed., U. of
Toledo,
475-481 (1977) - short summary of EPH evidence with technical
critiques and
author responses.
[33] Science Digest 90, 78-82 + 94-95 (1982) - popular exposition
of the EPH
and its implications.
==============
(9) 1680 COMET
>From Duncan A. Lunan <astra@dlunan.freeserve.co.uk
>
Dear Benny,
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
the following:
"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?
Best wishes,
Duncan Lunan
=============
(10) JOSHUA IMPACT
>From Brian Moore < bmoore@freeserve.co.uk
>
Benny,
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
powers."
=============
(11) AND FINALLY: ASTEROID IMPACT HAZARDS "GREATLY
OVERSTATED"
>From New Scientist, 30 January 2002
http://www.newscientist.com/news/news.jsp?id=ns99991861
ASTEROID IMPACT HAZARDS "GREATLY OVERSTATED"
Jeff Hecht
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
global effect.
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".
Particle uncertainty
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
climate.
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
0.1 micrometres.
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
International
Scientists
To:
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
telescope.
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.
Signatories:
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
http://www4.tpg.com.au/users/tps-seti/pr_oz_sg.pdf