CCNet 20/2002 - 8 February 2002

"Scientists camping out in the Mongolian snow at minus 30 degrees C
have made the first recordings of an elusive sound: the crackle and pop
of a meteor shower[1]. Their observations defy all current explanations
of what happens when debris burns up on entry to the Earth's
--Philip Ball, Nature Science Update

"We can also ask how long it will take at the present discovery rate
to find 90% of the NEAs brighter than H=18. The present total number of
discovered NEAs of H </= 18.0 is 587. Taking a nominal value of 1000 as
the total population, that implies that the survey is now 59%
complete. It appears that, especially if the discovery efficiency of the
last 5 months can be sustained, the Spaceguard Survey may be on track for
90% completion by 2008 or 2009. However, this statement is dependant
on what number is assumed for the total population, since the discovery
rate needed to finish the job depends on the number of objects remaining to
be discovered. For example, if the total population is only 800 (we consider
this impossibly low, but is still 100 above one of the estimates of two
years ago), then 90% completion requires discovering only 133 more
objects. For an assumed population of 1000, we need 313 more discoveries
to reach 90%, and for an assumed population of 1200, an additional
493 discoveries are needed to achieve 90% completion."
--David Morrison, NEO News

    The Canberra Times, 5 February 2002

    The Age, 7 February 2002

    The Guardian, 6 February 2002

    David Morrison <>

    Ron Baalke <>

    Andrew Yee <>

    Ron Baalke <>

    Ron Baalke <>

    Gerhard Hahn <>

     Gerta Keller <gkeller@Princeton.EDU >

     Alastair McBeath <>



>From The Canberra Times, 5 February 2002

By SIMON GROSE, Science Editor

At least 90 scientists around the world believe the southern hemisphere is
Earth's soft underbelly when it comes to asteroid attack and Australia
should do something about it.

Joined by Australian scientific commentators Professor Paul Davies and Dr
Karl Kruselnicki, they wrote to the Prime Minister, John Howard, and several
senior ministers on January 28 urging the Federal Government to renew
financial support for the international Spaceguard program.

"A much greater search effort, including a larger telescope, is needed to
detect asteroids that pass through southern skies," the letter says.

The group, which includes astronomers and other scientists from 17
countries, says it would cost several million dollars to set up an incoming
asteroid watch facility in Australia but some of this might be covered by
contributions of equipment from the United States.

"Operational costs should be less than $1 million per year," the letter
says. "This is a highly cost-effective investment in the prevention of loss
of life and severe economic damage from asteroid impacts."

Australia contributed to the Spaceguard effort until 1996 when the
Government withdrew funding. Asteroid tracking is still undertaken at Siding
Springs Observatory, funded by the US in association with the Australian
National University, and NASA funds a NSW amateur astronomer to follow up
reports of asteroids.

More than a quarter of the signatories are from the US, followed by Russia
with 13 and Britain with 12.

Last month a spokesperson for the Science Minister, Peter McGauran, said the
Government was willing to reconsider the issue.

More information at [NOTE: despite the misspelling the
link is correct on the web page]

c2002 The Canberra Times


>From The Age, 7 February 2002


The possibility that alien life thrives in our galaxy has been boosted by
Sydney physicists who say planets such as Jupiter, which protects the Earth
from rogue asteroids, are more common than previously thought.

Through some mathematical wizardry, the professor of astrophysics at the
University of New South Wales, Charley Lineweaver, concluded that there were
50 per cent more Jupiter-like planets among the Milky Way's 300 billion
stars than previously thought.

This means there may be 30 billion star systems capable of supporting life.

Scientists have found 74 planets outside the solar system by observing stars
"wobbling" - a gravitational effect caused by orbiting planets.

They are all many times the size of Jupiter and are close to their host
stars, which is a poor condition for a star system to support life.

Professor Lineweaver said that because of technical limitations, we could
not see smaller planets. This had created the false statistical assumption
that most planets were very hot giants.

"It's a bit like lining up everybody in the world and only looking at people
above six foot eight and then you say, 'Wow, people are tall!"' he said.

With a colleague, Daniel Grether, Professor Lineweaver rejigged the maths
with what he calls "an unbiased sample".

Jupiter's massive gravity acts as a shield, sucking in most rock debris left
over from the formation of the sun and the solar system before it can
threaten Earth through a catastrophic asteroid collision such as the one
that wiped out the dinosaurs.

It is believed life on Earth did not begin to develop beyond single-cell
organisms until the heaviest cosmic bombardment of ceased about 3.8 billion
years ago.

"It tells us that life may have formed on Earth as soon as it possibly could
have," Professor Lineweaver said.

As recently as 1994, Jupiter's immense gravity pulled comet Shoemaker-Levy
into a death plunge. Had it hit Earth, the comet would have wiped out life.

In a separate development, more than 80 leading international scientists
have written to the Federal Government asking it to restart Australia's
contribution to the Spaceguard program, a United States-led project to spot
dangerous asteroids.

Professor Lineweaver's research will be published in the journal
Astrobiology and has impressed some Australian scientists.

Vince Ford from the Australian National University's Mount Stromlo
Observatory, described the research as "pretty damned exciting".

"It's another little step along the way to saying there are more Earth-like
planets," he said. "Ten years back, the chances seemed to be pretty slim.
Now it's starting to look as though there are planets all over the place."

Scientists will soon be able to see clearly enough into space to test
Professor Lineweaver's calculations. "At the moment, it's like having a boat
with a radar and the radar just cannot see something over the horizon," he
said. "In the next few years, this will change. We will start to see
Jupiters. We're just on the verge of being able to get these numbers."

Copyright The Age Company Ltd 2002.


>From The Guardian, 6 February 2002

A stream of comets is falling into the sun, writes Duncan Steel
Duncan Steel

Theory and observation go hand in hand in science. Until recently we were
limited to a theoretical evaluation of just what is a snowball's chance in
hell. But now we have experimental verification. As expected, the chance is
essentially zilch.

Comets are snowballs. Dirty ones, with rock and organic chemicals mixed in,
but snowballs none the less. And hell, one imagines, is much like the sun's
surface. With a temperature near 6,000 C, it's more than red-hot.

Comets have a major obstacle to pass before they can plunge into the sun.
Surrounding our local star is the corona, the multimillion-degree solar
atmosphere that can only be seen during an eclipse, which occurs rarely.
Satellite studies of the corona have enabled astronomers to see a multi tude
of comets make their death plunge.

To better understand the solar atmosphere and its effect on the terrestrial
environment we need continuous monitoring.

The solution is obvious, though costly. Produce an artificial eclipse using
a satellite-borne telescope and a black disk to occult the sun. Several
instruments of this type have flown, one of the most successful being Soho
(the solar and heliospheric observatory), a joint project of ESA and Nasa.

In the Soho image pictured, the large dark area straddling the centre
results from the obscuring disk. The white circle inside it indicates the
size of the sun. Several bright regions are seen around the disk's
periphery, showing outward gas flows in the corona.

But there is also an obvious bright streak at the lower right. This is a
small comet. Successive satellite images, obtained in October, showed it to
be falling into the solar furnace.      Almost 400 comets have been
identified using Soho. Although it is operated by professional teams, they
are mostly interested in solar physics. This means that many comets pass
unnoticed and remain in archives for years before amateurs identify possible

Champion among these is Michael Oates, a member of the Manchester
Astronomical Society. He has found well over a hundred comets in Soho
images. Although Soho detects some comets near the sun that will turn around
and pass outwards again most are seen in their death throes. Many are so
small, not much bigger than a house, that they hardly deserve to be called
comets. They produce a detectable trail because as the intense solar
radiation causes their constituent ice to     evaporate, dust is released,
which scatters sunlight.

These tiny comets, often called sungrazers, are interesting because the
majority seem to follow almost the same path. That is, they appear to be
fragments of a much larger comet that broke apart millennia ago.

We saw the same sort of thing happen, on a smaller scale, a few years ago.
Comet Shoemaker-Levy 9 was found in orbit around Jupiter, apparently having
broken apart in 1992, just before its discovery, when it flew too close to
the planet. By the time of the collision with Jupiter in July 1994, its
20-odd major fragments had separated sufficiently for the fireworks to
continue for more than a week.

With sungrazer comets, the spreading is much greater. In the late 19th
century, Heinrich Kreutz, working in Kiel, Germany, noted the orbital
similarity of several bright comets observed in the preceding decades. They
became known as the Kreutz group, but until Soho entered operation at the
end of 1995 it was never suspected how many individual members the complex
might contain. There are certainly tens of thousands to be found, and the
parent of the swarm must have been a behemoth, more than a hundred
kilometres in size and so over a thousand times the mass of Comet Halley.

The history of the Kreutz parent breakup is gradually being pieced together.
To explain the fragment dispersion, a time scale of at least 10,000 years is
required, but there have been subsequent disintegration events. In 372 BC
the Greek astronomer Ephorus saw a bright comet break asunder. One of its
two daughters seems to have been observed again about every 350 years since,
the other taking 700 years.

Each time subsidiary splits have taken place, the stream of debris has built
up. But why do comets split? Some fall apart for no apparent reason.
Shoemaker-Levy 9 was torn into pieces by the tidal force of Jupiter's
gravity when it strayed too close. But what causes them to fall apart is
apparently thermal stress. As each split occurs, more of the ice is exposed,
and the fragments get smaller until on the next visit they vaporise. Giant
comets such as the Kreutz progenitor exist, and when they split, they leave
myriad smaller bodies zipping through space, each potentially lethal.

Although the Kreutz comets have orbits crossing that of the Earth, their
orientation is such that they consistently miss us. Just as well, else these
snowballs would be giving us hell.

Copyright 2002, Guardian Newspapers Limited


>From David Morrison <>

NEO News (02/02/02) Spaceguard progress & Australian challenge

Dear friends and students of NEOs:

Here are three items: (1) an annual update on the progress of the Spaceguard
Survey, which is very nearly on target to meet the 90% goal by 2008; (2) an
open letter to the government of Australia, signed by many members of the
NEO community, supporting an Australian spaceguard effort; and (3) a story
from discussing this open letter.

David Morrison


Alan Harris (JPL) and David Morrison (NASA Ames)

The Spaceguard Goal as adopted by NASA is to discover 90% of the near Earth
asteroids (NEAs) larger than 1 km (actually, brighter than absolute
magnitude H=18) before the end of 2008. This is a summary of progress
through the end of 2001, with more than 100 new discoveries of NEAs brighter
than H=18, bringing the total to 587 as of January 28, 2002. The total
number of known NEAs of all sizes is 1743.

The following table shows the discoveries of total NEAs and of NEAs brighter
than H=18, listed by month and observing team during 2001. The months are
actually lunations, full moon to full moon, starting with the full moon of
January 9, 2001, and ending with the full moon of January 28, 2002, a total
of 13 "months." The observing groups listed are LINEAR (MIT), LONEOS (Lowell
Observatory), NEAT-Maui (JPL), NEAT-Palomar (JPL; new), Spacewatch-I (Kitt
Peak), and
Spacewatch-II (Kitt Peak; new)

       LINEAR  LONEOS  NEAT-M  NEAT-P   SW-I   SW-II   Other |  Total

Jan   22  6    1  0    3  0    -  -    1  0    -  -    0  0 |  27   6
Feb   19  6    1  0    2  1    -  -    1  0    -  -    0  0 |  23   7
Mar   15  5    8  0    4  1    -  -    1  0    -  -    2  0 |  30   7
Apr   12  3    6  1    2  1    -  -    2  0    -  -    0  0 |  22   5
May   11  3    4  2    7  3    5  1    2  0    -  -    0  0 |  29   9
Jun    9  4    2  1    0  0    5  3    0  0    -  -    0  0 |  16   8
Jul    1  0    5  2    3  0   13  4    0  0    -  -    0  0 |  22   6
Aug   18  4    3  2    7  3   12  1    3  0    -  -    0  0 |  43  10
Sep   47 17   10  2    0  0    7  2    1  0    -  -    0  0 |  65  21
Oct   35  4    0  0    3  0   11  1    4  0    2  0    0  0 |  55   5
Nov   35  7    3  1    1  0    2  0    1  0    3  0    0  0 |  45   8
Dec   45  8    2  0    2  1    4  1    1  0    0  0    2  0 |  56  11
Jan   48 13    1  1    4  0    4  1    3  0    0  0    1  1 |  61  16
Tot  317 80   46 13   38 10   63 14   20  0    5  0    5  2 | 494 119

The next table groups the discoveries into 6-month intervals for easier
comparison with earlier years. It also drops the final lunation:

LINEAR LONEOS NEAT SpacewatchOther Total

01-1 88  27 22   4 28  10   7   0 2  0 147  41

01-2 181  40 23   7 65  13 15   0 2  0 286  60
Tot     269  67 45  11 93  23 22   0 4  0 433 101

It is particularly notable how much LINEAR's discovery rate picked up in the
second half of the year. A preliminary look at discovery magnitudes suggests
this is largely due to reaching to fainter magnitude, around visual
magnitude V=19.5, while previously the limit was near V=19.0. Both NEAT
systems are getting down to around V=19.5 too. It is this improvement in the
detection limits that keeps the discovery rate so high; without such
improvements we would expect a drop-off as the survey becomes more complete.
The average discovery rate for 2002 is 9 per lunation, approximately the
same as in 2000 (10 per lunation)

We can also ask how long it will take at the present discovery rate to find
90% of the NEAs brighter than H=18. The present total number of discovered
NEAs of H </= 18.0 is 587. Taking a nominal value of 1000 as the total
population, that implies that the survey is now 59%
complete. It appears that, especially if the discovery efficiency of the
last 5 months can be sustained, the Spaceguard Survey may be on track for
90% completion by 2008 or 2009. However, this statement is dependant on what
number is assumed for the total population, since
the discovery rate needed to finish the job depends on the number of objects
remaining to be discovered. For example, if the total population is only 800
(we consider this impossibly low, but is still 100 above one of the
estimates of two years ago), then 90% completion requires discovering only
133 more objects. For an assumed population of 1000, we need 313 more
discoveries to reach 90%, and for an assumed population of 1200, an
additional 493 discoveries are needed to achieve 90% completion.

We may be still a little shy of the mark for 90% completion by the end of
2008, but not seriously so for the nominal population of 1000. If there are
as many as 1200, then we will have to go deeper (perhaps beyond magnitude
V=20) to reach the goal in 2008. Or we would need to increase sky coverage,
for example by adding a telescope at a Southern Hemisphere site whose long
winter nights (hopefully clear) would complement the short and often cloudy
summer nights in the US Southwest.

Detailed modeling of the survey and analysis of the discovery statistics is
in preparation by Harris and will be published later in the professional


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


>From Ron Baalke <>

Meteors go pop in the night

Recordings of sounds from shooting stars defy explanation.

Nature Science Update
Philip Ball
February 6, 2002

Scientists camping out in the Mongolian snow at minus 30 degrees C have made
the first recordings of an elusive sound: the crackle and pop of a meteor
shower[1]. Their observations defy all current explanations of what happens
when debris burns up on entry to the Earth's atmosphere.

Some meteor booms are simply acoustic waves like those from supersonic
aircraft. But for centuries there have been rumours of more baffling
'electrophonic' noises occurring at the same time as meteors become visible.

Because light travels much faster than sound, there should be a delay
between the appearance of a meteor and its sound - just as thunder generally
comes seconds after a lightning flash. In fact, meteors burn up so high in
the atmosphere that this time delay ought to be a few minutes.

Because one of the leading candidate theories is that electrically charged
particles streaming  behind meteors interact with the Earth's magnetic field
and produce radio waves, which cause the electrophonic noises. These radio
waves are broadcast to an observer at the speed of light. They could be
converted to sound by exciting vibrations in objects at ground level.

Full story here:


>From Andrew Yee <>

International Leonid Watch - Croatia


Slaven Garaj
Department of Physics
Swiss Federal Institute of Technology Lausanne
Tel.: +41 21 693 4461

Dejan Vinkovic
Department of Physics and Astronomy
University of Kentucky
Tel.: +1 859 257-8741

For immediate release: January 20, 2002

Recording of mysterious meteor sounds

Joined by the International Leonid Watch - Croatia (ILWC) project, a group
of scientists presented the first instrumental detection of elusive
electrophonic meteor sounds. In November 1998, the researchers from the
Croatian Physical Society and the University of Kentucky organized an
expedition to Mongolia to observe the anticipated Leonid meteor shower and
shed some light on the phenomenon. The complete data analysis revealed two
electrophonic sounds that provided several important clues about the nature
of this longstanding astronomical mystery.

In the year 1676, Geminian Montanari from Italy realized that the normal
sounds produced by a bright fireball require several minutes to reach the
ground. The same is true when thunder lags behind distant lighting. However,
the mystery was born when he noticed that some people claimed they heard
sounds simultaneously with the meteor.

It was not until 1980 that the electrophonic sounds had their revival in the
work by Colin S. L. Keay. Intrigued by these sounds, he proposed that
meteors could produce very low frequency (VLF) electromagnetic waves. These
radio waves travel with the speed of light, thus reach an observer almost
simultaneously with the appearance of the meteor. Then they make a sound by
simply vibrating an ordinary object.

However, something was missing in this picture. The Leonid meteors are very
fragile and burn out too high in the atmosphere, contradicting the Keay's
physical model of VLF meteor emission. Nevertheless, a spectacular Leonid
storm of 1833 yielded a list of electrophonic sound reports. These reports
and anticipated large number of meteors indicated that the 1998 Leonids were
a good target for the ILWC

The expedition site was far from populated area to avoid radio and audio
noise. Environmental conditions were harsh, with temperatures as low as -30
C (-22 F). The meteor shower appeared and numerous bright meteors
illuminated the snow covered Mongolian plane. The experiment included a
video camera, VLF radio receivers, and microphones acoustically isolated
from the observers.

Two fireballs produced a short duration "pop"-like sound, with one of them
captured on video. The sounds resemble deep "pops" reported in 1833, but the
analysis of all collected data revealed surprises. Damir Kovacic from the
Cognitive Neuroscience Sector at SISSA, Trieste, Italy, coordinated the
sound detection experiment. "First of all, finally we have a strong
indication that our electrophones were indeed produced by the
electromagnetic radiation", he says, "but it is rather of much lower
frequency than expected."

The picture had become even more blurred when the theoretical analysis was
applied to the data. "There are two major theories, including the one by
Keay, about the physical process of radio
emission from meteors. Both of them failed to explain the data", says Dejan
Vinkovic, a member of the team and coordinator of the Global Electrophonic
Fireball Survey (GEFS) at the University of Kentucky. "Basically, we are
back to the drawing board, where we have to start thinking about refining
the theory for Leonids."

There are some important clues, though. "It is interesting to notice that
both electrophonic sounds were created when the meteors were crossing the
border of the nighttime ionosphere, a layer of charged particles", says the
project leader Slaven Garaj from the Swiss Federal Institute of Technology
Lausanne. "Also, the energy of meteor may not be sufficient to invoke large
electric fields needed to produce electrophonic sounds. Thus, a strong
coupling of a meteor
with the ionosphere has to be taken in account in any future theory."

The paper about these results will appear in the Journal of Geophysical
Research. Other members of the team are Goran Zgrablic and Neven Grbac
(University of Zagreb, Croatia), Silvija Gradecak (Swiss Federal Institute
of Technology Lausanne), Nikola Biliskov and Zeljko Andreic (Rudjer Boskovic
Institute, Croatia).

After the expedition to Mongolia, the team initiated the GEFS project with
the goal of collecting witness reports of electrophonic sounds and
coordinating future experiments. There are many new reports about
electrophonic sounds from the recent 2001 Leonids this November. If you have
heard an electrophonic sound, please send a report to the GEFS project at
the web-address:

Images, videos and additional information are available at the project's web


>From Ron Baalke <>

NASA's comet tour challenges teachers and students to enter contest

FOR RELEASE:  Feb. 5, 2002

Contact:  David Brand
Office:  607-255-3651

ITHACA, N.Y. -- NASA's Contour space mission and Cornell University are
challenging students and their teachers in the United States to participate
in the spacecraft's forthcoming exploration of comets.

They are being invited to participate in the Cornell and Contour Comet
Challenge, with the grand prize for the winners a trip to Kennedy Space
Center at Cape Canaveral Spaceport, Florida, to witness the launch of the
spacecraft scheduled for July 1.  The NASA mission, officially the Comet
Nucleus Tour, is being managed by the Applied Physics Laboratory at the
Johns Hopkins University, with Cornell's Department of Astronomy leading the
international science team.

As part of Cornell's educational outreach for the mission, students and
their teachers are being challenged to devise a program to educate and
involve their communities about Contour's goal to study at least two comets
as they travel through the inner solar system. The spacecraft will provide
the closest look ever at a comet's nucleus.

The teams submitting the two winning programs -- one in grades 5 through 8
and one in grades 9 through 12 -- will be invited to attend four days of
launch-related activities, including interviews with mission scientists and
engineers, at Kennedy Space Center.  Each team will be allowed a budget of
up to $1,000 for its educational program. The winning teams, each consisting
of a teacher and a student, will be chosen by a panel of educators and
scientists on the basis of the originality and feasibility of the submitted

Students don't need a lot of background knowledge either on Contour or about
comets to participate in the program, explains Laura Lautz, the mission's
education and public outreach coordinator at Cornell. "The key is, they need
to be curious," she says.  Beyond that, the
teachers and students can develop any kind of presentation they choose: a
program in conjunction with a local museum, a web-based program or even a
video.  Students will be encouraged to speak in public and to write articles
for local or student newspapers.  As well as the two winning teams, two
teams from each state will be chosen to receive a kit of Contour materials
so that they can follow through with their plans to share the mission's
comet exploration with their communities.  These teams also will be able to
watch the launch on their computers via Web streaming, and to ask questions
of mission scientists following the launch.  For more information on the
space mission and how to enter the competition, go on line to

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

o Cornell Department of Astronomy:

o NASA Discovery Program:


>From Ron Baalke <>

Congressmen show support for O'Keefe, NASA budget
February 6, 2002


This year will be the final year Rohrabacher will serve as chairman of the
space subcommittee because of term limit rules for committee chairs.
Rohrabacher plans to use his final year in part to push through legislation
he plans to introduce in the near future to establish an award named after
the late astronaut Pete Conrad. The award would go each year to the
astronomer who discovers the largest near-Earth object, an incentive for
more people to look for objects that could pose a hazard to the Earth. "If
we got 10,000 young people looking into the sky," he said, "even if they
don't find anything it is still a good thing."


Full story here:


>From Gerhard Hahn <>

On behalf of the editors of the COMETS II Book we distribute the following


Gerhard Hahn

PS.: The second announcement for the Asteroids, Comets, Meteors 2002
Conference (ACM2002) will be made shortly.


                                 COMETS II

               Response must by received by February 10, 2002

Dear Colleagues,

Since the publication in 1982 of the Space Science Series Book "Comets",
there have been dramatic advances in cometary science. Spacecraft have
visited four comets, and the IR and millimeter ranges have been
systematically explored revealing a wealth of new molecular species.
Hundreds of transneptuniam objects, which are the likely progenitors of the
short-period comets, have been discovered during the past decade. A new era
is now opening during which coma samples will be studied with spaceborne and
ground-based instruments. Hardware advances will continue to deliver
new remote-sensing results at an increasingly rapid pace. In addition,
theoretical advances and new computational resources allow complex systems
to be modeled more accurately than before, thus providing a much clearer
understanding of processes such as coma structure and evolution, nucleus
activity, coma and solar system nebula physics and chemistry, and orbital

For these reasons, the time has come to begin work on "Comets II", a new
book to be published in the Space Science Series of the University of
Arizona Press. A Scientific Organizing Committee (SOC) of 16 international
members has been formed and has made plans for the organization and content
of this book. The editors of Comets II will be Michel C. Festou, H. Uwe
Keller, and Harold A. Weaver.

The purpose of this message, sent on behalf of the Editors and the SOC, is
to invite you to participate in the Comets II project. More specifically,
this message is a solicitation of ideas for chapter topics and a
solicitation of volunteers for chapter authors. If you would like to
recommend chapters for the book or would like to volunteer to write a
particular chapter, we would like to hear from you NO LATER THAN February
10, 2002.

We hope that you will consider contributing to this effort, as we expect
Comets II to be the fundamental source of information on comets for both
students and researchers during the next decade.

A detailed information notice for Comets II chapter authors and contributors
is available at:

If you do not anticipate being an author, please consider serving as a
reviewer and complete the attached form. If you have any questions, you can
direct them to the editors using the contact information supplied in the
information notice.

FEBRUARY 10, 2002.

Thanks in advance for your cooperation.

Dr. Richard Binzel University of Arizona Space Science Series Director



>From Gerta Keller <gkeller@Princeton.EDU >

Dear Benny

I might contribute to the debate on Impact dust and K/T mass extinctions by
pointing out some common misconceptions regarding the empirical
paleontological record and inaccuracies in Smit's comments with respect to
it. It won't settle the controversy, but it will help clear muddy waters.

Jan Smit and I go back a very long time and have been on opposite sides for
just as long. I have always admired his unshakable conviction that a single
impact at the K/T boundary was the sole cause for the mass extinction - and
his devoted research to finding evidence in support of that impact. I have
been just as devoted to compiling a global paleontological database (e.g.
extinctions, faunal turnovers, climate, sea level changes, spherules, PGEs,
volcanic ash) that would help understand the nature of the K/T mass
extinction and environmental changes associated with it, and whether the K/T
impact scenario could explain it. The biotic yardstick are planktic
foraminifera, the one microplankton group that was nearly wiped out by the
K/T mass extinction. It is no secret that I have not found a good fit
between the empirical data and the impact theory. It is also no secret that
a very large number of paleontologists across all fields of research have
the same problem. Just see the survey article by MacLeod and 23 other
paleontologists (l997) who could not reconcile their empirical records with
a sudden mass extinction at the K/T boundary. And there are many many more.

So, when Jan Smit states that Keller is just plain wrong and there is no
strong decline in populations during the last 0.5-1.0 m.y. of the Cretaceous
in planktic foraminifera or any other fossil groups, except rudists and
inoceramids, and that "On the contrary, these planktic species thrive -
almost unchanged - up to the global ejecta layer itself. No preceding
decline there." He speaks from his unshakable conviction - it is also an
argument he has used for the past 20 years. But contrary evidence has been
growing and growing and growing.

But really, the controversy between supporters of the single impact
hypothesis and paleontologists who see longterm causes is largely one of
apples and oranges. For single impact supporters, the only important record
is the few centimeters above and below the impact horizon at the K/T
boundary and what happened during that time. For paleontologists, that "drop
in the bucket" is just part of the longer term record. What came before is
just as important to understand what happened at the end of the Cretaceous.

So when we separate the apples and oranges, the controversy gets smaller.
Smit is right in that there was a sudden catastrophe at the K/T boundary
"impact horizon" which generally consists of a thin red clay layer with an
iridium anomaly and frequently clay altered spherules presumed to have been
originally glassy microtektites. More than any other group, planktic
foraminifera suffered the most extreme mass extinction at this time. There
is no controversy here, except for a minor squable about whether almost all
went extinct precisely at the impact layer (all according to Smit),or
whether the mass extinction selectively wiped out only the 2/3 (~45-50
species) tropical and subtropical species, but let the ecologically more
adaptable species survive for some time (Keller). This matter was settled by
a blind test in l997 in favor of a significant number of survivors (Masters,
l997; Olsson, l997, Extebarria, l997, Canudo, l997). It should also be
mentioned in this context that pollen extinctions are largely restricted to
the US Interior, and that the fossil record of dinosaurs wiped out the K/T
impact is still highly controversial (Archibald, l996).

But the severity of the K/T-impact mass extinction can not be assessed
simply by the number of species disappearing. Although 2/3 of the species of
planktic foraminifera extinct is a major catastrophe, the significance of it
is much less when we consider that nearly all of these species were already
endangered and very rare or only sporadically present during the last
200,000-300,000 years of the Cretaceous; their combined relative abundance
in the foraminiferal population was less than 5% (Keller, l996; Luciani,
l997; Abramovich et al.,l998). Thus for the already stressed tropical and
subtropical species, the K/T impact was the straw that broke the camel's
back. The questions we should be asking is why this group was already so
stressed by the end of the Cretaceous? What caused their pre-K/T decline?

Those questions have led some of us to investigate the environmental changes
during the last few hundred thousand years of the Cretaceous - and we were
amply rewarded. That longterm record is where it really gets interesting. It
is an interval of extreme environmental changes and high biotic stress. Here
are some of the significant findings for this pre-K/T interval:

1) The longterm late Cretaceous (e.g. Maastrichtian, 71-65 Ma) cooling
reached the maximum low about 65.5 Ma, coincident with a sea level lowstand
(Barrera, l994; Li and Keller, l998).

2) A rapid greenhouse warming occurred between 65.4-65.2 Ma (Barrera, l994;
Li and Keller, l998).

3) Major Deccan volcanism between 65.4-65.2 Ma (Hoffmann et al., 2000).

4) Multiple glass spherule layers (up to 4) in late Cretaceous sediments of
NE Mexico between about 65.2-65.3 Ma (Stinnesbeck et al., 2001; Keller et

5) Multiple glass spherule layers (three) in late Cretaceous sediments of
Israel between about 65.2-65.3 Ma (Keller et al., in prep.)

6) One glass spherule layer in late Cretaceous sediments of the Indian Ocean
dated about 65.3 Ma (in progress).

7) Climate gradually cooled during the last 100,000 years of the Cretaceous
(Li and Keller, l998; Barrera, l994).

8) Biotic effects accompanying these environmental changes are severe (see
Keller, 2001 for a review):

        Rudists extinct (Johnson and Kauffman, l996)
        Bivalves show severe declines (Macellari, l986)
        Ammonites decline strongly (Ward and Kennedy, l993)
        Palynoflora decrease (Meon, l990; Nichols,
        Tropical-subtropical planktic foraminifera strongly decline (see

9) Biotic effects on planktic foraminifera are severe, causing a decrease in
tropical and subtropical species diversity and abundance in open marine
environments, and dominance of ecologically tolerant biserial species
(e.g.Keller,l996; Luciani, l997; Abramovich et al., l998; Kucera and
Malmgren, l998; Olsson et al., 2001).

10) Very high stress conditions are observed in the latest Cretaceous (last
0.5 m.y.) of the eastern Tethys (Egypt, Israel) where species richness is
50% lower than at equivalent latitudes elsewhere and the disaster species
Guembelitria cretacea dominates (60-90%)(Abramovich et al., l998; Keller, in
prep.). Until now, such high Guembelitria dominance has only been observed
in post-K/T environments, and has been considered a unique response to the
high stress conditions of the K/T impact event (Smit, l982).

11) Productivity is strongly reduced during the last ~300,000 years of the
Cretaceous and coincident with the blooms of the disaster species

Until recently I used to say that these major climatic and sea level changes
accompanied by volcanism could easily account for the observed strong
decline in species diversity and species population abundances. I still
believe that is possible. Except now there is the evidence of multiple glass
spherule layers. We still don't know whether the three glass spherule layers
in Mexico and Israel represent three events, or one event and subsequent
reworking. Further discoveries of these spherule layers will answer that
question. However, this much is certain, there is at least one spherule
producing event about 300,000 years prior to the K/T boundary. Also still
arguable is the origin of these glass spherules - whether impact or
volcanic. Either way the evidence indicates that the event(s) that produced
them, and Deccan volcanism, are responsible for the greenhouse warming and
the high stress biotic environment. Current data also suggest that the
maximum biotic stress environment appears to be centered in the eastern

Gerta Keller, Princeton University

Abramovich et al., l998, Geololgy 26, 63-66.
Archibald, l996, Cretaceous/Tertiary mass extinction: biotic and
environmental changes (MacLeod & Keller, eds.) W.W. Norton & Co.,p. 373-399.

Barrera, l994, Geology 22, 877-880.
Canudo, l997, Mar. Micropaleo. 29, 73-76.
Hoffmann et al., EPSL 180, 13-27.
Johnson & Kauffman, l996, Cretaceous/Tertiary mass extinction: biotic and
environmental changes (MacLeod & Keller, eds.) W.W. Norton & Co.,p. 231-274.

Keller, l996, ibid, p.49-84.
Keller, 2001, Planet. & Space Science, 49, 817-830.
Keller, 2002, GSA Spec. Pub. 356
Kucera & Malmgren, l998, Paleo-3,
Li & Keller, l998, Geology 26, 995-998.
Macellari, l986, J. Paleontol. Mem. 18, 1-55.
MacLeod and 23 others, l997, J. Geol. Soc. London 154, 265-292.
Masters, l997, Mar. Micropaleo. 29, 77-79.
Meon, l990, Rev. Paleobot. Palynol., 65, 85-94.
Olsson, l997, 80-84
Olsson et al., 2001, J. Foram. Res., 31(3): 275-282.
Orue-etxebarria, l997, 85-88.
Smit, l982, GSA Spec. Pub.
Stinnesbeck et al., 2001, Canadian Journal of Earth Sciences, 38, 229-238
Ward & Kennedy, l993, Paleontol. Soc. Mem. 34, 1-58.

Gerta Keller
Department of Geosciences
Princeton University
Princeton, NJ, 08544, USA
phone: 609 258 4117
fax: 609 258 1671


>From Alastair McBeath <>

Dear Benny,

Goran Johansson's further comments on these items (CCNet 17/2002, 30
January) appear rather confused, what with transferring 7th century BC
Assyrian omen Reports back now not just to the 10th, but the 14th, century
BC and singling out another moderately long-reigning Babylonian king (though
two others in the same century - Burnaburiash II before and Nazimaruttash
after - enjoyed similar reigns of ~23 (Kurigalzu II), ~27 (B II) and ~25 (N)
years); transferring the polar Novaya Zemlya mirage type to the
Mediterranean climes of Canaan; and suggesting the Roman Ovid and Latin
Minerva belong to the Greek canon (try instead Homer's "Iliad" 4:73 and
lines following, for Pallas Athene's descent like a fiery meteor/meteorite
from Olympos to Ilios; the historical siege of Ilios/Troy probably dates to
the end of the 13th century BC. The correct Ovid reference for the incident
is 'Fasti' 6: 421-423).

To paraphrase my earlier points about the ancient Mesopotamian omen texts
(CCNet 9/2002, 14 January), while some protases may refer to genuine
astronomical events, some clearly do not. Dating them and tying them to
specific events is appallingly difficult; in many cases, impossible to
achieve with any certainty. Goran seems to want someone else to read through
the numerous published omen collections he hasn't seen to check for such
correlations, but in fact this work has already been accomplished by, for
example, Hermann Hunger, whose first work of many discussing the
Mesopotamian omina was published in 1969. As Goran has already dismissed
Hunger's conclusion that the Report omina cannot be linked to actual events,
based on a lifetime of work on the original clay tablets, in favour of his
own reading of one text translation covering a tiny fraction of the omina
(CCNet 4/2002, 7 January), there seems little point in trying to take this
matter further.

Joshua 10:11-14 has the Amorite armies of the five kings defeated by Yahweh
at Gibeon, and the god then pursues the fleeing armies down the Descent of
Beth-Horon hurling huge hailstones at them along the way, apparently killing
more than the Israelites managed with their swords. The important
translation is that these are not stones but hailstones. A similar
misconception sometimes arises because of earlier translations poetically
using the word "stones" for "hailstones" in the Exodus 9:13-35 description
of the seventh so-called "plague" on Egypt, of hail, for instance. I've
mentioned before that the King James' Bible should not be relied upon for
critical text interpretations.

The Joshuan command to Yahweh causing the Sun and Moon to stand still is a
real oddity, not least as it has the very unusual case of a human commanding
the god (though the book of Joshua centres around building up the role of
this warrior-prophet in the conquest of ancient Palestine, including
miraculous occurrences and a few anachronisms). There is the possibility
some misunderstanding over the solstice (= "sun-standing") times is involved
in this, and rather than a miraculous or unknown natural occurrence, it may
originally have been a dating mechanism, perhaps indicating a coincidence of
the solar and lunar stand-stills. Curiously, the action detailed from the
Passover, dated to the 14th of the first month, to the defeat of the
Amorites (Joshua 5:10-10:14) could plausibly have taken ~59-73 days, while
the period between the 14th of the first (lunar) month, in modern April or
early May, to the summer solstice would have been between ~50-78 days. The
couplet itself, "Sun, stand still over Gibeon,/ and, moon, you too, over the
Vale of Aijalon!" (Joshua 10:13) is stated as deriving from the lost poetic
collection 'The Book of the Just', which recurs elsewhere in the Early
Prophets (e.g. 2 Samuel 1:18). As with other aspects of 'Joshua', whether a
real event is referred to, and whether it was originally associated with the
prophet Joshua, or was simply added-in to his mythos in its surviving form
to indicate his greatness, remains unknown. Joshua's text, along with most
of the early biblical books such as the Pentateuch, is very poorly dated, to
perhaps sometime within the 10th to 4th centuries BC as the work we now
know. Similarly, it draws on earlier oral and written sources, and was
subject to unknown numbers of revisions. The historical Israelite conquests
in, and settlement of, Palestine described in the book may well date to
c.1220 BC and subsequent years, perhaps up to c.1200, though the matter is
not definitively settled, as there is little archaeological evidence to
support the Joshuan conquest, while some of the settlement details
especially are anachronistic.

Alastair McBeath,


>From, 7 February 2002

Meteorite Hunter: The Search for Siberian Meteorite Craters
by Roy A. Gallant

For the last ten years Prof. Roy A. Gallant has been digging around the
notoriously treacherous Siberian wastelands so (thankfully!) you and I don't
have to.

His mission: To uncover the mystery surrounding what's known today as the
Tunguska Event, the 1908 meteorite impact that was so great it exploded with
a force 2000 times the size of the Hiroshima blast, its shockwave circling
the earth twice.

But what was the object? A comet's nucleus? Or a stony asteroid? Braving the
region's natural predators (from bears to blood-thirsty bugs), Gallant,
using research never before seen outside Russia, attempts to find answers in
a book that is part history, part travelogue and part scientific inquiry. What's more dangerous, Siberian mosquitoes or rocks from space?

Roy A. Gallant: I'll take the mosquitoes. At least you can hit back.

Q: Because the 1908 meteor exploded aboveground, little is known about the
object. What new insights can you give us? Was it a comet or an asteroid?

A: Not really any new insights into the cause of the event, more a matter of
accumulating evidence tending to support the notion that the exploding
object was a comet nucleus. This is the collective opinion of most Russian
investigators; although some say they cannot confidently rule out a stony
asteroid. Although computer modeling can be helpful, it is not a reliable
substitute for the types of field investigations I report in my book.

Q: Based on your research, what did the event look like to an observer
standing at a (barely) safe distance?

A: There was blinding light from the explosion--violent flash accompanied by
an extremelhy hot and violent wind, and there was a pressure wave strong
enough to knock people down. Add to that thunderous noise sounding like
batteries of artillery fire. Than the expansive forest  burst into flame.
Many close to the blast were temporarily deafened, struck dumb and
speechless, and fell to the ground in a state of shock.

Q: What would happen if a similar event occurred over a metropolitan region?

A: If there had been a difference of one hour when the Tunguska object
struck, it would have exploded over St. Petersburg and killed about 500,000

Q: Experts agree it's only a matter of time before a much larger object hits
the planet. How worried are you about the survival of civilization?

A: I'm not at all worried since there's nothing I or any one else can do
(sic!) to prevent a planet-crunching asteroid a few kilometers in diameter
from largely destroying the civilized world. It's a numbers game. We simply
have no way of knowing when we'll be hit again. You read a lot of
numbers--certain size asteroids striking Earth every 1000 or 50,000 or
500,000 years. If we haven't been hit for a long time, does that mean we are
likely to be hit soon? Not necessarily. Any one versed in probability theory
can  tell you that the past occurrence of the sum of seven turning up on the
next dice toss has nohing whatever to do with the number of times seven has
shown up in the previous 20 or so tosses.

Q: Who are your heroes and how have they influenced your work?

A: I have many heroes in science, among them Charles Darwin and others like
him who devoted a great part of their lives nurturing a old hypothesis and
watching it evolve into theory, and eventually gain the status of scientific
principle, all through theie tireless and methodical collection of evidence.
But science tends not to be down that way any more. Just turn to the title
page of  mose major articles in the journals NATURE and SCIENCE and see the
multiple by-lines, sometimes up to a dozen or so investigators. The new
technologies in biology and physics, for example, are making a rarity out of
the potential Darwins or a Copernicus.

Q: What most upsets you about science or scientists?

A: There's nothing about science as a means of investigating the natural
world that upsets me, even though a scientists' search for truth is bound to
step on toes every now and then. For the most part, I think scientists are a
pretty honest lot with well defined goals. The scientists who do not fit
that pattern are those who have sold out to the tobacco, nuclear, and
certain other industries that try to convince us that their product or
activity is perfectly safe, when they know just the opposite is true.

Q: If you controlled a $1 billion foundation, what research effort would you

A: Since a billion dollars isn't all that much money these days, I'd look
for a relatively modest research effort, perhaps one directed more toward
education rather than expensive hardware that might teach us how to mine an
asteroid. In the field of astronomy, perhaps an effort to identify the
misconceptions young people hae about basic astronomy, space, space travel,
the nature and probability of life elsewhere in the universe and the
philosophical implicatioins of its discovery. The second, and major, part of
my program would be the preparation, publication, and distribution of
educational materials at the junior high and up levels. Such materials would
be relatively inexpensive, and their funds generated would go back into the
program to make it largely self-sustaining.

Q: Why should we spend money on space exploration over research into deadly

A: I see no reason why we shouldn't be doing both at the same time.

Q: What is the most beautiful aspect to space?

A: Its silence and profoundly humbling aspect.

Copyright 2002,

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