PLEASE NOTE:
*
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
atmosphere."
--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
(1) AUSTRALIA FAILS WORLD ON ASTEROIDS: SCIENTISTS
The Canberra Times, 5 February 2002
(2) EXPERTS FIND MORE JUPITERS
The Age, 7 February 2002
(3) COMETS GET A SNOWBALL'S CHANCE
The Guardian, 6 February 2002
(4) SPACEGUARD PROGRESS
David Morrison <dmorrison@arc.nasa.gov>
(5) METEORS GO POP IN THE NIGHT
Ron Baalke <baalke@jpl.nasa.gov>
(6) RECORDING OF MYSTERIOUS METEOR SOUNDS
Andrew Yee <ayee@nova.astro.utoronto.ca>
(7) NASA'S COMET TOUR CHALLENGES TEACHERS & STUDENTS TO ENTER
CONTEST
Ron Baalke <baalke@jpl.nasa.gov>
(8) PETE CONRAD AWARD FOR NEAR-EARTH OBJECTS?
Ron Baalke <baalke@zagami.jpl.nasa.gov>
(9) COMETS II BOOK: CALL FOR CHAPTERS AND PARTICIPANTS
Gerhard Hahn <gerhard.hahn@dlr.de>
(10) IMPACT DUST AND K/T EXTINCTIONS
Gerta Keller <gkeller@Princeton.EDU
>
(11) MESOPOTAMIAN OMENS (AGAIN), AND JOSHUA
Alastair McBeath <mcbal.gwyvre@virgin.net>
(12) METEORITE HUNTER: SPACE.COM INTERVIEW WITH ROY A GALLANT
Space.com, 7 February 2002
==============
(1) AUSTRALIA FAILS WORLD ON ASTEROIDS: SCIENTISTS
>From The Canberra Times, 5 February 2002
http://canberra.yourguide.com.au/detail.asp?class=news&subclass=national&category=general%20news&story_id=125501&y=2002&m=2
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 www.spacegarduk.com
[NOTE: despite the misspelling the
link is correct on the web page]
c2002 The Canberra Times
==============
(2) EXPERTS FIND MORE JUPITERS
>From The Age, 7 February 2002
http://www.theage.com.au/news/national/2002/02/07/FFXY41ZZBXC.html
By DAVID WROE
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.
===========
(3) COMETS GET A SNOWBALL'S CHANCE
>From The Guardian, 6 February 2002
http://www.guardian.co.uk
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
comets.
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
============
(4) SPACEGUARD PROGRESS
>From David Morrison <dmorrison@arc.nasa.gov>
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 Space.com discussing this open letter.
David Morrison
=================================
SPACEGUARD: HOW ARE WE DOING?
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
literature.
+++++++++++++++++++++++++++++++++++++++++++
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 dmorrison@arc.nasa.gov.
For additional
information, please see the website: http://impact.arc.nasa.gov.
If anyone
wishes to copy or redistribute original material from these
notes, fully or
in part, please include this disclaimer.
===========
(5) METEORS GO POP IN THE NIGHT
>From Ron Baalke <baalke@jpl.nasa.gov>
http://www.nature.com/nsu/020204/020204-3.html
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:
http://www.nature.com/nsu/020204/020204-3.html
============
(6) RECORDING OF MYSTERIOUS METEOR SOUNDS
>From Andrew Yee <ayee@nova.astro.utoronto.ca>
International Leonid Watch - Croatia
Contacts:
For ILWC:
Slaven Garaj
Department of Physics
Swiss Federal Institute of Technology Lausanne
E-Mail: slaven.garaj@epfl.ch
Tel.: +41 21 693 4461
http://fizika.org/ilwcro
For GEFS:
Dejan Vinkovic
Department of Physics and Astronomy
University of Kentucky
E-Mail: dejan@ccs.uky.edu
Tel.: +1 859 257-8741
http://gefs.ccs.uky.edu
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
project.
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:
http://gefs.ccs.uky.edu
Images, videos and additional information are available at the
project's web
site:
http://fizika.org/ilwcro/results/index.html
===========
(7) NASA'S COMET TOUR CHALLENGES TEACHERS & STUDENTS TO ENTER
CONTEST
>From Ron Baalke <baalke@jpl.nasa.gov>
http://www.news.cornell.edu/releases/Feb02/contour.contest.deb.html
NASA's comet tour challenges teachers and students to enter
contest
FOR RELEASE: Feb. 5, 2002
Contact: David Brand
Office: 607-255-3651
E-mail: deb27@cornell.edu
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
plans.
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
http://www.contour2002.org
Related World Wide Web sites: The following sites provide
additional
information on this news release. Some might not be part of
the Cornell
University community, and Cornell has no control over their
content or
availability.
o Cornell Department of Astronomy: http://astrosun.tn.cornell.edu
o NASA Discovery Program: http://discovery.nasa.gov
============
(8) PETE CONRAD AWARD FOR NEAR-EARTH OBJECTS?
>From Ron Baalke <baalke@zagami.jpl.nasa.gov>
http://www.spaceflightnow.com/news/n0202/06congress/
Congressmen show support for O'Keefe, NASA budget
BY JEFF FOUST
SPACEFLIGHT NOW
February 6, 2002
[snip]
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."
[snip]
Full story here:
http://www.spaceflightnow.com/news/n0202/06congress/
============
(9) COMETS II BOOK: CALL FOR CHAPTERS AND PARTICIPANTS
>From Gerhard Hahn <gerhard.hahn@dlr.de>
On behalf of the editors of the COMETS II Book we distribute the
following
CALL FOR CHAPTERS AND PARTICIPANTS
Gerhard Hahn
LOC ACM2002
PS.: The second announcement for the Asteroids, Comets, Meteors
2002
Conference (ACM2002) will be made shortly.
---------
COMETS II
CALL FOR CHAPTERS AND PARTICIPANTS
------------------------------------------------------------------------
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
dynamics.
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:
http://webast.ast.obs-mip.fr/people/festou/comets2_information_notice.html
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.
PLEASE NOTE AGAIN THAT THE DEADLINE FOR RESPONDING TO THIS
SOLICITATION IS
FEBRUARY 10, 2002.
Thanks in advance for your cooperation.
Dr. Richard Binzel University of Arizona Space Science Series
Director
==========================
LETTERS TO THE MODERATOR *
==========================
(10) IMPACT DUST AND K/T EXTINCTIONS
>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
al.,2002).
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
below)
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
Guembelitria.
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
Tethys.
Gerta Keller, Princeton University
References:
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
email: gkeller@princeton.edu
phone: 609 258 4117
fax: 609 258 1671
====================
(11) MESOPOTAMIAN OMENS (AGAIN), AND JOSHUA
>From Alastair McBeath <mcbal.gwyvre@virgin.net>
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,
<vice_president@imo.net>
===========
(12) METEORITE HUNTER: SPACE.COM INTERVIEW WITH ROY A GALLANT
>From Space.com, 7 February 2002
http://www.space.com/spacelibrary/books/library_gallant_020208.html
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.
SPACE.com: 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
people.
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
fund?
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
diseases?
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, Space.com
--------------------------------------------------------------------
CCNet is a scholarly electronic network. To
subscribe/unsubscribe, please
contact the moderator Benny J Peiser <b.j.peiser@livjm.ac.uk>.
Information
circulated on this network is for scholarly and educational use
only. The
attached information may not be copied or reproduced for any
other purposes
without prior permission of the copyright holders. The fully
indexed archive
of the CCNet, from February 1997 on, can be found at
http://abob.libs.uga.edu/bobk/cccmenu.html.
DISCLAIMER: The opinions, beliefs and viewpoints expressed in the
articles
and texts and in other CCNet contributions do not necessarily
reflect the
opinions, beliefs and viewpoints of the moderator of this network