PLEASE NOTE:
*
CCNet 98/2000 - 29 September 2000
---------------------------------
"Do you need to pack all this
stuff?" Noah said to his wife.
"We're only going for 40 days
and 40 nights, you know. It's
not a luxery cruise. All I'm
taking is this rough woven garment
and a pair of sandals in case
these ones get sweaty."
"I'll need something for when
it gets cool in the evenings."
"You can't possibly need 15
identical mud-coloured woven
garments," Noah persisted.
[...]
It appears that the argument
continued for most of the voyage,
with Noah's wife protesting that
he had gone completely over
the top with all the creatures he
had taken on board. Eventually,
they compromised: she agreed to
throw four pairs of evening shoes
into the water if he would ditch
the "utterly pointless"
ostriches. In fact, Noah went back
on the deal and just released
a dove."
---Oliver Pritchett on
"Noah's pet project goes overboard"
The Sunday
Telegraph, 17 September 2000
(1) SIR ARTHUR C CLARKE'S OPEN LETTER TO THE PEOPLE OF LIVERPOOL
SpaceDaily, 28 September 2000
(2) NASA'S LANGLEY FIRST STOP IN BLAST TO LOOK AT IMPACT CRATER'S
PAST
NASANews@hq.nasa.gov
<NASANews@hq.nasa.gov>
(3) ROYAL ASTRONOMICAL SOCIETY MEETING ON ASTEROIDS AND
METEORITES
Duncan Steel <D.I.Steel@salford.ac.uk>
(4) CONTROVERSY ABOUT RISK ASSESSMENT OF LARGE EARTHQUAKES IN THE
U.S.
Stanford News Service <stanford.report@forsythe.stanford.edu>
(5) TROUBLE ALERT: BRITISH FIRM OFFERS DISASTER-MONITORING
SATELLITE
SPACE.com 28 September 2000
(6) TEMPORAL VARIATION OF THE ZODIACAL DUST CLOUD:
BILL NAPIER ON COMETARY DUST LOADING &
CLIMATE CHANGE
(7) OVERESTIMATING THE IMPACT RATE:
DAVID HUGHES QUESTIONS THE SPACEGUARD SURVEY
(8) GRAVITY ANOMALIES IN THE CHICXULUB IMPACT CRATER
G.L. Kinsland et al., GEOPHYSICAL RESEARCH
LETTERS 27
(9) PHYSICAL PROPERTIES OF THE NUCLEUS OF COMET 2P/ENCKE
Y.R. Fernandez et al., ICARUS 147: (1) 145-160
SEP 2000
(10) THE JAPANESE SPACEGUARD ASSOCIATION & THE NEO PROBLEM
S. Isobe, PLANETARY AND SPACE SCIENCE
48: (9) 793-795 AUG 2000
(11) DETERMINING MATERIAL STRENGTH & BULK PROPERTIES OF NEOS
W.F. Huebner & J.M. Greenberg,
PLANETARY AND SPACE SCIENCE 48
(12) CORRECTION TO "MICKEY MOUSE SCIENCE: HOW WALT DISNEY'S
ACCOUNT OF
THE XF11 AFFAIR IS FOSTERING AN URBAN
MYTH" from CCNet 97/2000 -
Alan W. Harris <awharris@lithos.jpl.nasa.gov>
(13) ANOTHER HUGE IMPACT DISASTER ~20,000 YEARS BP?
Giesinger Norbert <norbert.giesinger@siemens.at]
(14) FULLERENES: SEARCHING FOR SMOKING GUNS & IMPACT SIGNALS
Bob Kobres <bkobres@uga.edu>
(15) VOLCANIC CRATERS ON THE MOON: HOW SCIENTIFIC AMERICAN GOT IT
WRONG
Michael Paine <mpaine@tpgi.com.au>
============
(1) SIR ARTHUR C CLARKE'S OPEN LETTER TO THE PEOPLE OF LIVERPOOL
From SpaceDaily, 28 September 2000
http://www.spacedaily.com/news/spaceguard-00b.html
"The UK has a proud tradition of building fine scientific
instruments,
especially astronomical telescopes, and Liverpool has become a
distinguished centre for this high technology industry. I think
that it
would be most fitting if the engineers and craftsmen of
Merseyside built
the premiere British Spaceguard telescope, for the benefit of the
whole
country. Such an undertaking will be a significant technical
challenge,
but the result will contribute substantially to the protection of
our
only home - the Earth.
There is another excellent reason why Liverpool should be
involved. It
was there that Phillip Cleator founded the British Interplanetary
Society in 1933, and one of the Society's earliest supporters was
Mr
John Moores. Those who ridiculed the idea of travel beyond the
Earth
would have been amazed to know that before the end of the
century,
Space would be a matter of vital concern to everyone.
Sixtyfive million years ago, an asteroid impact in what is now
South
America changed the biology of our planet, and gave us mammals
our
window of opportunity. Science-fiction writer Larry Niven summed
it up
perfectly: "The dinosaurs became extinct because they didn't
have a
space programme."
FULL STORY at http://www.spacedaily.com/news/spaceguard-00b.html
==================
(2) NASA'S LANGLEY FIRST STOP IN BLAST TO LOOK AT IMPACT CRATER'S
PAST
From NASANews@hq.nasa.gov
<NASANews@hq.nasa.gov>
David E. Steitz
Headquarters, Washington,
DC
September 28, 2000
(Phone: 202/358-1730)
Chris Rink
Langley Research Center, Hampton, VA
(Phone: 757/864-6786)
RELEASE: 00-152
NASA'S LANGLEY FIRST STOP IN BLAST TO LOOK AT IMPACT CRATER'S
PAST
The Department of the Interior is drilling a hole in NASA's
back yard. But officials at NASA's Langley Research Center in
Hampton, VA, don't mind. This National Research Laboratory sits
on
the edge of a huge crater where both agencies are collecting
geological data from an ancient extraterrestrial event.
Thirty-five million years ago, a two-mile-wide bolide (meteor or
comet) hit the tip of Virginia's Eastern Shore. When it struck,
the fireball reshaped the land, disrupted the existing water
table, and dislodged deeper sediment to higher levels across a
56-
mile-wide area.
The Department of the Interior's U.S. Geological Survey (USGS)
Chesapeake Bay Impact Crater Project is a multi-year,
multi-agency
study of the sombrero-shaped, underground valley. Langley is
located on the outer rim of the York-James Peninsula crater area
and is hosting the USGS research activity. The USGS has been
taking core samples from a planned 2,700-foot-deep drill site
since July.
NASA will benefit from the drilling in the form of an atmospheric
fingerprint left by the bolide's impact. A senior research
scientist at Langley's Atmospheric Sciences Competency, Dr. Joel
S. Levine, looks forward to the shared science and agency
cooperation.
"The USGS drilling project at Langley will permit a detailed
investigation of a very significant event in the history of our
planet that affected all four components of the Earth system --
the atmosphere, the ocean, the land, and the biosphere,"
said
Levine. "We are working closely with USGS scientists to
assess
what new information about the Earth's early atmosphere may be
obtained from analysis of the cores to be obtained during the
drilling."
In addition, the USGS Western Earthquake Team is conducting a
seismic reflection and refraction survey. This involves small,
controlled, non-destructive explosions on Langley property to
create underground geological pictures of the rim of the largest
crater in North America.
The crater was discovered after core samples taken off the coast
of New Jersey were compared to ones made in southeastern
Virginia.
Along with a petroleum company's rock formation study made during
an oil search in the Chesapeake Bay, the combined test data
indicated a large crater. The USGS formally announced the
discovery in 1994.
NASA's participation in this research is part of the agency's
Earth Science Enterprise, a long-term research program dedicated
to understanding how human-induced and natural changes affect our
global environment.
Web sites for the Chesapeake Bay Impact Crater Project are
at:
http://woodshole.er.usgs.gov/epubs/bolide/
http://marine.usgs.gov/fact-sheets/fs49-98/
http://water.usgs.gov/pubs/FS/FS-048-99/
================
(3) ROYAL ASTRONOMICAL SOCIETY MEETING ON ASTEROIDS AND
METEORITES
From Duncan Steel <D.I.Steel@salford.ac.uk>
"Asteroids and Meteorites", London, Friday 13th October
Organisers: Dr Sarah Dunkin (UCL/RAL) skd@star.ucl.ac.uk, Dr
Manuel
Grande (RAL) m.grande@rl.ac.uk
and Dr Sara Russell (NHM) sarr@nhm.ac.uk
Summary: The vast majority of meteorites are thought to be
samples of
asteroids. Meteorites show variations in elemental and isotopic
abundances that are believed to reflect differences in the
heliocentric
distances of their parent bodies. However, definite links between
meteorite classes and specific asteroids are rarely achieved.
Asteroid
research will benefit greatly from the NEAR-Shoemaker mission,
which
will spend one year in orbit around Eros, and is already
returning much
detailed information.
Programme
Morning Session Chair: Manuel Grande
10:30-10.35 Introduction (M. Grande)
10:35-10:55 Diversity of Meteorite Parent Bodies (M. Grady)
10:55-11:15 The Asteroid-Meteoroid Connection (D. Steel)
11:15-11:35 Early Asteroids (D. Hughes)
11:35-11:55 The chronology of asteroid formation and
evolution
(J.Whitby)
11:55-12:10 Bridging the chondrite-achondrite discontinuity
(R. Ash)
12:10-12:30 Cosmochemical Instrumentation for an asteroid
mission(I.Wright)
12:30-12:50 Impact Hazard Assessment (M. Bailey)
Lunch 12:50- 14:00
Afternoon Session Chair: Sara Russell
14:00-14:20 NEO observations (A. Fitzsimmons)
14:20-14:35 Co-orbital Asteroids (T Christou)
14:35-14:50 Asteroid geology: Carbonaceous chondrite parent
bodies
(P.Bland)
14:50-15:30 Results from NEAR-Shoemaker (P. Clarke)
General Session: Orbital Dynamics of Asteroids(C. Murray)
The Government NEO report (H. Atkinson)
For further details see:
http://www.ras.org.uk/meetings/00-2001.htm
All 'G/BGA/MIST' Discussion Meetings are normally held in the
Lecture
Theatre of the Geological Society (GS) at Burlington House.
This is a 'G' (Geophysics/Planetary Science)
=================
(4) CONTROVERSY ABOUT RISK ASSESSMENT OF LARGE EARTHQUAKES IN THE
U.S.
From Stanford News Service <stanford.report@forsythe.stanford.edu>
9/26/00
CONTACT: Mark Shwartz, News Service (650) 723-9296;
e-mail mshwartz@stanford.edu
COMMENT: Paul Segall, Department of Geophysics (650)
725-7241;
e-mail segall@pangea.stanford.edu
Shelley Kenner, Caltech (626) 395-3861;
e-mail kenner@gps.caltech.edu
EDITORS: Kenner and Segall`s report, "A mechanical
model for intraplate
earthquakes: application to the New Madrid seismic zone,"
appears in the
Sep. 29 issue of Science magazine.
EMBARGOED FOR RELEASE until 2 p.m. U.S. Eastern Time on Thurs.,
Sept.
28, 2000
Relevant Web URLs:
http://www.ceri.memphis.edu/usgs/
New Madrid earthquakes still threaten the central United States,
scientists conclude
The threat of large earthquakes striking the New Madrid seismic
zone
remains all too real for people in St. Louis, Memphis and other
parts of
the central United States - despite recent reports to the
contrary.
That is the conclusion of a new study by geophysicists Shelley J.
Kenner
and Paul Segall published in the journal Science.
According to the authors, devastating earthquakes could rip
through the
New Madrid seismic zone along the Mississippi River sometime this
century - potentially causing widespread destruction from
Arkansas to
Iowa.
"We can`t say for certain there aren`t going to be any
earthquakes in
the next few decades," says Kenner, a postdoc in geophysics
at Caltech
and lead author of the Sept. 29 Science study.
"There was a sequence of large earthquakes in the past, and
it could
happen again," adds Segall, a professor of geophysics at
Stanford.
Winter of 1811
According to the U.S. Geological Survey (USGS), the central
Mississippi
Valley is the most earthquake-prone region of the United States
east of
the Rocky Mountains. Most quakes in the area are relatively small
and
occur within the 100-mile-long New Madrid seismic zone that
extends
along the Mississippi from Missouri to Arkansas.
During the winter of 1811 to 1812, the sparsely populated New
Madrid,
Mo., area was jolted by a series of three powerful earthquakes
now
estimated to have been of magnitude 7.5 to 8.3. The quakes caused
church
bells to ring a thousand miles away in Boston and even changed
the
course of the Mississippi River.
Paleoseismic evidence collected in recent decades indicates that
strong
"earthquake triplets" similar in magnitude to the
1811-12 temblors have
occurred approximately every 500 years along the New Madrid fault
and
are likely to happen again.
Earthquake controversy
Some geologists say there is a 90 percent chance that earthquakes
of
magnitude 6 to 7 will strike the region in the next 50 years,
causing
extensive damage and injury - especially in now heavily populated
urban
areas such as St. Louis and Memphis, which are built along the
Mississippi on unstable mud banks.
But in April 1999, Science magazine published a controversial
study,
which concluded that "the hazard posed by great earthquakes
in the New
Madrid seismic zone appears to be overestimated."
The authors of the 1999 study, led by geologist Seth Stein of
Northwestern University, wrote that a large earthquake would not
strike
the region for at least 1,000 years.
"It is also possible that 1811-12-style earthquakes may
never recur,"
according to the Stein research team.
The authors used Global Positioning System (GPS) satellite
measurements
to track ground movement in the New Madrid region between 1991
and 1997,
but observed "little, if any motion" within the fault
zone.
According to Stein and his co-authors, this lack of movement
suggests
that it would take at least 1,000 years to accumulate enough
stress
along the fault to generate a magnitude 7 earthquake - and at
least
2,500 years for a magnitude 8 temblor to occur.
But Kenner and Segall disagree with the conclusions reached by
Stein and
his colleagues.
"We`re not disputing their GPS data," says Segall.
"We`re saying that,
if you use good data in an inappropriate model, your conclusions
will be
inappropriate."
Segall points out that the 1999 Stein study used
earthquake-prediction
models for California`s San Andreas fault and applied them to the
New
Madrid seismic zone - a completely different type of fault
system.
The San Andreas is a "transform fault" that marks the
boundary between
two tectonic plates - the North American and the Pacific. These
two
massive land formations constantly grind past one another. As the
Pacific plate moves northward, stress and strain accumulate along
the
fault, triggering large and small earthquakes. The relatively
rapid
movement of the Pacific plate is easily observed by GPS and
ground-based
detectors.
But the New Madrid is an "intraplate fault" located in
the middle of the
North American plate, not at the boundary. And while large
segments of
the San Andreas are clearly visible, the New Madrid fault lies
hidden
under deep layers of sediment.
"Intraplate zones are something of a mystery," notes
Segall. "We can`t
even map the fault, so we don`t really know how big it is."
"As scientists, we don`t understand what`s happening in the
intraplate
setting all that well," adds Kenner. "What we tried to
do in our current
Science study is to come up with a model that`s a better
approximation
of the New Madrid seismic zone."
The Kenner-Segall model suggests that there is a preexisting weak
zone
beneath the New Madrid fault where stress accumulates over time.
"You may not be able to see very much stress
accumulation," observes
Segall, "but it`s there."
After many years, the stress shifts from the weak zone toward the
surface, where it builds up and eventually causes the fault to
rupture,
triggering a large earthquake as the ground slips some 15 to 30
feet.
How often do these major quakes occur? Every 250 to 4,000 years,
say
Kenner and Segall, which means that another sequence of large
temblors
could strike by the middle of the century - perhaps sooner.
"The New Madrid fault is like a crack in the wall,"
comments Segall.
"You try to cover it with plaster, but the crack reappears
over and over
again. It`s always going to be there, because it`s a preexisting
weakness.
"I can`t emphasize enough that there is a huge uncertainty
when it comes
to intraplate events," he adds. "For example, we don`t
know why the
earthquakes come in triplets, but it has happened on a regular
basis in
the past."
Earlier this month, the Federal Emergency Management Agency
(FEMA)
released a study listing the U.S. metropolitan areas at greatest
economic risk from earthquakes. St. Louis ranked 16th.
"If you live in the New Madrid area, you may still have an
earthquake
problem," says Segall. "The most prudent thing for
people to do is to
prepare."
-By Mark Shwartz-New Madrid
============
(5) TROUBLE ALERT: BRITISH FIRM OFFERS DISASTER-MONITORING
SATELLITE
From SPACE.com 28 September 2000
http://www.space.com/cgi-bin/email/gate.cgi?lk=T5&date=000928&go=/businesstechnology/business/disaster_sat_000927.html
Trouble Alert: Satellite Fleet to Monitor Disasters
By Anatoly Zak
Staff Writer
posted: 07:00 am ET
28 September 2000
An English satellite developer plans to launch a constellation of
five
satellites in early 2002 devoted to monitoring natural and
human-made
disasters from orbit.
Surrey Small Satellite Technology (SSTL) hopes to use the new
network to
facilitate management and relief efforts in crisis situations
ranging
from civil strife and industrial accidents to droughts,
earthquakes,
fires and landslides. Unlike multipurpose Earth-observing
satellites
that have monitored mishaps in the past, SSTL's satellite fleet
will be
solely dedicated to disaster observation.
FULL STORY at
http://www.space.com/cgi-bin/email/gate.cgi?lk=T5&date=000928&go=/businesstechnology/business/disaster_sat_000927.html
============
(6) TEMPORAL VARIATION OF THE ZODIACAL DUST CLOUD:
BILL NAPIER ON COMETARY DUST LOADING &
CLIMATE CHANGE
Bill Napier, Armagh Observatory, <wmn@star.arm.ac.uk>
Abstract:
A Markov chain model has been constructed to investigate
fluctuations
in the mass of the zodiacal cloud. The cloud is specified
by a
three-dimensional grid, each element of which contains the
numbers of
dust particles as a function of semi-major axis, eccentricity and
mass. The evolutionary pathways of dust particles due to
radiation
pressure are described by fixed transition probabilities
connecting
the grid elements. Other elements are absorbing states
representing
infall to the Sun or ejection to infinity: particles entering
these
states are removed from the system. Particles are injected
through the
breakup of comets entering short-period, high-eccentricity orbits
at
random times, and are subject to the Poynting-Robertson effect
and
removal through collisional disintegration and radiation
pressure. The
main conclusions are that the cometary component of the zodiacal
cloud
is highly variable, and that in the wake of giant comet entry
into a
short-period, near-Earth orbit, the dust influx to the Earth's
atmosphere may acquire a climatically significant optical depth.
Accepted for publication in the Monthly Notices of the Royal
Astronomical Society
============
(7) OVERESTIMATING THE IMPACT RATE:
DAVID HUGHES QUESTIONS THE SPACEGUARD SURVEY
A New Approach to the calculation of the cratering rate of Earth
over
the last 125 + or - 25 million years.
From: Monthly Notices of the Royal Astronomical Society, Vol 317,
429-437
(2000)
By David W. Hughes, Sheffield University
The recent cratering record of the surface of Earth is
re-examined using
a new technique that concentrates on estimating the mean areas
occupied
by individual craters, together with the gradients of linear
plots of
crater numbers verses crater ages. This analysis indicates
that the
lower limit of the rate at which craters have been produced over
the
last 125 +- 25 million years is, for example
(12.0 +- 0.7) x 10-15 km-2 yr-1 for D > 2.4 km craters
(9.5 +- 0.6) x 10-15 km-2 yr-1 for D > 5.0 km craters
(6.5 +- 0.5) x 10-15 km-2 yr-1 for D > 12 km craters, and
(3.0 +- 0.3) x 10-15 km-2 yr-1 for D > 22 km craters.
These figures indicate that previous researchers have
considerably
overestimated the rate at which small (2.4 < D < 20 ) km
craters are
being produced. It is also found that the relationship
between crater
production rate and crater diameter is not a simple power law in
the 2.4
< D < 40 km diameter range. On the most stable
regions of the Earth's
continents, and over the last 125 +- 25 Myr it seems that the
rate at
which craters are eroded below the detection limit does not
depend on
crater diameter throughout the above size range.
=============
(8) GRAVITY ANOMALIES IN THE CHICXULUB IMPACT CRATER
G.L. Kinsland, M. Hurtado & K.O. Pope: Detection of
groundwater conduits
in limestones with gravity surveys: Data from the area of the
Chicxulub
Impact Crater, Yucatan Peninsula, Mexico
GEOPHYSICAL RESEARCH LETTERS 27: (8) 1223-1226 APR 15 2000
Small negative gravity anomalies are found in gravity data from
along
the northwestern shoreline of the Yucatan Peninsula These
anomalies are
shown to be due to elongate, shallow anomalous porosity zones
in-the
Tertiary carbonates. These zones are caused primarily by
groundwater
solution and are presently active conduits for groundwater flow.
The
association of these small gravity anomalies with known
topographic and
structural features of the area, which partially overlies the
Chicxulub
Impact crater, indicates their development was influenced by
structures,
faults and/or fractures, within the Tertiary and pre-Tertiary
carbonates.
Addresses:
Kinsland GL, Univ Louisiana, Dept Geol, Lafayette, LA 70501 USA.
Univ Louisiana, Dept Geol, Lafayette, LA 70501 USA.
Inst Mexicano Petr, Mexico City 07730, DF, Mexico.
Geo Eco Arc Res, Washington, DC 20001 USA.
Copyright © 2000 Institute for Scientific Information
================
(9) PHYSICAL PROPERTIES OF THE NUCLEUS OF COMET 2P/ENCKE
Y.R. Fernandez, C.M. Lisse, H.U. Kaufl, S.B. Peschke, H.A.
Weaver, M.F.
A'Hearn, P.P. Lamy, T.A. Livengood, T. Kostiuk: Physical
properties of
the nucleus of Comet 2P/Encke
ICARUS 147: (1) 145-160 SEP 2000
We report a new study of the nucleus of Comet 2P/Encke, which the
CONTOUR spacecraft is scheduled to encounter in November 2003.
During
the comet's close approach to Earth in July 1997, we measured the
mid-infrared thermal and optical scattered continua with data
from the
TIMMI instrument (imaging) at the ESO 3.6-m telescope (wavelength
lambda
from 8 to 12 mu m), the ISOPHOT instrument (photometry) aboard
ISO (3.6
mu m less than or equal to lambda less than or equal to 100 mu
m), and
the STIS instrument (imaging) aboard HST (5500 Angstrom less than
or
equal to lambda less than or equal to 11000 Angstrom). The
optical
images show the nucleus with very little coma contamination, and
the ISO
photometry allowed us to separate the comatic and nuclear
contributions
to the ESO images. We used the Standard Thermal Model for slow
rotators
to calculate an effective nuclear radius of 2.4 km +/- 0.3 km.
The
comet's mid-IR light curve implies a nuclear rotation period of
15.2 h
+/- 0.3 h, although some subharmonics of this also satisfy the
data. If
we assume that the nucleus is a triaxial ellipsoid in principal
short
axis rotation with the axis direction in 1985 as derived by
Sekanina
(1988, Astron. J. 95, 911), then by combining our data with light
curves
from the 1980s we find that the nucleus' angular momentum vector
migrates, making a would-be circle in less than 81 years, and
that one
axial ratio is at least 2.6. The nucleus' optical linear phase
coefficient is 0.06 mag/degree, making it one of the most
phase-darkened
objects known. The surface is also rougher than that of most
asteroids,
The visual geometric albedo is 0.05 +/- 0.02, within the range
found for
other cometary nuclei. (C) 2000 Academic Press.
Addresses:
Fernandez YR, Univ Maryland, Dept Astron, College Pk, MD 20742
USA.
Univ Maryland, Dept Astron, College Pk, MD 20742 USA.
Univ Hawaii Manoa, Astron Inst, Honolulu, HI 96822 USA.
Space Telescope Sci Inst, Baltimore, MD 21218 USA.
European So Observ, D-85748 Garching, Germany.
European Space Agcy, Satellite Tracking Stn, E-28080 Madrid,
Spain.
Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218
USA.
CNRS, Astron Spatiale Lab, F-13376 Marseille 12, France.
NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.
Copyright © 2000 Institute for Scientific Information
=================
(10) THE JAPANESE SPACEGUARD ASSOCIATION & THE NEO PROBLEM
S. Isobe: The position of the Japanese Spaceguard Association
with
regard to NEO problems
PLANETARY AND SPACE SCIENCE 48: (9) 793-795 AUG 2000
The Japanese Spaceguard Association, set up in October 1996, has
been
proposing a scenario to solve NEO problems. In addition to
activities
such as public lectures and publication of a newsletter, we are
trying
to get support from the government and private organizations to
build
ground-based, space-based and lunar-based telescopes. The
construction
of two ground-based telescopes began in January 1999, and will be
operational in 2000.
Proposals for lunar-based and space-based NEO missions are under
discussion within NASDA, Japan. In this paper, we show the basis
for the
ideas at each stage although there is still continuing discussion
within
the JSGA. (C) 2000 Elsevier Science Ltd. All rights reserved.
Addresses:
Isobe S, Natl Astron Observ, 2-21-1 Osawa, Mitaka, Tokyo 181,
Japan.
Japan Spaceguard Assoc, Tokyo, Japan.
Copyright © 2000 Institute for Scientific Information
===============
(11) DETERMINING MATERIAL STRENGTH & BULK PROPERTIES OF NEOS
W.F. Huebner & J.M. Greenberg JM: Needs for determining
material
strengths and bulk properties of NEOs. PLANETARY AND SPACE
SCIENCE 48:
(9) 797-799 AUG 2000
Near-Earth Objects (NEOs) are now being discovered and followed
up at a
higher rate than ever before. However, physical characterization
of
these objects is restricted to their surface properties. For the
purpose
of mitigation (i.e., to nudge a potentially hazardous object out
of its
orbit), it is necessary to determine the bulk properties of NEOs,
such
as material strengths, composition, structure, and moments of
inertia.
We discuss some of the needs and suggest several experiments to
fulfill
these requirements. We also urge that NASA, ESA, and other space
agencies establish Support Offices for Microgravity Research for
Small
Solar System Bodies. (C) 2000 Elsevier Science Ltd. All rights
reserved.
Addresses:
Huebner WF, SW Res Inst, Instrumentat & Space Res Div, PO
Drawer 28510,
San Antonio, TX 78228
SW Res Inst, Instrumentat & Space Res Div, San Antonio, TX
78228 USA.
Leiden Univ, Huygens Lab, Raymond & Beverly Sackler Lab
Astrophys,
NL-2333 CA Leiden, Netherlands.
Copyright © 2000 Institute for Scientific Information
============================
* LETTERS TO THE MODERATOR *
============================
(12) CORRECTION TO "MICKEY MOUSE SCIENCE: HOW WALT DISNEY'S
ACCOUNT OF
THE XF11 AFFAIR IS FOSTERING AN URBAN
MYTH" from CCNet 97/2000 - 28
September 2000
From Alan W. Harris <awharris@lithos.jpl.nasa.gov>
In yesterday's CCNet, Benny Peiser wrote:
>So what's wrong with exposing this kind of "scientific
blunder" on a
>mailing list for NEO observers? For a start, Discover.com, as
Victor
>Noto has correctly pointed out, is a small Disney Company
entertainment
>website and not, as Harris seemed to believe, identical to
the science
>journal Discovery.com.
Alan Harris replies:
It turns out you and Victor Noto seem to have gotten it wrong.
Discover.com, where the article in question appears, is in fact
the web
site of the magazine DISCOVER, perhaps the widest selling popular
science magazine in the U.S. and generally regarded as reasonably
respectable. You yourself describe Discovery [sic] as a
"scientific
journal." Discovery.com is the web site of the Discovery
television
channel and is unrelated to Discover magazine.
You then followed with this gratuitous remark:
>After all, if you want to expose a scientific blunder and
>wish to take the mickey out of scientists, you'd better get
your facts
>right.
I can't agree more.
Alan Harris
MODERATOR'S NOTE: I apologise for my oversight. I'm glad I've got
the
*main* issues of my corrections right.
================
(13) ANOTHER HUGE IMPACT DISASTER ~20,000 YEARS BP?
From Giesinger Norbert <norbert.giesinger@siemens.at]
Dear Dr. Peiser,
a) in connection with the recent listings of possible
recent impacts, I
found that a rather recent (20 000 yers?) possible impact
structure,
Iturralde Structure/Araona Crater in Northern Bolivia
is described in
http://svs.gsfc.nasa.gov/imagewall/LandSat/araona_crater.html
"The Araona Crater (also known as the Iturralde Structure)
is a
suspected crater from an impactor which struck northern Bolivia
approximately 20,000 years ago. The feature is believed to have
been
caused by a short period comet striking at 70 kilometres per
second and
splattering into the muddy alluvial flood plain in the Lower
Amazon
jungle. The impact created a circular depression which is now
roughly 8
kilometres across and 3 metres deep. The structure was discovered
in
1988 LandSat data, but was not visited successfully until 1998
because
the region is inaccessible. Future expeditions hope to finally
settle if
the feature truly is the impact crater it appears to be, and if
so,
determine the nature of the impactor."
b) Years ago, I read in Verschuur's book of a Tunguska-type
area in New
Zealand with a possible connection of the lunar event (Giordano
Bruno?)
in 1078 A.D. Was it studied in between in greater detail and
where may I
find a good description?
Sincerely Yours
Norbert Giesinger
Vienna
norbert.giesinger@siemens.at
==================
(14) FULLERENES: SEARCHING FOR
SMOKING GUNS & IMPACT SIGNALS
From Bob Kobres <bkobres@uga.edu>
On the subject of what to look for to discern past impact events
that
may have left no conspicuous dents.
If I had some monies to apply to this I'd be hunting for
Bucky-Balls in
Siberia! As far as I've been able to learn no one has
probed this
possibility.
Mildly carbonated.
bobk
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
From:
http://www.sciencenews.org/20000325/fob1.asp
[. . .]
Fullerenes are hollow, spherical molecules made of pure carbon
(SN:
6/27/98, p. 406). The most famous member of the family is
buckminsterfullerene, consisting of 60 carbon atoms arranged in
the
pattern of a soccer ball. On Earth, fullerenes can be made in the
lab
and have been found in rocks seared by lightning strikes.
Luann Becker of the University of Hawaii in Honolulu and her
group
isolated fullerenes from the Allende and Murchison meteorites.
Both are
carbonaceous chondrites, a rare meteorite type that contains much
organic material. The researchers found, trapped inside the
fullerenes,
noble gases whose isotopic profile did not match those of gases
on
Earth.
The researchers also isolated fullerenes from a clay sediment
layer
deposited during an asteroid impact 65 million years ago. Some
scientists believe that this collision, marking the so-called
Cretaceous-Tertiary (KT) boundary, led to the demise of the
dinosaurs
(SN: 3/1/97, p. S20). The sediment fullerenes also contain noble
gases
with unusual isotope ratios.
[. . .]
From:
http://exosci.com/news/171.html
A University of Hawaii researcher and her colleagues from NASA's
Space
Science Division have confirmed that a new form of carbon
previously
made in the laboratory also exists in nature. The finding
indicates that
the pure carbon molecules known as fullerenes could have been a
factor
in the early history of Earth and might even have played a role
in the
origin of life. The scientists' report will appear in the July 15
issue
of the British journal Nature. Becker also will share their
findings
with fellow scientists during the triennial meeting of the
International
Society on the Origins of Life July 11-15 in San Diego, Calif.
"It's not every day that you discover a new carbon molecule
in nature;
that's what makes this interesting," Becker says. "If
it played a role
in how the earth evolved, that would be important."
Fullerenes are soccer-ball shaped molecules (hence their name,
which
honors geodesic-dome designer Buckminster Fuller) of 60 or more
carbon
atoms. Their discovery in 1985 as only the third form of pure
carbon
(along with diamonds and graphite) earned U.S. scientists Robert
F. Curl
Jr. and Richard E. Smalley and British researcher Harold Kroto
the 1996
Nobel Prize in Chemistry.
The trio accidentally synthesized these three-dimensional forms
of
carbon molecules in the laboratory while trying to simulate the
high-temperature, high-pressure conditions in which stars form.
Scientists hypothesized that fullerenes also exist naturally in
the
universe. Becker, who earlier discovered the presence of
fullerenes in
deposits at the site of the Sudbury impact crater in Ontario,
Canada,
and her colleagues were able to document naturally occurring
fullerenes
by exploiting a unique property characteristic of organic
molecules.
Unlike their pure-carbon cousins, which maintain a solid state,
fullerenes can be extracted in an organic solvent.
Becker crushed a piece of the Allende meteorite, demineralized
the
sample with acids, and used the organic solvent to extract
fullerenes
from the residue. The scientists found not only the C60 and C70
molecules believed to be most prevalent, but also significant
quantities
of C100 to C400 molecules. This is the first discovery of higher
fullerenes in a natural sample.
Because the multiple atoms in the molecule form a hollow, closed
cage
that can trap gasses inside, they may have delivered from their
stellar
birthplace both the carbon that is an essential element to life
and the
volatiles that contributed to the planetary atmospheres needed
for the
origin of life. At the very least, the molecules and their
contents will
tell scientists more about the early solar nebula or presolar
dust
existing when meteorites like Allende were formed.
The research is supported by a grant from the NASA Cosmochemistry
Program.
From:
http://vh50010.vh5.infi.net/menu/stories/43928.htm
[. . .]
Closer examination of a giant meteor impact crater near Sudbury,
Ontario, has confirmed the possibility that some of Earth's
chemistry,
including the organic molecules that give us life, could have
been
imported from space.
In a paper published in Science magazine last week, scientists
said they
found ancient helium atoms trapped inside soccer ball-like
Carbon-60
molecules scattered around the 700-square-mile blast site.
That helium turns out to be 5-billion years old and not of this
Earth.
Carbon-60, commonly known as the buckyball, was only recently
discovered
in the lab, but the researchers found it had been lying around
the
Sudbury crater for the 2-billion years since the collision.
Because of
its hollow, ball-like shape, Carbon-60 can harbor another element
inside
it, in this case helium.
The ratio of rare helium-3 to helium-4 in the Sudbury samples
points
directly to outer space, said Robert Poreda, an associate
professor of
earth sciences at the University of Rochester who made the
measurements.
"The ratio of the helium inside the buckyballs is what we
typically find
in meteorites," Poreda said. "It's much higher than the
ratio found
anywhere on Earth, now or throughout Earth's history."
[. . .]
From:
http://www.nanocentral.com/nanosci/materials/carbonchem/Aldersey_TRC60.html
[. . .]
It was five years before help came. In the meantime, Smalley's
group
trapped atoms inside successively smaller fullerenes. By showing
that
there was a point at which the fullerene burst open and released
the
trapped molecule they provided strong circumstantial evidence to
support
hollow sphere structure. Theoretical chemists made good use of
these
five years to do calculations that also confirmed the stability
of this
structure. Then in 1990, Wolfgang Krätschmer and Konstantinos
Fostiropoulos at the Max Planck Institute for Nuclear Physics in
Heidelberg, Germany, and Donald Huffman and Lowell Lamb at the
University of Arizona in Tucson succeeded in making
buckminsterfullerene
in visible quantities for the first time, not in an elaborate
cat's
cradle of lasers and cluster beams, but in a simple vacuum
chamber with
an electric arc between two carbon rods. By another unusual
interdisciplinary twist of this tale, these people were
physicists who,
while investigating the light-scattering properties of carbon
smoke,
found themselves making in a test-tube the molecule that every
chemist
wanted.
Where the graphite rods came into contact, an electric current of
around
100 amps created a carbon vapor. Upon condensation on special
surfaces
or even on the walls of the vacuum chamber Krätschmer and
Huffman found
that under certain conditions the soot contained a small
percentage of
carbon-60. This could be purified by careful vaporization and
recondensation or by dissolving the soot in a solvent and
extracting the
desired constituent. The beauty of the process was anybody could
do it.
[. . .]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Soot--it might be worth probing this stuff too:
From: Natural Catastrophes During Bronze Age Civilisations
(BAR
International Series 728 1998), The Soil Record of an Exceptional
Event
at 4000 B.P. in the Middle East, by Marie-Agnes Courty.
[page102]
A common component of the dust layer for all the sites reported
here
consists of unusual angular, black, vesicular grains that are
made
predominantly of carbon (~50%) although they do not
morphologically
resemble either carbonised plant residues or fossil combustibles
(Fig.
7d). They are finely fissured, dense and often contain
phosphate
inclusions. Their large vesicles are often filled by a Mg-Ca rich
alumino-silicate glass similar to the type 1 glass described
above [.a
Ca-Mg rich alumino-silicate glass with variable proportions of Fe
and
the presence of uncommon inclusions such as pure nickel grains
(Fig.
6j), zinc of copper, that can be geochemically defined as a
pyroxene
glass.] and a fine vesicular pure silica glass.
[page107]
Therefore, unambiguous evidence , such as shocked quartz, the
presence
of tektites, an iridium anomaly, or the occurrence of silicon
carbide
and diamond are generally preferred to recognise impact-induced
ejecta
layers. None of these fingerprints has so far been
retrieved from the 4
kyr. B.P. dust layer. However, the occurrence of multi-site
ignition
together with black carbon production resulting from extensive
biomass
burning, also reported to be caused by asteroid impacts, provides
indirect evidence to support an extra-terrestrial
hypothesis. Various
puzzling particles of the dust assemblage still require to be
further
elucidated, i.e. the carbon-rich black vesicular grains and the
metal
grains possibly linked to impact-induced lightning, and also the
nature
of the phenomenon responsible for the propagation of a surface
shock
wave and local explosion.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
More info:
http://neon.mems.cmu.edu/bucky/other-refs.html
http://gaus90.chem.yale.edu/window.html
http://xbeams.chem.yale.edu/~cross/fullerene.html
http://buntzen.sfu.ca/vpresearch/rm/percival.html
Bob Kobres
bkobres@uga.edu
http://abob.libs.uga.edu/bobk
706-542-0583
Main Library
University of Georgia
Athens, GA 30602
=============
(15) VOLCANIC CRATERS ON THE MOON: HOW SCIENTIFIC AMERICAN GOT IT
WRONG
From Michael Paine <mpaine@tpgi.com.au>
Dear Benny,
Shortly after reading the CCNet postings about the history of
impact
crater theories I received my October (2000) Scientific American
and
found the following.
regards
Michael Paine
SCIENTIFIC AMERICAN OCTOBER 1850
http://www.sciam.com/2000/1000issue/100050100.html
MOONSCAPE-"The most remarkable feature of the lunar surface
is the great
number of rings, or craters, which almost entirely cover it,
overlaying,
intersecting and apparently elbowing each other out of the way.
It is
now pretty well demonstrated that these rings were the result of
intense
volcanic action at some remote period. In six-eighths of the
lunar
volcanic mountains, there was a cone in the center of the ring.
The same
thing is observed on extinct volcanic mountains on the earth, the
cone
in the center being the fruit of the last efforts of the expiring
volcano. The moon has a proportionately larger surface area in
relation
to its mass than does the earth, and this fact was sufficient to
explain the greater number of volcanic discharges that cover the
surface
of the moon."
c2000 Scientific American
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