PLEASE NOTE:
*
CCNet, 22 December 1999
------------------------
QUOTE OF THE DAY
"In the debate about CO2 and
climate change,
evidence from the past may be useful to
understand what is going on in the
present time
... Based on the analysis of stomatal
frequency
in birch leaves we found that the sharp
rise in
temperature at the Younger Dryas/Early
Holocene
transition (ca 11250 years ago) came
together
with a sharp rise in atmospheric CO2.
Actually it
seems that the temperature rise was
somewhat
earlier than the CO2-rise. We certainly
need more
data, but our evidence may indicate that
the
CO2-rise was the RESULT of the
increasing
temperature with the ocean as a CO2
source"
-- Bas van Geel,
University of Amsterdam
(1) GEMINID ACTIVITY 1999
Juergen Rendtel <jrendtel@aip.de>
(2) BOLIDE OVER SWEDEN
Lars Franzen < lars.gvc1@gig.gu.se >
(3) MELTING METEORITES: DIFFICULT EXPERIMENTS ON WEIRD ROCKS
PSR DISCOVERIES, December 1999
(4) DEFLECTION OF GALACTIC DUST BY SOLAR RADIATION
Andrew Yee <ayee@nova.astro.utoronto.ca>
(5) CO2 AND CLIMATE CHANGE
Bas van Geel <vangeel@bio.uva.nl>
(6) GREENHOUSE AND GLOBAL WARMING: THE FACTS AND THE
POLITICS
Andrew Glikson <geospectral@spirit.com.au>
(7) THINK TANKS & GLOBAL WARMING
Michael Paine <mpaine@tpgi.com.au>
(8) GLOBAL WARMING, DOOMSDAY PREDICTIONS & THE CCNET
Benny J Peiser <B.J.Peiser@livjm.ac.uk>
(9) ICE AGES & THE HIMALAYAS
Larry Klaes <lklaes@bbn.com>
(10) THE IMPRINT OF THE K/T IMPACT IN CLAY MINERALS
P. Debrabant et al., UNIV SCI & TECH
LILLE
(11) PALEOENVIRONMENTAL CHANGES ACROSS THE K/T BOUNDARY
A. Pardo et al., PRINCETON UNIVERSITY
(12) LARGE SCATTERED PLANETESIMALS
J.M. Petit et al., NICE OBSERVATORY
(13) LIGHTCURVE & ALBEDO OF ASTEROID 433 EROS
M.D. Hicks et al., CALTECH,JET PROP LAB
(14) "CRATERS" SCREEN SAVER
Juan Zapata-Arauco <juanwisdomquest@yahoo.com>
(15) AND FINALLY: SCIENTISTS SEEN AS 'GEEKS' BY PUPILS
BBC Online News, 21 December 1999
==============
(1) GEMINID ACTIVITY 1999
From Juergen Rendtel <jrendtel@aip.de>
I M O S h o w e r C i r c u l a r
GEMINID Activity 1999
Only 4 weeks after the fascinating Leonid meteor storm many
observers
worldwide used the opportunity to record the maximum of the
Geminids.
This shower is known for high rates lasting for several hours.
Below
is a first overview of ZHRs calculated from reports received by
the
IMO's Visual Commission until December 17, 1999. The rates are
based
on reports of the following observers:
Jure Atanackov,
Slovenia
Mike Linnolt, USA
Juan A. Aveledo,
Cuba
Vladimir Lukic, USA
Neil Bone,
UK
Robert Lunsford, USA
Amol N. Chitale,
India
Francisco Munhoz, Cuba
Ian W. Cooper, New
Zealand Sven
Nather, Germany
Tim Cooper, South
Africa
Prakash Nitsure, India
Asdai Diaz Rodriguez,
Cuba Alexei Pace,
Malta
Frank Enzlein,
Germany
Arvind Paranjpye, India
Yuwei Fan, P.R.
China
Trevor Pendleton, UK
Sandy Ferguson,
Canada
Tushar Purohit, India
Mildred Formosa,
Malta
Rui Qi, P.R. China
Kai Gaarder,
Norway
Jurgen Rendtel, Germany
Martin Galea,
Malta
Mileny Roche Lamas, Cuba
Petros Georgopoulos,
Greece Francisco A.
Rodriguez, Spain
George Gliba,
USA
Wade A.. Selvig, Canada
Roberto Gorelli,
Italy
Miguel A. Serra, Spain
Michal Haltruf, Czech
Rep. Umberto Mule
Stagno, Malta
Sun Hao, P.R.
China
Mike Stephens, Canada
Takema Hashimoto,
Japan
Chensheng Sun, P.R. China
Roberto Haver,
Italy
Tony Tanti, Malta
Kamil Hornoch, Czech
Rep.
Gabriela Triglav, Slovenia
Richard Huziak,
Canada
Mihaela Triglav, Slovenia
Rahul Jani,
India
Di Wang, P.R. China
He Jingyang, P.R.
China
Xiandong Yin, P.R. China
Albert Kong,
UK
Kim Youmans, USA
Wen Kou, P.R.
China
Ilkka Yrjola, Finland
Andrew Krochko,
Canada
Joseph Zammit, Malta
Robert Leyland, USA
Adrian Leylen, Cuba
Dong Li, P.R. China
All ZHRs were calculated with a constant population index of
r=2.6
and a zenith coefficient of gamma=1.0. We find the known activity
"plateau" between December 14, 01h UT until about 18h
UT with ZHRs
of the order of 100 or above. The highest ZHRs occurred between
13 and 18h UT (at 262.20 deg solar longitude).
Previous analyses of magnitude data yielded a value of r<2.6
(approximately 2.2) especially towards the end of the mentioned
plateau. Hence some of the ZHRs, derived from observations under
poor skies will be overestimated in this preliminary summary.
This also contributes to the large scatter of the averages. The
list
gives averages of all available intervals and the standard
deviation.
Time and solar longitude refer to the middle of the averaged
intervals, #Int is the number of intervals averaged.
Date Time
Sol # ZHR +-
1999 UT (2000.0) Int
Dec 13 00.0h 260.542 2
27 5
02.0 .608
4 45 10
04.5 .714
7 37 8
11.5
261.011 2 39 12
14.5 .138
3 48 11
17.5 .265
5 65 16
21.0 .434
10 78 25
23.0 .520
17 72 20
Dec 14 00.5 .562
11 86 27
01.5 .604 11
106 23
02.5 .646
8 95 22
03.5 .689
8 95 24
04.5 .731
8 90 25
05.5 .774
10 90 24
06.5 .816 10
110 30
07.5 .859 9
105 40
08.5 .901 7
100 30
09.5 .943 8
105 35
10.5 .985
6 95 15
12.0
262.049 4 98 6
14.0 .134 8
135 20
16.0 .219 15
133 30
18.0 .304 24
120 40
20.5 .409 19
100 25
23.0 .515
5 69 34
Dec 15 01.0 .600
5 60 9
03.0 .685
3 60 15
05.0 .769
2 44 5
07.0 .854
2 24 7
We thank all observers who submitted their data promptly. A
detailed
analysis will be prepared for a future issue of the IMO Journal
WGN.
Of course, we are grateful for all further reports.
Juergen Rendtel
IMO President
December 19, 1999
================
(2) BOLIDE OVER SWEDEN
From Lars Franzen < lars.gvc1@gig.gu.se
>
Dear Benny,
Today's local newspapers (21 Dec.) report on a bolide passage
over
western Sweden yesterday evening. Weather was all clear and it
was
visible over a large area. It had a north-southerly course. In
Swden
it was first reported appr. 100 km north of Gothenburg. Later at
20.13 (UTC+1) over Gothenburg or somewhat west, 20.15 over
Hallands
Väderö (a small island 200 km S Gothenburg. Even later over
Kastrup
airport in Denmark. Air traffic controller Lars-Ake Hedin at
Landvetter Airport Gotheburg reports: "At 20.13 we saw a
bright
shining object, like the back-flames of a fighter aircraft. It
moved
parallel to the horison at high speed. We saw it for 10 seconds.
Other air traffic control reports made us evaluate the speed at
3000-4000 km/h."
In spite me being on my way home just this time I didn't see it
myself, unfortunately.
Yesterday I got the first reports from my ICP-MS analyses of peat
ash
from Sweden. There are two very marked positive anomalies in
composition including, Ir, Os, I, Zn, W and many other elements
coiciding exactly wity my spherule layers at 2.5 m and 3.75 m.
These
layers have been dated at (calibrated) 300 +- 200 B.C. and 1200
+-
200 BC. The new results from this ongoing investigation now lead
me
to conclude that we have had at least two major impact events in
prehistoric time. My material includes 2300 B.C. but there are no
chemical signs of an event then, possibly due to minerotrophical
conditions in the bog att that time, the surrounding input of
elements in such an environment biasing the atmospheric fallout.
I will continue with 5 other bog stratigraphies the same way, the
method allows me to detect concentrations down to c. 10 ppt with
present preparation techniques.
Until next have a nice Chistmas and New Year celebration..
Lars Franzén
================
(3) MELTING METEORITES: DIFFICULT EXPERIMENTS ON WEIRD ROCKS
From PSR DISCOVERIES, December 1999
http://www.soest.hawaii.edu/PSRdiscoveries/Dec99/indarch.html
Difficult Experiments on Weird Rocks
Written by G. Jeffrey Taylor
Hawai'i Institute of Geophysics and Planetology
Enstatite meteorites are a diverse group of strange rocks.
They contain little or no oxidized iron, a rare occurrence
in the Solar System. Nevertheless, melting experiments on
these oxygen-depleted meteorites give clues about magma
compositions and core formation in asteroids. Tim McCoy
(Smithsonian Institution), Tamara Dickinson (Catholic
University), and Gary Lofgren (Johnson Space Center) heated
an enstatite chondrite (called Indarch) to a range of
temperatures above the temperature of initial melting. They
found that the sulfide minerals in the rock melted at 1000o
C. This disproved a hypothesis that the calcium sulfide in
the rock formed at a very high temperature in the gas-dust
cloud from which the planets formed and survived melting in
igneous enstatite meteorites. The experiments also indicate
that the metallic iron and sulfide minerals begin to form
connected networks when only about 20% of the rocky
material is melted. This suggests that core formation in
the asteroid could have taken place at such low amounts of
melting, rather than requiring much higher amounts of
melting as some scientists have argued. The experiments
also show that igneous enstatite meteorites could have
formed from unmelted enstatite chondrites.
FULL STORY AT
http://www.soest.hawaii.edu/PSRdiscoveries/Dec99/indarch.html
==============
(4) DEFLECTION OF GALACTIC DUST BY SOLAR RADIATION
From Andrew Yee <ayee@nova.astro.utoronto.ca>
Max Planck Institute for Nuclear Physics
Heidelberg, Germany
Contact:
Markus Landgraf
ESA/ESOC
Darmstadt/Germany
E-Mail: mlandgra@esoc.esa.de
Phone: +49-6151-90-3627
Fax: +49-6151-90-2625
14-12-99
"Ulysses" measures the deflection of galactic dust
particles by solar radiation
An international team of scientists from NASA, the
University of Florida at Gainesville, and the Max Planck
Institute for Nuclear Physics in Heidelberg, Germany,
observed the deflection of galactic dust grains by solar
radiation (Science 17 December 1999). Galactic dust grains
are very small, about four tenth of a micron in diameter.
Due to their small mass their motion towards the sun is
decelerated when the particle is hit by a solar photon.
The discovery of the phenomenon was made possible by
measurements of the ESA/NASA spacecraft "Ulysses".
"Ulysses" is on an orbit about the Sun since end-1990.
It
carries a highly sensitive dust detector that was built at
the Max Planck Institute. The ulysses dust detector can
detect dust particles as small as one tenth of a micron in
diameter. Prof. Eberhard Gruen, the head of the Heidelberg
dust group, leads the Ulysses dust measurements. Regarding
the measurement of galactic dust he remarks: "Galactic dust
particles do not belong to our solar system, they stream
into it from the outside. They are not very abundant, every
cubic kilometer contains about 10 of them. Fortunately,
they move quite fast through the solar system, roughly with
26 kilometer per second. Thanks to the high sensitivity of
the Ulysses instrument we detect about two galactic dust
particles every week."
Because of Ulysses's elliptic orbit, its distance from the
Sun varies between 1.3 astronomical units (AU, 1AU =
distance of the Earth from the Sun) to 5.4 AU. This allows
the scientists to investigate the properties of galactic
dust at different distances from the Sun. For each dust
particle, the dust detector measures the impact velocity
and the mass. In order to compare the Ulysses measurements
with astronomical observations of galactic dust, the
investigators determined the distribution of grain masses,
i.e. how many small and how many big dust particles hit the
detector. They were surprised to find that particles in a
certain mass range were missing in the data collected by
Ulysses close to the Sun, compared to the number of
particles in this mass range that were collected at larger
solar distances.
Dr. Markus Landgraf of the Johnson Space Center of NASA,
who graduated at the Max Planck Institute with Prof. Gruen,
explains the observed phenomenon: "In a certain mass range
cosmic dust grains absorb or reflect light very
effectively. This is the case when the grains's sizes are
compareable to the average wavelength of the radiation.
According to Newton's princple of action equals reaction,
every absorbed or reflected photon transfers momentum to
the dust grain. For the galactic grains that we find
missing at small distances from the Sun, this repelling
force, also called radiation pressure, is larger than solar
gravity. Therefore the grains move slower and slower as
they approach the Sun, until they stop and start moving
into the opposite direction. They may also be deflected to
the side, if they do not approach the Sun head-on." The
minimal distance that can be reached by a dust grain
depends on the grain's initial velocity and the strength of
radiation pressure that the grain experiences. From the
observation that grains were missing inside 4 AU, but could
be detected outside 4 AU, the team determined that for
these grains radiation pressure is 40 to 80% stronger than
solar gravity.
Galactic dust is a indigenous part of the galactic
interstellar medium. It provides the substance from which
stars and planets are formed. The analysis of galactic dust
grains can reveal basic information about the early phases
of the planetary formation process. Despite the
astronomical observations of galactic dust that are
conducted since the 1930ies, not much is known about these
enigmatic constituents of the Milky Way. For this reason,
the Max Planck Institute for Nuclear Physics proposes a
space mission named DUNE (DUst Near Earth), in order to
measure the chemical composition of galactic grains
directly. As a first step to realize DUNE, the European
Space Operation Center (ESOC) in Darmstadt, Germany,
performs a mission analysis.
[Image caption: http://www.mpg.de/news99/news54_99.htm
]
Figure: An electron microscope image of a cosmic dust
particle. This is how probably the galactic dust particles
that are detected by Ulysses look like. These particles are
found in Earth's atmosphere, where they are collected by
high flying aircraft. In order to determine if cosmic dust
particles are of solar origin or if they come from the
Milky Way, their trajectory and velocity have to be
measured directly in space. CREDIT: Institute of
Planetology, University at Muenster
===============
(5) CO2 AND CLIMATE CHANGE
From Bas van Geel <vangeel@bio.uva.nl>
Dear Benny,
In the debate about CO2 and climate change, evidence from the
past may
be useful to understand what is going on in the present time. I
would
like to refer to a paper in which changes at the end of the last
Glacial were reconstructed:
Wagner, F., Bohncke, S.J.P., Dilcher, D.L., Kürschner, W.M., van
Geel,
B. and Visscher, H. 1999. Century-scale shifts in early Holocene
atmospheric CO2 concentration. Science 284: 1971-1973.
http://www.sciencemag.org/cgi/content/full/284/5422/1971?ijkey=5sjIHV9J7WAt2
See also http://www.sciencemag.org/cgi/content/full/286/5446/1815a
for
comments and response as it was published on 3 December.
Based on the analysis of stomatal frequency in birch leaves we
found
that the sharp rise in temperature at the Younger Dryas/Early
Holocene
transition (ca 11250 years ago) came together with a sharp rise
in
atmospheric CO2. Actually it seems that the temperature rise was
somewhat earlier than the CO2-rise. We certainly need more data,
but
our evidence may indicate that the CO2-rise was the RESULT of the
increasing temperature with the ocean as a CO2 source (compare:
Nigel
Calder, 1999. The carbon dioxide thermometer and the cause of
global
warming. Energy and Environment (10) 1-18.
Best wishes,
Bas van Geel
Dr Bas van Geel |
Internet E-mail :vanGeel@bio.uva.nl
University of Amsterdam | Phone secr.
:+31-20 525 7844
Faculty of Biology | Direct
phone :+31-20 525 7664
Kruislaan
318 |
Fax
:+31-20 525 7878
NL - 1098 SM Amsterdam
|
The Netherlands
|
The Netherlands Centre for Geo-ecological Research
(ICG)
===============
(6) GREENHOUSE AND GLOBAL WARMING: THE FACTS AND THE POLITICS
From Andrew Glikson <geospectral@spirit.com.au>
Benny,
I refer to recent contributions re-global warming, by
Patrick J. Michael of the Cato Institute (CCNet, 11.12.99)
and by Roy W. Spencer of the Competitive Enterprise
Institute (CCNet 17.12.99).
I would dearly love to believe that, as these authors
suggest, computer model predictions of future global
warming are unreliable and CO2-consumption by plants such
as Loblolly pine is capable of slowing down or even
reversing the increase of 0.2-0.35 deg./C/decade recorded
this century. For if not, ensuing polar ice melting,
collapse of Antarctic ice shelves, and consequent sea level
rises directly threaten vast coastal regions and inland
plains (ie. Netherlands, north Germany, Florida,
Bangladesh) and coral islands - among other consequences.
More than half the world's urban populations lives in such
low-lying areas.
Unfortunately, I find it hard to reconcile the optimistic
view by the above authors with records correlating
accelerated anthropogenic emissions and global warming
through the 20th century, including:
1. Accelerated rise in greenhouse gases since about 1850,
as measured in ice cores, including CO2 (from 280 to 340
ppm), CH4 (from 800 to 1600 ppb), N2O (from 275 to 295 ppb)
and CFC-12 (from nil in 1950 to near 550 ppt at
present)(Ledley et al., Eos, 28 September, 1999).
2. The sharp upturn from a slow cooling trend (-0.1 to -0.3
deg/C between A.D. 1000 - 1910) to accelerated warming
(-0.3 to +0.76 deg/C between A.D. 1919 - 1998), based on
dendroclimatic (tree rings), coral and ice core records,
consistent with the onset of the industrial age (Mann et
al., 1999, Mann et al., 1998).
3. On the basis of these and a range of other observations
(including the currently measured thinning of Arctic and
Antarctic ice shelves) the American Geophysical Union
Council released an official statement (Eos, 1999, vol. 80,
No. 29, p.454), stating among other: "...Present
understanding of the Earth climate system provides a
compelling basis for legitimate public concern over future
global and regional scale changes resulting from increased
concentrations of greenhouse gases..." and, in view of the
uncertainties inherent in climate change predictions:
"Nonetheless, scientific understanding based on peer
reviewed research must be central to informed
decision-making."
Inherently the question of climate change, like many other,
becomes bedevilled by economic and thereby political
considerations. Understandably the fossil fuel industries
would hardly welcome limits on anthropogenic emissions, nor
large scale introduction of viable alternative and
non-polluting technologies, ie. hydrogen, solar, wind, hot
rocks, geothermal energies. Apart from a progressive switch
to these technologies, indeed TREES
(including the magic
Loblolly pine) are the key to long term climatic recovery.
In Australia alone, in the wake of European settlement, the
forrest coverage has been reduced from 15% to 7% of the
continent. Perhaps just part of the $trillions going into
VIRTUAL LIFE computer technologies (not to mention the
military) should be diverted to slow down or even reverse
the REALITY of an accelerating climatic change and
deforrestation?
Andrew Glikson
geospectral@spirit.com.au
Australian National University
Canberra, A.C.T. 0200
18 December, 1999
===============
(7) THINK TANKS & GLOBAL WARMING
From Michael Paine <mpaine@tpgi.com.au>
Dear Benny,
I believe you are treading on shaky ground by covering
"think tank"
studies on global warming. Passionate debates are likely to flow
from
this issue and it may overwhelm the main objectives of CCNet.
For an alternative view of the contribution of think tanks to
this type
of debate see Examining the role of think tanks by Sharon Beder,
Engineers Australia, November 1999.
http://www.engaust.com.au/ea/1199neweng.html
"Many of the more conservative corporate-funded think tanks,
in
particular, have sought to spread confusion about the scientific
basis of environmental problems, to oppose environmental
regulations
and promote free market remedies to those problems."
regards
Michael Paine
===============
(8) GLOBAL WARMING, DOOMSDAY PREDICTIONS & THE CCNET
From Benny J Peiser <B.J.Peiser@livjm.ac.uk>
It is a good old British custom to talk about the
weather in order to avoid arguing over party politics.
The reason why this practice has been so successful in
this country that still tries to maintain tactfulness
and polite manners is simple to understand: Everyone
concedes that personal views about and predictions of
the weather are pure conjecture that will often turn
out to be utterly wrong. It would be foolish to have
strong opinions about the weather. To have an opinion
about what the weather may be in fifty or one hundred
years seems even more absurd.
Yet, for the last two decades or so scientists,
politicians and environmental doomsday prophets around
the world have created an atmosphere in which ordinary
climate research has become increasingly stifled by
alarmist insinuation and innuendo. According to many
scientists and popular belief, global warming is the
most portentous crisis that mankind is facing in the
near future. Sceptics who dispute this apocalyptic
perspective and who question whether there is any hard
evidence for such trepidation are often accused of
political incorrectness and attacked as acolyte of
environmental cataclysm.
Ever since I posted the essay by Fred Hoyle and
Chandra Wickramasinghe, I have been strongly adviced by
a number of subscribers not to post any sceptical
research on global warming on the CCNet. Instead of
being relieved by information which suggest that the
grim predictions of environmental campaigners may be
based on flawed hypotheses, some people appear rather
disappointed that global warming prophecies might not
be accurate after all. Nevertheless, it is important
to realise that there is a distinct lack of consensus
among the scientific community about global warming.
As long as this is the case, nobody should be
compelled to accept any of the conflicting hypotheses
at face value.
From a historical point of view, such apocalyptic
commotion is nothing new. Throughout recorded history,
apocalyptic movements have frequently prophecised - on
religious grounds - the impending dilapidation of the
world. What is distinct in the global warming tumult
is that many scientists and research institutes, as
well as political parties throughout the world, have
contributed to the swelling of concern to near mass
hysteria - oblivious to the fact that the global
warming alarm had a scientific precursor only two
decades ago: the climatic cooling trend of the 1950s
and 1960s led to a minor global cooling hysteria in
the 1970s.
This is not the place to discuss in detail the
evidence in favour and against the allegation that
environmental hell will break loose if we don’t
drastically reduce the emission of so-called
"greenhouse" gases. Given that the CCNet is a
scholarly forum that focuses on *all* aspects of
neo-catastrophist studies, both terrestrial and
extraterrestrial, it will continue to critically
monitor debates in these fields of scientific
research. I would like to reassure subscribers that
the issues of global warming, ice ages or impact
disasters (whether past or future) or indeed any
potential environmental predicament will be assessed
on the CCNet exclusively from a scientific, i.e.
critical point of view. In this respect, it is
completely irrelevant whether the research in question
is funded by big business, governmental agencies,
lobby groups or academic funding agencies.
What counts on CCNet, and what only counts, is the
hard evidence presented and the reliability of the
methods used for making predictions. This has been the
hallmark of this network all along. As far as I am
concerned, it will remain this way in the future.
Benny J Peiser
22 December 1999
=============
(9) ICE AGES & THE HIMALAYAS
From Larry Klaes <lklaes@bbn.com>
A recent PBS Nova program titled "Cracking the Ice Age"
explores
the theory that the Himalayan mountain range caused the Ice Ages
of the last 35 million years about the same time that the India
subcontinental plate started pushing into the Asian plate.
The details can be found here:
http://www.pbs.org/wgbh/nova/ice/
Larry
================
(10) THE IMPRINT OF THE K/T IMPACT IN CLAY MINERALS
P. Debrabant*), E. Fourcade, H. Chamley, R. Rocchia,
E. Robin, J.P. Bellier, S. Gardin, F. Thiebault: The
imprint of the Chicxulub asteroid impact in clay
minerals from the Cretaceous/Tertiary boundary in
Guatemala. BULLETIN DE LA SOCIETE GEOLOGIQUE DE
FRANCE, 1999, Vol.170, No.5, pp.643-660
*) UNIV SCI & TECH LILLE FLANDRES ARTOIS,CNRS,UMR 85
77,F-59655 VILLENEUVE DASCQ,FRANCE
The clay mineral assemblages of the Cretaceous-Tertiary
(K/T) transition recorded in southern Peten sedimentary
rocks have been studied in sections dated by calcareous
nannofossils and foraminifera. The deposits contain cosmic
and impact remains (iridium,Ni-rich magnetite, tektite) and
typical Cheto smectites resulting from weathered tektites
(glass spherules) produced by the Yucatan impact. The clay
mineral assemblages are used for describing the
palaeoenvironmental and tectonic evolution of southern
Peten near the K/T boundary. Copyright 1999, Institute for
Scientific Information Inc.
============
(11) PALEOENVIRONMENTAL CHANGES ACROSS THE K/T BOUNDARY
A. Pardo*), T. Adatte, G. Keller, H. Oberhansli:
Paleoenvironmental changes across the Cretaceous-Tertiary
boundary at Koshak, Kazakhstan, based on planktic foraminifera
and clay mineralogy. PALAEOGEOGRAPHY PALAEOCLIMATOLOGY
PALAEOECOLOGY, 1999, Vol.154, No.3, pp.247-273
*) PRINCETON UNIVERSITY,DEPT GEOSCI,PRINCETON,NJ,08544
The Koshak section of the Mangyshlack Peninsula, Kazakhstan, is
one of the most complete Cretaceous-Tertiary (K-T) transitions
known from the boreal Paratethys. Cretaceous species richness
is low (11 to 13 species), except for a peak of 20 species near
the K/T boundary in the uppermost Maastrichtian (top 50 cm)
that represents the temporary incursion of low-latitude taxa.
This maximum species richness occurred during climatic warming
associated with increased humidity, as suggested by clay
mineral analyses.. Biofacies analysis suggests external platform
conditions at this time, followed by a more humid climate, a
sea-level transgression, and deepening basinal facies in the
lower Danian Subzone P1a. Shallower platform conditions resumed
in Danian Subzones P1b and P1c, accompanied by a cooler and
probably more arid climate. No abrupt mass extinction occurred
at the Koshak K/T boundary which is marked by an Ir anomaly, a
clay layer and the first appearance of Tertiary planktic
foraminifera. The influx of lower-latitude species ends at or
before the K/T boundary, whereas the majority of the indigenous
Cretaceous assemblage survived into the Danian. These data
suggest that long-term climatic changes may have been the
principal factors in the progressive demise of the Cretaceous
planktic foraminifera in the eastern boreal Paratethys. (C)
1999 Elsevier Science B.V. All rights reserved.
============
(12) LARGE SCATTERED PLANETESIMALS
J.M. Petit*), A. Morbidelli, G.B. Valsecchi: Large
scattered planetesimals and the excitation of the small
body belts. ICARUS, 1999, Vol.141, No.2, pp.367-387
*) NICE OBSERVATORY NICE,CNRS,BP 4229,F-06304 NICE 4,FRANCE
We study the dynamical excitation that large planetesimals,
scattered either by Neptune or Jupiter, could have provided to
the primordial Edgeworth-Kuiper belt and the asteroid belt.
Using both a refined Monte Carlo approach and direct numerical
integration, we show that the Monte Carlo method is useful only
to give qualitative insight into the resulting excitation, but
cannot be trusted from a quantitative viewpoint. According to
our direct integrations, Neptune-scattered planetesimals of
mass from a few tenths to one Earth mass could have ejected
most of the bodies from the primordial Edgeworth-Kuiper belt,
thus explaining the large mass deficiency of the present belt
up to about 50 AU. The remaining bodies are left on orbits with
eccentricity and inclination comparable to those observed. This
dynamical excitation is not restricted to the inner part of the
belt but may extend to 100 AU. We also show that Pluto has too
small a mass to destabilize the motion of other bodies in the
2:3 mean motion resonance with Neptune. The same mechanism
involving Jupiter-scattered planetesimals of about one Earth
mass can excite the outer asteroid belt, hence depleting it of
most of its primordial mass. However, this fails to excite the
inner belt. In the case where the planetesimals are isolated by
mutual gravitational perturbations on long-lived main-belt-like
orbits, safe from encounters with Jupiter, the resulting
asteroid belt is very similar to the currently observed one, in
terms of mass deficiency, excitation in eccentricity and
inclination, and radial mixing. Pallas-like bodies are also
obtained. However, the decoupling of planetesimals from Jupiter
on well-behaved orbits is rather improbable (2% of our
simulations), and the resulting asteroid belt is very
critically dependent on the mass of the scattered planetesimals
and their residence time in the belt. (C) 1999 Academic Press.
============
(13) LIGHTCURVE & ALBEDO OF ASTEROID 433 EROS
M.D. Hicks*), B.J. Buratti, D.L.Rabinowitz: The lightcurve
and geometric albedo of 433 Eros during the 1998
apparition. ICARUS, 1999, Vol.141, No.2, pp.411-414
*) CALTECH,JET PROP LAB,MS 183-501,4800 OAK GROVE
DR,PASADENA,CA,91109
We obtained R-band photometry of 433 Eros at the Table Mountain
0.6-m telescope during its 1998 apparition. Our five nights of
photometry yields a rotational period P-sid = 5.27048 +/-
0.00064 h and visual geometric albedo for 433 Eros of 0.27(-
0.06)(+0.03), high, but within the range of S-type asteroids,
Utilizing lightcurve data from the 1974/1975 apparition we
solved for rotational pole position (RA = 00:46.9, DEC =
+19:30.5; J2000) and axial ratios of 1.0:0.388:0.375, which are
both significantly different from previously derived values.
(C) 1999 Academic Press.
==========
(14) "CRATERS" SCREEN SAVER
From Juan Zapata-Arauco < juanwisdomquest@yahoo.com
>
Dear Benny:
May be many CCNet subscribers already know and use this: "A
Windows
screen saver that simulates cratering of initially flat terrain,
obeying the same power law relating crater size to number
observed on
airless solar system bodies."
Anyone interested go to
http://www.fourmilab.ch/craters/
for free downloading of something that beautifully remind us of
our
duty against nature in the next millenium.
Happy Holidays!
Juan
===========
(15) AND FINALLY: SCIENTISTS SEEN AS 'GEEKS' BY PUPILS
From the BBC Online News, 21 December 1999
http://news.bbc.co.uk/hi/english/education/newsid_573000/573635.stm
Scientists have a serious image problem among the young,
claims a survey published by psychologists.
In a survey of attitudes of 15 to 17 year olds, scientists
were perceived in a negative light, as boring, work
obsessed and 'geeks'.
Rather than being seen as white-coated technocrats,
carrying out vital research, the survey found that
scientists were stereotyped as "dangerous cranks" who
spent
too long in the laboratory.
The survey, carried out by the psychology department at the
University of Bath, interviewed over 250 teenagers about
how they saw scientists now and in the future.
These findings come as schools face shortages of science
teachers and after reports that an offer of a £5,000 bonus
for student science teachers was failing to attract enough
recruits.
Even though scientists were not seen favourably, their work
was recognised as improving the quality of life. By the
year 2030, the teenagers expected scientists to have
developed cures for important diseases and found answers to
environmental problems.
But there was some ambivalence about the advances made by
science, with fears that scientists were "interfering"
with
nature and creating weapons of mass destruction.
The research was carried out by Dr Helen Haste, Kevin Rice,
and Yiannis Zacharious, who presented their work on Tuesday
at the British Psychological Society's conference at the
Institute of Education.
Copyright 1999, BBC
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