PLEASE NOTE:
*
CCNet 27/2001 - 16 February 2001
--------------------------------
"The core system by which the scientific community allots
prestige
(in terms of oral presentations at major meetings and publication
in
major journals) and funding is a non- validated charade whose
processes
generate results little better than does chance. Given the fact
that most
reviewers are likely to be mainstream and broadly supportive of
the
existing organization of the scientific enterprise, it would not
be
surprising if the likelihood of support for truly innovative
research
was considerably less than that provided by chance."
--David F. Horrobin, BioMedNet, 2 February 2001
"The question remains the same in principle regarding
potentially
intelligent extraterrestrial life forms, i.e. whether Homo
Sapiens would
take care and responsibility of the well being of such alien life
forms
more than it has toward its own member - through repeated
genocidal
wars and holocaust? A more immediate ethical question is whether
the
$trillions proposed for space colonization should not be used to
feed hungry
humans and restore ruined natural habitats? Such value
judgments are
relevant to the extent of human "moral reason" and
"sympathy for
others".
--Andrew Glikson, Australian National University, 15
February 2001
(1) FLAMING METEOR OBSERVED OVER NORTHERN IRELAND
Ron Baalke <baalke@jpl.nasa.gov>
(2) U.S. COMPANY CLAIMS IT OWNS EROS
Orbital Development, 13 February 2001
(3) ASTEROID MISSION EXTENDED
BBC, 15 February 2001
(4) VASIL'EV NIKOLAI VLADIMIROVICH, RUSSIAN TUNGUSKA RESEARCHER
Andrei Ol'khovatov <olkhovatov@mtu-net.ru>
(5) SOMETHING ROTTEN AT THE CORE OF SCIENCE?
BioMedNet, 2 February 2001
(6) LIVERPOOL SYMPOSIUM 2001: ARMAGEDDON - THE END IS NIGH.
Rosalind King <es0u80e9@liverpool.ac.uk>
(7) 2001: A CELEBRATION OF BRITISH SCIENCE FICTION
The Science Fiction Foundation
(8) IRIDIUM IN COMETS
Jeremy Tatum <UNIVERSE@uvvm.UVic.CA>
(9) IMPACTS AND VULCANISM
Michael Paine <mpaine@tpgi.com.au>
(10) THE ETHICAL DIMENSION OF SPACE COLONIZATION
Andrew Glikson <geospectral@spirit.com.au>
(11) HOW MANY RUBBLE PILES ARE IN THE ASTEROID BELT?
Bagatin AC, Petit JM, Farinella P
(12) ASTEROID OBSERVATIONS FROM THE EUROPEAN SOUTHERN OBSERVATORY
Carvano JM, Lazzaro D, Mothe-Diniz T,
Angeli CA, Florczak M
(13) BASIC TARGETING STATEGIES FOR RENDEZVOUS AND FLYBY MISSIONS
TO
NEAR-EARTH ASTEROIDS
Perozzi E, Rossi A, Valsecchi GB
(14) THE LATE ASTEROIDAL & COMETARY BOMBARDMENT OF EARTH
Dauphas N, Robert F, Marty B
(15) ENDURANCE LIFETIME OF ICE FRAGMENTS IN COMETARY STREAMS
Beech M, Nikolova S
(16) NUMERICAL EVALUATION OF THE YARKOVSKY EFFECT
Spitale J, Greenberg R
(17) GEOMETRIC CONSTAINTS & THE SIZE DISTRIBUTION OF
ASTEROIDS
Bagatin AC, Petit JM
(18) SEARCHING FOR TROJAN ASTEROIDS
Jorba A
(19) A STUDY OF CYBELE ASTEROIDS
Lagerkvist CI, Erikson A, Lahulla F, De
Martino M, Nathues A, Dahlgren M
==============
(1) FLAMING METEOR OBSERVED OVER NORTHERN IRELAND
From Ron Baalke <baalke@jpl.nasa.gov>
http://www.ic24.net/mgn/THE_MIRROR/NEWS/P11S6.html
Fireball Riddle
'Flaming meteor' sparked 2-day hunt for plane crash
The Mirror (United Kingddom)
February 15, 2001
THE fireball which sparked a major search operation for a crashed
plane may
have been a meteor, it was learned yesterday.
Helicopters, troops, police and ambulance crews were mobilised
after locals
saw the flames and smoke streaking across the sky near the
border.
It was feared that a light aircraft had gone down. But a two-day
search
operation was called off last night as speculation grew it was an
extra-terrestrial rock.
Full story here:
http://www.ic24.net/mgn/THE_MIRROR/NEWS/P11S6.html
==============
(2) U.S. COMPANY CLAIMS IT OWNS EROS
From Orbital Development, 13 February 2001
http://www.OrbDev.com
Orbital Development (http://www.OrbDev.com)
welcomes NASA's NEAR spacecraft
upon the spacecraft's successful landing on the Asteroid Eros.
Eros is owned
by Orbital Development, says the company's founder, Gregory
Nemitz. OrbDev
has owned the property since 03 Mar 2000 when a Class D property
claim was
filed with the Archimedes Institute.
"It is the wild frontier up there." says Nemitz.
"Since there are no laws
governing private property claims in Outer Space. the first
claimant gets
ownership of it." This concept may sound foreign to
Americans, but
precedents are well entrenched throughout history. "The
Outer Space Treaty
of 1967 prohibits National Governments from making property
claims in space,
so NASA and the NEAR project cannot make a superseding claim for
Eros, based
on NEAR's successful landing." says Nemitz.
Presently, in space advocacy groups, property rights in space is
a hot
topic. Several factions are promoting various property rights
regimes.
Nemitz says, "In the end, it doesn't matter who owns a space
property first.
A good example of this concept, is found in the history of the
Internet
address, Space.com. The first owner was a kid in New Mexico. A
bunch of
suits made the kid an offer, bought the property, and made
Space.com in to
what it is today."
According to their website, the Archimedes Institute Claims
Registry service
has been established to lower the cost of doing business in space
by helping
to reduce the legal uncertainties associated with a wide variety
of space
activities. By providing an objective and public opportunity for
individuals, corporations and other entities to register property
claims,
liens and judgments the Archimedes Institute is encouraging the
formation of
new, efficient and equitable legal standards for the sensible
development of
the high frontier.
The off-Earth property registry includes this information on
Orbital
Development's claim:
The Archimedes Institute Record of the Claim
http://permanent.com/archimedes/claims/d200003031631.htm
Name of Claimant: Gregory William Nemitz
Corporate or Other Affiliation: Orbital Development
Address: 8301-252 Mission Gorge Road, Santee, CA 92071 USA
Telephone: 619-528-0520
E-mail: gnemitz@orbdev.com
Website: http://www.orbdev.com
Facsimile: 413-460-6480
Date: 03 Mar 2000
Class of Property Claim: D
Level of Control:
"fee simple" or "outright ownership, free &
clear" and regard it as real
property owned by Orbital Development of San Diego, California,
USA.
Basis for Making Claim:
As an Near-Earth Asteroid, Eros is a potential resource base for
construction materials and propellants. A recreational tourist
facility will
be built into the spaces cleared by mining.
Precise Description of Claim:
The entire asteroid, Eros. And a volume of space 50km in altitude
into space
from every point on the surface of the asteroid.
===========
(3) ASTEROID MISSION EXTENDED
From the BBC, 15 February 2001
http://news.bbc.co.uk/hi/english/sci/tech/newsid_1170000/1170499.stm
Nasa is still receiving signals from the first spacecraft to land
on an
asteroid and has extended the mission by 10 days to gather
important
scientific information. Scientists hope the data from Near (Near
Earth
Asteroid Rendezvous) Shoemaker, which landed on Eros on Monday,
will help
them understand the relationship between space rocks like Eros
and
meteorites that have fallen to Earth.
Dr Jay Bergstralh of the American Space Agency Nasa, said on
Wednesday: "We
will extend the operation by 10 days to gather further data on
the
abundances of elements on the asteroid."
At a post-landing press briefing at Nasa's headquarters in
Washington DC,
the mission team revealed details of how they landed the craft.
'Success'
"The secret of success here is that we did our homework
several times," said
Dr Bobby Williams of Nasa's Jet Propulsion Laboratory, Pasadena,
California.
"For a spacecraft that is not built to land this came off
extraordinarily
well."
More than 60 images were taken by Near Shoemaker craft on its
descent.
The pictures show boulders strewn across the surface of Eros,
some of them
twice the size of Near, others only the size of a golf ball.
While they give clues to the make-up of the asteroid, they also
raise
further mysteries.
"Some of the big questions have been answered but
fortunately many mysteries
remain," said Joseph Veverka, Imaging Team Leader, Cornell
University,
Ithaca, New York.
"That is the whole point of exploration and discovery."
Faster, cheaper, better
The touchdown ended a five-year journey by the craft, one of the
first of
Nasa's "faster, better, cheaper" missions.
It was a remarkable feat for a probe that was only designed to
orbit, rather
than land. And, against all odds, Near is still transmitting
signals to
mission control.
Scientists believe that the signals could continue for the next
few weeks
until the Sun, which powers the craft's solar panels, moves out
of range.
Before the touchdown, Near had already orbited Eros for a year,
sending back
some 160,000 images of the rocky surface.
Asteroids, material left over from the formation of the Solar
System, are
rocky and metallic objects that orbit the Sun but are too small
to be
considered planets.
Because asteroids are material from the very early Solar System,
scientists
are interested in their composition.
Data on the object could also be useful well into the future, as
there is a
chance that Eros could collide with the earth in roughly 1.5m
years.
Copyright 2001, BBC
===========
(4) VASIL'EV NIKOLAI VLADIMIROVICH, RUSSIAN TUNGUSKA RESEARCHER
From Andrei Ol'khovatov <olkhovatov@mtu-net.ru>
Dear Dr. Peiser,
I have a sad news: a coordinator of the 1908 Tunguska
event research,
academician Vasil'ev Nikolai Vladimirovich died in Kharkov,
Ukraine on
February 15. He was involved in Tunguska research since late
1950s, and
became informal leader of the research since early 1960s. Almost
the whole
of his life he tried to resolve the mystery of the Tunguska
event, but his
life was too short for this.... His name will be associated
with the Tunguska
event research as well as Kulik's name....
Sincerely,
Andrei Ol'khovatov
Russia, Moscow
olkhov@mail.ru
www.geocities.com/olkhov
===============
(5) SOMETHING ROTTEN AT THE CORE OF SCIENCE?
From BioMedNet, 2 February 2001
http://news.bmn.com/hmsbeagle/95/viewpts/op_ed
By David F. Horrobin
Reprinted with permission from Trends in Pharmacological
Sciences, Vol. 22,
No. 2, February 2001
Posted February 2, 2001 · Issue 95
Abstract
A recent U.S. Supreme Court decision and an analysis of the peer
review
system substantiate complaints about this fundamental aspect of
scientific
research. Far from filtering out junk science, peer review may be
blocking
the flow of innovation and corrupting public support of science.
The U.S. Supreme Court has recently been wrestling with the
issues of the
acceptability and reliability of scientific evidence. In its
judgement in
the case of Daubert v. Merrell Dow, the court attempted to set
guidelines
for U.S. judges to follow when listening to scientific experts.
Whether or
not findings had been published in a peer-reviewed journal
provided one
important criterion. But in a key caveat, the court emphasized
that peer
review might sometimes be flawed, and that therefore this
criterion was not
unequivocal evidence of validity or otherwise. A recent analysis
of peer
review adds to this controversy by identifying an alarming lack
of
correlation between reviewers' recommendations.
The Supreme Court questioned the authority of peer review.
Many scientists and lawyers are unhappy about the admission by
the top legal
authority in the United States that peer review might in some
circumstances
be flawed [1]. David Goodstein, writing in the Guide to the
Federal Rules of
Evidence - one of whose functions is to interpret the judgement
in the case
of Daubert - states that "Peer review is one of the sacred
pillars of the
scientific edifice" [2]. In public, at least, almost all
scientists would
agree. Those who disagree are almost always dismissed in
pejorative terms
such as "maverick," "failure," and
"driven by bitterness."
Peer review is central to the organization of modern science. The
peer-review process for submitted manuscripts is a crucial
determinant of
what sees the light of day in a particular journal. Fortunately,
it is less
effective in blocking publication completely; there are so many
journals
that most even modestly competent studies will be published
provided that
the authors are determined enough. The publication might not be
in a
prestigious journal, but at least it will get into print.
However, peer
review is also the process that controls access to funding, and
here the
situation becomes much more serious. There might often be only
two or three
realistic sources of funding for a project, and the networks of
reviewers
for these sources are often interacting and interlocking. Failure
to pass
the peer-review process might well mean that a project is never
funded.
Science bases its presumed authority in the world on the
reliability and
objectivity of the evidence that is produced. If the
pronouncements of
science are to be greeted with public confidence - and there is
plenty of
evidence to suggest that such confidence is low and eroding - it
should be
able to demonstrate that peer review, "one of the sacred
pillars of the
scientific edifice," is a process that has been validated
objectively as a
reliable process for putting a stamp of approval on work that has
been done.
Peer review should also have been validated as a reliable method
for making
appropriate choices as to what work should be done. Yet when one
looks for
that evidence it is simply not there.
Why not apply scientific methods to the peer review process?
For 30 years or so, I and others have been pointing out the
fallibility of
peer review and have been calling for much more openness and
objective
evaluation of its procedures [3-5]. For the most part, the
scientific
establishment, its journals, and its grant-giving bodies have
resisted such
open evaluation. They fail to understand that if a process that
is as
central to the scientific endeavor as peer review has no
validated
experimental base, and if it consistently refuses open scrutiny,
it is not
surprising that the public is increasingly skeptical about the
agenda and
the conclusions of science.
Largely because of this antagonism to openness and evaluation,
there is a
great lack of good evidence either way concerning the objectivity
and
validity of peer review. What evidence there is does not give
confidence but
is open to many criticisms. Now, Peter Rothwell and Christopher
Martyn have
thrown a bombshell [6]. Their conclusions are measured and
cautious, but
there is little doubt that they have provided solid evidence of
something
truly rotten at the core of science.
Forget the reviewers. Just flip a coin.
Rothwell and Martyn performed a detailed evaluation of the
reviews of papers
submitted to two neuroscience journals. Each journal normally
sent papers
out to two reviewers. Reviews of abstracts and oral presentations
sent to
two neuroscience meetings were also evaluated. One meeting sent
its
abstracts to 16 reviewers and the other to 14 reviewers, which
provides a
good opportunity for statistical evaluation. Rothwell and Martyn
analyzed
the correlations among reviewers' recommendations by analysis of
variance.
Their report should be read in full; however, the conclusions are
alarmingly
clear. For one journal, the relationships among the reviewers'
opinions were
no better than that obtained by chance. For the other journal,
the
relationship was only fractionally better. For the meeting
abstracts, the
content of the abstract accounted for only about 10 to 20 percent
of the
variance in opinion of referees, and other factors accounted for
80 to 90
percent of the variance.
These appalling figures will not be surprising to critics of peer
review,
but they give solid substance to what these critics have been
saying. The
core system by which the scientific community allots prestige (in
terms of
oral presentations at major meetings and publication in major
journals) and
funding is a non-validated charade whose processes generate
results little
better than does chance. Given the fact that most reviewers are
likely to be
mainstream and broadly supportive of the existing organization of
the
scientific enterprise, it would not be surprising if the
likelihood of
support for truly innovative research was considerably less than
that
provided by chance.
Objective evaluation of grant proposals is a high priority.
Scientists frequently become very angry about the public's
rejection of the
conclusions of the scientific process. However, the Rothwell and
Martyn
findings, coming on top of so much other evidence, suggest that
the public
might be right in groping its way to a conclusion that there is
something
rotten in the state of science. Public support can only erode
further if
science does not put its house in order and begin a real attempt
to develop
validated processes for the distribution of publication rights,
credit for
completed work, and funds for new work. Funding is the most
important issue
that most urgently requires opening up to rigorous research and
objective
evaluation.
What relevance does this have for pharmacology and
pharmaceuticals? Despite
enormous amounts of hype and optimistic puffery, pharmaceutical
research is
actually failing [7]. The annual number of new chemical entities
submitted
for approval is steadily falling in spite of the enthusiasm for
techniques
such as combinatorial chemistry, high-throughput screening, and
pharmacogenomics. The drive to merge pharmaceutical companies is
driven by
failure, and not by success.
The peer review process may be stifling innovation.
Could the peer-review processes in both academia and industry
have destroyed
rather than promoted innovation? In my own field of
psychopharmacology,
could it be that peer review has ensured that in depression and
schizophrenia, we are still largely pursuing themes that were
initiated in
the 1950s? Could peer review explain the fact that in both
diseases the
efficacy of modern drugs is no better than those compounds
developed in
1950? Even in terms of side-effects, where the differences
between old and
new drugs are much hyped, modern research has failed
substantially. Is it
really a success that 27 of every 100 patients taking the
selective 5-HT
reuptake inhibitors stop treatment within six weeks compared with
the 30 of
every 100 who take a 1950s tricyclic antidepressant compound? The
Rothwell-Martyn bombshell is a wake-up call to the cozy
establishments who
run science. If science is to have any credibility - and also if
it is to be
successful - the peer-review process must be put on a much
sounder and
properly validated basis or scrapped altogether.
David F. Horrobin, a longtime critic of anonymous peer review,
heads Laxdale
Ltd., which develops novel treatments for psychiatric disorders.
In 1972 he
founded Medical Hypotheses, the only journal fully devoted to
discussion of
ideas in medicine.
References
1. Daubert v. Merrel Dow Pharmaceuticals 509 U.S. 579 (1993),
509, 579.
http://caselaw.lp.findlaw.com/scripts/getcase.pl?navby=search&court=US&case=/us/509/579.html
)
2. Goodstein, D. 2000. How Science Works. In U.S. Federal
Judiciary
Reference Manual on Evidence, pp. 66-72.
3. Horrobin, D.F. 1990. The philosophical basis of peer review
and the
suppression of innovation. J. Am. Med. Assoc. 263:1438-1441.
4. Horrobin, D.F. 1996. Peer review of grant applications: A
harbinger for
mediocrity in clinical research? Lancet 348:1293-1295.
5. Horrobin, D.F. 1981-1982. Peer review: Is the good the enemy
of the best?
J. Res. Commun. Stud. 3:327-334.
6. Rothwell, P.M. and Martyn, C.N. 2000. Reproducibility of peer
review in
clinical neuroscience: Is agreement between reviewers any greater
than would
be expected by chance alone? Brain 123:1964-1969.
7. Horrobin, D.F. 2000. Innovation in the pharmaceutical
industry. J. R.
Soc. Med. 93:341-345.
Copyright 2001, © Elsevier Science Limited 2000
===============
(6) LIVERPOOL SYMPOSIUM 2001: ARMAGEDDON - THE END IS NIGH.
From Rosalind King <es0u80e9@liverpool.ac.uk>
LIVERPOOL SYMPOSIUM 2001: ARMAGEDDON - THE END IS NIGH.
www.pcweb.liv.ac.uk/helenk/Herdman
Programme of Events
Saturday 24th February - Science Lecture Block.
10.15am Tea and coffee
MORNING SESSION: Chair: Alex Fordham
President, Herdman Earth Sciences Society
10.30am Lecture 1 Dr. Dave Pyle (Cambridge)
'Supervolcano'-How big? How rare? How
important?
11.15am Questions
11.30am Lecture 2 Dr. Peter Kokelaar (Liverpool University)
Whopper volcanoes, super-slides,
mega-tsunamis and the hazards of hype.
12.15am Questions
12.30pm Lunch break
AFTERNOON SESSION: Chair: Prof Nick Kusznir
(University of Liverpool)
1.30pm Lecture 3 Prof Stephen Self (Open University)
Volatile release in flood basalt eruptions
and implications for
mass extinction.
2.15pm Questions
2.30pm Lecture 4 Dr. Iain Gilmour (Open University)
Mountains from the Sky....Life and death
from outer space?
3.15pm Questions
3.30pm Lecture Dr. Benny Peiser (Liverpool John Moores
University)
Preventing Armageddon: Cosmic disasters and
social response.
4.15pm Questions
4.30pm Afternoon tea and cake
5.00pm END
The symposium is one of a kind, with the Liverpool Earth Science
Department
being the only UK department to have such an event. It has been
run by the
Herdman Earth Sciences Society for many years and is sponsored by
the
geological industries. Past themes have included, The Origin of
Life (2000)
and Glaciations - past, present and future (1997).
This year it is going to be bigger than before with students
coming from
Leeds, Staffordshire and Birmingham Universities, as well as the
Liverpool
Geological Society.
For further information, please contact:
Miss Rosalind C. King
Symposium Secretary
Earth Sciences Department
University of Liverpool
es0u80e9@liverpool.ac.uk
===============
(7) 2001: A CELEBRATION OF BRITISH SCIENCE FICTION
From The Science Fiction Foundation
http://www.sf-foundation.com/events/2001con.html
2001: A CELEBRATION OF BRITISH SCIENCE FICTION
28 June - 1 July 2001
Foresight Centre, University of Liverpool, England
Guests of Honour:
Brian Aldiss - Stephen Baxter - Nicola Griffith - Gwyneth Jones -
Ken
MacLeod - John Clute
The year 2001 is a significant year in British science fiction:
it is the
100th anniversary of the publication of H. G. Wells's The First
Men in the
Moon and the 50th of John Wyndham's The Day of the Triffids. It
is also the
50th anniversary of "The Sentinel", the Arthur C.
Clarke story which formed
the basis of the film 2001: A Space Odyssey.
To celebrate this memorable date the Science Fiction Foundation
is calling
for papers on all aspects of British Science Fiction of the
post-war period.
While celebrating the writers and themes of the past, we will
also examine
the writers and themes of the present and future, and discuss the
nature of
science fiction in the 21st Century, tracing themes such as the
Cosy
Catastrophe, the Regional Voice, the New Wave (s), Feminism,
Politics, the
End of Empire, Children's sf, Neo-Victorianism, Steampunk,
Utopias,
Dystopias, Generation Conflict.
The Science Fiction Foundation and the University of Liverpool
has called
for papers on all aspects of post-war British Science Fiction
(written sf,
art, music, film and television), but particularly on Arthur C.
Clarke
(patron of the Science Fiction Foundation) and John Wyndham
(whose papers
are held by the University of Liverpool). An extensive list of
post-war
British science fiction authors can be found below.
Costs
The conference should cost £285 or $428 INCLUDING meals and
hotel
accommodation (3 nights).
Deposits £20/$35 for attendance to be sent to Dr. Farah
Mendlesohn,
Middlesex University, White Hart Lane, London N17 8HR, UK.
We will be presenting papers on: our guest....
. . . and authors such as Arthur C. Clarke and John Wyndham
. . . and also such authors as: Kingsley (and Martin) Amis ; J.G.
Ballard ;
Iain M. Banks ; Barrington Bayley ; Stephen Baxter; Eric Brown ;
Molly Brown
; John Brunner ; Ken Bulmer ; Richard Calder ; D.G. Compton ;
Susanna Clarke
; Michael Coney ; Storm Constantine ; Richard Cowper ; Jack
Deighton ;
Terrance Dicks ; Peter Dickinson ; Christopher Evans ; Nicholas
Fisk ;
Maggie Furey ; Mary Gentle ; Colin Greenland; Nicola Griffith ;
Jon
Courtenay Grimwood ; Ann Halam ; Peter F. Hamilton ; M. John
Harrison ;
Robert Holdstock ; Fred Hoyle ; Simon Ings ; Diana Wynne Jones ;
Colin Kapp
; Garry Kilworth ; Louise Lawrence ; Tanith Lee ; James Lovegrove
; Ken
MacLeod ; Paul McAuley ; Ian McDonald ; J T McIntosh ; Graham
Dunstan Martin
; John Meaney ; China Miéville ; Michael Moorcock ; Patrick
Moore ; Kim
Newman ; Jeff Noon ; Stephen Palmer; Terry Pratchett ;
Christopher Priest ;
Philip Pullman ; Alastair Reynolds ; Michael Scott Rohan ; Keith
Roberts ;
Justina Robson ; Eric Frank Russell ; Bob Shaw ; Alison Sinclair
; Michael
Marshall Smith ; Brian Stableford ; William F. Temple ; Ian
Watson ; Robert
Westall; David Wingrove; James White; Ronald Wright. . .
For more information about the conference, contact Andy Sawyer
<asawyer@liverpool.ac.uk>
============================
* LETTERS TO THE MODERATOR *
============================
(8) IRIDIUM IN COMETS
From Jeremy Tatum <UNIVERSE@uvvm.UVic.CA>
It is argued by some that the presence of iridium in the K/T
boundary layer
is evidence of a cometary collision; it is argued by others that
the
presence of iridium in volcanic magmas militates against the
cometary
hypothesis.
The presence or absence of iridium in the K/T boundary layer or
in volcanic
magmas tells us nothing whatever about whether or not a comet may
at some
time have collided with Earth, for the following reasons.
1. Iridium has never been detected in the spectrum of any
comet.
2. You would not expect to detect iridium in the spectrum
of a comet
since iridium is a highly refractory element which could be
vaporized
and its emission spectrum excited when the comet is so close to
the Sun
(i.e. in the daytime sky) so that a spectrum cannot be +
obtained.
3. Even if iridium were detected in a cometary spectrum,
this would not
enable us to determine how much iridium was in the comet because
the
necessary oscillator strengths of the relevant lines have not
been
determined in the laboratory.
As a consequence of this, it is not known by cometary scientists
whether
iridium does or does not occur in comets, or, if it does, how
much.
Iridium may be present in meteorites, but, as far as I know, it
has never
been detected or identified in an asteroid, although presumably
the
gamma-ray spectrometer aboard NEAR-Shoemaker has the capability
of doing so
now.
It is high time that a brake was put on the highly speculative
scenari about
the early history of the solar system that are being published on
an almost
daily basis with little or no foundation of scientific fact or
understanding.
Jeremy B. Tatum
=================
(9) IMPACTS AND VULCANISM
From Michael Paine <mpaine@tpgi.com.au>
Hermann,
Thank you for your article just posted on CCNet. If you don't
mind I have
added your comments to my Craters and Extinctions web page:
http://www4.tpg.com.au/users/tps-seti/crater.html
My graph illustrates the possible link between craters, vulcanism
(flood
basalt eruptions) and mass extinctions. If the three are linked
then we know
that either impacts or vulcanism can cause extinctions and
that impacts can
cause vulcanism but, of course, vulcanism cannot cause
impacts.
The P/T boundary is the major uncertainty on the graph since a
crater has
not been found (although there are candidates). You seem to
provide an
interesting solution to this puzzle - the P/T impact was so large
that the
resulting tectonic events covered the evidence. The examples of
huge impacts
around the solar system are, I understand, all on bodies that are
not as
tectonically active as the Earth so we should be cautious about
assuming
similar outcomes on Earth.
regards
Michael Paine
=============
(10) THE ETHICAL DIMENSION OF SPACE COLONIZATION
From Andrew Glikson <geospectral@spirit.com.au>
Dear Benny,
I appreciate Stephen Ashworth's note (CCNet 15-02-01) regarding
my letter
"Life on Eros - the ethical dimension of space
exploration" (CCNet
14-02-01), and share his hopes for "all human races being
capable of moral
reason" and of "intellectual reflection and sympathy
for others".
In so far as evolutionary theory and evidence identify biological
systems as
Darwinian food chains, members of Homo Sapiens may be unique in
holding high
conscientious aspirations, although whether the species is
successful in
living up to such ideals may be questioned by current rates of
antropogenically induced extinction of plant and animal species.
The relations between Homo Sapiens and bacteria is reciprocal:
Bacterial
processes are in the root of all biological activity - i.e. some
bacteria
enable digestion of food whereas other microbe species infect and
kill
complex organisms. By definition such basic biological processes
fall
outside the scope of an ethical choice.
The potential effects of extraterrestrial colonization on
planetary
bacterial cultures have been the subject of concern from two
points of view:
(1) contamination of Earth by returning space crafts and rock or
soil
samples, and (2) effects of inadvertently exported terrestrial
microbes on
planetary organic systems. The first has been of
subjectively greater
concern, since it potentially affects US. The second was
considered more
academic, as it potentially endangers OTHERS, at present unknown,
life
forms.
The question remains the same in principle regarding potentially
intelligent
extraterrestrial life forms, i.e. whether Homo Sapiens would take
care and
responsibility of the well being of such alien life forms more
than it has
toward its own member - through repeated genocidal wars and
holocaust? A
more immediate ethical question is whether the $trillions
proposed for space
colonization should not be used to feed hungry humans and restore
ruined
natural habitats? Such value judgments are relevant
to the extent of human
"moral reason" and "sympathy for others".
I thank Stephen Ashworth for his comments.
Andrew Glikson
Australian National University
Canberra, ACT 0200
16-02-2001
=============
* ABSTRACTS *
=============
(11) HOW MANY RUBBLE PILES ARE IN THE ASTEROID BELT?
Bagatin AC, Petit JM, Farinella P: How many rubble piles are in
the asteroid
belt?
ICARUS 149: (1) 198-209 JAN 2001
We have developed a new Version of the code built by Campo
Bagatin et al.
(1994a, Planet. Space Sci. 42, 1079- 1092; 1994b, ibid., 42,
1099-1107) and
Campo Bagatin (1998, Ph.D. thesis, University of Valencia) to
model the
collisional evolution of the asteroid size distribution. The new
code
distinguishes between "intact," unfractured asteroids
that did not undergo
catastrophic collisions and asteroids converted by energetic
collisions into
reaccumulated bodies, or "rubble piles." The
distinction can also be made on
a physical ground by assigning different collisional parameters
to the two
kinds of objects, with the objective of simulating the different
responses
to energetic impacts that rubble piles may have-due to their
different
structure-in comparison to unshattered bodies. Rubble-piles
abundance when
such targets are supposed to transfer less kinetic energy to the
fragments
turns out to be generally higher than monolithic asteroids.
We have run a number of simulations of the collisional evolution
process to
assess the size range where reaccumulated bodies should be
expected to be
abundant in the main asteroid belt. We find that this diameter
range goes
from about 10 to 100 km, but may extend to smaller or larger
bodies,
depending on the prevailing collisional response parameters, such
as the
strength of the material the strength scaling law, the fraction
of kinetic
energy of the impact transferred to the fragments, and the
reaccumulation
model. Both the size range and the resulting fraction of rubble
piles vary
widely depending on the input parameters, which reflects the
large
uncertainties still present in the modelization of high-velocity
impact
outcomes. In particular, the simulations that take into account
the derived
"hydrocode" scaling laws (Davis et at. 1994, Planet.
Space Sci. 42, 599-610)
show that nearly 100% of the main belt asteroids larger than a
few
kilometers should be reaccumulated objects, On the other hand,
the present
code shows that the scaling law recently proposed by Durda et al.
(1998,
Icarus 135, 431-440) produces almost no rubble pile. This scaling
law was
pro-posed to match the actual population of asteroids, which it
fails to do
if collisional processes are accounted for in a self-consistent
way. (C)
2000 Academic Press.
Addresses:
Bagatin AC, Observ Cote Azur, F-06003 Nice, France.
Observ Cote Azur, F-06003 Nice, France.
===========
(12) ASTEROID OBSERVATIONS FROM THE EUROPEAN SOUTHERN OBSERVATORY
Carvano JM, Lazzaro D, Mothe-Diniz T, Angeli CA, Florczak M
Spectroscopic survey of the Hungaria and Phocaea dynamical groups
ICARUS 149: (1) 173-189 JAN 2001
We observed 29 Hungaria and 31 Phocaea asteroids at the European
Southern
Observatory (Chile) in the wavelength range 4900-9200 Angstrom.
The Phocaea
and the Hungaria are both high-inclination groups, located at the
inner edge
of the main belt near the nu (5), nu (6), and nu (16) secular
resonances. We
confirm that the Hungaria group is composed mainly of E-type
asteroids but
with a relatively large number of S-types. The Phocaea group, on
the other
hand, is composed mainly of S-type asteroids. We discuss the
possible
implications of the observed composition distribution on the
origin and
evolution of these high-inclination groups. (C) 2001 Academic
Press.
Addresses:
Carvano JM, Observ Nacl Rio De Janeiro, Dept Astrofis, BR-20921
Rio De
Janeiro, Brazil.
Observ Nacl Rio De Janeiro, Dept Astrofis, BR-20921 Rio De
Janeiro, Brazil.
CEFET, Dept Fis, BR-80000 Curitiba, Parana, Brazil.
Copyright © 2001 Institute for Scientific Information
==========
(13) BASIC TARGETING STATEGIES FOR RENDEZVOUS AND FLYBY MISSIONS
TO
NEAR-EARTH ASTEROIDS
Perozzi E, Rossi A, Valsecchi GB: Basic targeting strategies for
rendezvous
and flyby missions to the near-Earth asteroids
PLANETARY AND SPACE SCIENCE 49: (1) 3-22 JAN 2001
Missions to asteroids and comets are becoming increasingly
feasible both
from a technical and a financial point of view. in particular,
those
directed towards the Near-Earth Asteroids have proven suitable
for a
low-cost approach, thus attracting the major space agencies as
well as
private companies. The choice of a suitable target involves both
scientific
relevance and mission design considerations, being often a
difficult task to
accomplish due to the limited energy budget at disposal. The aim
of this
paper is to provide an approach to basic trajectory design which
allows to
account for both aspects of the problem, taking into account
scientific and
technical information. A global characterization of the
Near-Earth Asteroids
population carried out on the basis of their dynamics, physical
properties
and flight dynamics considerations, allows to identify a group of
candidates
which satisfy both, the scientific and engineering requirements.
The
feasibility of rendezvous and flyby missions towards them is then
discussed
and the possibility of repeated encounters with the same object
is
investigated, as an intermediate scenario. Within this framework,
the
capability of present and near future launch and propulsion
systems for
interplanetary missions is also addressed. (C) 2001 Elsevier
Science Ltd.
All rights reserved.
Addresses:
Perozzi E, Observ Paris Meudon, DESPA, 5 Pl Jules Janssen,
F-92195 Meudon,
France.
Observ Paris Meudon, DESPA, F-92195 Meudon, France.
Telespazio, I-00156 Rome, Italy.
CNR, Ist CNUCE, I-56126 Pisa, Italy.
CNR, Area Ric, Reparto Planetol, IAS, I-00133 Rome, Italy.
============
(14) THE LATE ASTEROIDAL & COMETARY BOMBARDMENT OF EARTH
Dauphas N, Robert F, Marty B: The late asteroidal and cometary
bombardment
of Earth as recorded in water deuterium to protium ratio
ICARUS 148: (2) 508-512 DEC 2000
The deuterium to protium (D/H) ratio of the deep mantle may be a
remnant of
the hydrogen isotopic composition of Earth forming planetesimals,
which
later evolved as a result of the late accretion of asteroids and
comets, If
so, the mass of asteroids and comets incident on Earth since the
time of its
accretion is estimated to be 4 x 10(20)-2 x 10(22) kg. The
combined use of
water D/H ratios, the lunar cratering record, and terrestrial
mantle
siderophiles would favor a rather low mass fraction of comets
among
impacting bodies (less than or similar to0.01). Asteroids,
comets, and the
early Earth contributed to 0-0.5, 0-0.1, and 0.5-0.9 of Earth's
water
inventory, respectively. A two stage model is advocated in which
escape to
space of terrestrial volatiles predated the late accretion of
extraterrestrial gases. We wish to emphasize that our
interpretations and
conclusions might evolve in the future when additional data on
asteroids,
comets, and Earth's interior become available. (C) 200 Academic
Press.
Addresses:
Dauphas N, CNRS, Ctr Rech Petrog & Geochim, EP 2031, 15 Rue
Notre Dame
Pauvres, F-54501 Vandoeuvre Nancy, France.
CNRS, Ctr Rech Petrog & Geochim, EP 2031, F-54501 Vandoeuvre
Nancy, France.
Museum Natl Hist Nat, Lab Mineral, CNRS, URA 736, F-75005 Paris,
France.
Ecole Natl Super Geol, F-54501 Vandoeuvre Nancy, France.
===========
(15) ENDURANCE LIFETIME OF ICE FRAGMENTS IN COMETARY STREAMS
Beech M, Nikolova S: The endurance lifetime of ice fragments in
cometary streams
PLANETARY AND SPACE SCIENCE 49: (1) 23-29 JAN 2001
The endurance lifetime against sublimation of meter- to
decameter-sized ice
fragments are calculated for typical cometary orbits. It is found
that such
bodies can survive for multiple perihelion passages. For
fragments traveling
along orbits similar to those of typical meteor shower producing
comets, the
sublimation mass loss rate drives radial variations equivalent to
1-0.5 m
per orbit. We review the available data with respect to the
possible
presence of large objects within the Perseid, Lyrid, Leonid and
alpha
-Capricornid streams. Invoking cometary aging and surface
fragmentation
events as the mechanism for placing large meteoroids within
cometary
streams, we find no compelling reasons to doubt that large
meteoroids are
intermittently present in most, if not all cometary-derived
meteoroid
assemblages. (C) 2001 Elsevier Science Ltd. All rights reserved.
Addresses:
Beech M, Univ Regina, Camp Coll, 3737 Wascana Pkwy, Regina, SK
S4S 0A2,
Canada.
Univ Regina, Camp Coll, Regina, SK S4S 0A2, Canada.
Univ Regina, Dept Phys, Regina, SK S4S 0A2, Canada.
Univ Western Ontario, Dept Phys & Astron, London, ON N6A 3K7,
Canada.
===========
(16) NUMERICAL EVALUATION OF THE YARKOVSKY EFFECT
Spitale J, Greenberg R: Numerical evaluation of the general
Yarkovsky
effect: Effects on semimajor axis
ICARUS 149: (1) 222-234 JAN 2001
The Yarkovsky effect may play a key role in the orbital evolution
of
asteroids and near-Earth objects. To evaluate the acceleration
under a wide
range of conditions, a three-dimensional finite-difference
solution to the
heat equation is applied to homogeneous, spherical stony bodies
with 1-,
10-, and 100-m diameters. This approach employs neither the
linearized
boundary conditions, the plane-parallel heat flow approximation,
nor the
assumption of fast rotation used in earlier work. Thus we can
explore a wide
range of orbital elements and physical properties. Our work
agrees well with
earlier results in the regimes where their approximations are
valid. We
investigate a wide range of spin states, including both the
"seasonal" (very
fast rotation) and "diurnal" (zero obliquity) extremes
of the Yarkovsky
effect. We find that, for orbits with high eccentricity, the
semimajor axis
can change much faster than for circular orbits, For such orbits,
the
orientation of the rotation axis with respect to the direction of
pericenter
is critical in determining the evolution. A stony main-belt
asteroid of
diameter 1 m on a high-eccentricity orbit could change its
semimajor axis by
more than 1AU in 1.5 Myr. (C) 2001 Academic Press.
Addresses:
Spitale J, Univ Arizona, Lunar & Planetary Lab, Tucson, AZ
85721 USA.
Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA.
============
(17) GEOMETRIC CONSTAINTS & THE SIZE DISTRIBUTION OF
ASTEROIDS
Bagatin AC, Petit JM: Effects of the geometric constraints on the
size
distributions of debris in asteroidal fragmentation
ICARUS 149: (1) 210-221 JAN 2001
It is commonly accepted that the formation of asteroid families
is the
consequence of catastrophic impacts on former parent bodies: (K.
Hirayama,
Proc. Imp. Acad. Tokyo 9, 482-485, 1933). But to reproduce the
puzzling
steep size distributions of the currently known asteroid families
has been,
up to now a task in which recent modeling techniques of
fragmentation have
typically failed. The role of geometric constraints in the
production of
fragments in asteroidal collisions is an issue that has been
investigated in
recent times only by Tanga ct al. (Icarus 141, 65-78, 1999) and
that might
give some insight into the understanding of high-velocity
collisional
processes. Improvements to the approach by Tanga ct al. are
introduced in
the present work in order to take into account in a more
realistic way the
different shapes that the largest remnants may have when formed
in
high-velocity collisional events involving spherical parent
bodies. We also
consider the case in which the parent body and the largest
remnant are cubes
and the fragments are (a) cubes and (b) parallelepipeds, instead
of spheres.
A somewhat uniform power-law behavior in the size;distributions
of the
randomly generated fragments is found in the numerical
simulations-not
detected by Tanga et al.-and an analytical derivation of the
upper limit to
the corresponding exponent is given. Further improvements are
introduced in
the model in order to refine it and allow any fragment to develop
any shape
and to account for the fact that fragments form more or less at
the same
time, not sequentially. Finally, the results of the refined model
are
compared with the size distributions of the observed actual main
belt
asteroid families, and encouraging agreement is obtained in most
cases. (C)
2000 Academic Press.
Addresses:
Bagatin AC, Observ Cote Azur, CNRS, BP 4229, F-06304 Nice 4,
France.
Observ Cote Azur, CNRS, F-06304 Nice 4, France.
=========
(18) SEARCHING FOR TROJAN ASTEROIDS
Jorba A: A numerical study on the existence of stable motions
near the
triangular points of the real Earth-Moon system - A dynamical
systems
approach to the existence of Trojan motions
ASTRONOMY AND ASTROPHYSICS 364: (1) 327-338 DEC 2000
In this paper we consider the existence of stable motions for a
particle
near the triangular points of the Earth-Moon system. To this end,
we first
use a simplified model (the so-called Bicircular Problem, BCP)
that includes
the main effects coming from the Earth, Moon and Sun. The
neighbourhood of
the triangular points in the BCP model is unstable, as happens in
the real
system. However, here we show that, in the BCP, there exist sets
of initial
conditions giving rise to solutions that remain close to the
Lagrangian
points for a very long time. These solutions are found at some
distance from
the triangular points. Finally, we numerically show that some of
these
solutions seem to subsist in the real system (by real system we
refer to the
model defined by the well-known JPL ephemeris), in the sense that
the
corresponding trajectories remain close to the equilateral points
for at
least 1 000 years. These orbits move up and down with respect to
the
Earth-Moon plane, crossing this plane near the triangular points.
Hence, the
search for Trojan asteroids in the Earth-Moon system should be
focused on
these regions and, more concretely, in the zone where the
trajectories reach
their maximum elongation with respect to the Earth-Moon plane.
Addresses:
Jorba A, Univ Barcelona, Dept Matemat Aplicada & Analisi,
Gran Via 585,
E-08007 Barcelona, Spain.
Univ Barcelona, Dept Matemat Aplicada & Analisi, E-08007
Barcelona, Spain.
Copyright © 2001 Institute for Scientific Information
=============
(19) A STUDY OF CYBELE ASTEROIDS
Lagerkvist CI, Erikson A, Lahulla F, De Martino M, Nathues A,
Dahlgren M:
A study of Cybele asteroids - I. Spin properties of ten asteroids
ICARUS 149: (1) 190-197 JAN 2001
As a part of an observational program on Cybele asteroids we have
obtained
lightcurves of 10 of the larger asteroids. In this paper the
results are
presented for 229 Adelinda, 260 Huberta, 401 Ottilia 420
Bertholda, 466
Tisiphone, 522 Helga, 570 Kythera, 713 Luscinia, 909 Ulla, and
1467 Mashona.
Spin properties have been determined for the first time far 8 of
these
asteroids, (C) 2001 Academic Press.
Addresses:
Lagerkvist CI, Astron Observ, Box 515, S-75120 Uppsala, Sweden.
Astron Observ, S-75120 Uppsala, Sweden.
DLR, Inst Space Sensor Technol & Planetary Explorat, D-12489
Berlin,
Germany.
Astron Observ, Madrid 28014, Spain.
Osservatorio Astron Torino, I-10025 Pino Torinese, Italy.
Copyright © 2001 Institute for Scientific Information
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