PLEASE NOTE:
*
CCNet 66/2001 - 11 May 2001
---------------------------
"The long-term survival of our species may depend not only
on
negating menacing asteroids and comets that threaten Earth, but
colonizing free space, the Moon and Mars, researchers said at a
recent
conference at Princeton University. Their idea of an
"insurance plan" to
first protect and then proliferate humanity into the cosmos
involves taking
up residence in large 10,000-person habitats, positioned between
Earth and the Moon at first, and later spreading out to other
niches within
our solar system. But first, we must make sure that life is not
wiped
out by a passing space rock."
--Leonard David, Space.com, 10 May 2001
"The dinosaurs were wiped out by an asteroid that smacked
the Earth
65 million years ago, but they survived another cataclysmic event
--
perhaps another asteroid impact -- that snuffed out 80 percent of
all species about 200 million years ago, scientists said on
Thursday.
[...] Peter Ward said this calamity had tremendous similarities
to two of
the other five mass extinctions that have ravaged Earth over the
past
500 million years. Like those, Ward said it appears this mass
extinction was caused by a giant rock from space. "We know
now that
asteroid impact can cause rapid extinction," Ward said in an
interview. "It
may not be an asteroid. But if it isn't an asteroid, it acts like
an
asteroid, put it that way."
--Will Dunham, Reuters, 10 May 2001
(1) INSURANCE PLANS FOR HUMANITY'S SURVIVAL
Space.com, 10 May 2001
(2) COLLAPSE OF SIMPLE LIFE FORMS LINKED TO MASS EXTINCTION 200
MILLION
YEARS AGO
Andrew Yee <ayee@nova.astro.utoronto.ca>
(3) SUDDEN PRODUCTIVITY COLLAPSE ASSOCIATED WITH THE
TRIASSIC-JURASSIC
BOUNDARY MASS EXTINCTION
Science Vol 292 p1148 1 May 2001
(4) ANCIENT MASS EXTINCTION HAPPENED SUDDENLY
CNN, 10 May 2001
(5) DINOSAURS SURVIVED CATACLYSM 200 MILLION YEARS AGO
Reuters, 10 May 2001
(6) STELLAR CANNIBALISM: THE HARSH DESTINY OF A PLANET?
Andrew Yee <ayee@nova.astro.utoronto.ca>
(7) THE END IS SHY
Andrew Yee <ayee@nova.astro.utoronto.ca>
(8) ASTEROIDS, COMETS, METEORS - ACM2002
Gerhard Hahn <ACM2002@dlr.de>
(9) ITALIAN RESEARCHERS FIND TRACES OF LIFE IN METEORITES: PRESS
SpaceDaily, 10 May 2001
(10) CLIMATE CHANGE "LED TO APPEARANCE OF FIRST HUMANS"
BBC News Online, 9 May 2001
(11) ASIA DRIED AFRICA
Nature, 10 May 2001
(12) IMPACT-TRIGGERED BREAK-UP OF COMET C/1999 S4 (LINEAR)
I. Toth
(13) AN ATTEMPT TO DETECT VULCANOIDS
G. Schumacher & J. Gay
(14) YARKOVSKY-DRIVEN LEAKAGE OF KORONIS FAMILY MEMBERS
D. Vokrouhlicky
(15) LIGHTCURVE & COLOURS OF UNUSUAL MINOR PLANET 1998 WU24
J.K. Davies et al.
(16) SOLAR SAIL OPERATIONS AT ASTEROIDS
E. Morrow et al.
(17) A POSSIBLE LONG-LIVED ASTEROID POPULATION AROUND SATURN
M.D. Melita & A. Brunini
(18) IMAGING OF SMALL-SCALE FEATURES ON EROS
J. Veverka et al.
(19) OBSERVATIONS OF 804 HISPANIA
M. Calabresi & G. Roselli
(20) AND FINALLY: TRADE GROWING IN STOLEN METEORITES
BBC News Online, 11 May 2001
=============
(1) INSURANCE PLANS FOR HUMANITY'S SURVIVAL
From Space.com, 10 May 2001
http://www.space.com/scienceastronomy/planetearth/mass_drivers_010510.html
By Leonard David
Senior Space Writer
PRINCETON, N. J. - Move it, or lose it.
The long-term survival of our species may depend not only on
negating
menacing asteroids and comets that threaten Earth, but colonizing
free
space, the Moon and Mars, researchers said at a recent conference
at
Princeton University.
Their idea of an "insurance plan" to first protect and
then proliferate
humanity into the cosmos involves taking up residence in large
10,000-person
habitats, positioned between Earth and the Moon at first, and
later
spreading out to other niches within our solar system.
But first, we must make sure that life is not wiped out by a
passing space
rock.
Mass driver work reactivated
Asteroids are worrisome intruders in near-Earth space, as well as
vast
storehouses of diverse materials, said Lee Valentine, executive
vice
president of Princeton University's Space Studies Institute
(SSI), which is
starting up a focused effort to develop planetary defense
technology, he
said.
Work done by Gerard O'Neill and teams of students to build a mass
driver --
an electromagnetic accelerator -- is soon to be reactivated, said
Valentine.
Several versions of a mass driver were pursued in years past -- a
concept
originally developed at the Massachusetts Institute of
Technology, under the
direction of Henry Kolm and O'Neill.
The workings of a mass driver (which are also known as
"linear
accelerators") are straightforward. A long track or tunnel
is lined with
electromagnets which are wired so they can be switched on and off
like
Christmas tree lights. A magnetic object placed at one end is
then carried
along on "waves" of magnetic force, created by
switching the electromagnets
on and off in the right rhythm. By accelerating the waves of
magnetism the
object can be accelerated almost endlessly. On a body with
weak-enough
gravity, objects can be easily accelerated to escape velocity --
without
having to fire a single rocket.
The last, substantive work on a mass driver was done in 1983-84,
Valentine
said.
One duty for a mass driver, as first proposed, was to move raw
lunar
material efficiently and economically to high Earth orbit for
processing.
But the same type device can also be used as a reaction engine
for pushing
asteroids to useful locations.
"A mass driver is a satisfactory engine for moving asteroids
or comets,"
Valentine said. Even better, for altering the trajectory of a
rocky
mini-world in the event it's streaking toward Earth, he said.
Valentine said that SSI, in concert with the Robotics Institute
at Carnegie
Mellon University in Pittsburgh, Pennsylvania, will be looking
into mass
driver technology. Making such a device more rugged, upping its
performance
and demonstrating robotic excavation, loading and firing of a
mass driver as
a prototype planetary defense system are to be reviewed, he said.
Wait and watch
"You can convert a hit to a miss using the mass
driver," said George
Friedman, SSI board of directors member. Ostensibly, advance
spotting of an
impending Earth impactor would allow many years of preparatory
time.
An expert on detection and deflection of potentially harmful
bodies,
Friedman said a mass driver would be built on an asteroid, which
would also
be covered with solar collectors that supply solar power to run
the driver
operations. Chunks of the asteroid would be electromagnetically
catapulted
out into space, nudging the giant piece of space flotsam in a
non-nuclear
way, he said.
"In a year or two, you can move the trajectory of something
that would have
hit the Earth," Friedman said.
At present, we know that there are about 1,000 asteroids roughly
larger than
a half mile (1 kilometer) in diameter whose orbits cross Earth's.
These are
large enough to inflict serious global consequences in a
collision.
Furthermore, upwards of 250,000 smaller space rocks are out there
too. They
are considered more on the city-buster side of terror from the
sky.
Cataloging the "bigger guys" is coming along
beautifully, said asteroid
expert, said John Lewis of the Lunar and Planetary Laboratory at
the
University of Arizona in Tucson. Radical new technology is needed
to find
the smaller objects, he added.
Lewis said asteroid cataloging is necessary to help discern which
objects
should be treated more as a resource than as a threat. Also, once
an
asteroid's orbit is nailed down, observers are needed to re-check
an
object's whereabouts from time to time.
"The idea is to nail the orbit well enough the first time
around so that you
will acquire it the next time around," Lewis said.
"Follow-up is cheap and easy compared to discovery,"
Lewis said.
Survival 101
The "pay-as-you-go" orbital flight of Dennis Tito was
hailed as a signal
that a market for human presence in space is evolving, said
Lewis. "More
power to him," he said.
Lewis called Tito's trek as a sign that "the monolithic,
government-controlled monopoly on space is cracking."
But what the world really needs now is a life insurance policy,
said J.
Richard Gott III, astrophysicist at Princeton University.
"This is a planet
littered with the bones of extinct species showing us that such
catastrophes
on Earth happen to individual species on a routine basis,"
he said.
Gott said that we should be asking ourselves what space program
can be
undertaken in the next 40 years. He advocates a self-supporting
colony in
space as a goal that would change the course of history and help
the
prospects for our species to survive.
Gott struck a tone similar to that of John F. Kennedy's
circa-1960s quest to
land a man on the Moon. "Space colonization is a challenge
that this
generation should be willing to accept and one that it should be
unwilling
to postpone," he said.
"I think we should care about our survival as a
species," Gott told
SPACE.com.
Spreading out via space colonies and a settlement on Mars
increases our
chances for survival. Being a multi-planet species not only
lessens the
chance of humans being wiped out by an Earth impacting asteroid,
but also
validates that Neil Armstrong's "one small step" on the
Moon can be truly
viewed as a history-changing event, he said.
Copyright 2001, Space.com
==========
(2) COLLAPSE OF SIMPLE LIFE FORMS LINKED TO MASS EXTINCTION 200
MILLION
YEARS AGO
From Andrew Yee <ayee@nova.astro.utoronto.ca>
University of Washington
Seattle, Washington
FROM: Vince Stricherz, 206-543-2580 ,vinces@u.washington.edu
FOR IMMEDIATE RELEASE: May 10, 2001
Collapse of simple life forms linked to mass extinction 200
million years
ago
A mass extinction about 200 million years ago, which destroyed at
least half
of the species on Earth, happened very quickly and is
demonstrated in the
fossil record by the collapse of one-celled organisms called
protists,
according to new research led by a University of Washington
paleontologist.
"Something suddenly killed off more than 50 percent of all
species on Earth,
and that led to the age of dinosaurs," said Peter Ward, a UW
Earth and space
sciences professor.
Evidence indicates the massive die-off was linked with an abrupt
drop in
productivity, the rate at which inorganic carbon is turned into
organic
carbon through processes such as photosynthesis. The waning
productivity
coincided with a sharp decline in radiolaria (included among
protists),
which was the focus of the new research. One example of
productivity, Ward
explained, occurs in the spring when fertilizer washes into
waterways and
triggers large algae blooms. The processes at work in that
scenario were
reversed 200 million years ago, he said.
There is no definitive evidence yet on what caused the demise of
so many
species, Ward said. However, the suddenness of the event is
similar to two
better-known mass extinctions - one 250 million years ago at the
end of the
Permian period that killed some 90 percent of all species, the
other 65
million years ago at the end of the Cretaceous period that sent
the
dinosaurs into oblivion.
The extinction 200 million years ago, at the boundary between the
Triassic
and Jurassic periods, killed the last of the mammal-like reptiles
that once
roamed the Earth and left mainly dinosaurs, Ward said. That
extinction
happened in less than 10,000 years, in the blink of an eye,
geologically
speaking.
Ward is the lead author on a paper detailing the evidence,
published in the
May 11 edition of the journal Science. Others participating in
the research
are James Haggart and Howard Tipper of the Geological Survey of
Canada in
Vancouver, British Columbia; Elizabeth Carter, a researcher at
Oregon's
Portland State University; David Wilbur, a UW oceanography
research
scientist; and Tom Evans, a UW junior in chemistry and Earth and
space
sciences.
The evidence from the extinction was gathered at two sites in the
Queen
Charlotte Islands, off Canada's British Columbia coast.
"These sites are among the most remote places in the
world," Ward said.
"There are no roads anywhere close by. The forests are
virgin old growth,
and the wave action is such that you can't get there by
boat."
Samples from a spot called Kennecott Point, in the northern Queen
Charlottes, and from Kunga Island, about 100 miles to the
southeast, showed
a sharp decline in the presence of organic carbon, even at places
where
levels of inorganic carbon rose. The organic carbon decline
correlated with
the decline of radiolarians, one-celled organisms that serve as a
food
source for a number of marine species.
"These provide the best record of how nasty the extinction
was at this
boundary," Ward said.
The mass extinction 200 million years ago occurred just before
the breakup
of Pangea, which contained all the land on Earth in one
supercontinent. At
the time, the Queen Charlotte Islands - which now lie between 52
and 54
degrees north latitude - were probably on the equator or in the
southern
hemisphere, Ward said.
"These are tropical fossils. There are many kinds of fossils
in these
rocks," he said.
And they tell a story of a calamity that came on with stunning
swiftness.
"This is the first time ever that we can see how sudden this
event was," he
said. "It was very quick, not a long protracted
episode."
Ward now has done research on the last three of the Earth's mass
extinctions
(scientists know of five) and has found that each happened quite
quickly.
Bolstered by a recent astrobiology grant from the National
Aeronautics and
Space Administration, he plans to lead researchers back to the
Queen
Charlottes this summer to look for more clues in the
Triassic-Jurassic
extinction, including potential causes.
For more information, contact Ward at 206-543-2962 or argo@u.washington.edu
==============
(3) SUDDEN PRODUCTIVITY COLLAPSE ASSOCIATED WITH THE
TRIASSIC-JURASSIC
BOUNDARY MASS EXTINCTION
Science Vol 292 p1148 1 May 2001
http://www.sciencemag.org/content/current/
Sudden Productivity Collapse Associated with the
Triassic-Jurassic Boundary
Mass
Extinction
P. D. Ward, 1 * J. W. Haggart, 2 E. S. Carter, 3 D. Wilbur, 4 H.
W. Tipper,
2 T. Evans 1
The end-Triassic mass extinction is one of the five most
catastrophic in
Phanerozoic Earth history. Here we report carbon isotope evidence
of a
pronounced productivity collapse at the boundary, coincident with
a sudden
extinction among marine plankton, from stratigraphic sections on
the Queen
Charlotte Islands, British Columbia, Canada. This signal is
similar to
(though smaller than) the carbon isotope excursions associated
with the
Permian-Triassic and Cretaceous-Tertiary events.
=============
(4) ANCIENT MASS EXTINCTION HAPPENED SUDDENLY
From CNN, 10 May 2001
http://www.cnn.com/2001/TECH/science/05/10/mass.extinction/index.html
By Richard Stenger
CNN
(CNN) -- A cataclysmic event quickly killed off most of the
species on Earth
about 200 million years ago, after which dinosaurs began their
long reign on
the planet, according to a report to be published in Friday's
edition of the
journal Science.
"This mass extinction has been known for a long time, but
this is the first
study to show that it happened suddenly," said
paleontologist Peter Ward,
lead author of the report.
"This is the first time that we can see how sudden the event
was. It was
very quick. Not a long, protracted episode."
Researchers found evidence of the rampant die-off, which took
place on the
boundary of the Triassic and Jurassic periods, by studying the
fossil record
of common marine plankton from the era.
Between 50 and 80 percent of life on the planet didn't survive
the
catastrophic period, which lasted less than 10,000 years -- the
blink of an
eye in geological terms.
Various causes suspected; dinos spared
An asteroid collision, like those thought to have sparked other
large-scale
extinctions over the ages, is among the suspected causes of the
episode. One
such event 65 million years ago ended the age of dinosaurs.
A sudden change in climate induced by a burst of volcanic
activity may also
have triggered the event. Ward and his colleagues noted that the
die-off
took place just before the breakup of Pangea, a supercontinent
that included
all the landmasses on Earth.
Curiously, the extinction killed off mammal-like reptiles that
once roamed
the Earth, but spared the dinosaurs, according to the report.
"Perhaps
creatures reproducing with buried eggs survived and large animals
with live
births did not," Ward speculated.
The researchers from the United States and Canada trudged through
thick
forests on remote islands off British Columbia to gather fossil
evidence
showing sharp, correlating collapses in organic carbon -- a
marker of plant
life productivity -- and radiolarians, single-cell organisms that
served as
a food source for many marine species.
"These provide the best report of how nasty the extinction
was at this
boundary," Ward said.
Copyright 2001, CNN
==========
(5) DINOSAURS SURVIVED CATACLYSM 200 MILLION YEARS AGO
From Reuters, 10 May 2001
http://news.excite.com/news/r/010510/14/news-science-extinction-dc
By Will Dunham
WASHINGTON (Reuters) - The dinosaurs were wiped out by an
asteroid that
smacked the Earth 65 million years ago, but they survived another
cataclysmic event -- perhaps another asteroid impact -- that
snuffed out 80
percent of all species about 200 million years ago, scientists
said on
Thursday.
By studying the fate of a type of marine plankton, single-celled
organisms
called Radiolaria, researchers found that the mass extinction was
a sudden
event, not the prolonged die-off that experts previously had
thought. The
extinction occurred at the boundary between the Triassic and
Jurassic
periods during the Mesozoic era.
The event provided the death knell for most species and helped
crown the
dinosaurs, which arose earlier in the Triassic, as the rulers of
the Earth,
said Peter Ward, a University of Washington paleontologist who
led the
study.
Ward said this calamity had tremendous similarities to two of the
other five
mass extinctions that have ravaged Earth over the past 500
million years.
Like those, Ward said it appears this mass extinction was caused
by a giant
rock from space.
"We know now that asteroid impact can cause rapid
extinction," Ward said in
an interview. "It may not be an asteroid. But if it isn't an
asteroid, it
acts like an asteroid, put it that way."
Most scientists believe an asteroid strike caused the mass
extinction at the
end of the Cretaceous period that killed the dinosaurs and
ushered in the
age of mammals. In February, scientists presented evidence that
an asteroid
or comet impact also caused the even bigger extinction at the
boundary
between the Permian and Triassic periods 250 million years ago.
EVIDENCE OFF THE COAST OF BRITISH COLUMBIA
Ward's team gathered evidence about the extinction 199.6 million
years ago
at two remote sites in the Queen Charlotte Islands off Canada's
British
Columbia coast, examining fossil samples indicating a collapse of
the
plankton population.
The researchers found an abrupt drop in the rate at which
inorganic carbon
was turned into organic carbon by life forms through processes
such as
photosynthesis.
The organic carbon decline coincided with the disappearance of
more than 50
species of radiolarians, which served as a food source for
numerous marine
species and whose disappearance was an indicator of a major
biological
crisis.
The study was published in the journal Science.
Ward said the research indicated it took less than 10,000 years
for the mass
extinction to unfold. It could have taken place even more quickly
-- perhaps
in an instant, he added.
"This thing was real fast," Ward said.
At the time, most dinosaurs were relatively small, and they were
locked in a
survival-of-the-fittest battle with other well-adapted animals,
including
the mammal-like reptiles -- the biggest of which were among the
major
herbivores of their day.
"These suckers are huge, they're hulking," Ward said.
But the mammal-like reptiles -- whose earlier forms gave rise to
the first
true mammals -- perished in the calamity.
"One of the great mysteries has been ... why would these
creatures, which
are seemingly better adapted for eating a variety of plant
sources, die out
and the dinosaurs not? And the answer is: Mass extinction doesn't
give a
hoot about your adaptations for everyday life. There's a lottery
involved,
for whatever reason," Ward said.
Also nearly wiped off the planet were the ammonoids -- marine
predators that
resembled a giant squid in coiled cone shell.
DEATH FROM THE SKY?
Ward said there are ongoing studies to try to confirm an asteroid
as the
cause. Ward said he has found evidence of little carbon molecules
called
buckminsterfullerenes -- or buckyballs -- that hint at a space
rock as the
culprit. He said a massive crater in Quebec called the
Manicouagan
structure, which measures 60 miles wide, could be the impact
site. The
crater has been dated to 214 million years ago, but Ward said the
date may
be too old.
Ward said alternative theories include an explosion of a nearby
star that
could have blown off the Earth atmosphere's ozone layer and sent
temperatures soaring, or massive volcanic activity, possibly
related to the
breakup of the archaic supercontinent known as Pangea.
Scientists know very little about the mass extinctions that took
place 350
million and 420 million years ago, Ward said.
Copyright 2001, Excite.com
===========
(6) STELLAR CANNIBALISM: THE HARSH DESTINY OF A PLANET?
From Andrew Yee <ayee@nova.astro.utoronto.ca>
ESO Education and Public Relations Dept.
Contacts
Garik Israelian and Rafael Rebolo
Instituto de Astrofisica der Canarias
La Laguna, Tenerife, Spain
Tel.: +34-922-605200
email: gil@ll.iac.es and rrl@ll.iac.es
Nuno Santos and Michel Mayor
Observatoire de Geneve
Switzerland
Tel.: +41-22-755-2611
email: nuno.santos@obs.unige.ch
and michel.mayor@obs.unige.ch
Embargoed until Wednesday, May 9, 2001, at 20:00 hrs CEST (18:00
UT)
ESO Press Release 10/01
The Harsh Destiny of a Planet? The VLT Uncovers Traces of Stellar
Cannibalism
Summary: Did the star HD 82943 swallow one of its planets?
What may at a first glance look like the recipe for a dramatic
science-fiction story is in fact the well-considered conclusion
of a serious
scientific study, to be published by a group of astronomers in
Switzerland
and Spain [1] in tomorrow's issue of the international
research journal "Nature".
Using the very efficient UVES high-resolution spectrograph at the
ESO VLT
8.2-m KUEYEN telescope, they have convincingly detected the
presence of the
rare isotope Lithium-6 (6Li; [2]) in this metal-rich, solar-type
dwarf star
that is also known to possess a planetary system, cf. ESO Press
Release
13/00.
Unlike the Lithium-7 (7Li) isotope of this light element, any
primordial
Lithium-6 would not survive the early evolutionary stages of a
metal-rich
solar-type star. The Lithium-6 now seen in HD 82943 must
therefore have been
added later, but from where? The astronomers believe that this
observation
strongly suggests that the star has at some moment engulfed one
of its
planets, whose Lithium-6 was then deposited in the star's
atmosphere.
This surprising discovery represents important observational
evidence that
planets may fall into their host stars.
Text with all links and the photo is available on the ESO Website
at URL:
http://www.eso.org/outreach/press-rel/pr-2001/pr-10-01.html
=============
(7) THE END IS SHY
From Andrew Yee <ayee@nova.astro.utoronto.ca>
From Nature, 9 May 2001
[ http://www.nature.com/nsu/010510/010510-7.html
]
Wednesday 9 May 2001
The end is shy
By PHILIP BALL
About seven billion years from now our Sun will start to expire.
In its
initial death throes it will become a 'red giant' star large
enough to
engulf our planet, spelling the end for life on Earth. The planet
itself may
ultimately evaporate like a snowflake falling into a fire, new
research suggests.
Kacper Rybicki of the Polish Academy of Sciences in Warsaw and C.
Denis of
the University of Liège in Belgium are among the first to take
tidal forces
into account in calculating the Earth's end game. They conclude
that our
planet's unique good fortune to be located just far enough from
the Sun to
support life makes its final fate extremely hard to gauge [1].
Venus, our neighbour on the sunward side, doesn't really have a
chance -- it
is almost certain to be evaporated, their research suggests.
Mars, the next
planet out from the Earth, should survive the Sun's red-giant
phase, as will
the more distant planets. As the Sun then cools and shrinks to a
dim, dense
white dwarf star, these planets will continue in their orbits --
traumatized, no doubt, but more or less intact.
The Sun won't burn for ever, because its fuel -- hydrogen -- will
run out.
Nuclear fusion converts hydrogen, the lightest element, to helium
(the
second lightest). When nearly all the hydrogen has been consumed,
the Sun
will become a red giant.
Then the Sun will begin to fuse helium instead, making still
heavier
elements. As helium ignites in the core, the Sun will emit a
flash of heat
and light, signalling the end of its red-giant phase. More than
100 million
years later, further changes in the fusion process will cause it
to emit a
series of other heat pulses. Eventually, running out of anything
to burn,
the Sun will cool and shrink.
The fate of the planets during this turbulent time depends on
many things.
One is whether the Sun grows big enough to swallow them. Some
estimate that
a red-giant Sun will fall short of the current orbit of the
Earth, others
that it will exceed this.
But the distance between the Sun and the planets will itself
change during
this time. As a red giant, the Sun will throw off some of its
atmosphere.
This drop in mass will reduce its gravitational pull -- so the
planets will
move further out.
Planets engulfed by or close to the outermost layers of the Sun,
on the
other hand, will encounter drag forces, like fish swimming
through water.
This will slow them down, leading them to spiral into the Sun's
core.
Rybicki and Denis calculate the effects of these drag forces on
the orbits
of the planets. In particular, they consider tidal forces. The
Moon loses a
little energy as it sloshes the Earth's oceans back and forth,
and this
causes a tiny, constant decrease in the Moon's orbit. The same
would happen
to the Earth if the Sun's outer envelope were to come close
enough.
***
[The above paragraph was changed to the below on the Nature
web-site.
You might want to click on the highlighted text for a good
explanation of
of why the Moon is moving AWAY from Earth! bobk]
[Rybicki
and Denis calculate the effects of these drag forces on the
orbits
of the planets. In particular, they consider tidal forces. The
Moon is constantly
losing a little energy as it sloshes the Earth's oceans back and
forth. Similarly,
the Earth would also lose energy through tidal effects if the
Sun's outer envelope
were to come close enough, and this would make its orbit smaller.]
***
Previous studies of the fate of the Solar System have neglected
these tidal
effects. Without them, Earth and Venus move gradually further
from the
red-giant Sun. When they are included, Venus spirals inwards and
is
engulfed.
The Earth would probably survive -- to face the heat pulses that
follow the
red-giant phase. Each of these pulses would temporarily puff out
the Sun,
and the researchers say it is likely that one of the pulses would
engulf the
Earth and drag it down. Deep inside the Sun, the planet would
evaporate.
If the pulses are short enough, they might not set the Earth on
its terminal
spiral. Instead, the planet might cling to its orbit, baked but
still whole,
until the Sun recedes. Then it would join Mars and the outer
planets in a
grave procession around the fading Sun.
It would be nice to feel that our planet will indeed remain as a
kind of
cosmic gravestone -- but Rybicki and Denis think that evaporation
is a more
probable end.
[1] Rybicki, K. R. & Denis, C. On the final destiny of the
Earth and the
solar system. Icarus 151, 130-137 (2001).
© Macmillan Magazines Ltd 2001 - NATURE NEWS SERVICE
=======
(8) ASTEROIDS, COMETS, METEORS - ACM2002
From Gerhard Hahn <ACM2002@dlr.de>
Berlin, July 29 - August 2, 2002
Organized by
DLR - Institute of Space Sensor Technology and Planetary
Exploration,
Berlin-Adlershof and Technical University, TU - Berlin
First Announcement
The next meeting of the International Conference ASTEROIDS,
COMETS, METEORS
- ACM2002 will be held in Berlin from July 29 to August 2, 2002.
Location: The Conference will take place on the campus of the
Technical
University (TU-Berlin), located in the centre of Berlin.
Further information will be provided in the second announcement,
and on the
web page http://earn.dlr.de/ACM2002
.
In order to estimate the number of participants and to update our
mailing
list we would appreciate receiving your response by filling out
the on-line form. Please forward this message to other people you
feel could
be interested in the meeting.
We are looking forward to seeing you in Berlin.
Gerhard Neukum
Uri Carsenty
Gerhard Hahn
on behalf of the Local Organizing Committee
----------------------------------------------
Scientific Organizing Committee (SOC)
M. Ahearn, USA
C. Arpigny, Belgium
M.A. Barucci, France
E.L.G. Bowell, USA
Z. Ceplecha, Czech Republic
B.E. Clark, USA
M. Festou, France
G. Hahn (Co-Chair), Germany
A.W. Harris, USA
W. Huebner, USA
E.K. Jessberger, Germany
D.C. Jewitt, USA
H.-U. Keller, Germany
C.-I. Lagerkvist, Sweden
A.Milani, Italy
G. Neukum, Germany
H. Rauer (Co-chair), Germany
H. Reitsma, USA
R.M. West, ESO
I.P. Williams, U.K.
E. Sedlmayr, Germany
G. Schwehm, ESTEC
V. Zappala, Italy
Local Organizing Commitee (LOC)
J. Benkhoff
U. Carsenty (Chair)
D. Dolzycka
G. Hahn
A. Harris
S. Mottola
G. Neukum
H. Rauer
E. Sedlmayr
========
(9) ITALIAN RESEARCHERS FIND TRACES OF LIFE IN METEORITES: PRESS
From SpaceDaily, 10 May 2001
http://www.spacedaily.com/news/010510014102.tc9rjtea.html
ROME (AFP) May 10, 2001
Italian researchers have found traces of life in 4.5
billion-year-old
meteorites, according to the Italian daily Corriere della Sera.
Geologist Bruno D'Argegno and molecular biologist Giuseppe
Geraci, both from
the Federico II University in Naples, borrowed meteorite samples
from a
local museum and introduced them to a "physiological
solution," D'Argegno
told the paper.
"Then we saw these micro-organisms appear and begin to
move," the researcher
said.
The scientists noted 78 different types of bacteria -- known as
crystallo-microbes or "crim" for short -- which they
identified as being
similar to ones which existed on Earth some 3.5 billion years
ago.
The bacteria were described as very primitive organisms, with a
DNA network
but no immune system.
The two Italian experts presented their conclusions to the
Italian Space
Agency (ASI) on Wednesday, the paper said.
The space agency's scientific director, astrophsicist Giovanni F.
Bignami
hailed the findings as "an excellent basis for boosting
research programmes
dedicated to the search for life on other planets in the solar
system."
All rights reserved. © 2000 Agence France-Presse
============
(10) CLIMATE CHANGE "LED TO APPEARANCE OF FIRST HUMANS"
From the BBC News Online, 9 May 2001
http://news.bbc.co.uk/hi/english/sci/tech/newsid_1321000/1321867.stm
Climate change led to the appearance of the first humans
By the BBC's Andrew Craig
There is a new theory about what caused the change in the East
African
climate that may have led to the evolution of humans.
It was clearly a complex combination of circumstances that
created the
conditions in which our ancestors appeared
Two American researchers say that the catalyst may have been the
gradual
drifting of the Indonesian islands, rather than the North
Atlantic currents
which have usually been held responsible.
The first creatures that are usually described as human are
thought to have
evolved in East Africa after it became drier between four million
and
two-and-a-half million years ago.
Although there are rival theories, it is widely believed that as
forests
gave way to grassland, early hominids adapted by spending more
time on their
two feet, and scavenging meat as well as gathering fruit and
roots.
Rainfall change
But why did the African climate change? Mark Cane and Peter
Molnar, writing
in the journal Nature, say the answer may lie far to the east in
Indonesia,
whose islands divide the Indian Ocean from the Pacific.
Five million years ago, they believe, much of the water flowing
into the
Indian Ocean came from the Pacific's southern, warmer half. That
warm water
led to more rainfall in East Africa.
Our ancestors evolved in East Africa
But, as Australia and New Guinea drifted northwards, the warm
southern
current was blocked by such Indonesian islands as Halmahera,
which grew much
bigger at the time.
The result was a much higher proportion of cold, North Pacific
water
reaching the Indian Ocean. That meant less evaporation, and less
rain in
East Africa.
Until now, the dryer African climate has been ascribed to the
closing of the
gap between North and South America, and the subsequent flow of
the Gulf
Stream across the North Atlantic.
It was clearly a complex combination of circumstances that
created the
conditions in which our ancestors appeared.
Copyright 2001, BBC
===========
(11) ASIA DRIED AFRICA
From Nature, 10 May 2001
http://www.nature.com/nsu/010510/010510-12.html
Almost 3 million years ago a previously moist and warm east
Africa, which
was covered with tropical woodlands and green landscapes, was
transformed
into a dry, grass-covered savannah. It had been assumed1 that
this climatic
change originated in the north Atlantic. Now Mark Cane from the
Lamont-Doherty Earth Observatory in Palisades, New York, and
Peter Molnar of
the Massachusetts Institute of Technology argue that it could
have been
caused by the closure of the Indonesian seaway.
FULL STORY at http://www.nature.com/nsu/010510/010510-12.html
=============
* ABSTRACTS *
=============
(12) IMPACT-TRIGGERED BREAK-UP OF COMET C/1999 S4 (LINEAR)
Toth I: Impact-triggered breakup of comet C/1999 S4 (LINEAR):
Identification
of the closest intersecting orbits of other small bodies with its
orbit
ASTRONOMY AND ASTROPHYSICS 368 (3): L25-L28 MAR 2001
As we are still not certain of the causes of the splitting of
comet C/1999
S4 (LINEAR), we attempt to explain the initiation and/or
triggering of the
breakup of the nucleus of this comet by impact-induced events
from possible
larger debris or a debris cloud dispersed around the orbits of
known
asteroids. A computer search showed that Comet C/1999 S4 (LINEAR)
crossed
the orbits of seven known asteroids from December 1999 to March
2000.
Impact-induced activity may have initiated or contributed to the
breakup
process of this comet in late 1999 or early 2000 creating the
observed
fragments in July and August 2000.
Addresses:
Toth I, Konkoly Observ Budapest, POB 67, H-1525 Budapest, Hungary
Konkoly Observ Budapest, H-1525 Budapest, Hungary
Copyright © 2001 Institute for Scientific Information
========
(13) AN ATTEMPT TO DETECT VULCANOIDS
Schumacher G, Gay J: An attempt to detect Vulcanoids with
SOHO/LASCO images
I. Scale relativity and quantization of the solar system
ASTRONOMY AND ASTROPHYSICS 368 (3): 1108-1114 MAR 2001
We report an attempt to verify one of the predictions of Scale
Relativity
theory, namely that a small Vulcanoid should exist at 0.18 AU
from the Sun.
We have analyzed images taken by the coronograph LASCO aboard the
satellite
SOHO. Raw images are processed in order to eliminate cosmic ray
impacts,
stars and to improve the contrast. We have examined the resulting
cleaned-up
images both visually and by means of automatic detection using
our own
software. We have found no objects of visual magnitude 7 or
brighter,
corresponding to bodies with a diameter exceeding 60 km.
Addresses:
Schumacher G, CNRS, Observ Cote Azur, Dept Augustin Fresnel, UMR
6528, Av
Copernic, F-06130 Grasse, France
CNRS, Observ Cote Azur, Dept Augustin Fresnel, UMR 6528, F-06130
Grasse,
France
CNRS, Observ Cote Azur, Dept Augustin Fresnel, UMR 6528, F-06304
Nice 4,
France
Copyright © 2001 Institute for Scientific Information
=============
(14) YARKOVSKY-DRIVEN LEAKAGE OF KORONIS FAMILY MEMBERS
Vokrouhlicky D, Broz M, Farinella P, Knezevic Z: Yarkovsky-driven
leakage of
Koronis family members I. The case of 2953 Vysheslavia
ICARUS 150 (1): 78-93 MAR 2001
The orbit of the asteroid 2953 Vysheslavia is currently locked in
a tiny
chaotic zone very close to the 5:2 mean motion jovian resonance.
Its
dynamical lifetime is estimated to be of the order of only about
10 Myr.
Since Vysheslavia is a member of the Koronis family, such a short
dynamical
lifetime opens a variety of interesting questions concerning its
origin and
evolution. A. Milani and P. Farinella (1995, Icarus 115, 209-212)
considered
a number of plausible scenarios and suggested that most probably
Vysheslavia
is an outcome of a recent secondary fragmentation event in the
family. Here
we propose that Vysheslavia might have been placed on its
peculiar orbit by
a slow inward drift of the semimajor axis due to the Yarkovsky
effect.
Numerical simulations confirm that such evolutionary processes
can take
100-500 Myr, a period comparable to but still shorter than the
probable age
of the family ton the order of a Gyr), depending on the thermal
properties
of Vysheslavia's surface, the orientation of its spin axis, and
its size. we
have also integrated orbits of the asteroids 7340 (1991 UA(2))
and 1993
FR58, located very close to but outside the chaotic zone that
triggers
Vysheslavia's orbit instability, and we show that the orbits of
these
asteroids may also slowly evolve toward the chaotic zone. Such an
erosion of
the asteroid families, caused by a slow leakage to the nearby
powerful
resonances, could be fairly common in the main asteroid belt. (C)
2001
Academic Press.
Addresses:
Vokrouhlicky D, Charles Univ, Astron Inst, V Holesovickach 2,
CZ-18000
Prague 8, Czech Republic
Charles Univ, Astron Inst, CZ-18000 Prague 8, Czech Republic
Univ Trieste, Dipartimento Astron, I-34131 Trieste, Italy
Astron Observ, YU-11160 Belgrade 74, Yugoslavia
Copyright © 2001 Institute for Scientific Information
============
(15) LIGHTCURVE & COLOURS OF UNUSUAL MINOR PLANET 1998 WU24
Davies JK, Tholen DJ, Whiteley RJ, Green SF, Hillier JK, Foster
MJ, McBride
N, Kerr TH, Muzzerall E: The lightcurve and colors of unusual
minor planet
1998 WU24
ICARUS 150 (1): 69-77 MAR 2001
Minor planet 1998 WU24 is unusual in having the orbital
characteristics of a
Halley family comet but showing no sign of cometary activity. We
present
optical data that reveal a double-peaked lightcurve with a period
of 7.283
+/- 0.003 h and a peak-to-peak amplitude of similar to0.54 mag.
Infrared
spectroscopy and quasi-simultaneous BVRIJHK photometry reveal a
featureless
K-band spectrum and colors typical of D-type asteroids, and
suspected "bare"
comet nuclei (B-V = 0.78 +/- 0.034, V-R = 0.53 +/- 0.037, V-I =
0.99 +/-
0.035,V-J = 1.67 +/- 0,043, V-H = 2.10 +/- 0.076 and V-K = 2.34
+/- 0.102).
Image profiles from co-added frames in the R band indicate no
apparent
cometary activity, with an implied upper limit to the dust
production rate
of 150 g s(-1). Assuming a D-type albedo of 0.04 we derive a
spherical
equivalent diameter of 5.28 +/- 0.07 km although the lightcurve
amplitude
implies an irregular body with an axial ratio of 1.64: 1. We
conclude that
1998 WU24 is probably an inactive comet nucleus. (C) 2001
Academic Press.
Addresses:
Davies JK, Joint Astron Ctr, 660 N Aohoku Pl, Hilo, HI 96720 USA
Joint Astron Ctr, Hilo, HI 96720 USA
Inst Astron, Honolulu, HI 96822 USA
Univ Kent, Sch Phys Sci, Unit Space Sci & Astrophys,
Canterbury CT2 7NR,
Kent, England
Copyright © 2001 Institute for Scientific Information
==========
(16) SOLAR SAIL OPERATIONS AT ASTEROIDS
Morrow E, Scheeres DJ, Lubin D: Solar sail orbit operations at
asteroids
JOURNAL OF SPACECRAFT AND ROCKETS 38 (2): 279-286 MAR-APR
2001
The inherent capabilities of solar sails and that they need no
onboard
supplies of fuel for propulsion make them well suited for use in
long-term,
multiple-objective missions. They are especially well suited for
the
exploration of asteroids, where one spacecraft could rendezvous
with a
number of asteroids in succession. The orbital mechanics of solar
sail
operations about an asteroid, however, have not yet been studied
in detail.
Building an previous studies, we find both hovering points and
orbiting
trajectories about various sized asteroids using equations of
motion for a
solar sail spacecraft. The orbiting trajectories are stable and
offer good
coverage of the asteroid surface, although restrictions on sail
acceleration
are needed for smaller asteroids.
Addresses:
Morrow E, Univ Calif San Diego, Scripps Inst Oceanog 0214, Calif
Space Inst,
La Jolla, CA 92093 USA
Univ Calif San Diego, Scripps Inst Oceanog 0214, Calif Space
Inst, La Jolla,
CA 92093 USA
Univ Michigan, Dept Aerosp Engn, Ann Arbor, MI 48109 USA
Univ Calif San Diego, Scripps Inst Oceanog 0221, Calif Space
Inst, La Jolla,
CA 92093 USA
Copyright © 2001 Institute for Scientific Information
===========
(17) A POSSIBLE LONG-LIVED ASTEROID POPULATION AROUND SATURN
Melita MD, Brunini A: A possible long-lived asteroid population
at the
equilateral Lagrangian points of Saturn
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 322 (2):
L17-L21 APR 1
2001
The Lagrangian equilateral points of a planetary orbit are points
of
equilibrium that trail at 60 degrees, ahead (L4) or behind (L5),
the
trajectory of a planet. Jupiter is the only major planet in our
Solar system
harbouring a known population of asteroids at those locations.
Here we
report the existence of orbits close to the Lagrangian points of
Saturn,
stable at time-scales comparable to the age of the Solar system.
By scaling
with respect to the Trojan population we have estimated the
number of
objects that would populate the regions, which gives a
significant figure.
Moreover, mutual physical collisions over the age of the Solar
system would
be very rare, so the evaporation rare of this swarm arising from
mutual
interactions would be very low. A population of asteroids not
self-collisionally evolved after their formation stage would be
the first to
be observed in our planetary system. Our present estimations are
based on
the assumption that the capture efficiency at Saturn's
equilateral points is
comparable with the one corresponding to Jupiter, thus our
figures may be
taken as upper limits. In any case, observational constraints on
their
number would provide fundamental clues to our understanding of
the history
of the outer Solar system. If they existed, the surface
properties and size
distribution of those objects would represent unusually valuable
fossil
records of our early planetary system.
Addresses:
Melita MD, Univ Nacl La Plata, Astron Observ, Paseo Bosque
S-N,B1900FWA, La
Plata, Buenos Aires, Argentina
Univ Nacl La Plata, Astron Observ, La Plata, Buenos Aires,
Argentina
Copyright © 2001 Institute for Scientific Information
===========
(18) IMAGING OF SMALL-SCALE FEATURES ON EROS
Veverka J, Thomas PC, Robinson M, Murchie S, Chapman C, Bell M,
Harch A,
Merline WJ, Bell JF, Bussey B, Carcich B, Cheng A, Clark B,
Domingue D,
Dunham D, Farquhar R, Gaffey MJ, Hawkins E, Izenberg N, Joseph J,
Kirk R, Li
H, Lucey P, Malin M, McFadden L, Miller JK, Owen WM, Peterson C,
Prockter L,
Warren J, Wellnitz D, Williams BG, Yeomans DK: Imaging of
small-scale
features on 433 Eros from NEAR: Evidence for a complex regolith
SCIENCE 292 (5516): 484-488 APR 20 2001
On 25 October 2000, the Near Earth Asteroid Rendevous
(NEAR)-Shoemaker
spacecraft executed a low-altitude flyover of asteroid 433 Eros,
making it
possible to image the surface at a resolution of about 1 meter
per pixel.
The Images reveal an evolved surface distinguished by an
abundance of ejecta
blocks, a dearth of small craters, and smooth material infilling
some
topographic lows. The subdued appearance of craters of different
diameters
and the variety of blocks and different degrees of their burial
suggest that
ejecta from several impact events blanketed the region imaged at
closest
approach and led to the building up of a substantial and complex
regolith
consisting of fine materials and abundant meter-sized blocks.
Addresses:
Veverka J, Cornell Univ, Space Sci Bldg, Ithaca, NY 14853 USA
Cornell Univ, Ithaca, NY 14853 USA
Northwestern Univ, Dept Geol Sci, Evanston, IL 60208 USA
Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA
SW Res Inst, Boulder, CO 80302 USA
Rensselaer Polytech Inst, Ctr Sci, Dept Earth & Environm Sci,
Troy, NY 12180
USA
US Geol Survey, Flagstaff, AZ 86001 USA
Univ Hawaii, Hawaii Inst Geophys & Planetol, Honolulu, HI
96822 USA
Malin Space Sci Syst, San Diego, CA 92191 USA
Univ Maryland, Dept Astron, College Pk, MD 20742 USA
CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA
Copyright © 2001 Institute for Scientific Information
==========
(19) OBSERVATIONS OF 804 HISPANIA
Calabresi M, Roselli G: The rotation period of 804 Hispania: Some
considerations on its nature
ASTRONOMY AND ASTROPHYSICS 369 (1): 305-307 APR 2001
Photometric observations of 804 Hispania performed at the Teide
Observatory
during the opposition in September 1998 are presented and
analyzed. A
rotation period of 7.405 0.010 h was derived. It was possible to
confirm
that the lightcurve presents two maxima and minima. We discuss in
detail
some considerations on its nature.
Addresses:
Calabresi M, Frasso Sabino Observ, Assoc Roma Astrofili, Casella
Postale
4011, I-00100 Rome, Italy
Frasso Sabino Observ, Assoc Roma Astrofili, I-00100 Rome, Italy
Copyright © 2001 Institute for Scientific Information
==============
(20) AND FINALLY: TRADE GROWING IN STOLEN METEORITES
From the BBC News Online, 11 May 2001
http://news.bbc.co.uk/hi/english/uk/newsid_1324000/1324361.stm
Thieves may be stealing meteorites to order to feed a growing
international
trade, a BBC 5Live investigation has revealed.
Collectors are willing to pay vast sums for rare fragments of
rock from Mars
or the moon and there is increasing concern that thieves are now
stealing
them at their behest.
Meteorites, rock or metal fragments that have fallen to a
planet's surface
from space, have long been valued by scientists.
But now they are voraciously sought after by collectors and
traders.
A rare piece of lunar meteorite can sell for £20,000 a gram,
3,000 times the
price of gold.
Major thefts
And it is feared high prices and a ready market on the internet
are leading
criminals to target meteorites in collections and museums around
the world.
The BBC has learned of two major thefts in the past six months in
South
Africa and Germany.
Although police do not believe the two crimes were linked, the
value of the
stolen material is thought to run to several hundred thousand
pounds.
One of the pieces stolen in South Africa is said to be the only
fragment of
its kind in the world and has been described as
"scientifically priceless".
Police believe items are being stolen to order but fear thieves
may be
tempted to break large pieces into smaller fragments which are
easily sold
and virtually untraceable.
Copyright 2001, BBC
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