PLEASE NOTE:
*
CCNet 95/2001 - 30 August 2001
------------------------------
"The point from that is that the NASA Spaceguard goal (of 90
percent
of inner solar system asteroids larger than 1 km), which many
people have
criticized as being not ambitious enough, may in fact be
overdoing it.
Think carefully about the figures. Once one has found
three-quarters of
such objects then one has 60 percent of the hazard tied up (that
is,
three-quarters of 80 percent), with 20 percent of the hazard
still available
for attack by present means (80 minus 60): the brighter asteroids
in inner
solar system orbits, being found by relatively small telescopes.
But
that 20 percent is equalled by the 20 percent of the hazard (by
my
assumed figures) posed by Damocloids and active comets: objects
on
moderate-to long-period orbits that must be found on their
apparition of
impact when they are still at least beyond Saturn, and so in
essence
all are dark. This requires a deep, at least annual search of the
whole sky
with apertures of at least three metres, and preferably more.
That is
what needs to be done to make the biggest inroads into the
hazard, once
75 percent of the larger inner solar system Earth-crossing
asteroids have
been found."
--Duncan Steel, Salford University, 30 August 2001
"Our studies in southern China have revealed a remarkable
sulfur and
strontium isotope excursion at the end of the Permian, along with
a
coincident concentration of impact- metamorphosed grains and
kaolinite
and a significant decrease in manganese, phosphorous, calcium,
and
microfossils (foraminifera). These data suggest that an asteroid
or a comet
hit the ocean at the end of Permian time and caused a rapid and
massive
release of sulfur from the mantle to the ocean-atmosphere system,
leading to significant oxygen consumption, acid rain, and the
most
severe biotic crisis in the history of life on Earth."
--Kunio Kaiho et al, Geology: Vol. 29, No. 9, 2001
=================
(1) DAMN THOSE DAMOCLOIDS
Duncan Steel <D.I.Steel@salford.ac.uk>
(2) COMET-BOUND SPACECRAFT SAVED AGAIN
Space.com, 28 August 2001
(3) METEORITE HUNT IS ON IN COLORADO
Ron Baalke <baalke@jpl.nasa.gov>
(4) EXPERTS GET LOTS OF AID IN COLORADO METEORITE HUNT
Ron Baalke <baalke@jpl.nasa.gov>
(5) EARTH'S LIGHT SHOW IS A CLUE TO FINDING HABITABLE NEIGHBOURS
Andrew Yee <ayee@nova.astro.utoronto.ca>
(6) WEIRED CHEMISTY: RADIATION-DRIVEN REACTIONS ON JUPITER'S
MOONS
Andrew Yee <ayee@nova.astro.utoronto.ca>
(7) END-PERMIAN CATASTOPHE BY COSMIC IMPACT
Kunio Kaiho, et al.
(8) DEVELOPMENT OF A TARGET MARKER FOR LANDING ON ASTEROIDS
Sawai S, et al.
(9) THE ARCETRI NEO PRECOVERY PROGRAMME
Boattini A, et al.
(10) PHOTEMETRIC OBSERVATIONS OF 9 NEOS
Szabo GM, et al.
(11) GROUNDBASED INVESTIGATIONS OF ASTEROID 9969
Lazzarin M, et al.
(12) DETERMINATION OF ASTEROID MASSES
Michalak G
(13) DYNAMICAL CAUSES OF ASYMMETRY IN THE ARRANGEMENTS OF GAPS IN
THE
ASTEROID BELT
Markeev AP
(14) THE SIZE-FREQUENCY DISTRIBUTION OF THE ZODIACAL CLOUD
Grogan K, et al.
(15) THE ROTATION AXIS OF THE CENTAUR 5145 PHOLUS
Farnham TL
(16) THE PUZZLING CASE OF THE NYSA-POLANA FAMILY
Cellino A, et al.
(17) FORMATION OF MESOSIDERITES
Edward RDS, et al.
(18) A PAIR OF RESONANT PLANETS
Marcy GW. et al.
(19) RE: FROM MARS TO EARTH IN A METEORITE?
Jeff Foust <jeff@spacetoday.net>
(20) AND FINALLY: "MASTER CLASS ON ASTEROID GODDESS"
Boston Globe, 28 August 2001
==========
(1) DAMN THOSE DAMOCLOIDS
>From Duncan Steel <D.I.Steel@salford.ac.uk>
Dear Benny,
In CCNet dated 2001 August 28 you carried an interesting item
from
astronomy.com by Vanessa Thomas concerning the newly-discovered
'Damocloid'
2001 OG108, likely the largest known Earth-crossing asteroid. I'd
like to
make a few comments about the significance of this and similar
objects; that
is, Earth-crossing asteroids on Halley-type orbits. The high
inclination of
this object (80 degrees) adds weight to the conviction that it
may well be
an extinct (or dormant) comet. That in turn leads to an idea that
the albedo
is low (a few percent) and so the size in somewhat larger than
would be
calculated based on typical asteroidal albedos, as Ted Bowell
suggested: 15
km or maybe more. To tie this down it would be useful if thermal
infra-red
observations could be made as the object get closer to the Sun,
rendering
the albedo and hence the size. Similarly a cometary nature -
cometary
outgassing activity, I mean - might be indicated by high spatial
resolution
imaging showing a coma, or high spectral resolution observations
showing
emission lines.
Let me compliment the LONEOS team on their interesting discovery.
There is
more to it than that, though. Two Damocloids are now known with
Earth-crossing orbits, this one and 1999 XS35, the latter being
1-2 km in
size (absolute magnitude H=17.2). Both have been found by LONEOS.
Given that
LONEOS discovers only a small fraction of all NEOs (due to the
high
productivity of LINEAR, NEAT and Spacewatch, rather than any
fault of
LONEOS), this requires an explanation unless one puts it down to
chance.
There are of course various other Damocloids with perihelia
outside the
terrestrial orbit (such as 1996 PW found by NEAT, and 1997 MD10,
1998 QJ1,
2000 AB229, 2000 DG8, 2001 QF6 and (20461) 1999 LD31 found by
LINEAR, and
(15504) 1999 RG33 found by the Catalina Sky Survey, and 2000 VU2
found by
W.K. Yeung, plus 2000 HE46 found by LONEOS: see
http://cfa-www.harvard.edu/iau/lists/Others.html),
but the fact remains that
it is LONEOS that has turned up the two Earth-crossers amongst
them all.
Let us step back a decade. After we found Damocles at the
Anglo-Australian
Observatory in 1991 (it was actually Rob McNaught who spotted it,
as 1991
DA, on a photographic plate taken using the UK Schmidt
Telescope), we
predicted that awaiting discovery there must be many dark
asteroids on
elongated, comet-like orbits crossing the path of the Earth. It
is nice to
see that prediction being borne out at last, even if they do pose
a worrying
danger to us. (5335) Damocles itself has a present orbit that
comes sunwards
only so far as to just overlap the aphelion distance of
Mars, but its orbital instability is obvious (see, for example,
D.J. Asher,
M.E. Bailey, G. Hahn & D.I. Steel, 'Asteroid 5335 Damocles
and its
implications for cometary dynamics,' Monthly Notices of the Royal
Astronomical Society, 267, 26-42, 1994), and so the name given it
should
not be surprising to anyone knowing the story of the Sword of
Damocles.
Based solely on the existence of Damocles, David Asher and I
suggested that
perhaps ten percent of the large-body (>1-km) impact hazard
might be due to
dark Halley-type asteroids:
D.I. Steel & D.J. Asher, 'The past and future orbit of
(extinct
comet?) 1991 DA,' pp.65-73 in Periodic Comets (eds. J.A.
Fernandez & H.
Rickman), Universidad de la Republica, Montevideo, Uruguay, 1992.
Damocles itself, though, is large (H=13.3, much the same as the
H=13.0 of
2001 OG108). Asher and I were working on the assumption that some
form of
usual mass distribution would rule among Damocloids, with much
larger
numbers of smaller objects yet unseen. Both the LONEOS
discoveries in
question are rather larger than the norm for present NEO
discoveries, 2001
OG108 very much so. One might then suggest that this is because
LONEOS has a
small aperture (limiting discoveries to brighter objects), but
its wide
field explains why the other programmes have not turned up
similar objects. However, if indeed there are many smaller
(<2-km)
Earth-crossing Damocloids then one might expect the search
projects using
larger apertures (LINEAR, NEAT, Spacewatch) to have turned some
of them up.
One wonders, then, whether they do exist; or is there some
systematic
selection effect that is stopping the other searches from
detecting them?
Let me caution again, though, that this is based on a statistic
of just two
objects. On the other hand, all the Damocloids known are large
(bigger than
2 km, most much larger).
The existence or otherwise of a significant population of (say)
0.3 to 2 km
dark asteroids in Halley-type orbits is an important one from the
perspective of planetary defence. For the sake of argument, let
us assume
that the above given proportion of the impact hazard due to these
Damocloids
(10 percent) is broadly correct. There are arguments over the
proportion due
to active comets, long-period or otherwise, but again 10 percent
is in the
right ballpark. Together those make 20 percent, leaving 80
percent as being
the contribution of asteroids in inner solar system orbits. I
won't worry
about renormalisation: the figures are hazy, and if we knew the
real figures
then we'd know a lot more than we do now.
The point from that is that the NASA Spaceguard goal (of 90
percent of inner
solar system asteroids larger than 1 km), which many people have
criticized
as being not ambitious enough, may in fact be overdoing it. Think
carefully
about the figures. Once one has found three-quarters
of such objects then one has 60 percent of the hazard tied up
(that is,
three-quarters of 80 percent), with 20 percent of the hazard
still available
for attack by present means (80 minus 60): the brighter asteroids
in inner
solar system orbits, being found by relatively small telescopes.
But that 20
percent is equalled by the 20 percent of the hazard (by my
assumed figures)
posed by Damocloids and active comets: objects on moderate-to
long-period
orbits that must be found on their apparition of impact when they
are still
at least beyond Saturn, and so in essence all are dark. This
requires a
deep, at least annual search of the whole sky with apertures of
at least
three metres, and preferably more. That is what needs to be done
to make the
biggest inroads into the hazard, once 75 percent of the larger
inner solar
system Earth-crossing asteroids have been found. The time is upon
us.
One might argue that this is applying a lot of leverage to a
handful of
discoveries. The counter-argument is that the spotting of even
these few
dark Damocloids is a strong indicator of our lack of knowledge of
the
hazardous objects in the solar system. We must know more. We
are
dangerously ignorant.
Finally I note that the existence of large objects like 2001
OG108 on
Earth-crossing orbits must lead to a re-assessment of the
expected frequency
of impacts of sufficient energy to cause a mass extinction event.
Duncan Steel
=============
(2) COMET-BOUND SPACECRAFT SAVED AGAIN
>From Space.com, 28 August 2001
http://www.space.com/missionlaunches/ds1_fix_010828-1.html
By Robin Lloyd
Science Editor
NASA engineers have fixed a navigational glitch on the agency's
Deep Space 1
(DS1) probe after it was buffeted by solar weather, and the
spacecraft
remains on track for an attempted flyby of a comet next month.
The ion-propelled spacecraft lost focus on the stars it uses for
navigation
on Tuesday, Aug. 21, sending DS1 somewhat off course for nearly
three days.
Engineers suspect that a gust of ionized particles from the Sun
blurred the
vision on a science camera DS1 now uses for navigation, throwing
the probe
off craft.
If you think of a clock with its hands at noon to represent the
correct
pointing direction for the spacecraft, the error caused by the
glitch would
amount to pointing the craft at 15 seconds after noon, said DS1
Project
Manager Marc Rayman.
"It wasn't a gross error, but given that the field of view
of science camera
is very narrow and you have tight tolerances when flying a
spacecraft, that
was a big error for us," Rayman said.
Contrary to some media reports, the trouble was fixed in time for
a planned
initial observation of the probe's ultimate goal -- Comet
Borrelly, which
DS1 will attempt to fly by on Sept. 22.
Copyright 2001, Space.com
============
(3) METEORITE HUNT IS ON IN COLORADO
>From Ron Baalke <baalke@jpl.nasa.gov>
http://www.denverpost.com/Stories/0,1002,53%257E122416,00.html
Meteoric hunt is on for source of fireball
By Ann Schrader
Denver Post
Tuesday, August 28, 2001 - A fireball that lit up a wide swath of
the
Western sky on Aug. 17 was big, noisy - and it's missing.
Not missing, really; it just hasn't been found. Scientists from
the Denver
Museum of Nature & Science are on its hot trail, but they
need a little help
in pinpointing where it landed in Colorado.
The meteorite hunters have some clues about the blazing piece of
celestial
debris that was visible from Idaho to New Mexico: It was an
estimated 40
times brighter than a full moon; it may have weighed about a ton
when it
entered the atmosphere; it was moving at 11.25 miles per second;
and it
boomed and crackled.
>From eyewitness interviews, Murphy and two other museum
researchers have
pegged landfall in a 100-mile-square area in the eastern La
Garita Mountains
in Saguache County in the Rio Grande National Forest.
Full story here:
http://www.denverpost.com/Stories/0,1002,53%257E122416,00.html
=============
(4) EXPERTS GET LOTS OF AID IN COLORADO METEORITE HUNT
>From Ron Baalke <baalke@jpl.nasa.gov>
http://www.denverpost.com/Stories/0,1002,53%257E124425,00.html
Experts get lots of aid in finding meteorite
By Ann Schrader
Denver Post
Wednesday, August 29, 2001 - From a new round of witnesses to a
self-described "meteorite junkie," hundreds of
Coloradans are following the
hunt for the brilliant fireball that slammed into the state on
Aug. 17.
More than 150 people called or sent e-mails to the geology
department at the
Denver Museum of Nature & Science on Tuesday claiming to have
seen the
meteor after The Denver Post published a story about the search
for the
space debris. The meteorite is believed to have landed somewhere
in a
mountainous 100 square miles between Creede and Saguache.
Full story here:
http://www.denverpost.com/Stories/0,1002,53%257E124425,00.html
===========
(5) EARTH'S LIGHT SHOW IS A CLUE TO FINDING HABITABLE NEIGHBOURS
>From Andrew Yee <ayee@nova.astro.utoronto.ca>
News from PRINCETON UNIVERSITY
Office of Communications
Stanhope Hall
Princeton, New Jersey 08544-5264
Telephone 609-258-3601; Fax 609-258-1301
Contact:
Steven Schultz, (609) 258-5729, sschultz@princeton.edu
August 29, 2001
Earth's light show is a clue to finding habitable neighbors
Viewed from a star in some other corner of the galaxy, Earth
would be a
speck, a faint blue dot hidden in the blazing light of our sun.
Would there be any hint of that speck's amazing diversity of
life? According
to a paper in the Aug. 30 issue of Nature, a savvy alien would
find at least
one important clue: an interesting flicker in the pale blue
light.
While our neighbors Venus and Mars would reflect a fairly even
glow, Earth
would put on a little show. Earth's light would brighten and dim
as it
spins, because oceans, deserts, forests and clouds -- which are
all too
small to be seen from such a distance -- reflect varying amounts
of
sunlight. The variations, it turns out, are so strong and
distinctive that a
surprising amount of information could be taken from a simple ebb
and flow
of light.
Scientists at Princeton University and the Institute for Advanced
Study
conducted a detailed study of Earth's reflections not for
insights into an
alien's view of our home planet, but as a way for human
scientists to learn
about distant planets that may be like our own. They are
participating in
the early planning for a NASA mission known as the Terrestrial
Planet
Finder, a space probe that will scan the skies for planets
hospitable to
life.
"If you looked at our solar system from far away, and you
looked at the
terrestrial planets -- Mercury, Venus, Earth and Mars -- one of
the quickest
ways to see that Earth is unique is by looking at the light
curve," said Ed
Turner, professor of astrophysics and a co-author of the study.
"Earth has
by far the most complicated light curve."
Eric Ford, a graduate student, and Sara Seager, a member of the
Institute
for Advanced Study, developed the idea in collaboration with
Turner.
The standard thinking in the field had been that most of the
information
about an Earth-like planet would come from spectral analysis, a
static
reading of the relative component of different colors within the
light,
rather than a reading of changes over time. Spectral analysis
would reveal
the presence of gasses such as water vapor, carbon dioxide and
oxygen, in
the planet's atmosphere.
Looking at the change in light over time does not replace
spectral analysis,
but it could greatly increase the amount of information
scientists could
learn, said Turner. It may indicate, for example, the presence of
weather,
oceans, ice or even plant life.
"It's just one more tool, one more approach to a very tough
problem," said
Turner.
Although the idea that a planet's light would vary seems
straightforward,
the three scientists had no idea whether that variation would be
large or
small or what it would look like. After all, there are precious
few
opportunities to look at Earth from afar, noted Turner. He and
colleagues
reached their conclusions by studying existing research on the
light-scattering properties of everything from cornfields to
ocean waves.
They then invented computer models of Earth that incorporated the
data. The
results showed variations in light of up to 150 percent over the
course of a
day, with characteristic signatures for different terrestrial
features such
as deserts, forests and oceans.
Turner said he and colleagues will continue to refine the idea.
One possible
way to test their conclusions is to measure changes in how much
light from
Earth is reflected off the moon, a phenomenon known as
earthshine. But the
real test will be if and when someone finds the first Earth-like
planet.
That moment could come in the next decade or so. NASA is
exploring several
alternatives for a planet-finding mission that would launch in
2012 or
beyond, and also is seeking plans for smaller projects that could
be
launched in just a few years.
With characteristic understatement, Turner noted that if
Earth-like planets
were found "they would presumably be objects of tremendous
interest."
==========
(6) WEIRED CHEMISTY: RADIATION-DRIVEN REACTIONS ON JUPITER'S
MOONS
>From Andrew Yee <ayee@nova.astro.utoronto.ca>
RESEARCH NEWS & PUBLICATIONS OFFICE
Georgia Institute of Technology
430 Tenth Street, N.W., Suite N-116
Atlanta, Georgia 30318 USA
MEDIA RELATIONS CONTACTS:
John Toon
404-894-6986 Fax: 404-894-4545
E-mail: john.toon@edi.gatech.edu
or
Jane Sanders
404-894-2214 Fax: 404-894-6983
E-mail: jane.sanders@edi.gatech.edu
TECHNICAL CONTACT:
Thomas Orlando
Georgia Tech School of Chemistry and Biochemistry
404-894-4012
E-mail: thomas.orlando@chemistry.gatech.edu
Writer: John Toon
For Immediate Release: August 29, 2001
Weird Chemistry: Researchers Study Unique Radiation-Driven
Reactions in
Extreme Cold and High Vacuum of Jupiter's Moons
By his own admission, Thomas Orlando deals with "weird
chemistry." In fact,
the Georgia Institute of Technology researcher studies chemical
processes
that are literally out of this world -- reactions occurring on
the moons of
Jupiter, driven by extreme radiation at ultra-cold temperatures.
Based on laboratory simulations, work by Orlando and other
researchers is
helping planetary scientists understand data reported by a NASA
spacecraft
flying past the Galilean satellites Europa, Ganymede and
Callisto. The
studies provide new insight into the unique chemical reactions
that take
place on extremely cold icy surfaces under high vacuum, driven by
high-energy electrons and ions rather than normal thermal
processes.
The moons, which are gravitationally locked to Jupiter, co-rotate
with
Jupiter and lie within Jupiter's intense magnetosphere. Here they
are
constantly bombarded by radiation with the trailing sides
receiving a
greater radiation dose than the leading sides.
"When the magnetospheric particles (ions and electrons) are
smashing into
the surface of the moons, strange things happen even though the
surface is
about as cold as cold can be. Radicals are produced, ionization
occurs and
reactive species produce materials that wouldn't normally be
produced,"
explained Orlando, a professor in Georgia Tech's School of
Chemistry and
Biochemistry. "The bottom line is that weird chemistry goes
on when there is
too much energy."
Orlando discussed aspects of this "weird chemistry" at
the 222nd national
meeting of the American Chemical Society on August 29th in
Chicago. His
presentation was part of a chemical education section on the
importance of
radiation and high-energy chemistry in both the laboratory and
the real
world -- which includes the outer reaches of our solar system.
Near-infrared data sent from the Galileo spacecraft in 1997
indicated the
presence of frozen brine on the surface of Europa. This
suggestion was
mainly discussed by McCord and co-workers (Science 280, 1242-45,
1998) and
many planetary scientists believed the brine could have
originated in a
subsurface ocean beneath Europa's frozen crust. Brought to the
surface by
cryo-volcanic action, the brine would have been flash-frozen in
the extreme
cold (below 130 degrees Kelvin, or minus 145 degrees Celsius) and
ultra-high
vacuum (less than 10**-10 Torr).
To test that hypothesis, a team of scientists led by Orlando
(formerly of
Pacific Northwest National Laboratory) and Prof. Tom McCord of
the
University of Hawaii, duplicated the freezing of brine under
similar
conditions of temperature and vacuum, then cycled the samples
through the
thermal changes that occur on the surface of Europa.
Near-infrared analysis
of the resulting samples showed characteristics similar to what
the
spacecraft reported, supporting the brine theory.
"We made some pretty good connections to what the planetary
scientists had
seen on the surface of these moons," said Orlando. "We
thought about flash
freezing from the chemical physics standpoint because if you
freeze the
brine fast enough, you can 'lock' the waters of hydration into
their local
positions. These water molecules should have a different optical
signature
than the rest of the water molecules in ice."
Spacecraft have also measured oxygen molecules (O2) as part of a
tenuous
atmosphere on the moons. To understand how oxygen could be
produced and
liberated from extremely cold ice on the moons, Orlando's
research team at
Pacific Northwest National Laboratory bombarded ice samples with
an electron
beam much like those used in the microelectronics industry. The
result was
an unexpected reaction that involved the production of a stable
precursor
molecule that would not form under conditions seen by most
chemists.
Simulations may also help scientists construct a time line for
tracking the
evolution and transformation of the moons' surfaces. Since the
high
radiation is constantly changing the ice, understanding the rate
at which
those processes occur might allow researchers to date them --
particularly
if changes can be measured from one space mission to the next.
Beyond the Galilean satellites, Orlando's interest extends to
Mars, comets,
asteroids and even the dust found in space. "Radiation
induced processes are
generally the rule in outer space," he said. "They're
not limited to just
one system. We are just simulating what cosmic rays do. Cosmic
rays produce
electrons so we study the chemistry these electrons
initiate."
A chemical physicist, Orlando began studying chemical reactions
driven by
radiation while a researcher at Pacific Northwest National
Laboratory.
There, the interest was in the effects of radiation on production
of
hydrogen and oxygen from nuclear waste. Transitioning that
knowledge to
planetary science shows the value of interdisciplinary studies,
Orlando
says.
"We're working in an interesting area where chemical
physics, surface
science and radiation chemistry can help planetary scientists
address the
issues raised by the really superb mission data," he noted.
"The planetary
science community is getting data so good that we can take a
molecular view
of what's happening."
At Georgia Tech, Orlando has established a laboratory to continue
the study
of radiation effects on icy surfaces. Using equipment that can
produce
ultra-high vacuum and temperatures down to 15 Kelvin, he plans to
study the
production of hydrogen molecules, and to better understand how
small changes
in the processing conditions affect the characteristics of the
very cold ice
and what can be driven from it.
"The surface morphology and the surface temperature greatly
affect the
products you make," he said. "At one temperature, you
might make a lot of
O2. At another temperature, you may just sputter off water
molecules and get
water into the gas phase. The general radiation processing of
low-temperature water is still not completely
characterized."
Also on the agenda: photochemistry studies of iron oxides on
Mars, sulfuric
acid interaction with radiation -- and possible nanotechnology
and medical
applications using controlled electron-beam technology.
The research is sponsored by NASA and the Department of Energy.
The research
team conducting the brine studies included Thomas McCord, Gary
Hansen, and
Lisa Van Keulen of the University of Hawaii, and Glenn Teeter,
Matthew
Sieger and William Simpson of the Pacific Northwest National
Laboratory. A
paper on brine work was published in Volume 106 of the Journal of
Geophysical
Research. A paper on the oxygen production was published in
volume 394 of
Nature.
Related Information: NASA's Jet Propulsion Laboratory provides a
complete
overview of the Galileo mission, including images of the Jupiter
moons, at
http://galileo.jpl.nasa.gov
IMAGE CAPTIONS:
[ http://gtresearchnews.gatech.edu/newsrelease/jupiterice.html
]
[Image 1]
Prof. Thomas Orlando and Doctoral Student Janine Herring study
data from a
simulation. Orlando's research focuses on unique chemical
reactions driven
by radiation -- such as those occurring on the icy surfaces
of Jupiter's
moons. (Georgia Tech photo by Gary Meek, Georgia Tech
Research Corporation)
[Image 2]
Prof. Thomas Orlando and Doctoral Student Janine Herring adjust
components
on equipment used to bombard icy surfaces with an electron beam.
The system
is used to study the unique chemical reactions that occur on
Jupiter's
moons. (Georgia Tech Photo by Gary Meek, Georgia Tech Research
Corporation)
=========
(7) END-PERMIAN CATASTOPHE BY COSMIC IMPACT
Geology: Vol. 29, No. 9, pp. 815-818.
End-Permian catastrophe by a bolide impact: Evidence of a
gigantic release
of sulfur from the mantle
Manuscript Received by the Society November 27, 2000
Revised Manuscript Received May 1, 2001
Manuscript Accepted May 18, 2001
ABSTRACT
Our studies in southern China have revealed a remarkable sulfur
and
strontium isotope excursion at the end of the Permian, along with
a
coincident concentration of impact-metamorphosed grains and
kaolinite and a
significant decrease in manganese, phosphorous, calcium, and
microfossils
(foraminifera). These data suggest that an asteroid or a comet
hit the ocean
at the end of Permian time and caused a rapid and massive release
of sulfur
from the mantle to the ocean-atmosphere system, leading to
significant
oxygen consumption, acid rain, and the most severe biotic crisis
in the
history of life on Earth.
Addresses:
Kunio Kaiho*
Institute of Geology and Paleontology, Tohoku University, Sendai
980-8578,
Japan
Yoshimichi Kajiwara and Takanori Nakano
Institute of Geoscience, University of Tsukuba, Ibaraki 305,
Japan
Yasunori Miura
Department of Earth Sciences, Faculty of Science, Yamaguchi
University,
Yamaguchi 753-8512, Japan
Hodaka Kawahata
Marine Geology Department, Geological Survey of Japan, Ibaraki
305-8567,
Japan
Kazue Tazaki and Masato Ueshima
Department of Earth Sciences, Kanazawa University, Kanazawa
920-1192, Japan
Zhongqiang Chen and Guang R. Shi
School of Ecology and Environment, Deakin University, Rusden
Campus, 662
Blackburn Road, Clayton, Victoria 3168, Australia
© Copyright by Geological Society of America 2001
================
(8) DEVELOPMENT OF A TARGET MARKER FOR LANDING ON ASTEROIDS
Sawai S, Kawaguchi J, Scheeres D, Yoshizawa N, Ogasawara M:
Development of a
target marker for landing on asteroids JOURNAL OF SPACECRAFT AND
ROCKETS 38
(4): 601-608 JUL-AUG 2001
The proposed asteroid sample return mission MUSES-C calls for a
spacecraft
to approach an asteroid, touch down on its surface, and collect
samples that
will be returned to Earth. During the touchdown and sampling
phase, the
spacecraft will navigate relative to the asteroid surface using
optical
target markers placed on the asteroid surface before the final
approach. By
using the target marker as a reference point, navigation during
the landing
phase will be much more reliable and precise. Because of the
microgravity
environment on the asteroid surface, the settling time and
dynamics of the
target markers are items of interest. Thus, it is important to
design the
target marker with as small a coefficient of restitution as
possible to
minimize the settling time, which in turn minimizes the time the
spacecraft
must hover above the asteroid surface. To achieve this small
coefficient of
restitution, the target marker will be constructed out of a bag
with balls
stored internally. On impact, the balls will dissipate energy
relative to
each other and, hence, will dissipate the total energy of the
target marker.
To better predict the performance of such a target marker,
analytical and
numerical investigations are performed that model the motion of a
bouncing
target marker across the surface of a rotating asteroid. As a
result of the
analysis, some target limits on the target marker coefficient of
restitution
are developed. A series of microgravity tests are reported that
confirm the
basic design and show that the target value of coefficient of
restitution
can be reached.
Addresses:
Sawai S, Univ Michigan, Dept Aerosp Engn, Ann Arbor, MI 48109 USA
Univ Michigan, Dept Aerosp Engn, Ann Arbor, MI 48109 USA
Inst Space & Astronaut Sci, Space Syst Engn Div, Sagamihara,
Kanagawa
2298510, Japan
NEC Aerosp Syst Ltd, Engn Dept 1, Syst Div 1, Yokohama, Kanagawa
2248555,
Japan
Copyright © 2001 Institute for Scientific Information
========
(9) THE ARCETRI NEO PRECOVERY PROGRAMME
Boattini A, D'Abramo G, Forti G, Gal R: The Arcetri NEO Precovery
Program
ASTRONOMY & ASTROPHYSICS 375 (1): 293-307 AUG 2001
The Arcetri Near Earth Object Precovery Program (ANEOPP) is a
project
dedicated to the identification of images of Near Earth Objects
(NEOs) on
past archival materials, an activity usually referred to as
precovery. Going
years back in time to locate such images results in the
acquisition of very
good orbital information, which, in turn, allows astronomers to
perform more
accurate studies of the dynamical evolution and physical
characterization of
NEOs, as well as improve assessments of their impact hazard. We
discuss the
tasks involved in this work and the basic techniques used to
yield
successful identifications on photographic plates. Begun in
mid-1999, ANEOPP
has precovered more than 70 NEOs to date, which were previously
observed
only during the discovery apparition. The keys to obtaining these
results
have been: i) easy access to competitive collections both in
digital form
and as plastic copies; ii) traveling to additional collections;
iii) the
recent development of reliable algorithms to determine the
boundaries of the
recovery region, which is the portion of the celestial sphere
where an
asteroid with an uncertain orbit can be found at a given time.
Addresses:
Boattini A, Osserv Astron Roma, Via Frascati 33, I-00040 Rome,
Italy
Osserv Astron Roma, I-00040 Rome, Italy
CNR, IAS, I-00133 Rome, Italy
Osserv Astrofis Arcetri, I-50122 Florence, Italy
Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218
USA
Copyright © 2001 Institute for Scientific Information
============
(10) PHOTEMETRIC OBSERVATIONS OF 9 NEOS
Szabo GM, Csak B, Sarneczky K, Kiss LL: Photometric observations
of 9
near-earth objects
ASTRONOMY & ASTROPHYSICS 375 (1): 285-292 AUG 2001
We present new CCD observations of nine Near-Earth Asteroids
carried out
between February, 1999 and July, 2000. The bulk of the data was
acquired
through an R-C filter, while the minor planet 11 405 was observed
without
filter. We could determine synodic periods and amplitudes for 5
asteroids,
699: 3.(h)3, 0.(m)18; 1866: 2.(h)7, 0.(m)12; 1999 JD6: 7.(h)68,
1.(m)2; 2000
GK137: 4.(h)84, 0.(m)27; 2000 NM: 9.(h)24, 0.(m)30. Based on
observations
taken at different phases, we could infer a phase parameter m of
0.018 +/-
0.005 for 1865 Cerberus. An epoch-method yielded a sidereal
period of
0.(d)27024003(5) for this object with retrograde rotation. The
remaining 3
objects have only partial coverage, thus no firm conclusion on
their synodic
period is possible.
Addresses:
Kiss LL, Univ Szeged, Dept Expt Phys, Dom Ter 9, H-6720 Szeged,
Hungary
Univ Szeged, Dept Expt Phys, H-6720 Szeged, Hungary
Univ Szeged, Astron Observ, H-6720 Szeged, Hungary
Univ Szeged, Dept Opt & Quantum Elect, H-6701 Szeged, Hungary
Univ Szeged, Astron Observ, H-6701 Szeged, Hungary
ELTE Univ, Dept Phys Geog, H-1088 Budapest, Hungary
Copyright © 2001 Institute for Scientific Information
===============
(11) GROUNDBASED INVESTIGATIONS OF ASTEROID 9969
Lazzarin M, Fornasier S, Barucci MA, Birlan M: Groundbased
investigation of
asteroid 9969 Braille, target of the spacecraft mission Deep
Space 1
ASTRONOMY & ASTROPHYSICS 375 (1): 281-284 AUG 2001
Asteroid 9969 Braille (1992 KD) was encountered on July 29, 1999
by the Deep
Space 1 mission, the first of NASA's New Millennium Program,
launched on
October 24 1998. The data obtained by the space mission seem to
indicate a
composition of the object similar to that of Vesta. To complete
the
information obtained in the infrared region by the Deep Space 1
mission we
have performed a visible spectroscopic and photometric
investigation of the
asteroid respectively with the 1.5 m telescope and the NTT of
ESO, La Silla.
The spectrum was obtained in the spectral range 4500-8200
Angstrom and, for
the photometry, BVRI filters were used. In this paper we report
the results
of the analysis of the data obtained indicating that, on the
basis of our
visible data, the composition of the asteroid may range from
V-type to
Q-type, but we observe also a strong similarity to the H-type
ordinary
chondrites.
Addresses:
Lazzarin M, Dipartimento Astron, Vic Osservatorio 5, I-35122
Padua, Italy
Dipartimento Astron, I-35122 Padua, Italy
Observ Paris, F-92195 Meudon, France
Copyright © 2001 Institute for Scientific Information
=================
(12) DETERMINATION OF ASTEROID MASSES
Michalak G: Determination of asteroid masses - II. (6) Hebe, (10)
Hygiea,
(15) Eunomia, (52) Europa, (88) Thisbe, (444) Gyptis, (511)
Davida and (704)
Interamnia
ASTRONOMY & ASTROPHYSICS 374 (2): 703-711 AUG 2001
New masses of eight asteroids: (6) Hebe, (10) Hygiea, (15)
Eunomia, (52)
Europa, (88) Thisbe, (444) Gyptis, (511) Davida, and (704)
Interamnia, were
determined. In most cases, the masses were calculated by means of
the
least-squares method as the weighted means of the values found
separately
from the perturbations on several single asteroids. Encounters
suitable for
determination of masses of these asteroids were found from the
extensive
search for large asteroidal perturbations exerted by massive
asteroids on
4500 numbered minor planets. Most of the encounters found within
the search
had never before been used for mass determinations. The masses of
Hebe,
Hygiea, Eunomia, Europa, Thisbe, Gyptis, Davida and Interamnia
were
determined from perturbations on, respectively, 2, 8, 3, 4, 1, 1,
2 and 3
asteroids. As an outcome of the search for possible perturbers
among the 912
largest asteroids, we propose and use correct dynamical models
including
important perturbers for all asteroids under consideration. For
all new
asteroid masses, the influence of the variation of the masses of
asteroids
in the dynamical model is investigated. A discussion on
individual mass
determinations is also presented.
Addresses:
Michalak G, Wroclaw Univ Observ, Kopernika 11, PL-51622 Wroclaw,
Poland
Wroclaw Univ Observ, PL-51622 Wroclaw, Poland
Copyright © 2001 Institute for Scientific Information
============
(13) DYNAMICAL CAUSES OF ASYMMETRY IN THE ARRANGEMENTS OF GAPS IN
THE
ASTEROID BELT
Markeev AP: Dynamical causes of asymmetry in the arrangement of
gaps in the
asteroid belt
ASTRONOMY LETTERS-A JOURNAL OF ASTRONOMY AND SPACE ASTROPHYSICS
27 (7):
475-479 JUL 2001
The centers of the gaps observed in the asteroid belt are
displaced toward
Jupiter from their positions that correspond to the exact
commensurability
between the mean motions of an asteroid and Jupiter. Using the
current
theory of stability and nonlinear oscillations of Hamiltonian
systems, we
point out the dynamical causes of this asymmetry. Our analysis is
performed
in terms of the plane circular restricted three-body problem. The
orbits
that correspond to Poincare periodic solutions of the first kind
are taken
as unperturbed asteroid orbits. (C) 2001 MAIK
"Nauka/Interperiodica".
Addresses:
Markeev AP, Russian Acad Sci, Inst Problems Mech, Pr Vernadskogo
101, Moscow
117526, Russia
Russian Acad Sci, Inst Problems Mech, Moscow 117526, Russia
Copyright © 2001 Institute for Scientific Information
=============
(14) THE SIZE-FREQUENCY DISTRIBUTION OF THE ZODIACAL CLOUD
Grogan K, Dermott SF, Durda DD: The size-frequency distribution
of the
zodiacal cloud: Evidence from the solar system dust bands ICARUS
152 (2):
251-267 AUG 2001
Recent observations of the size-frequency distribution of
zodiacal cloud
particles obtained from the cratering record on the LDEF
satellite are the
latest evidence for a significant large particle population
(100-mum
diameter or greater) near 1 AU. Our previous modeling of the
Solar System
dust bands, features of the zodiacal cloud associated with the
comminution
of Hirayama family asteroids, has been limited by the fact that
only small
particles (25-mum diameter or smaller) have been considered. This
was due to
the prohibitively large amount of computing power required to
numerically
analyze the dynamics of larger particles. The recent availability
of
inexpensive, fast processors has finally made this work possible.
Models of
the dust bands are created, built from individual dust particle
orbits,
taking into account a size-frequency distribution of the material
and the
dynamical history of the constituent particles. These models are
able to
match both the shapes and amplitudes of the dust band structures
observed by
IRAS in multiple wavebands. The size-frequency index, q, that
best matches
the observations is approximately 1.4, a distribution in which
the surface
area (and hence the infrared emission) is dominated by large
particles.
However, in order to successfully model the "ten
degree" band, which is
usually associated with collisional activity within the Eos
family, we find
that the mean proper inclination of the dust particle orbits has
to be
approximately 9.35 degrees, significantly different from the mean
proper
inclination of the Eos family (10.08 degrees). (C) 2001 Academic
Press.
Addresses:
Grogan K, NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD
20771 USA
NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA
Univ Florida, Dept Astron, Gainesville, FL 32611 USA
SW Res Inst, Boulder, CO 80302 USA
Copyright © 2001 Institute for Scientific Information
==================
(15) THE ROTATION AXIS OF THE CENTAUR 5145 PHOLUS
Farnham TL: The rotation axis of the Centaur 5145 Pholus
ICARUS 152 (2): 238-245 AUG 2001
We present observations of the Centaur 5145 Pholus from January
2000 to
August 2000. A rotational lightcurve was assembled from both V
and R
measurements, confirming previous period determinations of 0.416
day but
exhibiting an amplitude over twice as high as previously
measured. This
lightcurve was then used in conjunction with previously published
lightcurves to solve for a north pole position of lambda (0) =
149 degrees,
beta (0) = +26 degrees (prograde rotation), and a sidereal period
of
0.4159256 +/- 0.0000016 day. As part of this analysis, the axial
ratios of
Pholus were found to be alb = 1.8 and b/c = 1.0. Color analyses
of the data
give an average V - R color of 0.71 +/- 0.03, which is slightly
lower than
the 0.75-0.84 range previously seen. This difference, combined
with the fact
that we see color variations as a function of rotation, suggest
that Pholus'
northern hemisphere contains bluer features than are seen in its
southern
hemisphere. (C) 2001 Academic Press.
Addresses:
Farnham TL, Univ Texas, Dept Astron, Austin, TX 78712 USA
Univ Texas, Dept Astron, Austin, TX 78712 USA
Copyright © 2001 Institute for Scientific Information
==============
(16) THE PUZZLING CASE OF THE NYSA-POLANA FAMILY
Cellino A, Zappala V, Doressoundiram A, Di Martino M, Bendjoya P,
Dotto E,
Migliorini F: The puzzling case of the Nysa-Polana family
ICARUS 152 (2):
225-237 AUG 2001
The Nysa-Polana dynamical family is one of the most complex
groupings
identified in the asteroid main belt. It has a generally twofold
structure
and is located in a region of the belt showing an unusual
abundance of the
fairly rare F-type taxonomic class. We present here new spectra
of 22 family
members, observed at ESO (European Southern Observatory) and at
CASLEO
(Complejo Astronomico El Leoncito, Argentina). We find evidence
that the
family is actually formed by two distinct groupings mutually
overlapping in
the space of orbital proper elements. The first group of objects,
consisting
of dark asteroids including several F-type members, can be named
after its
least-numbered member, 142 Polana. The second group consists of
S-type
asteroids and should be named after its most plausible
least-numbered
member, 878 Mildred. Some detailed physical analysis of the two
groupings
can be already attempted at this stage, including a reasonable
reconstruction of the original ejection velocity field for the
Mildred
family. However, we face here a number of intriguing problems
that deserve
further analysis. For instance, it is not clear how to interpret
the role of
the two largest nominal members of the clan, 44 Nysa and 135
Hertha, as well
as the presence of several large F-type asteroids apparently not
related,
but very close to the clan. Moreover, recent discoveries of
common spectral
features indicating hydrated minerals in the spectra of Nysa and
Hertha add
complexity to an already puzzling scenario. (C) 2001 Academic
Press.
Addresses:
Cellino A, Osservatorio Astron Torino, I-10025 Pino Torinese,
Italy
Osservatorio Astron Torino, I-10025 Pino Torinese, Italy
Observ Paris, DESPA, F-92190 Meudon, France
Univ Nice, F-06108 Nice, France
Copyright © 2001 Institute for Scientific Information
=================
(17) FORMATION OF MESOSIDERITES
Edward RDS, Haack H, Love SG: Formation of mesosiderites by
fragmentation
and reaccretion of a large differentiated asteroid
METEORITICS & PLANETARY
SCIENCE 36 (7): 869-881 JUL 2001
We propose that mesosiderites formed when a 200-400 km diameter
asteroid
with a molten core was disrupted by a 50-150 km diameter
projectile. To test
whether impacts can excavate core iron and mix it with crustal
material, we
used a low-resolution, smoothed-particle hydrodynamics computer
simulation.
For 50-300 km diameter differentiated targets, we found that
significant
proportions of scrambled core material (and hence potential
mesosiderite
metal material) could be generated. For near-catastrophic impacts
that
reduce the target to 80% of its original diameter and about half
of its
original mass, the proportion of scrambled core material would be
about 5
vol%, equivalent to similar to 10 vol% of mesosiderite-like
material. The
paucity of olivine in mesosiderites and the lack of metal-poor or
troilite-rich meteorites from the mesosiderite body probably
reflect biased
sampling. Mesosiderites may be olivine-poor because mantle
material was
preferentially excluded from the metal-rich regions of the
reaccreted body.
Molten metal globules probably crystallized around small, cool
fragments of
crust hindering migration of metal to the core. If mantle
fragments were
much hotter and larger than crustal fragments, little metal would
have
crystallized around the mantle fragments allowing olivine and
molten metal
to separate gravitationally. The rapid cooling rates of
mesosiderites above
850 degreesC can be attributed to local thermal equilibration
between hot
and cold ejecta. Very slow cooling below 400 degreesC probably
reflects the
large size of the body and the excellent thermal insulation
provided by the
reaccreted debris. We infer that our model is more plausible than
an earlier
model that invoked an impact at similar to1 km/s to mix
projectile metal
with target silicates. If large impacts cannot effectively strip
mantles
from asteroidal cores, as we infer, we should expect few large
eroded
asteroids to have surfaces composed purely of mantle or core
material. This
may help to explain why relatively few olivine-rich (A-type) and
metal-rich
asteroids (M-type) are known. Some S-type asteroids may be
scrambled
differentiated bodies.
Addresses:
Edward RDS, Univ Hawaii Manoa, Sch Ocean & Earth Sci &
Technol, Hawaii Inst
Geophys & Planetol, Honolulu, HI 96822 USA
Univ Hawaii Manoa, Sch Ocean & Earth Sci & Technol,
Hawaii Inst Geophys &
Planetol, Honolulu, HI 96822 USA
NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA
Copyright © 2001 Institute for Scientific Information
==============
(18) A PAIR OF RESONANT PLANETS
Marcy GW, Butler RP, Fischer D, Vogt SS, Lissauer JJ, Rivera EJ:
A pair of
resonant planets orbiting GJ 876 ASTROPHYSICAL JOURNAL 556
(1): 296-301,
Part 1 JUL 20 2001
Precise Doppler measurements during 6 yr from the Lick and Keck
observatories reveal two planets orbiting GJ 876 (M4V). The
orbital fit
yields companion masses of M sin i = 0.56 and 1.89 M-J, orbital
periods of P
= 30.1 and 61.0 days, semimajor axes of a = 0.13 and 0.21 AU, and
eccentricities of e = 0.28 and 0.10, respectively. The orbital
periods are
nearly in the ratio of 2: 1, unprecedented among major planets
but common
among moons and asteroids. Moreover, the axes of the elliptical
orbits
appear to be nearly aligned. The inner companion was not
recognized
previously owing to the 2: 1 ratio of periods, which allowed its
signature
to masquerade as added orbital eccentricity of the outer planet.
Dynamical
simulations show that the system is stable within a subset of the
observed
orbital parameters. The stability may be provided by a
mean-motion resonance
and the apparent alignment of the major axes. These planets pose
unsolved
questions about their formation and dynamical evolution, which
brought them
within 0.08 AU of each other and locked them in resonance.
Addresses:
Marcy GW, Univ Calif Berkeley, Dept Astron, 601 Campbell Hall,
Berkeley, CA
94720 USA
Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA
Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC
20015 USA
Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa
Cruz, CA 95064
USA
NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA
SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794
USA
Copyright © 2001 Institute for Scientific Information
============================
* LETTERS TO THE MODERATOR *
============================
(19) RE: FROM MARS TO EARTH IN A METEORITE?
>From Jeff Foust <jeff@spacetoday.net>
Benny,
> (9) FROM MARS TO EARTH IN A METEORITE?
>
> From Scientific American, 24 August 2001
> http://www.sciam.com/news/102700/1.html
For what it's worth, the article referred to above was first
published on 27
October 2000, not last Friday. The Science paper mentioned
in the article
was published on that date, and the current issue of Science has
no paper by
Weiss and Kirschvink.
Cheers,
Jeff Foust
jeff@spacetoday.net
=============
(20) AND FINALLY: "MASTER CLASS ON ASTEROID GODDESS"
>From Boston Globe, 28 August 2001
http://www.boston.com/dailyglobe2/240/nation/Heavens_smile_on_astrology_school_It_s_accredited+.shtml
Heavens smile on astrology school: It's accredited
By Giovanna Dell'Orto Associated Press, 8/28/2001
COTTSDALE, Ariz. - The stars were favorably aligned this month
for the
Astrological Institute, says founder Joyce Jensen, whose students
learn to
write horoscopes and give advice about the future.
The modest school in suburban Phoenix won accreditation from a
federally
recognized body, in what's believed to be a first for a school of
astrology.
Now the institute can seek approval from the US Education
Department for its
students to get federal grants and loans.
>From her observation of the celestial array, Jensen said she
now sees that
''this was a very good time'' for her school. But Jensen - a
60-year-old
Scorpio - also noted she's been seeking accreditation for years,
and
wouldn't have stopped no matter what the stars indicated.
Her institute, where courses include a ''master class on the
asteroid
goddesses'' and ''how to write an astrological column,'' offers
one program:
a diploma in astrology and psychology.
The institute received accreditation from the Accrediting
Commission of
Career Schools and Colleges of Technology after demonstrating
that its
teachers are qualified and that its graduates can be placed in
jobs, said
Elise Scanlon, head of the Arlington, Va.-based commission.
Scanlon and other officials in her field knew of no other schools
that have
been accredited to teach astrology, which is generally considered
a
pseudo-science.
Judith Eaton, head of the Council for Higher Education
Accreditation in
Washington, said the accreditation doesn't validate astrology,
but only
recognizes that the school fulfills its promises.
The institute occupies part of a former elementary school. Inside
its orange
front door, painted with a fiery sun, the school is sparsely
decorated.
Tuition is $5,300, with classes offered in the day and evening.
Full-time
students can earn a diploma in 12 months. But a majority of the
32 students
now enrolled come at night, after working day jobs.
To earn a diploma, they must pass six required courses: three
each in
astrology and psychology, plus at least four electives. Besides
learning
astrology, Jensen said, ''if you're going to be an astrologer,
you really
need the skills of counseling people.''
Graduates usually set up private practice, though some get hired
in holistic
healing centers, spas, and on cruise ships, Jensen said. She
hopes
eventually to offer an associate degree, which would require
further
accreditation.
With the respectability of accreditation and the possibility of
financial
aid, Jensen, an astrologer herself, hopes to draw younger people
more
interested in astrology as a profession than a know-thyself
pursuit. Many of
the students now are in their 30s.
''We haven't had young people for a long time'' because they lack
the money
to pay for the program, Jensen said.
Astrology dates to the time when it was believed that planets and
stars,
including the signs of the zodiac, revolved around the earth,
influencing
earthly events. Astrologers say that people's character and fate
are
directed by the position of the sun, moon, and planets at their
birth. These
positions are charted in a horoscope.
Scientists scoff at the pursuit.
Neil deGrasse Tyson, an astrophysicist who heads the Hayden
Planetarium in
New York, said astrology was discredited 600 years ago with the
birth of
modern science. ''To teach it as though you are contributing to
the
fundamental knowledge of an informed electorate is astonishing in
this, the
21st century,'' he said.
This story ran on page A2 of the Boston Globe on 8/28/2001.
© Copyright 2001 Globe Newspaper Company.
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