PLEASE NOTE:
*
CCNet 10/2001 - 22 January 2001
------------------------------
"The report of the task force on near-earth objects and
asteroids
was published last September, and the Government are considering
it. We
shall announce our response to it shortly. The Department of
Trade and
Industry has established a small implementation team to oversee
the
preparation of that response, which I am sure will be eagerly
awaited on
both sides of the House."
--Prime Minister Tony Blair, House of Commons, 17 January
2001
"For Dr. Tyson, the redefining of Pluto has historical
precedent. In
1801, astronomers combing the large gap between Mars and Jupiter
discovered Ceres, and for a short while, Ceres was a planet. Then
another large rock was found in the same region. And another.
Soon it
became apparent there was a ring of rocky bodies between Mars and
Jupiter.
Since astronomers did not want to call all of them planets, they
renamed
them asteroids. [...]
The new view of Pluto would recast it "from puniest planet
to king
of the Kuiper Belt," Dr. Tyson said. "And I think it's
happier that
way. I'm convinced our approach will prevail. It makes too much
scientific sense and too much pedagogical sense."
--Kenneth Chang, The New York Times, 22 January 2001
(1) PRIME MINISTER'S QUESTION TIME
House of Commons, 2001 January 17
(2) ASTEROIDS & DINOSAURS & JUNGLES, OH MY!
Planetary Society <tps@planetary.org>
(3) 2000 GENE SHOEMAKER NEO GRANT RECIPIENTS SELECTED
Planetary Society, January 2001
(4) COURAGEOUS HAYDEN PLANETARIUM RECLASSIFIES PLUTO WHILE
DOGMATICS FUME
The New York Times, 22 January 2001
(5) STATUS OF NASA'S SPACEGUARD SURVEY, JANUARY 2001
David Morrison <dmorrison@arc.nasa.gov>
(6) MARK SYKES HOPES ASTEROID MISSION WILL FLY
Andrew Yee <ayee@nova.astro.utoronto.ca>
(7) NATURAL HAZARD ROUNDTABLE IN U.S. SENATE TODAY
Harvey Leifert <HLeifert@agu.org>
(8) LEONIDS ROSE TO THE OCCASION
Andrew Yee <ayee@nova.astro.utoronto.ca>
(9) ANCIENT CRATER IS A WINDOW ON PAST
Ron Baalke <baalke@jpl.nasa.gov>
(10) SPACEGUARD UK UPDATE
J R Tate <spaceguard@dial.pipex.com>
(11) HOW DO WE KNOW THAT 'MARTIAN' METEORITES REALLY COME FROM
MARS?
Phil Bland <P.A.Bland@open.ac.uk>
(12) CELESTIAL PORTENTS
Barbara Becker <bjbecker@E4E.UCI.EDU>
==============
(1) PRIME MINISTER'S QUESTION TIME
From Prime Minister's Question Time,
House of Commons, 2001 January 17
http://www.parliament.the-stationery-office.co.uk/pa/cm200001/cmhansrd/cm010117/debtext/10117-04.htm#10117-04_spnew9
Q10. [144234] Mr. Lembit Öpik (Montgomeryshire): People laughed
when I first
raised the potential devastation that would result from an impact
between an
asteroid and the earth. There is no middle way with asteroids. In
the light
of that and of the Government's near-earth object task force
report, which
confirmed every claim that I had made about the dangers and made
14
recommendations for action, will the Prime Minister consider
raising the
matter, with the prospect for international co-operation, at the
next G8
summit?
The Prime Minister: The report of the task force on near-earth
objects and
asteroids was published last September, and the Government are
considering
it. We shall announce our response to it shortly. The Department
of Trade
and Industry has established a small implementation team to
oversee the
preparation of that response, which I am sure will be eagerly
awaited on
both sides of the House.
=============
(2) ASTEROIDS & DINOSAURS & JUNGLES, OH MY!
From The Planetary Society <tps@planetary.org>
NEWS RELEASE
The Planetary Society
65 N. Catalina Avenue, Pasadena, CA 91106-2301 (626) 793-5100 Fax
(626)
793-5528 E-mail: tps@planetary.org
Web: http://planetary.org
For Release: January 16, 2001
Contact: Susan Lendroth
Asteroids and Dinosaurs and Jungles, Oh My!
Join The Planetary Planetary Society's Interactive Expedition to
Belize
From January 16 to 28, 2001, The Planetary Society invites
armchair
explorers worldwide to join an expedition to Belize -- via the
Internet --
in search of what killed the dinosaurs. The Belize Diary will
link Internet
users with scientists in the field who are searching for evidence
of the
asteroid impact that many believe ended the age of the dinosaurs
65 million
years ago.
Scientists and volunteer field workers will post daily expedition
reports
and images in the Belize Diary on the Society web site at
http://planetary.org. They
will also select daily questions to answer from
those that are submitted by e-mail to tps@planetary.org.
This fourth Society expedition to Belize will continue the quest
to build a
more complete picture of what really happened when a comet or
asteroid
collided with Earth off the coast of the Yucatan. The resultant
Chicxulub
crater is regarded by many researchers as the smoking gun for
what caused
dinosaurs to disappear from our planet. When that asteroid
collided with
Earth, it ejected millions of tons of debris into the atmosphere,
ignited
wildfires, generated tsunamis, and probably altered our planet's
environment
so that the dinosaurs, and most other living things, could not
survive.
Team leaders Adriana Ocampo of NASA and Kevin Pope of Geo Eco
Research
[Adriana and Kevin have been CCNet members for many yeras] will
lead a group
of geological adventurers into the jungles of Belize to look for
further
evidence of the impact. Past Society expeditions to the region
have
collected samples of ejecta blanket material -- debris blasted
from the
Chicxulub crater when the asteroid crashed just off the coast of
the
Yucatan. The crater, now buried under the accumulated sediment of
millions
of years, is 200 to 300 kilometers across (about 125 to 190 miles
across).
This year's expedition has numerous scientific objectives:
· To determine how far from the point of impact debris fell in
Quintana Roo, Mexico and Northern and Central Belize.
· To identify and map the distribution of material deformed by
the
explosion (i.e. Pook's pebbles).
· Determine the stratigraphical relationships between ejecta
(debris
falling from impact) deposits in Quintana Roo, Mexico and
Northern and
Central Belize.
· To collect samples for detailed laboratory analysis.
· To perform a survey with a magnetometer to determine the
extent of
ejecta blanket and look for hydrothermal deposits.
· To measure the size of cobbles and pebbles in ejecta to
determine
the effect of atmospheric sorting during ballistic transport.
· To look for fossils to determine the age of rocks under, over,
and
in the ejecta blanket.
Discoveries from previous Belize expeditions include:
· The identification of a new species of crab that went extinct
at the
end of the Cretaceous period, named Carcineretes planetarius in
honor of
the Planetary Society;
· Identification of shocked quartz in northern Belize;
· Identification in Albion in northern Belize of an unusually
high
concentration of iridium at the boundary layer between the
Cretateous
and Tertiary periods;
· Identification of possible condensate material from the
impact's
vapor plume, including Pook's pebbles.
· Giant ejecta boulders 8 meters across; and
· A significant outcrop of ejecta material in Mexico, the
closest of
all known samples to the point of impact.
While this is the Planetary Society's fourth expedition to
Belize, it is the
fifth sent by the Society to study evidence of the Chicxulub
impact. Another
expedition went to Italy in 1996 to study core samples from that
same time
period.
CONTACT INFORMATION:
For more information, or to establish a web link with the Belize
Diary,
please contact Susan Lendroth at (626)793-5100 ext 214 or by
e-mail at
susan.lendroth@planetary.org.
THE PLANETARY SOCIETY:
Carl Sagan, Bruce Murray and Louis Friedman founded The Planetary
Society in
1980 to advance the exploration of the solar system and to
continue the
search for extraterrestrial life. With 100,000 members in over
140
countries, the Society is the largest space interest group in the
world.
The Planetary Society
65 N. Catalina Ave.
Pasadena, CA 91106-2301
Tel: (626) 793-5100
Fax: (626) 793-5528
E-Mail: tps@planetary.org
===========
(3) 2000 GENE SHOEMAKER NEO GRANT RECIPIENTS SELECTED
From the Planetary Society, January 2001
http://www.planetary.org/html/neo/SocietyProjects/ShoemakerGrant/2000ShoeGrants.html
2000 Gene Shoemaker Near Earth Object (NEO) Grants, totaling
$33,700 (US),
have been awarded to an international collection of amateur
astronomers and
researchers:
Herman Mikuz of Crni Vrh nad Idrijo,
Slovenia
David Dixon of New Mexico, United States
Jana Ticha of Ceske Budejovice, Czech
Republic
Tabare Gallardo of Montevideo, Uruguay
Cristovao Jacques of Belo Horizonte,
Brazil
Herman Mikuz
Crni Vrh nad Idrijo, SLOVENIA
The Planetary Society is awarding a Gene Shoemaker NEO grant for
$7,300, to
Herman Mikuz with the Crni Vrh Observatory to help complete the
construction
of a new 60cm telescope. The Crni Vrh Observatory is a privately
owned
observatory in Slovenia that has had a regular observing program
since 1985.
In 1997, the Crni Vrh Observatory began an asteroid observation
program. The
Observatory has been using a 36 cm telescope with a CCD camera
and filter
wheel to conduct their NEO research. They are now planning to
upgrade their
observing program with a 60cm telescope. Donations and private
funding have
helped to begin the process of building the new telescope. The
Shoemaker
Grant will also help to fund their ambitious project.
David Dixon
New Mexico, UNITED STATES
The Planetary Society is awarding a Gene Shoemaker NEO grant for
$7,300 to
David Dixon with the Jornada Observatory, an amateur observatory
in Las
Cruces, New Mexico, United States. With his grant money, Mr.
Dixon with
upgrade the observatory's current CCD camera to a larger CCD
chip, thus
increasing the sensitivity of the telescope. In addition, the
grant is
providing the funds necessary to automate the observatory's dome.
Jana Ticha
Ceske Budejovice, CZECH REPUBLIC
The Planetary Society is awarding a Gene Shoemaker NEO grant for
$6,000 to
Jana Ticha with the Klet Observatory in the Czech Republic. The
Klet
Observatory is a small professional observatory that has been
using a 0.57m
telescope and CCD camera to do CCD astrometry of NEOs. They are
now in the
process of constructing a 1m telescope. The grant money will be
used to
finish the optical system of the new telescope.
Tabare Gallardo
Montevideo, URUGUAY
The Planetary Society is awarding a Gene Shoemaker NEO grant for
$5,000 to
Tabare Gallardo with the Los Molinos Astronomical Observatory,
located just
north of Montevideo, Uruguay. Students from a local university
and area
amateur astronomers use the observatory's 35cm telescope to scan
the
southern skies for NEOs. The observatory also has an educational
program set
up for middle and high school students as well as an outreach
program for
the general public. The observatory will use the grant money to
replace
their broken CCD camera and purchase a filter wheel.
Cristovao Jacques
Belo Horizonte, BRAZIL
The Planetary Society is awarding a Gene Shoemaker NEO grant for
$7,900 to
Cristovao Jacques with the Wykrota Observatory near Belo
Horizonte, Brazil.
A local astronomy club founded this observatory in 1998. They
began with a
Meade LX-200 12-inch f/10 telescope for their NEO observations.
They now
have a 25-inch telescope, a second Meade LX-200 12-inch
telescope, and a
4-inch refractor. The two Meade telescopes are dedicated entirely
to NEO
research. The observatory will use the grant money to purchase
two CCD
cameras.
The Planetary Society would like to thank the other Shoemaker NEO
Grant
applicants.
--------------------------------------------------------------------------
http://www.planetary.org/html/neo/SocietyProjects/ShoemakerGrant/NEOGrantindex.html
NEO Research
The Planetary Society Making it Happen
The Gene Shoemaker NEO Grant
In an effort to advance the study of Near Earth Objects (NEOs),
the
Planetary Society created the Shoemaker Near Earth Object Grant
program in
1997. Named after planetary geologist Eugene Shoemaker, who
dedicated much
of his life to NEO research, the purpose of the grant program is
to increase
the rate of discovery and follow-up studies of asteroids and
comets in
Earth's vicinity. Grant funding is designed to aid amateur
observers,
observers in developing countries, and professional astronomers
who, with
seed funding, could greatly increase their programs'
contributions to this
critical research.
Scientists worldwide have only recently begun to understand
significance
NEOs have had to the evolution of Earth -- and life on Earth --
just as
impacts from comets and asteroids have contributed to the
evolution of
terrestrial planets throughout the solar system.
While various astronomical groups and NASA advisory committees
have strongly
recommended discovery of these objects be accelerated, government
support
for NEO search and follow-up programs remains modest. As a
result, the role
of amateur astronomers in NEO discoveries is increasingly
important.
Since its inception, The Planetary Society has awarded Shoemaker
NEO Grants
in 1997, 1998, and 2000.
In 1997, the committee awarded grants to four individuals: Gordon
Garradd,
Australia; Kirill Zamarashkin, Russia; Walter Wild, Illinois; and
Bill
Holiday, Texas. Their projects ranged from upgrading and
automating
equipment to building a new NEO research telescope.
In 1998, a total of $27,000 (U.S. dollars) went to three
individuals: Stefan
Gajdos, Slovak Republic; Paulo Holvorcem, Brazil; Frank
Zoltowski,
Australia. Their projects ranged from upgrading equipment, to
creating a
public outreach program.
The 2000 grant winners have just been announced. A total of
$33,700 (US)
were awarded to five winners from from Brazil, the Czech
Republic, Italy,
Slovenia, the United Stated, and Uruguay.
The Shoemaker NEO Grant is coordinated by Daniel D. Durda, an
asteroid
researcher at the Southwest Research Institute in Boulder,
Colorado. An
international advisory group reviews the proposals, included
noted
near-Earth object scientists:
- Andrea Caruzi, Instituto di Astrofisica Spaziale;
- Al Harris, JPL Scientist;
- Brian Marsden, Harvard-Smithsonian Center for Astrophysics;
- Alain Maury, Telescope de Schmidt-Observatoire de la Cote
d'Azur;
- Syuichi Nakano, Japanese astronomer; and
- Jorge Sahade, La Plata Observatorio Astronomico, Argentina.
===========
(4) COURAGEOUS HAYDEN PLANETARIUM RECLASSIFIES PLUTO WHILE
DOGMATICS FUME
From The New York Times, 22 January 2001
http://www.nytimes.com/2001/01/22/science/22PLAN.html
Planetarium Takes Pluto Off Planet A-List
By KENNETH CHANG
As she walked past a display of photos of planets at the Rose
Center for
Earth and Space, Pamela Curtice of Atlanta scrunched her brow,
perplexed.
There didn't seem to be enough planets. She started counting on
her fingers,
trying to remember the mnemonic her son had learned in school
years ago.
My Very Educated Mother Just Served Us Nine Pizzas.
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
"I had to go through the whole thing to figure out which one
was missing,"
she said.
Pluto. Pluto was not there. "Now I know my mother just
served us nine," Mrs.
Curtice said. "Nine nothings."
Quietly, and apparently uniquely among major scientific
institutions, the
American Museum of Natural History cast Pluto out of the pantheon
of planets
when it opened the Rose Center last February. Nowhere does the
center
describe Pluto as a planet, but nowhere do its exhibits declare
"Pluto is
not a planet," either.
"We're not that confrontational about it," said Dr.
Neil de Grasse Tyson,
director of the museum's Hayden Planetarium. "You actually
have to pay
attention to make note of this."
Still, the move is surprising, because the museum appears to have
unilaterally demoted Pluto, reassigning it as one of more than
300 icy
bodies orbiting beyond Neptune, in a region called the Kuiper
Belt
(pronounced KY-per).
"Pluto is noticeable by its difficulty to find," Dr.
Richard P. Binzel, a
professor of planetary science at the Massachusetts Institute of
Technology,
said of the Rose exhibits. "They went too far in demoting
Pluto, way beyond
what the mainstream astronomers think."
Dr. S. Alan Stern, director of Southwest Research Institute's
space studies
department in Boulder, Colo., also dislikes the change.
"They are a minority
viewpoint," he said. "It's absurd. The astronomical
community has settled
this issue. There is no issue."
The International Astronomical Union, the pre-eminent society of
astronomers, still calls Pluto a planet, one of nine of the solar
system.
Even a proposal in 1999 to list Pluto as both a planet and a
member of the
Kuiper Belt drew fierce protest from people who felt that the
additional
"minor planet" designation would diminish Pluto's
stature.
The proposal was abandoned, and the astronomical union, which is
based in
Paris, released a statement reaffirming that Pluto was and is a
planet.
"This process was explicitly designed to not change Pluto's
status as a
planet," the organization said.
But even some astronomers defending Pluto admit that were it
discovered
today, it might not be awarded planethood, because it is so small
- only
about 1,400 miles wide - and so different from the other planets.
While the international union's debate stirred considerable
astronomical
passion, the Rose Center's Plutoless planet display has not
generated much
controversy or consternation.
"I learned it one way for the first 50 years," said
Mrs. Curtice's husband,
William. "I'll learn it another way now, I guess."
Jane Levenson, an "explainer" at the center, says that
perhaps one out of
every 10 visitors asks her about the missing planet. She tells
them about
the debate over Pluto's status and says "a decision had to
be made" as the
museum was assembling the new exhibits.
"Children in particular ask," she said. "Children
say, `Did they forget
about Pluto?' Some even say, `Did you forget my friend Pluto?'
"
Ilisse Familia, a sixth grader from the Good Shepherd School in
Manhattan,
was surprised when she heard the museum no longer counted Pluto
among the
planets. "No wonder I couldn't find Pluto," she said.
"It's kind of weird."
As a planet, Pluto has always been an oddball. Its composition is
like a
comet's. Its elliptical orbit is tilted 17 degrees from the
orbits of the
other planets. Pluto was discovered on Feb. 18, 1930, by Clyde W.
Tombaugh,
and astronomers initially estimated it to be as large as Earth.
They have
since learned it is much smaller, smaller than Earth's Moon.
But Pluto continued to be called a planet, because there was
nothing else to
call it. Then, in 1992, astronomers found the first Kuiper Belt
object. Now
they have found hundreds of additional chunks of rock and ice
beyond
Neptune, including about 70 that share orbits similar to Pluto's,
the
so-called Plutinos.
"We're much more subtle, but not deviously subtle," Dr.
Tyson, the
planetarium director, said of the Hayden exhibits. "We
decided to organize
the information for the visitor in such a way that Pluto's
classification
would become self-evident."
The exhibits refer to the inner four "terrestrial
planets" - Mercury, Venus,
Earth, Mars - and the four gas giant planets - Jupiter, Saturn,
Uranus and
Neptune. Pluto, a small ball of rock and ice, does not fall into
either
group. "Pluto does not have a family except for the icy
bodies in the outer
solar system," Dr. Tyson said. "So we simply group it
with the Kuiper Belt.
In a sense, we're sidestepping the definitional problem
altogether."
A display describing the solar system includes this carefully
worded
sentence: "Beyond the outer planets is the Kuiper Belt of
comets, a disk of
small, icy worlds including Pluto."
A diagram of the planets shows eight, not nine, rings around the
Sun.
Other planetariums have not followed the Rose Center's lead. The
entryway to
the Adler Planetarium in Chicago includes bronze plaques of only
eight
planets, but that is because it opened just before Pluto was
officially
named. Inside, the exhibits include Pluto among the planets.
The Denver Museum of Nature and Science is building a $45
million,
30,000-square-foot space science center, scheduled to open in
2003. Those
exhibits will also still count nine planets in the solar system.
"We're
sticking with Pluto," said Dr. Laura Danly, curator of space
sciences at the
Denver museum. "We like Pluto as a planet."
But, she also said, "I think there is no right or wrong on
this issue. It's
a moving target right now, no pun intended, what is and is not a
planet."
Planet, in the original Greek word, meant "wanderer,"
referring to the dots
of light that moved across the night sky. When the 16th-century
astronomer
Nicolaus Copernicus realized that the universe did not revolve
around the
Earth, Earth became another planet circling the Sun.
For Dr. Tyson, the redefining of Pluto has historical precedent.
In 1801,
astronomers combing the large gap between Mars and Jupiter
discovered Ceres,
and for a short while, Ceres was a planet. Then another large
rock was found
in the same region. And another. Soon it became apparent there
was a ring of
rocky bodies between Mars and Jupiter. Since astronomers did not
want to
call all of them planets, they renamed them asteroids.
Just as Ceres, which turned out to be about 580 miles wide, was
reassigned
from planet to asteroid, Pluto should join the Kuiper Belt
objects, Dr.
Tyson said. "It's entirely analogous to the asteroid
belt," he said, "except
there's a 60-year delay between the discovery of the first and
second
objects."
The new view of Pluto would recast it "from puniest planet
to king of the
Kuiper Belt," Dr. Tyson said. "And I think it's happier
that way. I'm
convinced our approach will prevail. It makes too much scientific
sense and
too much pedagogical sense."
Copyright 2001, The New York Times
=============
(5) STATUS OF NASA'S SPACEGUARD SURVEY, JANUARY 2001
From David Morrison <dmorrison@arc.nasa.gov>
NEO News (01/20/01) Survey status
Dear Friends and Students of NEOs:
This edition of NEO News contains the annual summary of progress
toward the
Spaceguard goal of finding 90% of the Near Earth Asteroids (NEAs)
brighter
than absolute magnitude 18 (corresponding to diameter of 1 km) by
2008. I am
grateful to Don Yeomans and Alan Harris of JPL for this
information. As of
the end of 2000, we are more than halfway to this goal in terms
of numbers,
but not in terms of required time and effort.
Let me also take this opportunity to call to your attention the
bibliography
of technical publications dealing with NEOs and the impact
hazard. This
listing, beginning with 1992, is found on the NASA impact hazard
webpage
(impact.arc.nasa.gov). I have recently updated the bibliography
by adding
publications from 1999 and 2000. The annual rate of publication
continues to
grow as this field of study attracts more and more scientific
attention.
David Morrison
=====================================
THE STATUS OF THE SPACEGUARD SURVEY, JANUARY 2001
David Morrison
Alan Harris
Don Yeomans
During 2000 (up to January 8, 2001, to cover the final observing
month in
full), 125 NEAs of absolute magnitude H < 18.0 were
discovered, or
~10.5/month, from the tabulation by Harris. This is up from
around 7.5/month
the previous year. The total numbers to date (Jan 08) are N(all)
= 1254,
N(H<18) = 467. Following is a listing of the monthly (by
lunation)
discoveries of H < 18 and all. The dates correspond to new
moon each month:
date N(H<18) N(all)
2000.01 6 19
2000.10 10 28
2000.18 16 40
2000.26 12 30
2000.34 9 25
2000.42 6 21
2000.50 5 7
2000.58 12 29
2000.66 10 35
2000.74 9 43
2000.82 10 24
2000.90 13 43
2000.98 10 27
The above listing includes quite a few relatively bright (large)
NEAs. This
year's discoveries include 4 NEAs with H between 13 and 14, 8
NEAs with H
between 14 and 15, and 18 NEAs with H between 15 and 16. The
dozen
discoveries of new NEAs brighter than H = 15 are in a size range
that was
thought (on some models) to be already nearly complete.
The following breakdown by discovery team refers only to the
calendar year
2000 ending on December 31. Of the 109 new NEAs brighter than H =
18 listed
by Yeomans, 82 (75%) were discovered by the LINEAR program using
two USAF
telescopes in New Mexico, with 8 (7%) by the second-ranking
LONEOS program
at Lowell Observatory in Arizona. A number of additional smaller
search
programs contributed the remaining 18% of discoveries.
Harris has carried out an analysis of the rate of rediscoveries
from LINEAR
to estimate the total population of NEAs as a function of size.
The
resulting estimate is slightly more than 800 brighter than H =
18,
consistent with several other recent estimates in the 800-900
range.
However, Harris notes that such estimates based on rediscovery
will always
yield a lower bound for the total numbers, since they implicitly
assume that
the undiscovered population is similar to the discovered
population. Thus
any groups of NEAs that is more difficult to detect will be
underestimated
in the total just as they are undercounted in the observed
population.
Therefore the true total number of NEAs down to 1 km diameter is
probably as
high as 1000. Also note, however, that the statistically
undercounted groups
(those with orbits that don't bring them close to the Earth as
often) are
also probably less important in terms of the impact hazard than
are the
groups that do often come close. Finally, note that we continue
to discover
larger NEAs where the standard models indicate that we should
have a nearly
complete listing. The point of this complicated discussion is
that
estimating total populations is complex, especially if we are
primarily
interested in those NEAs that pose a potential impact hazard to
the Earth.
The calculations by Harris will appear in a future issue of
Icarus.
If we adopt an estimate of 1000 NEAs larger than 1 km, then we
have now
found 47%. If the true number is nearer 900, as indicated by
recent
estimates, then we now have 52% in our NEA catalogues. Either
way, we are
clearly beyond the halfway mark to the goal of finding 90% by
2008.
===========
(6) MARK SYKES HOPES ASTEROID MISSION WILL FLY
From Andrew Yee <ayee@nova.astro.utoronto.ca>
News Services
University of Arizona
Tucson, Arizona
Contact Information:
Mark V. Sykes, 520-621-5381, msykes@as.arizona.edu
Jan 19, 2001
UA Astronomer is Scientist For Proposed 'Dawn' Discovery Mission
By Lori Stiles
A University of Arizona astronomer is one big step closer to two
asteroids
that have recorded what the early solar system was like when the
terrestrial
planets formed.
NASA's Office of Space Science has selected three proposals for
detailed
study as candidates for the next Discovery mission to be launched
in
2005-2006. UA astronomer Mark V. Sykes is a scientist on the
proposed "Dawn"
mission. The mission is led by Christopher T. Russell of the
University of
California-Los Angeles.
"Dawn will study the conditions and processes of planet
formation during the
earliest epoch of our solar system by orbiting and studying two
of the
largest asteroids which have survived from this time, Ceres and
Vesta,"
Sykes said. Dawn builds on decades of asteroid and meteorite
studies, he
added.
"Ceres is more than a quarter the diameter of the moon, is
water-rich, and
has retained its primitive composition and condition. Vesta, on
the other
hand, was dry, heated to the point of melting, and preserves a
record of its
subsequent differentiation.
"Almost all asteroids that we observe today are the
fragments of larger
asteroids like Vesta and Ceres that were destroyed by ancient
catastrophic
collisions. By studying Vesta and Ceres, we gain a much greater
understanding of how these modern fragments were once put
together," Sykes
said.
Actually, scientists already have pieces of one of the asteroids
within
reach -- as meteorites that landed on Earth.
"Cratering collisions have knocked off pieces of Vesta,
which have been
recovered as meteorites. They provide us with detailed
information on
geochemical processes that have occurred within specific sites on
Vesta from
the time of its formation at the beginning of the solar
system," Sykes said.
"Going to Vesta will give us the big picture within which
these hand-sized
pieces fit. It will be like going from studying bits of hair,
nail, and bone
to seeing and studying the entire animal up close for the first
time," he
added.
Sykes, an associate astronomer at Steward Observatory,
specializes in the
study of asteroids, comets and interplanetary dust. He is the
Chair of the
Division for Planetary Sciences of the American Astronomical
Society.
NASA selected Dawn and two other proposed missions, called Kepler
and INSIDE
Jupiter, for further study from 26 proposals submitted last
August. Each
selected team will receive $450,000 to conduct a 4-month
implementation --
feasibility study. One of the proposals will be selected for full
development late this year.
According to a UCLA news release, the Dawn mission is proposed to
carry a
framing camera and mapping spectrometer provided by the German
Aerospace
Center, DLR, Institute of Sensor Technology and Planetary
Exploration in
Berlin; a laser altimeter experiment provided by the NASA Goddard
Space
Flight Center in conjunction with the Massachusetts Institute of
Technology;
a gamma ray/neutron spectrometer from the Department of Energy's
Los Alamos
National Laboratory; and a magnetometer provided by UCLA.
Ion engines would power the spacecraft to the asteroid belt,
where it first
orbits Vesta in an ever-tightening circle and then spirals
outward and heads
to its rendezvous with Ceres. Flybys of more than a dozen other
asteroids
along the way are planned.
[NOTE: Images supporting this release are available at
http://uanews.opi.arizona.edu/cgi-bin/WebObjects/UANews.woa/wa/SRStoryDetails?ArticleID=2937
]
===========
(7) NATURAL HAZARD ROUNDTABLE IN U.S. SENATE TODAY
From Harvey Leifert <HLeifert@agu.org>
Joint American Geophysical Union/
American Meteorological Society Release
January 18, 2001
AGU RELEASE NO. 01-4
For Immediate Release
AGU Contact: Harvey Leifert
(202) 777-7507
hleifert@agu.org
AMS Contact: Stephanie Kenitzer
410-672-6750
kenitzer@dc.ametsoc.org
Congressional panel to hold public roundtable on El Salvador
earthquake and
U.S. natural hazards challenges
WASHINGTON - The Congressional Natural Hazards Caucus will hold a
public
roundtable discussion on Monday, January 22, focussed on the
recent
earthquake in El Salvador and the broader natural hazards
challenges that
face the United States. The participants will include Senators
Ted Stevens
(R-AK) and John Edwards (D-NC), co-chairs of the caucus; Dr.
William Hooke,
Senior Fellow of the American Meteorological Society; and a
senior official
of the U.S. Geological Survey.
The senators will release a discussion document that says the
U.S. is
becoming more vulnerable to natural disasters and suggest actions
Congress
might take to solve the problem. These include the gathering of
accurate
data on the true costs of natural disasters, the cost and
effectiveness of
current mitigation efforts, improved warning systems, and better
coordination of long term recovery efforts.
The Congressional Natural Hazards Caucus was formed last year to
help
improve America's response to such potentially devastating events
as
earthquakes, volcanic eruptions, floods, tornados, tsunamis, and
hurricanes.
It seeks to coordinate responses of Congress, the Executive
Branch, and the
private sector in dealing with natural disasters.
The roundtable discussion is open to the public.
Date: Monday, January 22, 2001
Time: 2:30-3:15 PM
Venue: Room 138, Dirksen Senate Office Building
=========
(8) LEONIDS ROSE TO THE OCCASION
From Andrew Yee <ayee@nova.astro.utoronto.ca>
ESA Science News
http://sci.esa.int
17 Jan 2001
Leonids rose to the occasion -- despite bad weather
Dual Camera Observations
During the nights of 16-17 and 17-18 November, Joe Zender and
Detlef Koschny
of ESA's Space Science Department at ESTEC attempted to obtain
'stereo'
observations of the Leonid meteors with image intensified video
cameras.
These cameras are equipped with wide-angle lenses and can record
meteors that are too faint to be seen with the naked eye.
It was hoped that the various observing teams would be able to
obtain
parallel observations from four different locations 70 km to 100
km apart.
Zender was observing with a team from the Dutch Werkgroep
Meteoren at
Hogersmilde in the Netherlands. Unfortunately, poor weather only
allowed
his team to record about 1.5 hours of video data outside the time
of the
maximum activity.
Other teams had a little more success. On the night of 16-17
November, two
stations succeeded in observing simultaneously: Henry Henriks
(Werkgroep
Meteoren) located at the Heest Observatory and Joost Haartman,
Michiel
Brentjens and Roy Keeris (Werkgroep Meteoren) located near Almere
at the
Groene Kathedraal, were able to observe with the video cameras
for about 4
hours. However, activity was moderate and no dedicated peaks or
events could
be reported.
On the next night, the team in Hoogersmilde was able to observe
under good
conditions until 00.15 UT. When the clouds and rain closed in,
they were
able to dismantle their equipment and rapidly move to a
relatively
cloud-free area near Groningen. The camera equipment was set up
again by
03.20 UT, about 20 minutes before the predicted peak. Despite
problems with
the clouds and Moon, they were able to observe increasing
activity, with
about 30 meteors in the first hour. Overcoming more disruption
from the
weather, the team was able to recognise another spell of
increased activity
at about 04:45 UT. Visual and camera observations continued until
06.30 UT,
with another suggestion of increasing activity before dawn (from
05.30 UT to
06.15 UT).
Koschny's attempted observations in the Harz mountains of Germany
were also
plagued by bad weather. Apart from two sporadic meteors seen from
the
Max-Planck-Institute in Lindau-Harz on 17 November, there was
nothing to
report.
Simultaneous observations from different sites were not possible
on the
second night due to the continually changing location of the
teams, but it
is hoped that analysis of the videotapes will give a better idea
of the ZHR
(zenithal hourly rate) values. Everyone is hoping for better luck
with the
video observations next year!
Echoes of the Leonids
Jean-Pierre Lebreton and Trevor Sanderson from ESA's Space
Science
Department at ESTEC used radio signals rather than telescopes or
cameras to
observe the elusive meteors. Their technique used the ability of
plasma
(ionised gas) clouds around glowing meteor trails to reflect
radio waves.
The BBC helped the experiment by transmitting from Woofferton
until 06:00 UT
(7 Local time), and then switched to its normal transmission
schedule (from
Cyprus between 06:00 UT and 08:00 UT, and then from both
Woofferton and
Skelton from 08:00 UT onwards).
The radio recordings were excellent, with numerous very unusual
echoes which
can be attributed to the Leonids. Preliminary analysis of the
High Frequency
night-time radio observations indicates that the (non-sporadic)
activity
increased significantly on 18 November, but it seems there was
some activity
1-2 days before (16 and 17 November), and perhaps 1 day after (19
November).
A rise in activity was noticeable on 18 November between 03:00
and 05:00 UT,
and also from 07:00 UT onwards. Few daytime echoes could be
detected during
the transmission from Cyprus as the geometry was unfavourable.
However, the
activity at around 09:00 on 18 November was much higher than on
the days
before or after.
Despite pouring rain until 01:30, the team also managed to
capture a few
meteors against the bright Moonlit background on a video taken
with a
standard CCD camera. Some of the Leonids displayed impressive
trails that
lingered for a few seconds.
24 hour plots have been produced for the following 3 days : 17
November, 18
November, and 19 November. A reference plot, (when the BBC
transmission was
OFF over night) was also produced for 12 November.
Tell-tale Flashes on the Moon?
Håkan Svedhem of ESTEC's Science Department used a 25 cm
telescope and a
video camera to observe the dark hemisphere of the Moon on the
nights of
16-17 and 17-18 November, in the hope of seeing some Leonid
meteors impact
on the dark part of the Moon.
The search for impacts is a difficult, time-consuming business,
since a
flash typically lasts for only one or two video frames.
Expectations were
also limited since most impacts were predicted to occur on the
lunar far
side, and only a very small visible area at the Moon's northern
cusp was
exposed to the meteor stream.
Problems with condensation on the lens forced Svedhem to stop at
about 05:40
UT on 17 November -- unfortunate timing, since predictions
indicated that
the Moon would pass close to the 1932 dust stream at that time.
The next day proved more rewarding, and he was able to observe
the Moon from
02:19 UT onwards. After preliminary computer analysis of the
videotape,
Svedhem has so far found one unquestionable flash of light from
an impact
that took place at 05:42 on 18 November, but the search goes on
as he
continues to compare consecutive frames and filter out background
"noise".
USEFUL LINKS FOR THIS STORY
* Leonids 2000: ESA observation reports
http://sci2.esa.int/leonids/leonids2000/report.html#listen
* Listening to the Leonids
http://helio.estec.esa.nl/sound.html
* More images and sounds files of the Leonids
http://solarsystem.estec.esa.nl/planetary/radiometeor.htm
IMAGE CAPTIONS:
[Image 1:
http://sci.esa.int/content/searchimage/searchresult.cfm?aid=1&cid=12&oid=25781&ooid=18305
]
Composite image of 6 Leonids meteors.
[Image 2:
http://sci.esa.int/content/searchimage/searchresult.cfm?aid=1&cid=12&oid=25781&ooid=25861
]
Comet C/1999 S4 (Linear), 28 June 2000.
[Image 3:
http://sci.esa.int/content/searchimage/searchresult.cfm?aid=1&cid=12&oid=25781&ooid=25860
]
Radio recordings made on 12 November 2000 without a BBC
transmission and
before the Leonids appeared. Each panel represents 2 hours and
cover 25 Hz
in frequency. Note that high frequencies are at the bottom and
lower
frequencies at the top of the panel. For reference, a 1Hz Doppler
shift at
17640 kHz (carrier frequency for the BBC transmission) is caused
by a
Doppler velocity of ~ 17 m/s.
[Image 4:
http://sci.esa.int/content/searchimage/searchresult.cfm?aid=1&cid=12&oid=25781&ooid=25856
]
24 Hour radio recordings of the Leonids on 17 November 2000. Each
panel
represents 2 hours and cover 25 Hz in frequency. Note that high
frequencies
are at the bottom and lower frequencies at the top of the panel.
For
reference, a 1Hz Doppler shift at 17640 kHz (carrier frequency
for the
BBC transmission) is caused by a Doppler velocity of ~ 17 m/s.
[Image 5:
http://sci.esa.int/content/searchimage/searchresult.cfm?aid=1&cid=12&oid=25781&ooid=25858
]
24 Hour radio recordings of the Leonids on 18 November 2000. Each
panel
represents 2 hours and cover 25 Hz in frequency. Note that high
frequencies
are at the bottom and lower frequencies at the top of the panel.
For
reference, a 1Hz Doppler shift at 17640 kHz (carrier frequency
for the BBC
transmission) is caused by a Doppler velocity of ~ 17 m/s.
[Image 6:
http://sci.esa.int/content/searchimage/searchresult.cfm?aid=1&cid=12&oid=25781&ooid=25857
]
24 Hour radio recordings of the Leonids on 19 November 2000. Each
panel
represents 2 hours and cover 25 Hz in frequency. Note that high
frequencies
are at the bottom and lower frequencies at the top of the panel.
For
reference, a 1Hz Doppler shift at 17640 kHz (carrier frequency
for the BBC
transmission) is caused by a Doppler velocity of ~ 17 m/s.
=========
(9) ANCIENT CRATER IS A WINDOW ON PAST
From Ron Baalke <baalke@jpl.nasa.gov>
Desert News, 18 January 2001
http://www.deseretnews.com/dn/view/0,1249,245014897,00.html
By Joe Bauman
An enormous asteroid or comet that ripped into South Africa 2
billion years
ago gives a window into the formation of the continents,
according to
scientists from the University of Utah and South Africa.
Their report, "Birth of the Kaapvaal Tectosphere 3.08
Billion Years Ago," is
published in Friday's edition of the journal Science. The trio
studied a
huge crater structure in South Africa called the Vredefort impact
structure,
located in the Witwatersrand Basin. The crater is the largest
known remnant
of "the asteroid bombardment that affected this part of the
solar system" in
an early stage of Earth's history, Moser said.
An intense bombardment of space material pounded Earth in those
days, he
said. The theory is that "the planets themselves are kind of
like big
snowballs that have accumulated from materials in space."
This swept up much
of the primordial material around Earth.
Immediately after the impact, the crater was about 9 miles deep
and 185
miles across. "The Earth welled up to fill the hole,"
he said. Deeper layers
filled the crater. Moser proposed to the National Science
Foundation that
they should go to South Africa and examine the remnants of the
crater,
mapping the geologic strata that pushed in from deeper in the
Earth.
They also used sophisticated dating techniques to determine the
age of the
rocks, discovering that the underlying rocks had solidified 3.5
billion
years ago and that the material hit 2 billion years ago. Heat
released by
the impact melted some of the rocks, which changed the mineral,
in effect
resetting its clock. "I dated one of these impact
melts," which helped to
date the asteroid impact, Moser said.
Throughout the world, huge continental plates are continuously
shifting,
pushing up mountains and carving out rift valleys. When the
asteroid or
comet hit, it provided a snapshot of what rocks were at the time.
"The
meteorite impact basically exposed rocks from very deep
levels," and these
tell about the early types of plate tectonics, he said.
The team learned that this part of the African continent, which
is one of
the oldest known, "formed from the top down." Earth's
geology formed the
upper parts of the plate first, and they thickened over time, the
scientists
learned. Although the impact was nearly twice as large as the one
that wiped
out the dinosaurs 65 million years ago, it didn't kill any
sophisticated
species. At the time, as far as scientists know, Earth had no
life beyond
the single-cell level, he noted.
An interesting sidelight to the research is that these prototype
tectonic
plates were important to the formation of diamonds.
"Something in the
processes that formed these earlier plates also generated
diamonds," Moser
said. "When we look at the younger plate material, they
don't generate
diamonds." This is why diamonds are found mostly in southern
Africa, as it
is where the early type of tectonic plate remains.
Copyright 2001, Desert News
===========
(10) SPACEGUARD UK UPDATE
From J R Tate <spaceguard@dial.pipex.com>
It might appear that Spaceguard UK has been "dormant"
for some time, but
that is far from the case! As you are aware, the report of the
government
Task Force was published in September and has been received with
enthusiasm
worldwide. We are now waiting for the minister, Lord Sainsbury,
to make up
his mind what to do about it. The timeframe for the government
response has
already slipped from "before Christmas" to "at the
turn of the year", and a
sceptic could be forgiven for thinking that the aim of those in
power is to
let the fuss die down so the whole thing just fades away. This
will not be
the case. In collaboration with Benny Peiser in Liverpool and
Mark Bailey
in Armagh we are generating local and political support for the
manufacture
of the proposed 3-metre telescope at TTL in Liverpool and the
location of
the British NEO centre at Armagh. So far response has been good.
In October I attended The 9th Space Frontier Conference that was
held in Los
Angeles. The whole thing was rather bizarre - a mixture of vision
and
hard-nosed business. The latter was concentrated around the many
wealthy
patrons that were there, looking for things to spend their money
on. I was
unaware of this aspect, so arrived unprepared, but there are a
couple of
irons in the fire now!
The Americans simply cannot believe that Spaceguard UK has
achieved what it
has, with zero funding in only four years. They expend hundreds
of thousands
(literally) of dollars on their lobbying campaigns, and have
achieved
virtually nothing! In addition to my SGUK presentation to the
conference I
was invited to give one of the three lunchtime addresses to
delegates. I
scribbled down the story of SGUK so far, and told it as it has
been. The
story so far took them by storm. As a result I have been invited
to lecture
on Space Policy at the International Space University on Space
Policy. I
didn't even realise that I knew anything about Space Policy!
Many of you are aware that I have been considering some fairly
radical
decisions about the future of Spaceguard UK. Well, the time has
come; after
26 years in the Army I will be a civilian on 29th July next year.
Six months
ago my wife and I tried to buy a rather nice private observatory
in central
Wales, but another buyer pipped us at the post. However, having
joined
Spaceguard UK, the new owner has offered us the opportunity to
run the
observatory in the way that we initially wished to, but with a
significantly
better financial deal. Agreement has been reached, and, subject
to contract,
we will be moving "up the hill" during the summer. The
observatory has a
magnificent location and some splendid instruments. The latter
include a 13"
refractor, a 10" Schmidt camera, a 6 ½" Solar
telescope, a wonderful camera
obscura, a seismic station and a weather satellite ground
station. Although
the telescopes are not really suitable for NEO detection I hope
that we
might contribute to follow-up work, and they are ideal for
educational
purposes. My vision for the observatory is to continue and
develop the site
as a place of education in astronomy for the public, to make it a
"must see"
for visitors to the area and to use the facilities as a permanent
base for
Spaceguard UK. Much of the current work at the observatory
is aimed at
schools, and we would wish to continue this. Anne is a primary
teacher, and
will be invaluable in this respect. I believe that it will become
a
well-respected centre for Public Education in Science (PUS), and
we are
committed to making it so.
With the Task Force report published, the continuing increase in
membership,
our involvement with organisations both here and abroad and some
optimistic
plans for the future, Spaceguard UK is thriving, and will
hopefully continue
to do so for a long time yet. With the government and
professionals now
taking a more active role, the emphasis for Spaceguard UK should
shift back
to its original purpose - that of providing information to the
public and
other institutions. Amongst other activities, the development of
the Powys
Observatory will be a tremendous opportunity.
Jay Tate
Figheldean
January 2001
============================
* LETTERS TO THE MODERATOR *
============================
(11) HOW DO WE KNOW THAT 'MARTIAN' METEORITES REALLY COME FROM
MARS?
From Phil Bland <P.A.Bland@open.ac.uk>
Benny,
Just a small point relating to this discussion of where life
originated, and
the question that was raised as to whether 'Martian' meteorites
really do
come from Mars. It's not just that they're chemically evolved,
and so could
come from any active solar system body (Earth, Venus, or Io were
mentioned
as possible sources). Oxygen isotopes suggest pretty
categorically that
they're extraterrestrial (ie. they're not returning terrestrial
impact
ejecta). Io is way down deep in Jupiter's gravity well, and
getting anything
out of Venus atmosphere is pretty hard. Mars is the likeliest
candidate even
without the Viking data. With it, the association becomes
convincing. I'm
not an expert on Martian meteorites - I'm sure there is other
supporting
evidence - but based on the above, Mars is clearly the best
candidate parent
body for these samples.
Phil
============
(12) CELESTIAL PORTENTS
From Barbara Becker <bjbecker@E4E.UCI.EDU>
[as posted on HASTRO-L@WVNVM.WVNET.EDU]
Hi everyone!
I'm preparing to teach a course next quarter on plagues and
society (a
veeeeeery big stretch for an historian of astronomy) and am
currently
reading a book by Robert Gottfried entitled, _The Black Death:
Natural and
Human Disaster in Medieval Europe_.
In it, on p. 56, he cites a contemporaneous account by a
Carmelite friar and
master of theology at the University of Paris, Jean de Venette:
In the month of August 1348, after Vespers, when the sun was
beginning to set, a big and very bright star appeared above
Paris,
towards the west. It did not seem, as stars usually do, to be
very high
above our hemipshere, but rather, very near. As the sun set
and night came
on, this star did not seem to me or many other friars who were
watching it
to move from one place. At length, when night had come, this big
star, to the amazement of all of us who were watching, broke into
many different rays, and, as it shed these rays over Paris
towards the
east, totally disappeared and was completely annihilated. Whether
it was
composed of airy exhalations and was finally resolved into vapor,
I leave to
the decision of astronomers. It is, however, possible that it was
a
presage of the amazing pestilence to come, which, in fact,
followed very
shortly in Paris and throughout France and elsewhere, as I shall
tell....
Did astronomers of the day, in fact, interpret this event? Have
any
astronomers (or historians of astronomy) in modern times tried to
figure out
exactly what de Venette reported having seen? It sounds,
from his account,
that a rather long time was involved in this observation, so it
doesn't seem
possible that it could have been a bolide. How much time might
elapse
between vespers/sunset and darkness in a Parisian August?
Dying to know the answer,
Barb.
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