CCNet, 81/2000 - 30 August 2000
"Citing a report in The New York Times, The Associated Press
erroneously reported Aug. 19 that open water had been spotted
on the North Pole for the first time in 50 million years, a
possible sign of global warming. In a correction Tuesday, the
Times said it had misstated the normal conditions of sea ice
at the pole. It said open water probably has occurred there
before because the Arctic Ocean is about 10 percent ice-free
during a typical summer. The Times also said the lack of ice
at the North Pole is not necessarily a result of global
-- Associated Press, 29 August 2000
"Remarkably, most sungrazing comets appear to be fragments of a
single giant comet that broke apart near perihelion (closest
approach to the Sun) long ago. Brian Marsden speculates that the
parent might have been a bright comet seen by the Greek astronomer
Ephorus in 372 BC. Ephorus reported that the comet split in two.
Splits may have occurred again and again, producing the Kreutz
sungrazer family (named after the nineteenth-century German
astronomer who studied them in some detail). 'The association
of the Ephorus comet with the 'original' break-up is speculative,'
cautions Marsden. 'Some may argue that the breakup took place much
longer ago, while others might say that it happened in a somewhat
different manner and quite a bit more recently. We really don't
KNOW much about what happened.'"
-- Space Science, 28 August 2000
(1) SUDDENLY, EVERYONE WANTS A NEO PROTECTION PLAN
spacenews@SPACE.COM, 25 August 2000
(2) SPACE BASED DETECTORS AND GIANT COMETS
Bob Kobres <email@example.com>
(3) JAPANESE STUDENTS PROPOSE METEOR-WATCHING SATELLITE
SPACE.com, 29 August 2000
(4) HOP ON AN ASTEROID
The Guardian, 24 August 2000
(5) METEORITE HOLDS CLUES ABOUT RADIOACTIVITY IN THE EARLY SOLAR
Andrew Yee <firstname.lastname@example.org>
(6) "SORRY FOLKS, GREENHOUSE GASES NOT RESPONSIBLE FOR GLOBAL
(7) AND FINALLY: "SORRY FOLKS, POLE ISN'T MELTING AFTER ALL ..."
Nando Times, 29 August 2000
(1) SUDDENLY, EVERYONE WANTS A NEO PROTECTION PLAN
From spacenews@SPACE.COM, 25 August 2000
Canada's Asteroid Protection Plan
By Lee Siegel
25 August 2000
LOGAN, Utah - Canadian space and defense agencies are considering
construction of a small space telescope to detect possible
Earth-whacking asteroids and train the military to track satellites in
"We want to watch for rocks in the sky that might hit the Earth or that
we might want to mine," said Kieran Carroll, space projects manager for
Dynacon Enterprises Ltd. in Mississauga, Ontario, near Toronto. "And
while we are up there looking, we might as well be space traffic cops
and learn how to keep track of all the high-orbit satellites."
NESS would keep an eye out for rogue rocks near Earth, as well as
monitoring orbital traffic.
Concept studies for NESS - the Near Earth Space Surveillance
satellite - are underway with the support of the Canadian Space
Agency and Department of National Defense, Carroll said during the
14th annual Conference on Small Satellites in Logan, Utah.
The meeting, which ended August 24, was sponsored by the American
Institute of Aeronautics and Astronautics and Utah State
University's Space Dynamics Laboratory.
Dynacon now is prime contractor building another microsatellite to
carry Canada's first space telescope, MOST, which stands for
Microvariability and Oscillations of Stars because the 6-inch-
(15-centimeter-) wide telescope will study so-called "starquakes"
for clues to the age of the universe.
MOST is due for launch into low Earth orbit from Vandenberg Air
Force Base, California in early 2003 as a secondary payload to
Canada's Radarsat 2 on a Boeing Delta 2 rocket.
NESS would be Canada's second space telescope, modeled after the
115-pound (52-kilogram) MOST, but with possible improvements,
including a larger telescope and better computer, Carroll said.
He described MOST as a suitcase-shaped box measuring 25 by 23 by
10 inches (63 by 58 by 25 centimeters).
Carroll estimated NESS would cost $3 million to $4 million in
An orbiting asteroid search would be more effective at detecting a
class of Earth-threatening asteroids named Atens, which spend much
of their time inside Earth's orbit, and thus closer to the sun and
in daylit skies. There is no "sky glow" in space to prevent
daytime observations. Baffles to block sunlight could let NESS
look for asteroids closer to the sun.
About 65 Atens have been discovered, but some scientists believe
there may be several hundred larger than 0.6 mile (1 kilometer)
wide, as well as tens of thousands smaller ones.
Newly discovered asteroids frequently are lost to view within
days. NESS would be able to track them longer than ground-based
telescopes, allowing better determinations of their orbits, and
thus the threat they pose to Earth, Carroll said. NESS also would
study asteroids, including their mineral composition for possible
As for satellite tracking, Carroll said Canada is looking for new
ways to fulfill its responsibilities as the United States' partner
in the North American Aerospace Defense Command, which watches for
attacking missiles and tracks some 23,000 man-made objects in
Radar and optical telescopes have tracked most satellites from the
ground. But Canada's satellite-tracking optical telescopes and
cameras have been replaced by newer sensors, and radar is not good
at tracking high-altitude satellites, Carroll said.
"Canada's Department of National Defense has recently initiated a
Surveillance of Space (SOS) program in order to contribute new
Canadian sensors to the Space Surveillance Network," Carroll and
colleagues wrote in a paper prepared for the satellite conference.
The SOS program will include new ground-based telescopes and "will
also involve Canada launching a satellite system to track other
satellites," particularly those in high orbits, wrote Carroll and
researchers from the universities of Calgary, Victoria and British
Canada's Defense Research Establishment contracted with Dynacon
"to study how a microsatellite (NESS) based on the MOST design
could be used to conduct experimental satellite-tracking
activities," they added.
Carroll said NESS would be used for research "so the Canadian
military can learn about operating surveillance satellites" before
building a bigger system.
Why track high-orbit satellites?
"NORAD and U.S. Space Command want to know what's up in space,"
said John Pike, space policy analyst for the Federation of
American Scientists in Washington.
"The Russians may have [in high orbits] a few signals-intelligence
(eavesdropping) satellites, a few early-warning satellites and
they certainly have a lot of communications satellites," Pike
said. "We want to know what their capabilities are and what they
Carroll said NESS could track malfunctioning communications
satellites to help prevent collisions with other satellites, and
also monitor high-altitude Russian and Chinese communications
Pike called the proposed NESS satellite "a bargain at the price."
However, the money might be better spent on ground-based
telescopes to search for asteroids, said Brian Marsden, director
of the International Astronomical Union's Minor Planet Center,
which tallies and reports asteroid and comet discoveries.
"A few million dollars is indeed a lot of money," he said from
Cambridge, Massachusetts. "That's comparable to the amount put
into ground-based [asteroid-detection] work around the world."
Marsden also said the Canadians should make the telescope aperture
larger than 6 inches (15 centimeters). Nevertheless, a small
orbiting telescope "could be quite useful" because it would not be
affected by clouds, the atmosphere, the moon or daylight, and
could look for asteroids closer to the sun.
He said the danger posed by Aten asteroids "certainly is not being
addressed by the ground-based programs."
Copyright 2000, Space.com
(2) SPACE BASED DETECTORS AND GIANT COMETS
From Bob Kobres <email@example.com>
August 28, 2000 -- Last week, the ESA/NASA Solar and Heliospheric
Observatory shattered its own record for comet discoveries when
astronomers announced that the orbiting spacecraft had recorded its
200th sungrazing comet. Michael Oates, an amateur astronomer in
Britain, spotted SOHO-200 in an online image captured by one of SOHO's
coronagraphs. The picture showed the comet evaporating as it plunged
through the superheated solar corona.
"With 200 discoveries, SOHO is way ahead [of any other comet hunter],"
says Brian Marsden of Harvard University's Minor Planet Center. The
automated asteroid and comet search program "LINEAR is a distant second
with 50 comets. Among individuals, Carolyn Shoemaker is of course the
leader, with 30-something discoveries."
[. . .]
Remarkably, most sungrazing comets appear to be fragments of a single
giant comet that broke apart near perihelion (closest approach to the
Sun) long ago. Marsden speculates that the parent might have been a
bright comet seen by the Greek astronomer Ephorus in 372 BC. Ephorus
reported that the comet split in two. Splits may have occurred again
and again, producing the Kreutz sungrazer family (named after the
nineteenth-century German astronomer who studied them in some detail).
The sungrazers share an elliptical orbit that brings some of the
fragments less than 50,000 km from the Sun.
"The association of the Ephorus comet with the 'original' break-up is
speculative," cautions Marsden. "Some may argue that the breakup took
place much longer ago, while others might say that it happened in a
somewhat different manner and quite a bit more recently. We really
don't KNOW much about what happened."
The nucleus of the original comet may have been as wide as 100 km, or
10 to 20 times larger than an ordinary comet. Most of the short-lived
fragments seen nowadays by SOHO are tiny -- probably no more than a few
tens of meters across. Occasionally, pieces come along that are large
enough to survive the Sun's searing heat, and these can emerge from
their close encounter as bright naked-eye comets. One such fragment in
1965, Comet Ikeya-Seki, was visible in broad daylight. Scientists
estimate that Ikeya-Seki's icy nucleus was some kilometers wide.
University of Georgia
Athens, GA 30602
(3) JAPANESE STUDENTS PROPOSE METEOR-WATCHING SATELLITE
From SPACE.com, 29 August 2000,
LOGAN, Utah - Two Japanese college students who won a design contest
may see their idea put into orbit. Their winning concept was to send a
camera-equipped microsatellite to provide a unique view of the Leonid
meteor shower. Their professor is seeking aid to build and launch their
"We need your help to make our idea real" and launch the first
satellite designed to observe meteors, Kazuya Yoshida told hundreds of
experts attending the recent 14th annual Conference on Small
The satellite would cost at least $1 million, but "I don't have so huge
a budget," said Yoshida, an associate professor of aeronautics and
space engineering at Tohoku University in Sendai, Japan.
They now need help building the satellite and finding a place for it as
a secondary payload on a rocket launched in the months before the
annual Leonid meteors flash through the skies in November 2002, he
The 66-pound (30-kilogram) satellite's mission would last only
a week, spanning the predicted November 19, 2002, outburst of Leonid
meteors. Yoshida said the spacecraft couldn't be built in time for the
2001 meteor shower as earlier hoped. This November's Leonids are not
expected to be as spectacular as last year's, he added.
Yoshida was asking for help at the right place: Some 560 small
satellite experts came to the conference from universities, space
agencies, military organizations and companies around the world. The
annual gathering, which ended August 24, is sponsored by the American
Institute of Aeronautics and Astronautics and Utah State University's
Space Dynamics Laboratory.
Innovative proposals made one year at the conference often
move toward reality in subsequent years, he said.
As for Yoshida's one-man plea for help, "I haven't seen too many of
those succeed where you are holding out your hand and asking somebody
to fund you," Redd said. "But this is an appropriate place to do it.
There is a possibility, so why not get the idea out?"
The Leonid mission was conceived by Hiroshi Hamano and Satoko Abiko,
undergraduates at Tohoku University. Yoshida said it received first
prize in the new idea category at an annual satellite-design contest
sponsored by Japanese space agencies, academic societies and the Japan
FULL STORY at http://www.space.com/cgi-bin/email/gate.cgi?lk=T3&date=000829&go=/scienceastronomy/astronomy/leonidsat_000828.html
(4) HOP ON AN ASTEROID
From The Guardian, 24 August 2000
Hop on an asteroid. How do you traverse a small heavenly body? With
giant leaps, explains Duncan Steel
Try to land on the surface of the moon or Mars, and the force of
gravity will bring you in uncomfortably fast. That makes retrorockets
necessary, or some other mechanism to cushion the impact. But landing
on an asteroid or comet presents the converse problem: the target's
mass is too low to generate any substantial gravitational pull, and so
you may simply float off.
Up until now this has only been a concern for Hollywood scriptwriters
(as in the movies Deep Impact and Armageddon) and they tend to
circumvent the problem by ignoring the laws of physics. But now there
are plans to send various spacecraft to explore the surfaces of
asteroids and comets, and so a real scientific fix is needed.
The American Near-Shoemaker probe was placed in orbit around an
asteroid called Eros six months ago. Eros, at 20 miles across, is
fairly large as such things go, and so exerts sufficient gravitational
pull for Near's masters to work against, letting their satellite
circuit this rocky body and move in and out to take a closer look.
Eventually they will let Near-Shoemaker drop down low, and perhaps
nestle into the dusty surface of Eros. Barring some disaster with its
thrusters, the probe will make a soft landing.
Due for launch in 2003, but taking eight years to get to its prime
target, is the European Space Agency's Rosetta probe. When it
eventually approaches comet Wirtanen in 2011, the mother craft will
drop a module named RoLand. The comet is small, and so has low gravity.
In addition to that, ice and other volatile materials sublimating from
the surface of a comet produce an expanding vapour cloud, which could
push RoLand away. The trick will be first to get down to the surface,
and then to grapple with it, or anchor itself down. That accomplished,
samples will be taken and the behaviour of the comet monitored as it
comes closer to the sun over the following two years.
Before Rosetta gets to its comet, Japan plans to send a probe to
perform a cosmic pirouette with a near-earth asteroid. Both the
spacecraft and the asteroid have names that are hardly prosaic: the
former is called Muses-C, while the latter is stored as 1998 SF36 in
the astronomers' data banks.
The asteroid will eventually be given a more memorable name. It was
discovered by an American search team from New Mexico in late 1998, and
eventually it will have its orbit determined with sufficient precision
to allow a proper moniker to be allocated.
Astronomers don't like to give objects names until they are sure they
have enough data so as not to lose them amongst the myriad stars. As
the target of a space mission, plenty of telescopes will be keeping
track of 1998 SF36.
Muses-C is due for launch in November or December 2002, getting to its
destination three years later. Two small landing modules are planned.
One is a Japanese device named Minerva, while Nasa has built a tiny
rover currently called Muses-CN; again, one would imagine that a more
prosaic appellation will be found for it soon.
This little critter is only the size of a shoebox, and so is often
termed a nanorover (hence the N in the name). The plan is that it will
navigate around the asteroid surface not so much by turning its wheels,
but more by jumping like a grasshopper.
Everyone knows that when Neil Armstrong stepped onto the lunar surface,
he spoke of a "giant leap for mankind." Subsequent Apollo astronauts
illustrated that by bounding for the benefit of the television cameras,
showing that in the low gravity of the moon it is easier to take
twin-footed bounds than to walk. On an asteroid the situation is more
extreme, and an astronaut would be able to jump off it, never to
Low gravity is a drawback even for a robotic system. It means that the
tiny wheels of Muses-C would not be able to get much traction. Instead,
the idea is that the pivoting front and back pairs of wheels will
spring together to provide an upward thrust, pushing the rover off the
asteroid with a leap of a hundred yards or so.
In this low-g environment, everything seems to happen slowly. The rover
will take several minutes to rise on its trajectory, and then gradually
fall back to the surface. But it won't land on the spot where it
started. Asteroids spin on their axes every few hours. During the
rover's leap into space, the asteroid will have turned, and so the
rover will land perhaps a quarter of a mile away, take a look with its
tiny camera, and then jump again. In this way a wide range of surface
locations will be examined and compared.
But what if the rover lands on its back? Will it struggle to right
itself like an upturned beetle? They got round that by making Muses-CN
a reversible vehicle: it has solar cells on top and bottom, so it makes
no difference which way up it lands.
If a ride on a helter-skelter makes you feel dizzy, spare a thought for
this poor little fellow. Repeatedly kicking itself out into space, and
then slowly tumbling back again, its gyrations will make even the
multiple somersaults of Olympic divers and gymnasts look trivial. But
it does have the advantage of low gravity, and so no hard landings.
. Duncan Steel researches asteroids and comets at the University of
Copyright 2000, The Guardian
(5) METEORITE HOLDS CLUES ABOUT RADIOACTIVITY IN THE EARLY SOLAR SYSTEM
From Andrew Yee <firstname.lastname@example.org>
University of California-Los Angeles
Stuart Wolpert, email@example.com, (310) 206-0511
Harlan Lebo, firstname.lastname@example.org
For Immediate Use: August 25, 2000
METEORITE ANALYZED BY UCLA GEOCHEMIST CONTAINS CLUES ABOUT
RADIOACTIVITY IN THE EARLY SOLAR SYSTEM
Clues about our early solar system are revealed in an isotope analysis
of a primitive meteorite, reported by a UCLA scientist and French
colleagues in the cover story of the Aug. 25 issue of the journal
Analyzing ancient calcium-aluminum-rich inclusions, known as CAIs, in
samples of a meteorite that is more than four-and-a-half billion years
old, Kevin McKeegan, a UCLA research geochemist, reports that these
inclusions contain isotopes of the elements boron and beryllium in a
ratio that indicates that when the CAIs crystallized, they contained a
radioactive isotope, beryllium-10. This isotope has a half-life of
approximately 1.5 million years and is therefore long extinct, having
completely decayed to boron-10 long ago, McKeegan said.
Because this type of isotope is usually formed by the bombardment of
matter with cosmic rays, the research suggests that the CAIs bore
witness to "a high-radiation environment at the time of their formation
in the early solar system," McKeegan said.
"Four-and-a-half billion years ago, these calcium-aluminum-rich
inclusions melted and crystallized in the solar nebula before the Earth
and other planets were formed," McKeegan said. "These CAIs are the
oldest known solar system rocks."
McKeegan believes that while the Allende meteorite -- which landed in
Mexico in a shower of stones in 1969 -- came from the asteroid belt,
the CAIs inside of it probably did not originate there. Instead,
McKeegan surmises that these inclusions most likely formed much closer
to the young sun, and were carried by a wind to the asteroid belt,
where they conglomerated into an asteroid, a piece of which eventually
became a meteorite that fell to Earth. He believes that the CAIs, the
largest of which are about the size of a fingernail, are older than the
meteorite in which they are included.
How far did these CAIs travel before they were accreted into the
meteorite that eventually landed in Mexico? Nearly four times the
distance between the Earth and sun, McKeegan said.
This hypothesis is based on the work of University of California,
Berkeley, astrophysicist Frank Shu and his colleagues. According to
McKeegan, if this controversial idea is correct, then the sun went
through an "energetic phase where it spewed out high-energy nuclear
particles before the planets formed." Rocks, such as those inclusions
found within the Allende meteorite, witnessed this violent process, he
said. Very high temperature minerals coexist in the Allende meteorite
with low temperature materials, which supports the theory that the high
temperature materials came from a different region.
The CAIs contain a form of aluminum (aluminum-26) and calcium
(calcium-41) that were originally radioactive, but remained so for less
than a few million years, McKeegan said. Where did these radioactive
"extinct isotopes" within the CAIs come from?
Most scientists believe the aluminum-26 and calcium-41, like other
isotopes, were made in stars, and that little time elapsed from their
synthesis to when rocks were formed in the solar system. Some
astrophysicists have argued that to form the solar system in such a
short time (less than one million years), a nearby supernova must have
exploded, and that materials from this massive dying star were
incorporated into the sun, the Earth, and the other planets. According
to this theory, the exploding supernova would have provided the
radioactivity in the CAIs. However, the finding of beryllium-10 casts
doubt on this theory.
McKeegan and his colleagues consider it more likely that at least some
of the radioactivity came from nuclear reactions induced by the
collisions of energetic particles with dust or gas in the early solar
"We have compelling evidence in these CAIs that at the very beginning
of the solar system there was a high-radiation environment that caused
nuclear reactions to turn some of the rock radioactive," McKeegan said.
McKeegan and French research scientists Marc Chaussidon and Francois
Robert measured the isotope composition and abundances of lithium,
beryllium and boron from samples of CAIs known to contain aluminum-26.
They analyzed the small samples in a high-resolution ion microscope, a
powerful type of mass spectrometer, at Nancy, France. There are only
seven of these instruments in the world, including the first one at UCLA.
Unlike almost all other elements, lithium, beryllium and boron are made
not in stars, but primarily by high-energy nuclear reactions in
interstellar space, McKeegan said.
McKeegan's research was funded by a cooperative French-American program
through the National Science Foundation, and by NASA's Cosmochemistry
and Astrobiology programs.
(6) GREENHOUSE GASES NOT RESPONSIBLE FOR GLOBAL WARMING
David E. Steitz
Headquarters, Washington, DC August 29, 2000
Cynthia M. O'Carroll
Goddard Space Flight Center, Greenbelt, MD
NEW VIEW ON THE CULPRITS OF CLIMATE CHANGE PUBLISHED
Since climate change affects everyone on Earth, scientists
have been trying to pinpoint its causes. For many years,
researchers agreed that climate change was triggered by what they
called "greenhouse gases," with carbon dioxide from burning of
fossil fuels such as coal, oil, and gas, playing the biggest role.
However, new research suggests fossil fuel burning may not be as
important in the mechanics of climate change as previously
NASA funded research by Dr. James Hansen of the Goddard
Institute for Space Studies, New York, NY, and his colleagues,
suggests that climate change in recent decades has been mainly
caused by air pollution containing non-carbon dioxide greenhouse
gases, particularly tropospheric ozone, methane,
chlorofluorocarbons (CFCs), and black carbon (soot) particles.
Since 1975, global surface temperatures have increased by
about 0.9 degrees Fahrenheit, a trend that has taken global
temperatures to their highest level in the past millennium. "Our
estimates of global climate forcings, or factors that promote
warming, indicate that it is the processes producing non-CO2
greenhouse gases that have been more significant in climate
change," Hansen said.
"The good news is that the growth rate of non-carbon dioxide
greenhouse gases has declined in the past decade, and if sources
of methane and tropospheric ozone were reduced in the future,
further changes in climate due to these gases in the next 50 years
could be near zero," Hansen explained. "If these reductions were
coupled with a reduction in both particles of black carbon and
carbon dioxide gas emissions, this could lead to a decline in the
rate of climate change."
Black carbon particles are generated by burning coal and
diesel fuel and cause a semi-direct reduction of cloud cover. This
reduction in cloud cover is an important factor in Earth's
radiation balance, because clouds reflect 40 percent to 90 percent
of the Sun's radiation depending on their type and thickness.
Black carbon emission is not an essential element of energy
production and it can be reduced or eliminated with improved
Hansen's research looked at trends in various greenhouse
gases and noted that the growth rate of carbon dioxide in the
atmosphere doubled between 1950 and 1970, but leveled off from the
late 1970s to the late 1990s.
The other critical piece of information this research is
based on, in addition to greenhouse gas levels, is observed heat
storage, or warmer ocean temperatures, over the last century. Heat
storage in the ocean provides a consistency check on climate
change. The ocean is the only place that energy forms an
imbalance. In this case a warming can accumulate, and global ocean
data reveals that ocean heat content has increased between the
mid-1950s and the mid-1990s.
Hansen's paper, "Global Warming in the 21st Century an
Alternate Scenario," will appear in the August 29th version of the
Proceedings of the National Academy of Sciences.
More information on the paper can be found at:
NASA's Office of Earth Sciences, Headquarters, Washington,
DC, sponsor research that studies how human-induced and natural
changes affect our global environment.
For more information about the Earth Sciences Enterprise,
(7) AND FINALLY: "SORRY FOLKS, POLE ISN'T MELTING AFTER ALL ...."
From Nando Times, 29 August 2000
Copyright 2000, Nansdo Media
Copyright 2000, AP Online
North Pole not as wet as reported
The Associated Press
NEW YORK (August 29, 2000 10:07 a.m. EDT
http://www.nandotimes.com) - Citing a report in The New York Times, The
Associated Press erroneously reported Aug. 19 that open water had been
spotted on the North Pole for the first time in 50 million years, a
possible sign of global warming.
In a correction Tuesday, the Times said it had misstated the normal
conditions of sea ice at the pole. It said open water probably has
occurred there before because the Arctic Ocean is about 10 percent
ice-free during a typical summer.
The Times also said the lack of ice at the North Pole is not
necessarily a result of global warming.
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