PLEASE NOTE:
*
CCNet 125/2002 - 31 October 2002
-------------------------------
"Five years ago astronomers had a fright. Jim Scotti, using
the
36-inch Spacewatch telescope on Kitt Peak, spotted a dim speck of
light
moving through the constellation Cancer. It was an
asteroid--dark,
about 1 km wide, and it seemed to be heading for Earth. The Minor
Planet Center named it "1997 XF11." Newspapers and
magazines relayed the
worst: 1997 XF11 might hit our planet on Oct. 26, 2028. The
impact,
unleashing perhaps 2000 times more energy than the most powerful
nuclear
weapon ever tested, would be a global catastrophe. There is,
however, an
old amusement park proverb, "Fear - Death = Fun." So it
proved for
1997 XF11. Additional measurements showed that the asteroid would
not hit
Earth in 2028, although it will come close, about 2.5 lunar
distances
(954,000 km) away."
--NASA Science News, 31 October 2002
"The major problem with this [impact] hypothesis is that the
interior of the Moon is not cooperating. Most importantly, the
lower
lunar mantle, based on analyses of the Apollo 17 orange
pyroclastic
glass, has a chondritic, that is, primordial elemental and
isotopic
imprint. This primordial imprint would have disappeared or have
been
significantly modified if the mantles of the Earth and the
impactor had
already formed as required by the current Giant Impact
hypothesis. If
the Giant Impact hypothesis is not compatible with this evidence,
alternatives to it should be considered, including capture of a
small,
independent planet from a solar orbit near that of the
Earth's."
--Apollo 17 astronaut Harrison Schmitt, 29 October 2002
(1) HALLOWEEN ASTEROID: 1997 XF11 PASSES BY EARTH AGAIN THIS WEEK
NASA Science News for October 31, 2002
(2) "GIANT IMPACT HYPOTHESIS FOR MOON'S ORIGIN INCOMPATIBLE
WITH EVIDENCE"
Andrew Yee <ayee@nova.astro.utoronto.ca>
(3) INDIAN MEDIA FOCUS ON IMPACT HAZARD: "ASTEROIDS REMAIN A
SERIOUS THREAT
TO HUMAN LIFE"
Hindustan Times, 29 October 2002
(4) "ASTEROIDS ON COLLISION COURSE" - NOT
The Times of India, 31 October 2002
(5) SATELLITE DEBRIS RAINS ON CHINESE VILLAGE, INJURES BOY
Space Daily, 29 October 2002
(6) YOU SAY: "NASA PLANS MOON LASER TO DEFLECT
ASTEROIDS"
The Financial Times, 29 October 2002
(7) SUCCESS FOR ROSETTA'S TANSATLANTIC LINK
Andrew Yee <ayee@nova.astro.utoronto.ca>
(8) ANOMALOUS COSMIC RAYS ORIGINATE FROM COSMIC DUST, MAY EFFECT
EVOLUTION
Harvey Leifert <hleifert@agu.org>
(9) STAR DISKS AND NEO NONSENSE
Daniel Fischer <dfischer@astro.uni-bonn.de>
(10) AND FINALLY: OUR EARTH MAY HAVE A SPECIAL PLACE IN THE
UNIVERSE AFTER ALL
Nature Science Update, 30 October 2002
==============
(1) HALLOWEEN ASTEROID: 1997 XF11 PASSES BY EARTH AGAIN THIS WEEK
>From NASA Science News for October 31, 2002
http://science.nasa.gov/headlines/y2002/31oct_1997xf11.htm?list20392
Near-Earth asteroid 1997 XF11, which briefly scared astronomers
five years
ago, passes by Earth again this week on Halloween.
Oct. 31, 2002: Five years ago astronomers had a fright.
Jim Scotti, using the 36-inch Spacewatch telescope on Kitt Peak,
spotted a
dim speck of light moving through the constellation Cancer. It
was an
asteroid--dark, about 1 km wide, and it seemed to be heading for
Earth. The
Minor Planet Center named it "1997 XF11."
Newspapers and magazines relayed the worst: 1997 XF11 might hit
our planet
on Oct. 26, 2028. The impact, unleashing perhaps 2000 times more
energy than
the most powerful nuclear weapon ever tested, would be a global
catastrophe.
There is, however, an old amusement park proverb, "Fear -
Death = Fun." So
it proved for 1997 XF11. Additional measurements showed that the
asteroid
would not hit Earth in 2028, although it will come close, about
2.5 lunar
distances (954,000 km) away.
A frisson of dread? Yes. A global catastrophe? No.
The asteroid moved away from Earth after 1997 and it has since
been
generally forgotten. But the space rock hasn't really gone away.
In fact,
it's back. 1997 XF11 is gliding by Earth today--on Halloween--for
its
closest encounter until 2028.
"On Oct. 31st, 1997 XF11 will pass 25 lunar distances (9.5
million km) from
Earth. It's closer than it was when it was discovered in
1997," says Jon
Giorgini, a member of JPL's Solar System Dynamics Group. There's
nothing to
fear. On the contrary, astronomers welcome the encounter because
it is a
good opportunity to study the asteroid up-close.
"We started out knowing very little about this
asteroid--only that it's
approximately 1 km wide. 1997 XF11 has been circling the Sun in
total
anonymity for hundreds of millions of years. But now radar is
revealing its
nature."
Giorgini is one of a team of astronomers led by JPL's Steve Ostro
who are
"pinging" the asteroid using NASA's Goldstone radar in
the Mojave desert.
"The first radar measurement obtained last week,"
reports Giorgini, "reduced
the uncertainty in the distance to the asteroid by a factor of
540 (from +/-
2210 miles to +/- 4 miles). We can now reliably predict Earth
encounters for
an additional 107 years into the future--to the year 2209. There
is no risk
of 1997 XF11 hitting Earth during that time."
The orbit of 1997 XF11 carries it from a point near the orbit of
Venus out
to the asteroid belt and back again. One complete trip around the
Sun takes
1.73 years. These frequent visits to the inner solar system make
1997 XF11
harder to predict than some other asteroids.
"1997 XF11 has many encounters with Earth and Venus through
the years," says
Giorgini. Gravitational nudges from the two planets perturb the
asteroid's
orbit. "For other asteroids one might obtain several
centuries of
predictability from a single radar measurement, but for 1997 XF11
our
knowledge of its position is more quickly 'blurred.' The more
radar data we
get ... the better," he says.
Giorgini and colleagues will continue observing through November.
Radar data
accumulated over a period of time, says Giorgini, can be used not
only to
measure orbits but also to create 3-dimensional maps of
asteroids. Some have
weird forms: 216 Kleopatra, for example, looks like a dog bone.
Learning the
shapes of asteroids helps scientists understand how they're put
together--valuable information in case we ever need to deflect
one or blow
it apart.
Most asteroids (1997 XF11 included) are as dark as charcoal. They
shine only
because they reflect a few percent of the sunlight that hits
them. When 1997
XF11 is closest to Earth today, it will glow like a 13th
magnitude star--too
faint to see with the unaided eye or even binoculars.
Nevertheless amateur astronomers using 10" telescopes and
CCD cameras will
be able to detect 1997 XF11 as it glides through the
constellation
Capricornus. Optical observations, notes Giorgini, can tell us a
great deal
about the asteroid's rotation period and mineral composition. In
2028, when
1997 XF11 is only 2.5 lunar distances from Earth, optical
telescopes will
play a greater role in its study. The asteroid will brighten to
8th
magnitude, which is within reach of binoculars.
There's still much to learn. One thing, however, is already
clear: we're
safe from 1997 XF11 for at least another 200 years. This
Halloween asteroid
is not so scary after all.
Editor's note: Although 1997 XF11 comes closest to Earth this
week on Oct.
31st, its brightness won't peak until a few days later on Nov.
4th when the
asteroid will glow like a 12.8-magnitude star. If you have a
telescope and
wish to observe the asteroid, please visit JPL's Near-Earth
Object program
web site for an up to date ephemeris.
=============
(2) "GIANT IMPACT HYPOTHESIS FOR MOON'S ORIGIN INCOMPATIBLE
WITH EVIDENCE"
>From Andrew Yee <ayee@nova.astro.utoronto.ca>
Geological Society of America
Denver, Colorado
Contact: Ann Cairns
Phone: 303-357-1056; Fax: 303-357-1074
acairns@geosociety.org
FOR IMMEDIATE RELEASE: October 29, 2002
GSA Release No. 02-46
A Moonwalker's Perspective 30 Years Later: Harrison Schmitt to
Offer
"Shocking Revelations" at GSA Annual Meeting
The date was December 11, 1972, and the occasion was the last
Apollo mission
to the Moon. Apollo 17 astronaut Harrison Schmitt landed in the
Valley of
Taurus-Littrow, the only scientist and the last of 12 men to step
onto the
lunar surface. Standing in a brilliantly sun-lit valley deeper
than the
Grand Canyon and gazing at a nearly full Earth in a deep black
sky,
Schmitt's questions about the origins of the Moon and terrestrial
planets
and their subsequent history took on very personal significance.
Today, geoscientist Schmitt, literally one in six billion human
beings to
combine science with actual lunar exploration, continues to
ponder those big
questions.
He'll share some of the results of his synthesis of the research
of many
others on Tuesday, Oct. 29, at the annual meeting of the
Geological Society
of America in Denver, CO. At the GSA Planetary Geology division's
Gilbert
Lecture and Award Ceremony, Schmitt will discuss "A Lunar
Field Geologist's
Perspective 30 Years Later: Shocking Revelations about the Moon,
Mars, and
Earth."
Shocking? The orange "soil" or pyroclastic glass that
Schmitt found on the
Moon, for example, continues to provide clues about the origin of
the Moon.
In Schmitt's view, it also reveals why the prevailing Giant
Impact
hypothesis of the Moon's origins doesn't work.
"The major problem with this hypothesis," says Schmitt,
"is that the
interior of the Moon is not cooperating. Most importantly, the
lower lunar
mantle, based on analyses of the Apollo 17 orange pyroclastic
glass, has a
chondritic, that is, primordial elemental and isotopic imprint.
This
primordial imprint would have disappeared or have been
significantly
modified if the mantles of the Earth and the impactor had already
formed as
required by the current Giant Impact hypothesis.
According to Schmitt, "If the Giant Impact hypothesis is not
compatible with
this evidence, alternatives to it should be considered, including
capture of
a small, independent planet from a solar orbit near that of the
Earth's."
Similarly, many scientists agree that the Moon's 50 or so basins
greater
than 300km in diameter, as well as most other ancient lunar
craters, were
formed at about the same time by an apparent
"cataclysm" 3.9 billion years
ago. According to Schmitt, "the primary argument against
this hypothesis is
found in the sampling sites for Apollo and lunar meteorite
samples of
impact-created glass for which formation ages have been
determined. These
samples have come largely from the surface of the Moon most
affected by the
14 youngest large basin-forming impacts and debris thrown from
them. These
14 youngest impacts are, indeed, 3.9-3.8 billion years old based
on the
dating of Apollo samples. A variety of volcanic and impact
evidence
indicates that it is highly unlikely that all the 35 or more
older impact
basins formed during the same interval.
"One of the most exciting aspects of studying lunar origin
and evolution is
applying that understanding to the early Earth and Mars,"
says Schmitt. "And
herein lies a 'shocking' revelation about the possible origin of
Earth's
first continents."
The 2500km diameter basin on the far-side of the Moon, known as
South
Pole-Aitken, records an impact of an extraordinarily energetic
object near
the end of the period of smaller scale saturation cratering that
followed
the solidification of the lunar crust. South Pole-Aitken is just
the most
obvious manifestation of possibly three or four other such huge
early
impacts, including the 3200km diameter front-side basin called
Procellarum.
Schmitt estimates that the Procellarum basin formed at about 4.3
b.y and
South Pole-Aitken at about 4.2 b.y. If these formation ages are
in the
ballpark, they suggest an explanation for detrital zircon
(ZrSiO4) crystals
of about the same ages in very old sedimentary rocks on
Earth. Early impacts of the scale of South Pole-Aitken and
Procellarum,
occurring in water-rich environments such as the Earth and Mars,
would
create thick sheets of impact generated rock melt on a
continental scale. As
these magma sheets crystallized, zirconium concentrations may
have reached
levels that produced the very old zircons.
And what about Mars? Schmitt also suggests that there is evidence
for and
reason to believe that Mars had both early (older than 4.2
billion years)
and late (younger than 3.8 billion years) oceans due to separate
periods of
intense volcanic eruptions that included abundant
water. The shores of these two oceans appear to have been
identified in the
data returned by the Mars Surveyor spacecraft now in orbit around
that
planet. Further, he speculates that the most stable ecological
niche for
Martian life has been the boundary between the subsurface water
ice zone and
liquid water expected beneath that zone. If simple, one cell life
forms
evolved on Mars in parallel with their evolution on the Earth
prior to 3.8
billion years ago, they may have adapted to survive in this
global niche as
the surface of Mars became hostile to any life.
"Extrapolating what we now know about the Moon and applying
it to Earth,
Venus, Mars, and Mercury -- the terrestrial planets -- is one of
the primary
scientific returns of lunar research. But looking ahead, the Moon
will also
mature our thinking about the gas giants and other parts of the
solar
system," says Schmitt. For example, whether as a result of a
cataclysm or
not, where did the objects originate that created the 50 or more
large
basins on the Moon? He'll continue to contribute to that work,
this time
with his feet firmly planted on Earth, while developing a
business rationale
to return to the Moon for its energy resources.
"A Lunar Field Geologist's Perspective 30 Years Later:
Shocking Revelations
about the Moon, Mars, and Earth"
Harrison H. Schmitt
Gilbert Lecture - GSA Planetary Geology
Division
Tuesday, Oct. 29, 6:00-7:00 p.m.
CONTACT INFORMATION
During the GSA Annual Meeting, Oct. 27-30, contact Christa
Stratton at the
GSA Newsroom in the Colorado Convention Center, Denver, Colorado,
for
assistance and to arrange for interviews: (303) 228-8565.
Post-meeting contact information:
Harrison H. Schmitt
schmitt@engr.wisc.edu
505-823-2616
Ann Cairns
Director of Communications
Geological Society of America
acairns@geosociety.org
303-357-1056
========
(3) INDIAN MEDIA FOCUS ON IMPACT HAZARD: "ASTEROIDS REMAIN A
SERIOUS THREAT
TO HUMAN LIFE"
>From Hindustan Times, 29 October 2002
http://www.hindustantimes.com/news/181_93037,00040001.htm
Lalitha Vaidyanathan (Press Trust of India)
Mumbai, October 29
The Asteroids' 'hit and go' impact on Earth remains one of the
most serious
threats to human life as the current technology is incapable of
giving any
advance warning.
While several new technologies are also being developed, the
sudden and
violent impact of the near Earth objects (NEO) - mostly asteroids
- which
had earlier wiped out major faces of Earth - remains a challenge
for the
astronomers and defence personnel.
Besides, creating huge damage to the face of the Earth, such
violent
asteroid attacks could even be mistaken for a 'star war' or a
nuclear attack
and hence capable of triggering off even wars between nations at
the ground
level.
"In fact, there should be dedicated facilities to look for
the NEO as the
professional astronomers are interested only in searching for far
off
objects in the cosmos," says Dr Mayank Vahia, senior
astronomer at Tata
Institute of Fundamental Research (TIFR).
Such dedicated facilities could be used by more enthusiastic
students and
amateur astronomers, who could provide timely data that could be
used to
ward off possible mishap by near Earth grazing asteroids, he
said.
The astronomers at Nehru Centre said "we need to keep a
watch on these
asteroids missiles by both amateurs and professional astonomers
and the
scientists from the armed forces and should not compromise on the
data
collection and analysis.
Although early this month, the US Department of Defence had
confirmed an
apparent space rock that lit a fire in the night sky above a
remote region
of Siberia, scientists still struggle to pin down whether or not
the object
slammed into the planet.
Eyewitnesses in the Bodaido district had reported seeing a
fireball race
across the sky on October three. Hunters in that area later said
they found
a crater surrounded by burned forest.
A seismic monitor in the region, according to the British NEO
Information
Centre, possibly recorded the event.
The US defence monitored the rock by satellite from 62 kilometers
down to 30
kilometers above the ground. The agency attempts to track meteors
and
impacts in order to differentiate them from missiles and possible
nuclear
explosions.
"If failing to properly identify a cosmic object as it slams
into the planet
could result in an unnecessary nuclear exchange," few
military and asteroid
analysts have warned.
However, evidence for an actual impact near Bodaido has not been
verified by
scientists.
"Unfortunately, at present we do not know exactly what
happen here," said Dr
Michael Nazarov of the Laboratory of Meteoritics, Vernadsky
Institute of
Geochemistry and Analytical Chemistry.
"The Bodaido (seismic) station recorded a signal which
cannot be easily
interpreted," Nazarov said.
Ironically, the Bodaido event may go down in histroy as a
small-scale cousin
to another one in 1908, also in Siberia. Then, a meteor thought
to be about
the size of a football field exploded above the mostly
unpopulated Tunguska
region. Trees were leveled for hundreds of miles around.
The explosion was recorded by less sophisticated seismic
equipment farther
away, as compared to the Bodaido event, Nazarov pointed out in a
communication to CCNet, an electronic newsletter devoted largely
to NEO
research and discussion.
Nazarov said, it would be difficult to find any possible Bodaido
crater in
the remote region, since the event occurred at night and there
are few
witnesses to help scientists pin down the object's trajectory and
possible
impact location.
Scientists are eager to study impacts and any chunks of meteor
that might be
found in order to learn more about the compositions of their
parent bodies.
Some asteroids are more solid than others and more likely to
reach the
ground intact.
The threshold for an asteroid to be potentially devastating on a
local scale
is thought to be roughly the size of the 1908 Tunguska rock.
Just two weeks back, an asteroid theorist announced new
calculations showing
there are fewer of small "Tunguska" asteroids in
Earth's vicinity and that
they are likely to hit Earth bout once every 1,000 years.
Astronomers had thought such minor catastrophes occurred about
once per
century. Larger rocks capable of widespread devastation hit the
planet less
frequently, the scientists said.
Copyright 2002, Hindustan Times
FOR THE LATEST INFO ON THE SIBERIAN IMPACT EVENT SEE
http://abob.libs.uga.edu/bobk/ccc/cc102902.html
===========
(4) "ASTEROIDS ON COLLISION COURSE" - NOT
>From The Times of India, 31 October 2002
http://timesofindia.indiatimes.com/cms.dll/articleshow?artid=26805394
MUMBAI: There are nearly 500 enormous asteroids at present, which
in the
case of a collision with the Earth, will trigger off a
devastating
explosion, a million times stronger than the Hiroshma bomb,
77-year-old
American astronomer Tom Gehrels said here.
Asteroids are small planetary bodies which orbit the sun. Some of
them can
change course and hit the earth.
Gehrels, who was here to address a meeting at the Nehru Centre,
said that
space agencies of different countries had started projects to
tackle these
deadly asteroids.
In an earlier presentation in the US, he estimated that there
were nearly
1,700 asteroids which he described as "earth killers".
Of the 1,700 only a
fraction have been found. The 500 asteroids belonged to this
killer
category.
He said that over the years the probability of these killer
asteroids
slamming against the Earth have reduced. However, he added:
"They can still
hit and one has to be careful as an Armageddon-style explosion
cannot be
completely ruled out," he said.
He stated, "It is possible to divert these asteroids by
using ion propulsion
rocket engines." However, he was unable to say how many
nations have succeed
in executing such a tricky manoeuvre to save the Earth.
Copyright 2002, The Times of India
==============
(5) SATELLITE DEBRIS RAINS ON CHINESE VILLAGE, INJURES BOY
>From Space Daily, 29 October 2002
http://spacedaily.com/news/021029092451.vta2o5ag.html
BEIJING (AFP) Oct 29, 2002
A nine-year old boy in northern China was injured after debris
from a
satellite launch rained down on his remote village in Shaanxi
province,
state press reported Tuesday.
The boy, named Wu, was hit on his left foot by the metal debris,
part of a
Chinese-made rocket which launched an earth resource satellite
from the
Taiyuan Launch Center in neighboring Shanxi province on Sunday,
the Huashang
Daily reported.
In all, 19 pieces fell on the boy's village of Yanghe, in
Shaanxi's Danfeng
county, the report said.
The debris belonged to the outer shell of the Long March IV
carrier rocket
which protected the satellite as it was propelled into orbit, the
paper
said.
After the satellite separated from the rocket, the shell was
jettisoned and
was expected to fall in or around Danfeng county, it said, citing
space
officials.
Police in the village collected the 19 pieces and are awaiting
launch
officials to come and collect them, the report said.
The boy was hospitalized in a local infirmary, it said, not
saying how badly
he was injured.
The ZY-2 satellite, the second of its type, will transmit remote
sensing
data and help in the exploration of geologic resources,
environmental
protection, urban planning and disaster prevention, the report
said.
All rights reserved. © 2002 Agence France-Presse
=============
(6) YOU SAY: "NASA PLANS MOON LASER TO DEFLECT
ASTEROIDS"
>From The Financial Times, 29 October 2002
http://www.manufacturing.net/dn/index.asp?layout=articleWebzine&articleid=NEe1028179.5iw&industry=Aerospace+and+Defense&industryid=2017
Europe Intelligence Wire via NewsEdge Corporation : NASA
scientists are set
to turn the stuff of video games into reality as they investigate
using
moon-based lasers to deflect asteroids that threaten Earth.
They say lasers could shift the orbit of dangerous asteroids or
divert
smaller asteroids into their path in a method described as
''cosmic
billiards''.
It may sound fanciful, but the work is part of a serious
programme to deal
with the possibility that an asteroid will collide with our
planet at some
point in the future.
Jonathan Campbell, a researcher at Nasa's Marshall Space Flight
Centre in
Alabama, is looking at whether moon-based lasers could be used to
heat the
asteroid's surface to the point where a small part exploded. This
would not
break up the asteroid but could alter its trajectory. A sustained
series of
such laser attacks would be enough to deflect the asteroid, Nasa
believes.
The agency is already planning a comprehensive mapping system for
near-earth
asteroids.
Nasa engineer Dan Mazanek admitted: ''There may come an object
that's so
large you can't deflect it. But you could use a stockpile of
small asteroids
as a mechanism to fight the larger one, like a game of cosmic
billiards.''
Europe Intelligence Wire -- 10/20/02
Copyright ©2002 Financial Times Limited, All Rights Reserved
========
(7) SUCCESS FOR ROSETTA'S TANSATLANTIC LINK
>From Andrew Yee <ayee@nova.astro.utoronto.ca>
ESA Science News, 29 October 2002
http://sci.esa.int/content/news/index.cfm?aid=13&cid=36&oid=30847
With less than three months to go before Rosetta lifts off from
Kourou
spaceport in French Guiana, engineers from ESA, Alenia and
Astrium are
working feverishly to ensure that Europe's comet chaser meets its
narrow
launch window in January 2003.
Two major milestones in the extended Rosetta launch campaign have
been
successfully completed in recent weeks, and the project team is
delighted
with the progress that has been made since the 3-tonne spacecraft
was
delivered to Kourou in early September.
Once Rosetta had been set up in its launch configuration (without
the solar
arrays and high-gain antenna) and passed a leak test of its
propulsion
system, experts installed the final versions of the flight
software and
validated its electrical systems.
This was followed by the Final Acceptance Test, in which
engineers in the
payload preparation facility at Kourou worked around the clock
for eight
days to carry out extensive checks of Rosetta's computer 'brain'
to verify
that the spacecraft was responding as it should.
"This was the last full functional test of the spacecraft,
including its
payload, before liftoff," said Claude Berner, Rosetta
Payload and Operations
Manager. "It was a critical moment, but the test was
successfully completed
on schedule. We will not carry out another full functional test
until after the launch."
Confident that all was well with their deep-space explorer, the
Rosetta team
then conducted a complex system validation test with colleagues
at the
European Space Operations Centre (ESOC) in Darmstadt, Germany.
During a transatlantic link up that lasted almost round-the-clock
for 96
hours, specialists at ESOC checked that they could communicate
with the
spacecraft in real time as Rosetta responded to a series of
commands.
"The test was extremely successful," commented Paolo
Ferri, Rosetta
Operations Manager at ESOC. "We spent about 78 hours out of
the 96 hour
period sending commands, and every day we finished within half an
hour of
the scheduled time."
"We tried to operate the spacecraft in a realistic
manner," he explained.
"Members of the experiment teams were present in ESOC to
study the results
as we commanded all of the experiments both in sequence -- one
after the
other -- and then several at a time."
One of the most important aspects of the long-distance trial was
the attempt
to simulate the operations that would take place immediately
after launch.
"At the beginning of the test, we asked the Kourou crew to
put the
spacecraft into the configuration it will have just before
launch," said
Ferri. "Immediately after they manually triggered the
separation switches
(simulating the spacecraft separation from the Ariane
launcher) we took control and ran through the same sequence that
we will
follow on 13 January. It was a very real simulation of the first
day and a
half of Rosetta's mission."
"Although this was a very important test, it is just part of
the training
and validation procedures we have been practising since September
2002 and
that we will continue until launch," he added. "This
involves simulating all
of the early phases of the mission and rehearsing possible
failure situations."
With these two potential stumbling blocks out of the way,
Rosetta's launch
campaign is well on the way towards completion. Over the next few
weeks, the
spacecraft will assume its final flight configuration as the huge
solar
arrays and dish-shaped high gain antenna are installed. In late
November,
after a final 'go-no go' test, the spacecraft will be fuelled and
placed
under wraps prior to mating with its Ariane 5 upper stage.
USEFUL LINKS FOR THIS STORY
* More about Rosetta
http://sci.esa.int/rosetta/
IMAGE CAPTION:
[Image 1:
http://sci.esa.int/content/searchimage/searchresult.cfm?aid=13&cid=12&oid=30847&ooid=30848
]
[Image 2:
http://sci.esa.int/content/searchimage/searchresult.cfm?aid=13&cid=12&oid=30847&ooid=30851
]
Rosetta's team ensuring that the instruments Lander, Cosima,
Alice and Rosina respond to commands.
=============
(8) ANOMALOUS COSMIC RAYS ORIGINATE FROM COSMIC DUST, MAY EFFECT
EVOLUTION
>From Harvey Leifert <hleifert@agu.org>
American Geophysical Union/Southwest Research Institute
Joint Release
Date30 October 2002
AGU Release No. 02-35
For Immediate Release
AGU Contact: Harvey Leifert
(202) 777-7507
hleifert@agu.org
SwRI Contact: Maria Martinez
(210) 522-3305
mmartinez@swri.org
Univ. of Michigan Contact: Neal Lao
(734) 647-7087
njlao@engin.umich.edu
NSF Contact: Cheryl Dybas
(703) 292-7734
cdybas@nsf.gov
Some Cosmic Rays Originate Within Solar System, Researchers Find
WASHINGTON - Researchers have found that a portion of anomalous
cosmic rays
-- charged particles accelerated to enormous energies by the
solar wind --
results from interactions with dust grains from a belt of
comet-sized
objects near Pluto's orbit. These objects make up what is known
as the
Kuiper Belt, a remnant of the formation of the solar system.
"This novel finding shows how dust in the cosmos may play an
important role
for producing the most energetic particles known," says Dr.
Nathan
Schwadron, a senior research scientist in the Space Science and
Engineering
Division of Southwest Research Institute (SwRI) in San Antonio,
Texas. The
study by Schwadron and colleagues at SwRI and the University of
Michigan was
published October 30 in Geophysical Research Letters, a journal
of the American
Geophysical Union.
"Dust grains are produced in vast amounts through collisions
of Kuiper Belt
objects," says Schwadron. "These particles give us a
glimpse of the early
stages of our solar system when the dust content was much larger,
and could
parallel other more dusty stellar systems that exist now."
Recent observations of anomalous cosmic rays are puzzling because
of the
unexpected presence of iron, silicon and carbon, notes Schwadron.
"This
finding varies from the traditional explanation of anomalous
cosmic rays
which were thought to be devoid of easily charged elements."
The interstellar medium has lots of carbon, silicon and iron
atoms, but
electrical charging (ionization) of these elements prevents them
from
penetrating deeply within the solar system. "Our team looked
for a source
already inside the solar system to account for the unusual
anomalous cosmic
rays -- and we found one in the tiny comet-like grains from the
nearby
Kuiper Belt," says Schwadron.
As the grains produced by collisions in the Kuiper Belt drift in
toward the
sun, they are bombarded by solar wind particles, which causes
sputtering and
frees the carbon, silicon and iron atoms from within. At that
point, those
particles interact with solar radiation, transforming them into
ions
(charged particles). The solar wind then sweeps them out and
accelerates
them to anomalous cosmic ray energies at the edge of the solar
system, where
they are bounced to and fro by magnetic fields in the solar wind
and in the
medium beyond the solar system, according to Schwadron.
Tom Bogdan, program director in the NSF Division of Atmospheric
Sciences,
which partly funded the research, says, "This is a big step
toward solving
the long-standing mystery of the origin of the anomalous
component of cosmic
rays. The research underscores the power of remote sensing:
Sampling of
Kuiper Belt material with unmanned space probes is a huge and
difficult
enterprise. The detection locally of the anomalous cosmic ray
component
provides information on the conditions that prevail in this
remote region of
our solar system."
"Anomalous cosmic rays" are so named because they form
in the relative
vicinity of the Earth, near the sun, and have lower energy than
galactic and
intergalactic cosmic rays, which form in the far reaches of the
galaxy and
beyond. Cosmic rays, the most energetic particles in the cosmos,
move
throughout the universe at light speed and constantly bombard the
Earth.
"The discovery that anomalous cosmic rays can be generated
from material in
the Kuiper Belt provides a tool for understanding its mass
distribution and
composition and for probing the plasma-dust interactions in
space," says
Schwadron.
Cosmic rays also are believed to play a role in evolution.
"Cosmic rays are
a double-edged sword. They cause genetic mutation and are harmful
to living
organisms, but on the upside stimulate
biological evolution," Schwadron says. "Cosmic rays are
our only available
sample of matter from the far reaches of the distant galaxy, and
from other
galaxies. They can tell us a lot about what's in the universe,
and we can
now use them to study what's in the Kuiper Belt. Their
relationship to the
creation or maintenance of life is also worth a closer
look."
This program was supported with funding from NSF, NASA, and
SwRI.
**********
Notes for journalists:
The paper "The Outer Source of Pickup Ions and Anomalous
Cosmic Rays" by Dr.
Nathan A. Schwadron (SwRI), Dr. Michael R. Combi (University of
Michigan),
Dr. Walter F. Huebner (SwRI), and Dr. David J. McComas (SwRI)
appears in the
30 October issue of Geophysical Research Letters.
Journalists may receive a copy of the paper by pdf or fax (four
pages). Send
requests to Emily Crum, ecrum@agu.org
, providing your name, name of
publication, postal address, phone, fax, and email address. The
paper and
this press release are not embargoed.
Citation: Schwadron, N. A., M. Combi, W. Huebner, and D. J.
McComas, The
outer source of pickup ions and anomalous cosmic rays,
Geophys. Res. Lett.,
29(20), 1993, doi:10.1029/2002GL015829, 2002.
Contact information for authors:
Nathan Schwadron: nschwadron@swri.org
or (210) 522-5161
Mike Combi: mcombi@umich.edu
or (734) 764-7226
Dave McComas: dmccomas@swri.org
or (210) 522-5983
Walter Huebner: whuebner@swri.org
or (210) 522-2730
==========
(9) STAR DISKS AND NEO NONSENSE
>From Daniel Fischer <dfischer@astro.uni-bonn.de>
Dear Benny,
in CCNet of Oct. 8 you ran as item 8 a story from the Sunday
Telegraph on
the strange bronze-age 'star disk' found in Germany - much more
can be found
in http://www.astro.uni-bonn.de/~dfischer/mirror/243.html
(based on
otherwise unpublished information from the archaeoastronomer
investigating
the disk).
You may also enjoy (or rather not) the following letter I had to
fire at DER
SPIEGEL, Germany's most influential news magazine that just
doesn't get its
astronomy straight, let alone the NEO business ...
Regards,
Daniel
===========================================================================
"Asteroiden im Blick" - ein (offener) Leserbrief an den
SPIEGEL
Der allzuoft verzerrten Berichterstattung in Sachen Astronomie
des
bekanntesten deutschen Nachrichtenmagazins kann man ja in der
Regel durch
Ignorieren begegnen - aber die aktuelle
"Prisma"-Meldung "Asteroiden im Blick"
(SPIEGEL 44/2002 vom 28.10. S. 170 =
www.spiegel.de/spiegel/0,1518,220210,00.html)
ueber Vorarbeiten der
Universitaet von Hawaii fuer das geplante Panoramic Survey
Telescope and
Rapid Response System (Pan-STARRS) strotzt derart vor Fehlern und
Irrtuemern, dass einmal eine Richtigstellung not tut.
"Der Weltuntergang schien im vergangenen Sommer kaum noch
abzuwenden",
heisst es im ersten Satz zum Fall 2002 NT7*) - dabei hatte dieser
Asteroid
zwischen seiner Entdeckung und der endgueltigen Entwarnung
n i e eine
Einschlagswahrscheinlichkeit auf der Erde von mehr als 1:100 000.
"Dann gab
die NASA Entwarnung" - genau besehen waren es Aufnahmen
oesterreichischer
Amateurastronomen**), die dem Minor Planet Center die
entscheidende
Bahnverbesserung ermoeglichten. Die NASA betreibt lediglich einen
(von
mehreren) Online-Infodiensten zu aktuellen
Impaktwahrscheinlichkeiten***).
"Das Institut fuer Astronomie der Universitaet Hawaii plant
nun bis zum Jahr
2006 auf dem Mauna Kea die Errichtung eines Riesenteleskops, das
Himmelskoerper auf Kollisionskurs schon sehr frueh entdecken
soll" - das
stimmt nur halb: Das IfA hat zwar kuerzlich 3.4 Mio.$ von der
U.S. Air Force
erhalten, um Pan-STARRS zu planen****), doch dessen rund 40 Mio.$
teure
Realisierung ist ebenfalls ein Projekt der USAF, wenn auch mit
dem
IfA-Astronomen Nick Kaiser als fuehrendem Wissenschaftler*****).
Dass schliesslich Pan-STARRS alle gefaehrlichen Asteroiden ab 300
Metern
"mehr als 30 Jahre vor ihrem moeglichen Einschlag"
entdecken werde, ist eine
falsch wiedergegebene statistische Aussage: Die meisten - und
hoffentlich
alle - dieser Funde werden fruehestens in Jahrzehnten bis
Jahrhunderten oder
nie einschlagen, schliesslich kommt ein Impakt dieser
Groessenordnung nur
einmal alle zig tausend Jahre vor. Doch eine Garantie, dass nicht
einer der
zu entdeckenden Asteroiden schon morgen oder in einem Jahr im
Anflug ist,
kann Pan-STARRS natuerlich nicht bieten ...
Daniel Fischer
Skyweek / The Cosmic Mirror / MegaLithos News
www.geocities.com/skyweek
*) www.astro.uni-bonn.de/~dfischer/news/510.html#509
**) web.utanet.at/raab/pomod/2002NT7.html
***) neo.jpl.nasa.gov/risk
****) www.ifa.hawaii.edu/~kaiser/pan-starrs/pressrelease
*****) Space News vom 21.10.2002 Seite 20
============
(10) AND FINALLY: OUR EARTH MAY HAVE A SPECIAL PLACE IN THE
UNIVERSE AFTER ALL
>From Nature Science Update, 30 October 2002
http://www.nature.com/nsu/021028/021028-4.html
No time like the present: Intelligent life might be more likely
in a
Universe in flux.
PHILIP BALL
Ever since Copernicus put the Sun, rather than Earth, at the
centre of the
Universe, scientists and philosophers have suspected that there's
nothing
special about our cosmic time and place. But two physicists now
suggest
otherwise.
Only galaxies about the age of our Milky Way have the right
conditions for
intelligent life to develop, argue Jaume Garriga of the
University of
Barcelona, Spain, and Alexander Vilenkin of Tufts University in
Medford,
Massachusetts1. And that age, they say, might coincide with a
fundamental
change in the Universe.
What's more, the search for other planetary systems could tell us
whether
they're right or not.
Four years ago, astronomers discovered that the Universe's
expansion is
speeding up. Some think that this is because a dark energy is
opposing
gravity and driving all matter apart.
One idea is that this dark energy comes from the constant
creation and
annihilation of particles and antiparticles in 'empty' space. But
the
mystery is then why this 'vacuum energy' seems to be so small -
physics
predicts that it should dominate the way in which the Universe
behaves.
One day it will, say many cosmologists. The observations of the
accelerating
Universe, combined with studies of the early Universe, suggest
that in
several billion years vacuum energy will dwarf all other forms,
such as the
energy in light and stars.
But today vacuum energy accounts for about 70% of the Universe's
total
energy, whereas around 11 billion years ago, when the Universe
was young, it
accounted for about 10%.
Dark forces
We seem to be living at the point when vacuum energy is starting
to
dominate. But in cosmic terms this rise of vacuum energy has been
quite
quick - so it seems surprising that we just happen to be around
at this
special time in the Universe's history.
But Garriga and Vilenkin think that they might have worked out
why
intelligent life is likely to develop during this transition
period. The
conditions for civilizations to emerge, they suggest, will be
found mostly
in galaxies close to and rather like our own.
Distant, newly formed galaxies won't contain as much of the heavy
elements
such as silicon and iron needed for planets to form, they say.
This is
because they are smaller, and so their weak gravity is less able
to hold on
to the heavy elements spewed out by exploding stars.
Small galaxies are also more crowded - and so planets there will
be more
vulnerable to collisions or close encounters between stars. If
vacuum energy
was weaker in the distant past, it's unlikely that anyone would
have been
around to measure it.
Based on this reasoning, say Garriga and Vilenkin, the Universe's
current
dark-energy component should be roughly as large as observations
suggest. In
fact, they say, it should be a little larger, closer to 90%.
So considering dark energy in terms of the conditions needed for
intelligent
life leads not just to hand waving, but to testable predictions.
For
example, as ever more planets are found outside our Solar System,
it may be
possible to see whether only nearby galaxies house habitable
planets.
References
Garriga, J. & Vilenkin, A. Testable anthropic predictions for
dark energy.
Preprint, (2002).
© Nature News Service / Macmillan Magazines Ltd 2002
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