PLEASE NOTE:
*
CCNet 94/2002 - 15 August 2002
------------------------------
"The Queen found out how to save the world from a meteor
collision
from Leicester's space scientists. She listened intently as
experts
explained how they could remove the threat of asteroids hitting
the planet
as she toured Leicester's National Space Centre. Kevin Yates is
an
officer at the city-based Near Earth Objects Information Centre,
which
monitors the skies for threats of asteroids. Kevin, who works at
the
space centre, said: "She asked what we could do if one came
towards
Earth now. We talked about methods of pushing meteors off their
orbit
so they don't hit earth."
--Leicester Mercury, 2 August 2002
"The U.S. Space Command is reviewing a plan to create a
clearinghouse that gathers and analyzes data regarding impending
Earth
impacts from asteroids or comets. The information node would also
assess possible damage stemming from an incoming object. Such a
clearinghouse, if established, would merge military and civilian
talent to
help minimize damage and loss of life due to a strike from
space."
--Leonard David, Space.com, 5 August 2002
(1) GERMAN ARMCHAIR ASTRONOMER FINDS 500TH SOHO COMET VIA
INTERNET
Space.com, 14 August 2002
(2) SOHO COMET 500 DISCOVERED - WINNER OF CONTEST DECLARED
Paal Brekke <pbrekke@esa.nascom.nasa.gov>
(3) CLOSE ACCOUNTER WITH AN ASTEROID
Astronomy.com, 11 August 2002
(4) BEGIN ASTEROID DEFENSE WORK IMMEDIATELY
New Haven Register, 6 August 2002
(5) 'READY TO TACKLE ARMAGEDDON'
BBC News Online, 9 August 2002
(6) AMATEURS WIN NEO GRANTS
Astronomy.com, 13 August 2002
(7) NEW OBSERVATIONS OF 1998 OX4 ELIMINATE ANOTHER 'VIRTUAL
IMPACTOR'
Asteroid/Comet Connection, 7 August 2002
(8) COMETS: A KEY TO A PARALLEL UNIVERSE
The Independent, 12 August 2002
(9) THE SLOAN DIGITAL SKY SURVEY MOVING OBJECT CATALOG
Zeljko Ivezic <ivezic@astro.Princeton.EDU>
(10) ROYAL PAIR REACH THE FINAL FRONTIER
Leicester Mercury, 2 August 2002
(11) U.S. MILITRAY CONSIDERS COORDINATED CLEARINGHOUSE TO MONITOR
AND
RESPOND TO NEO THREAT
Space.com, 5 August 2002
(12) RESEARCHER SEEKS TO MAKE OUTER SPACE EVENTS EASY TO PREDICT
Steve Koppes <s-koppes@uchicago.edu>
(13) NEOS AT THE ACM
David Morrison <dmorrison@arc.nasa.gov>
(14) RESEARCHER STUDIES FOLKLORE FOR CLUES ABOUT TSUNAMI
Associated Press, 12 August 2002
(15) SCIENTISTS BELIEVE DINOSAURS UNDER THREAT BEFORE ASTEROID
STRUCK
Ananova, 12 August 2002
(16) THE PLANET X SAGA
Phil Plait's Bad Astronomy, July 2002
(17) UFO REPORTS CAUSE A PANIC IN INDIA
MSNBC, 12 August 2002
(18) AND FINALLY: COSMOLOGISTS BAFFLED BY UNIVERSE'S 'MIRACULOUS'
WORKING
Andrew Yee <ayee@nova.astro.utoronto.ca>
===============
(1) GERMAN ARMCHAIR ASTRONOMER FINDS 500TH SOHO COMET VIA
INTERNET
>From Space.com, 14 August 2002
http://www.space.com/scienceastronomy/comet_500_020814.html
Using an image obtained over the Internet, German armchair
astronomer Rainer
Kracht has discovered the 500th comet attributed to the
Sun-observing SOHO
spacecraft.
While SOHO (Solar and Heliospheric Observatory) was designed to
monitor
solar flares and other space weather that can hit Earth,
professional
astronomers and amateur comet hunters long ago realized they
could spot the
distinct trail of comets rushing toward the Sun as they prepared
to round it
or crash into it.
A small object spotted by Rainer Kracht of Elmshorn in Germany,
in an image
from SOHO received via the Internet, has been officially
confirmed as Comet
2002 P3 (SOHO). It is the 500th comet discovered with the
ESA-NASA solar
spacecraft and it made its closest approach to the Sun at 16:05
Universal
Time on Monday, 12 August.
The video clip shows the comet (in the small black square) moving
over a
four-hour period. The larger black square shows a close-up of the
comet over
time that has been superimposed on the movie.
More than 75 percent of the 500 SOHO comets have been found by
amateurs.
Most comets form beyond Pluto and never visit the inner solar
system.
However, when they do, some make perilously close passes to the
Sun. A few
survive to head back out, but many are swallowed.
Kracht's comet has been officially named 2002 P3 (SOHO). It made
its closest
approach to the Sun Aug. 12.
The LASCO coronagraph on SOHO, designed for seeing outbursts from
the Sun,
uses a mask to block the bright rays from the visible surface. It
monitors a
large volume of surrounding space, and as a result it is the most
prolific
discoverer of comets in the history of astronomy.
The biggest tallies have come from Kracht, the German, Mike Oates
in England
and Xavier Leprette from France. In a form of "virtual
astronomy," they
engaged in a bit of a race for discovery, going back over SOHO
pictures from
1996 to 1999 to find dozens of comets that professionals had
overlooked.
Kracht, a mathematics, physics, computer science and astronomy
teacher at
the Kooperative Gesamtschule Elmshorn in Elmshorn, has found 63
comets since
August 2001 with the help of SOHO data and images.
Oates leads all armchair comet hunters with 136 discoveries.
Number 500 is a very faint comet compared to many other more
spectacular
sun-grazers, according to a statement issued by NASA. SOHO is a
cooperative
effort of NASA and the European Space Agency.
Copyright 2002, Space.com
===============
(2) SOHO COMET 500 DISCOVERED - WINNER OF CONTEST DECLARED
>From Paal Brekke <pbrekke@esa.nascom.nasa.gov>
A small object spotted by Rainer Kracht of Elmshorn in Germany,
in an image
from SOHO received via the Internet, has been officially
confirmed as Comet
2002 P3 (SOHO). It is the 500th comet discovered with the
ESA-NASA solar
spacecraft and it made its closest approach to the Sun at 16:05
Universal
Time on Monday, 12 August. Diane McElhiney of won a contest run
by the SOHO
science team for guessing that date and time for SOHO-500. Her
prediction
was too early by only 103 minutes.
The LASCO coronagraph on SOHO, designed for seeing outbursts from
the Sun,
uses a mask to block the bright rays from the visible surface. It
monitors a
large volume of surrounding space, and as a result it became the
most
prolific discoverer of comets in the history of astronomy.
Most of them are
small sungrazer comets that burn up completely in the Sun's hot
atmosphere.
More than 75% of the discoveries have come from amateur comet
hunters around the world
watching the freely available SOHO images on the web.
The biggest tallies have come from Mike Oates in England, Rainer
Kracht in
Germany and Xavier Leprette in France. They went back over
pictures from
1996-99 and found dozens of comets that the professionals had
overlooked.
Kracht, a mathematics, physics, computer science and astronomy
teacher at
the Kooperative Gesamtschule Elmshorn in Elmshorn, Germany has
discovered 63
comets since August 2001 with the help of SOHO data and
images. Mike Oates
from Manchester, England is the highest-scoring discoverer of
comets ever,
with 136 to his name, while Rainer Kracht has discovered 63.
The comet has been designated as C/2002 P3 (SOHO) with a
perihelion time of
Aug 12 at 16:04:48 UT. Perihelion is the comets closest approach
to the Sun
SOHO-500 was a very faint comet compared to many other more
spectacular sun
grazing comets.
Images and movies can be found here:
http://sohowww.nascom.nasa.gov/pickoftheweek/
The video clip shows the comet (in the small black square) moving
over a
four-hour period. The larger black square shows a close-up
of the comet
over time that has been superimposed on the movie.
Links to other more spectacular comets:
http://sohowww.nascom.nasa.gov/hotshots/2001_10_24/
http://sohowww.nascom.nasa.gov/hotshots/2000_08_21/
http://sohowww.nascom.nasa.gov/hotshots/2002_01_08/
Alle images: SOHO (ESA/NASA)
The SOHO-500 Comet Contest
A sweepstake run by the SOHO science team for guessing the date
and time of
the 500th comet attracted 1256 entries. The winner of the
"Guess the
perihelion time of the SOHO-500 comet" contest is Diane
McElhiney who missed
by only 1 hour and 43 minutes. The runner up is William
Trost.
Diane McElhiney 08/12/2002 14:22 (missed by 1:43)
William Trost 08/12/2002 12:01 (missed by 4:04)
>>> NOTE: Contact info to reach the winners can be
obtained by contacting me
And these were the prizes that will be awarded to the winners:
Grand prize: collector edition SOLARMAX DVD and Solarmax T-shirt.
Runner up: standard edition SOLARMAX DVD and Solarmax T-shirt.
SOLARMAX DVD courtesy of Slingshot Entertainment and Solarmax
T-shirts and
posters courtesy the Museum of Science and Industry - Chicago.
Solarmax (http://WWW.Solarmovie.com),
A Heliograph Production
(http://www.Helio.com.au)
in
association with the Museum of Science and Industry - Chicago
(http://WWW.MSIChicago.org),
with support from the National Science
Foundation and ESA. Distributed by Musuem of Science and Industry
Film
Distribution. VHS and DVD distributed by Slingshot Entertainment
(http://www.slingshotent.com/ss_title_solarmax.htm)
available at video
retailers worldwide."
For more information on the contest and prizes, go to
http://soho.nascom.nasa.gov/cometcontest/
To learn more about SOHO and sungrazing comets, go to
http://soho.nascom.nasa.gov/
and http://sungrazer.nascom.nasa.gov/
================
(3) CLOSE ACCOUNTER WITH AN ASTEROID
>From Astronomy.com, 11 August 2002
http://www.astronomy.com/Content/Dynamic/Articles/000/000/000/974xdpoz.asp
Asteroid 2002 NY40 will be on display for observers this week.
by Elesa Janke
Dust off those binoculars and ready your scopes: A rare
opportunity awaits
skywatchers in the Northern Hemisphere this month. On the morning
of August
18, asteroid 2002 NY40 will sail within 330,000 miles (530,000
kilometers)
of Earth, only 1.3 times farther away than the moon.
"Flybys like this happen every 50 years or so," says
Don Yeomans, manager of
NASA's Near-Earth Object Program office at the Jet Propulsion
Laboratory.
In other words, this is an opportunity no observer will want to
miss.
Discovered by astronomers on July 14th, the space rock, although
faint now,
will continue to brighten over the coming week, finally reaching
9th
magnitude on August 18th. While faint compared to stars, for an
asteroid
that's quite bright.
"Asteroids are hard to see, because they're mostly black
like charcoal,"
explains Yeomans. Most are carbon-rich "C-type"
asteroids, which reflect 3
to 5 percent of the light that hits them, but other types can
reflect more.
"We don't know yet what this asteroid is made of, but we'll
have a much
better idea by the end of August."
On the night of closest approach, the asteroid will cruise past
Vega, the
brightest star in summer evening skies. While not readily visible
from the
Southern Hemisphere, observers in the Northern Hemisphere will be
able to
view the asteroid as a dot of light, moving 8 degrees per hour.
Every four
minutes, it will cover the same distance in the sky as the
diameter of the
moon. From North America, the best view occurs after sunset on
August 17th,
while Europeans should catch it in the predawn hours of August
18th.
Just hours after closest approach, 2002 NY40 will cross Earth's
orbit en
route to the sun, changing phases as it goes. While the asteroid
is in its
full phase now, showing us its sunlit side, it will quickly grow
darker with
each changing phase, much like the moon. It will then become
completely dark
and impossible to view.
Scientists will take advantage of the sunlit view while it lasts.
One team
of observers at the giant Arecibo radar in Puerto Rico will
bounce radio
waves off the asteroid as it approaches Earth. Such radar data
help produce
three-dimensional maps that can provide valuable information
about the space
rock's shape, as well as whether its orbit will ever bring it too
close for
comfort.
"At present, we know there's little risk of a collision with
2002 NY40 for
decades," says Jon Giorgini of the radar team at JPL.
"When the Arecibo
measurements are done, the orbit uncertainties should shrink by
more than a
factor of 200."
In addition, after 2002 NY40's flyby, astronomers hope to know
much about
the asteroid's chemical makeup.
"Don't forget," adds Yeomans, "most asteroids pose
no threat to Earth. But
they do contain valuable metals, minerals, and even water that we
might tap
in the future."
Copyright © 1996-2002 Kalmbach Publishing Co.
===============
(4) BEGIN ASTEROID DEFENSE WORK IMMEDIATELY
>From New Haven Register, 6 August 2002
http://www.zwire.com/site/news.cfm?newsid=4962277&BRD=1281&PAG=461&dept_id=7581&rfi=6
By Joseph Perkins
Some say the world will end in fire, / Some say in ice. / From
what I've
tasted of desire / I hold with those who favor fire. / But if it
had to
perish twice, / I think I know enough of hate / To say that for
destruction
ice / Is also great / And would suffice."
The Robert Frost poem "Fire and Ice" comes to mind in
the wake of last
week's startling report announcing that astronomers discovered a
mile-wide
asteroid that could collide with Earth in as few as 17 years,
destroying
life as we know it. A few days later, the Jet Propulsion
Laboratory in
Pasadena issued a statement on its Web site saying that new
observations had
determined the asteroid, designated 2002 NT7, would miss the
Earth after
all.
That's comforting, because 2002 NT7 had become the most
threatening space
object ever detected, according to Benny Peiser, an
anthropologist and
expert on the social impact of cosmic collisions at Liverpool
John Moores
University in England. Were the asteroid to crash into the Earth
- which,
according to JPL, remains a possibility in 2060 - the results
would be
catastrophic.
"In the worst case scenario," Peiser told the Reuters
news agency, "a
disaster of this size would be global in its extent, would create
a meltdown
of our economic and social life, and would reduce us to Dark Age
conditions."
That's why it behooves federal space officials to develop an
asteroid
defense plan and deploy a system that can deflect a killer
asteroid as soon
as possible.
While threats to humanity posed by global warming, by pestilence,
by war are
taken seriously, the threat posed by an asteroid collision
prompts little
concern, despite that more than 200 asteroids - ranging in size
from a few
yards to more than five miles wide - have orbits that intersect
the Earth's.
The near indifference to the threat of a killer asteroid probably
stems from
the perception that the danger is remote. In fact, said Peiser,
asteroids
the size of 2002 NT7 "only hit the Earth every 1 or 2
million years." It is
hard for most of us to get too excited about such an unlikely
threat when
there are so many immediate threats (like terrorists blowing up
skyscrapers).
Yet, it is not inconceivable that in the not-too-distant future
an asteroid
not as sizable as 2002 NT7 will suddenly appear on a collision
course with
Earth.
While that asteroid may not destroy life as we know it, like the
six-mile-wide asteroid that wiped out the dinosaurs 65 million
years ago, it
still could do considerable damage. Indeed, if an asteroid no
bigger than
three-quarters of a football field penetrated the Earth's
atmosphere, it
could release the energy equivalent of a 4-megaton nuclear bomb.
It so
happens that an asteroid of that size passed within 288,000 miles
of the
Earth (1.2 times the distance to the moon) in March. Scientists
didn't
notice the object, dubbed 2002 EM7, until four days after the
fact.
And that asteroid was no aberration. In June, another space rock,
designated
2002 MN, passed within 74,000 miles of Earth. Astronomers didn't
detect the
100-yard-long object until three days later. It stands to reason
that if
astronomers missed 2002 EM7 and 2002 MN, as close as they were to
Earth,
there are other asteroids that also have escaped detection.
It seems only a matter of time before one of them crosses the
Earth's path.
"Sooner or later - and no one can really tell us which it
will be - we will
find an object that is on a collision course," said Peiser.
"That is as
certain as 'Amen' in church. And eventually we will have to
deflect an
object from its collision course."
Right now, no nation on Earth is prepared to undertake such a
mission. And
scientists speculate that it could take a matter of decades
before some
country has the capability. Which is why the nation's space
agency needs to
get moving on an asteroid defense program. If we wait until
astronomers
actually detect a doomsday asteroid, it may be too late to do
anything about it.
Joseph Perkins is a columnist for the San Diego Union-Tribune,
350 Camino de
la Reina, San Diego 92108. E-mail: Joseph.Perkins@UnionTrib.com
.
©New Haven Register 2002
================
(5) 'READY TO TACKLE ARMAGEDDON'
>From The BBC News Online, 9 August 2002
http://news.bbc.co.uk/1/hi/sci/tech/2166598.stm
By Ivan Noble
BBC News Online science staff
A space mission to knock a potential rogue asteroid off course is
undergoing
feasibility studies with money from the European Space Agency
(Esa).
Deimos-Space
A Spanish company, Deimos-Space, is designing the mission and
hopes its
plans will convince Esa to give the go-ahead for a full scale
test on a real
asteroid.
The company has come up with a plan, which it calls the Don
Quixote mission,
to launch a pair of probe spacecraft called Hidalgo and Sancho at
a far off
asteroid.
One would hit the asteroid at extremely high speed, deflecting it
slightly
from its orbit.
The other would observe the asteroid and make highly accurate
measurements
of what happened to it after the impact.
Asteroid billiards
The idea is that the mission would tell scientists how hard they
would have
to hit a real rogue asteroid heading for Earth in order to
deflect it
safely.
Deimos plans to finish its study early in 2003 and hopes Esa will
then come
up with the cash for the actual mission.
The company is optimistic.
"We believe that the outcome of this mission would be good
science,"
Deimos-Space's Jose-Antonio Gonzalez told BBC News Online.
"And we are trying to demonstrate the feasibility of the
mission, not only
in terms of astrodynamic calculations or technology requirements
but also
financially," he said.
The company expects plenty of public and scientific interest in
the project.
High-speed impact
"That's why we expect this mission to go on with the next
phases, or at
least with even more detailed studies on the key aspects of the
mission," he
said.
If it does, a suitable asteroid will be selected and then Hidalgo
will slam
into it at extremely high speed, probably around 10 kilometres
(six and a
half miles) per second.
Sancho will be orbiting the asteroid at a safe distance to see
what happens.
If all goes to plan, the asteroid's orbit will be disturbed in
the beginning
by a few fractions of a millimetre.
The idea is that Sancho will measure this tiny shift and feed the
data back
to Earth.
Tiny changes in orbit can become much larger over time and Deimos
wants to
use the experiment to calculate how to knock a real rogue
asteroid off
course.
Early warning
Whether such an approach to dealing with an asteroid threat would
work would
depend largely on how much warning there is.
Hidalgo and Sancho would take many months to reach their target.
Any Hidalgo-like satellite used to deflect an incoming hazard
would have to
hit it in just the right place and at just the right speed.
Getting it right would involve great precision, but, as Mr
Gonzalez points
out, would not require the nuclear super-rockets of science
fiction.
If the project does get the go-ahead, the Don Quixote mission
would provide
valuable information about the composition of the target
asteroid.
"This mission would provide, for the first time, a look
inside the
asteroids," said Mr Gonzalez.
"The results of the experiment would either validate our
proposed strategy
or might mean we have to think of other solutions, such as
placing a huge
solar sail on the asteroid's surface to use the solar wind to
change its
trajectory."
Copyright 2002, BBC
================
(6) AMATEURS WIN NEO GRANTS
>From Astronomy.com, 13 August 2002
http://www.astronomy.com/Content/Dynamic/Articles/000/000/000/977amlbn.asp
The Planetary Society awards funding to five private programs
dedicated to
near-Earth objects.
by Vanessa Thomas
It seems we've been hearing a lot more reports of asteroids and
comets
zipping past our planet lately. Has Earth recently entered a more
populated
space, increasing the number of encounters with these smaller
neighbors?
Nope. It's just that we humans recently have become more aware of
our
immediate cosmic surroundings and have begun to pay more
attention to these
near-Earth objects (NEOs).
To improve our awareness and understanding of these frequent
passers-by (and
potential impactors), the Planetary Society established the
Shoemaker
Near-Earth Object Grant program in 1997. Named after the late
planetary
geologist Eugene Shoemaker (who studied asteroids, comets, and
their impacts
with the larger bodies of the solar system), the grant helps both
amateur
and professional astronomers enhance their own NEO projects.
This year, the Planetary Society is awarding a total of $28,290
to five
deserving NEO programs on three continents.
John Broughton of Reedy Creek Observatory in Queensland,
Australia, is an
active observer of NEOs and has discovered several asteroids,
including
those named after the Beatles, Elvis Presley, Buddy Holly, the
Beegees, and
Brian Wilson. Broughton will receive $8,140 from the Planetary
Society to
buy an Apogee CCD camera to use on a new computer-controlled
18-inch
(46-centimeter) telescope, which will conduct follow-up
observations of
fast-moving NEOs and those not visible from the Northern
Hemisphere.
Amateur NEO observer Matt Dawson will also purchase a new Apogee
CCD camera
to use at the Roeser Observatory in Luxembourg and the Cote de
Meuse
Observatory in France. The camera will allow Dawson to observe
objects as
faint as 21st magnitude.
Richard Kowalski of Florida founded the Minor Planet Mailing List
four years
ago to provide an opportunity for minor-planet observers around
the world to
communicate with each other. In the past, Kowalski has spent his
own money
to maintain the list, and will receive a $900 grant to support
the list and
related websites for the next three years.
Amateur astronomer James McGaha of Tucson, Arizona, will use
$10,000 to
automate the 24-inch (62-centimeter) telescope at his Grasslands
Observatory
55 miles from his home. This will improve the telescope's
efficiency in the
NEO observations it makes.
Roy Tucker, also of Tucson, currently has three telescope-camera
systems
observing NEOs, but the resulting data is more than he can
handle. Tucker
will receive $2,950 for software and computer equipment to
distribute his
observations to other local amateurs who can help reduce and
analyze the
data.
The five winners were selected by an international advisory group
from 37
proposals received from 13 countries. "With so many highly
qualified
proposals, the selection committee's choice was a difficult
one," states the
Planetary Society's announcement of this year's winners.
The Planetary Society is not yet accepting applications for the
next round
of Shoemaker NEO Grants, but you can watch for updates or learn
more about
the grant program from the Society's website.
Copyright © 1996-2002 Kalmbach Publishing Co.
=============
(7) NEW OBSERVATIONS OF 1998 OX4 ELIMINATE ANOTHER 'VIRTUAL
IMPACTOR'
>From Asteroid/Comet Connection, 7 August 2002
http://www.hohmanntransfer.com/news.htm
1998 OX4, which had been on the JPL Risks page, and was listed on
the NEODyS
Risk page as a lost object, has now been recovered. This was
announced
Thursday in MPEC 2002-P34, which equates OX4 with an object
discovered 6
August by NEAT. OX4 is an eccentric Earth-crossing asteroid
perhaps 200
meters/yards across that was originally discovered by Jim Scotti
at
Spacewatch on 26 July 1998. It was observed into the next month
and then was
not seen again until now. The net result of this recovery is one
less object
on the risk pages, with JPL removing it the same day.
It was evening at NEODyS when this correllation was published,
and it took
until Friday morning for its list to drop 1998 OX4, an old
acquaintance. OX4
played a big role in bringing Andrea Milani, Steven Chesley (now
at JPL),
Andrea Boattini, and Giovanni Valsecchi at the University of Pisa
to develop
the "virtual impactor" concept. The year after OX4 was
discovered and lost,
they said, we have found a solution to the problem raised by 1998
OX4; the
same method could be applied to other similar cases of lost
potential
impactors which might be discovered in the future. In short, the
idea is to
replace a full recovery campaign, requiring an inordinate amount
of
observational resources, with a targeted search for only those,
among the
possible orbital solutions for 1998 OX4, which lead to impacts;
we call
these the Virtual Impactors.
An example of putting this concept to work came in January 2001
when two
Spaceguard observing campaigns successfully failed to find 1998
OX4 on paths
that had been projected as leading to possible impact solutions
for several
different years, especially 2014, thus completely removing those
possibilities.
==============
(8) COMETS: A KEY TO A PARALLEL UNIVERSE
>From The Independent, 12 August 2002
http://news.independent.co.uk/world/science_medical/story.jsp?story=323682
Why do comets burn up and vanish far quicker than they should?
One theory -
that they are made of 'mirror matter' - could help to explain the
greatest
mystery of our universe. Marcus Chown reports
12 August 2002
Comets may be composed of matter hitherto unknown to science,
according to a
physicist in Australia. If he's right, we may at last have found
the
identity of the mysterious "dark matter" believed to
make up at least 90 per
cent of the mass of the universe. What's more, it could mean
there is
another universe occupying our own, complete with invisible
stars, planets
and even life.
Why would anyone want to make such an outrageous claim about
comets?
"Because they are disappearing and nobody knows where,"
says Robert Foot of
the University of Melbourne.
To appreciate the comet mystery, it's necessary to know that
comets orbit in
their countless billions in the frigid wastes far beyond the
outermost
planets. This mass of comets is known as the Oort cloud.
Occasionally, the
gravity of a passing star nudges the cloud so that one falls
Sunward. There
are then two possibilities: either it swings round the Sun and is
catapulted
back to the Oort cloud, never to be seen again; or a close
encounter with a
giant planet such as Jupiter or Saturn steals some of its speed
so it
becomes trapped in the inner solar system, condemned to swing
round the Sun
at regular intervals, like Halley's Comet.
The problem is that every time a trapped comet passes close to
the Sun, a
metre or so of its surface ice boils off into space. Comets are
dirty
snowballs, typically a few kilometres across, so common sense
says they
ought to be able to survive scores of orbits around the Sun
before being
totally melted away. "The puzzle is they don't," says
Foot. "Most vanish for
ever after passing close to Sun for the first time."
The leading explanation for this disappearing act is that the
comets are
largely made of rock with a thin coating of surface ice. They
therefore
"turn off" after one passage by the Sun, having
depleted the ices that
generate their glowing heads and tails. In effect, they become
asteroids.
Recently, however, Harold Levison and his colleagues at the
Southwest
Research Institute in Boulder, Colorado, have put paid to this
theory. They
have found that the number of asteroids is far too low to account
for the
expected number of cometary remnants. "These objects are
simply not where we
expect them to be," says Levison.
Foot is convinced he can explain the mystery of the disappearing
comets. In
his new book, Shadowlands, he speculates that many comets might
be made of a
new type of matter called "mirror matter", which gives
out no light. The
idea is that they contain only a small amount of ordinary matter,
and that
this ordinary matter evaporates after passing by the Sun, leaving
an
invisible core of mirror matter.
Mirror matter is a hypothetical type of matter required to
restore nature's
flawed left-right symmetry. Nature, for reasons nobody
understands, has
chosen fundamental laws that exhibit the maximum possible
symmetry. For
instance, the laws are the same today as they were yesterday, the
same in
New York as they are in London; and they respect myriad other,
more abstract
symmetries too. But in one respect nature is not symmetric. The
laws are not
the same when reflected in a hypothetical mirror. "Electrons
and other
elementary particles are, in a sense, left-handed," says
Foot. "Although
most scientists have come to accept that God is left-handed,
somehow it has
always bothered me."
Foot's unease has led him to embrace a radical idea - that
nature's
left-right symmetry isn't really flawed, it only looks that way.
For every
known particle, there is actually a particle that interacts in a
right-handed way. So, in addition to electrons and quarks and
photons of
light, the universe contains mirror electrons and mirror quarks
and mirror
photons. These combine to make mirror atoms and mirror matter.
Mirror atoms would interact with ordinary atoms very weakly and
so produce
no light. They are a prime candidate for the dark matter, the
"missing mass"
that astronomers know must exist (from the gravitational pull it
exerts) but
cannot see. They believe it makes up at least 90 per cent of the
mass of the
universe. "If I'm right, there is an invisible mirror
universe occupying the
same space as our universe, complete with mirror galaxies, mirror
stars and
perhaps even mirror life," says Foot.
All this would be little more than science fiction if it weren't
for
baffling experiments at CERN, the European centre for particle
physics.
Ortho-positronium, an atomic system in which an electron orbits a
like-spinning anti-electron, or "positron",
disintegrates 0.1 per cent
faster than the theory of quantum electrodynamics (QED) says it
should. It
might not seem much of a discrepancy, but QED is the most
successful
physical theory ever devised, and it usually predicts
experimental results
to many, many decimal places. According to Foot, the discrepancy
can be
perfectly explained if there is an additional decay route,
speeding up the
loss of ortho-positronium. "I believe that ortho-positronium
is
'oscillating' into mirror ortho-positronium, then decaying in the
mirror
world before it can oscillate back," says Foot.
Efforts are now under way at CERN to repeat the experiment.
According to
Foot's CERN colleague, Sergei Gninenko, the mirror matter
explanation could
be confirmed or refuted by next year.
Mirror matter, if it exists, would have been formed in abundance
alongside
normal matter in the Big Bang in which the universe was born 12
to 14
billion years ago. "It would therefore be surprising if some
did not get
incorporated into the interstellar dust cloud out of which the
Sun, planets
and comets condensed 4.6 billion years ago," says Foot.
Foot believes that there is in fact abundant evidence of mirror
matter in
the solar system. In addition to the puzzle of the disappearing
comets, he
points out that there have been many sightings of fireballs
streaking down
the sky and hitting the ground but leaving no debris or crater.
The most
famous occurred near the Tunguska River in Siberia in 1908, when
a
100,000-tonne body devastated a huge area of forest yet left no
crater or
substantial debris. "A space body made of mirror matter
perfectly fits the
bill," says Foot.
According to Foot, Tunguska was not unique: "Mysterious
impacts that could
be due to mirror bodies occur almost yearly." He points to
an impact on 18
April last year 50km from Amman, the capital of Jordan. More than
100 people
in a funeral procession saw a yellow fireball hit the ground,
burning rocks
and a tree. "Mysteriously, there was no debris," says
Foot. "I think it
could have been a small mirror body."
But perhaps the most tantalising evidence for the existence of
mirror matter
in our neighbourhood is coming from Nasa's Pioneer 10 and 11
probes,
launched in 1972 and 1973 and currently streaking out towards the
stars. For
the past 30 years, both have been experiencing a mysterious force
of one
ten-billionth of a G, which is pulling them back towards the Sun
and slowing
them down. "The Nasa astronomers are totally baffled,"
says Foot. "They've
ruled out all mundane effects such as fuel leaks and heat
leaks."
John Anderson, an astronomer at Nasa's Jet Propulsion Laboratory
in
California, has worked on the Pioneer project since 1970. He
says: "For the
life of me, I can't think of what could be causing the
effect."
Foot, of course, is ready with a mirror-matter explanation.
"The anomalous
force could simply be drag as the probes fly through a thin cloud
of mirror
matter," he says. "You'd only need a few Earth masses'
worth - too little to
have any noticeable effect on the orbits of the outer planets,
Uranus and
Neptune."
Foot could be accused of seeing mirror matter everywhere; an
ironic
observation, as mirror matter is invisible. However, he says he
is well
aware of the danger and freely admits that there is a chance he
is wrong.
Quoting Bertrand Russell, he says: "It's good to have an
open mind, but not
so open that your brains fall out."
'Shadowlands' by Robert Foot, Universal Publishers, £18.95
Copyright 2002, The Independent
==============
(9) THE SLOAN DIGITAL SKY SURVEY MOVING OBJECT CATALOG
>From Zeljko Ivezic <ivezic@astro.Princeton.EDU>
We announce the first public release of the SDSS Moving Object
Catalog, with
SDSS observations for 58,117 asteroids. The catalog lists
astrometric and
photometric data for moving objects observed prior to Dec 15,
2001, and also
includes orbital elements for 10,592 previously known objects. We
analyze
the correlation between the orbital parameters and optical colors
for the
known objects, and confirm that asteroid dynamical families,
defined as
clusters in orbital parameter space, also strongly segregate in
color space.
Their distinctive optical colors indicate that the variations in
chemical
composition within a family are much smaller than the
compositional
differences between families, and strongly support earlier
suggestions that
asteroids belonging to a particular family have a common origin.
The catalog is available at http://www.sdss.org/science/index.html
as "SDSS
Moving Object Catalog".
Zeljko Ivezic (Princeton University)
Mario Juric (Zagreb University,
Visnjan Observatory)
Robert H. Lupton (Princeton University)
Serge Tabachnik (Princeton University)
Tom Quinn (University
of Washington)
for the SDSS Collaboration
---------------------------------------------------------------------
===============
(10) ROYAL PAIR REACH THE FINAL FRONTIER
>From Leicester Mercury, 2 August 2002
http://www.thisisleicestershire.co.uk/displayNode.jsp?nodeId=42629&command=d
isplayContent&sourceNode=42628&contentPK=2274411
The Queen found out how to save the world from a meteor collision
from
Leicester's space scientists.
She listened intently as experts explained how they could remove
the threat
of asteroids hitting the planet as she toured Leicester's
National Space
Centre.
The Queen also learned how Leicester was playing a major role in
the first
mission to Mars - and chatted to NASA's top astronauts via a
satellite
link-up.
Kevin Yates is an officer at the city-based Near Earth Objects
Information
Centre, which monitors the skies for threats of asteroids.
Kevin, who works at the space centre, said: "She asked what
we could do if
one came towards Earth now. We talked about methods of pushing
meteors off
their orbit so they don't hit earth."
She also met Helen Sharman, Britain's first woman astronaut.
Afterwards she joined dignitaries and guests in the informal
atmosphere of
the exhibition's main auditorium before delivering a speech and
sitting down
to lunch.
The Duke of Edinburgh also enjoyed a tour of the space centre.
After being
shown inside a life-size mock-up of the International Space
Centre's
Columbus Module, tour guide Vicky Brightman explained to the Duke
the
problems astronauts face when they need to eat.
Copyright 2002, Leicester Mercury
===============
(11) U.S. MILITRAY CONSIDERS COORDINATED CLEARINGHOUSE TO MONITOR
AND
RESPOND TO NEO THREAT
>From Space.com, 5 August 2002
http://space.com/news/asteroid_watch_020805.html
By Leonard David
Senior Space Writer
COLORADO SPRINGS, COLORADO -- The U.S. Space Command is reviewing
a plan to
create a clearinghouse that gathers and analyzes data regarding
impending
Earth impacts from asteroids or comets. The information node
would also
assess possible damage stemming from an incoming object. Such a
clearinghouse, if established, would merge military and civilian
talent to
help minimize damage and loss of life due to a strike from space.
Science Applications International Corporation's (SAIC) Space,
Air and
Information Group undertook the study here, labeling it the
Natural Impact
Warning Clearinghouse Concept of Operations.
The report's range of findings and recommendations are now under
consideration by high level officials within the U.S. Space
Command, the
organization that funded the work.
A model for the clearinghouse idea is the already established
U.S. military
command and control warning structure that deals with ballistic
missile and
space attack.
Proactive approach
The SAIC study looked into identifying key players that would be
involved in
not only asteroid and comet detection, but also consequences
resulting from
a cosmic hit. Groups were studied that sift through astronomical
data, those
that determine risk of impact, and organizations capable of
modeling the
aftermath of an Earth impactor.
"The key is to take highly technical data, reduce it, and
process that
information into something that is comprehensible and trusted by
decision
makers in various communities," said Timothy K. Roberts, the
SAIC analyst
that headed the study.
"What we've put together is the basis of an approach to be
proactive,"
Roberts told SPACE.com. "Or you can wait and be reactive,
hoping that all
those astronomers are right and we have years and years of
warning," he
said.
Warning: information gap ahead
Roberts said the SAIC work is meant to find a way to bridge an
information
gap. "That is a gulf that nobody has crossed," Roberts
said. "What is
missing is a way to take technical information and put it into
terms that
decision makers can understand and use," he said.
Moving piles of astronomical data into formats usable by senior
military and
civilian groups responsible for impact prediction, mitigation and
post-strike issues is sorely needed. Air bursting events -- of
which there
are already numbers of wake-up calls -- as well as objects
smacking the
ground must be taken into account, Roberts said.
At present, various groups collect Near Earth Object data. The
U.S.
military, via its network of spaceborne sensors, also snares
loads of useful
fireball information - objects that skirt through the Earth's
atmosphere.
"But in this application, it's not being used. It never gets
to command and
control nodes that are trusted inputs to the senior officials in
the user
community," Roberts said. "They have to be comfortable
about the data they
are getting," he said.
"There hasn't been a nuclear attack on the United States.
But we simulate
that a lot. We practice to make sure we get it right. The people
in that
chain are used to seeing certain things and are used to thinking
on a
certain scale. What we want to do is put this [asteroid/comet
threat] in the
same context. I want to make it routine," the SAIC analyst
said.
Exploring the possibilities
Experts from the U.S. military, NASA, sky monitoring groups, as
well as the
Federal Emergency Management Agency (FEMA), took part in the SAIC
study. The
$92,000 assessment began in earnest last October and was
delivered to the
U.S. Space Command in June.
Roberts said that the study itself does not say the clearinghouse
concept is
a U.S. Space Command mission, or a Department of Defense mission,
nor a
mission of the federal government. "The study merely
explores the
possibilities," he said.
"To be best of my knowledge, this is the first look at a
warning system. The
first is rarely the best...but my objective is to get it on the
table,"
Roberts said.
In defining any interagency melding of capabilities to create a
Natural
Impact Warning Clearinghouse, there are various options
available.
An actual building could house such work, staffed by experts.
Alternatively, the clearinghouse could be co-located between FEMA
and part
of the newly created United States Strategic Command, the
USSTRATCOM Command
Center. That entity merges the U.S. Space Command and U.S.
Strategic Command
(StratCom). The merger is designed to improve combat
effectiveness and speed
up information collection and assessment needed for strategic
decision-making. The merged command -- to be completed in October
2002 --
would be responsible for both early warning of and defense
against missile
attack as well as long-range conventional attacks. The preferred
location
for the command headquarters is Offutt Air Force Base in
Nebraska.
Furthermore, this hub could be virtual - a network of analysts
and groups
that gather, sort through and review, and carry out risk
judgements. And in
a worst-case mode, groups would model the ramifications of an
object cutting
into Earth's atmosphere.
"A number of options exists. There are pros and cons for all
of them,"
Roberts said.
Mother Nature's shooting gallery
"There's a very high analogy between the warning systems we
have in place
for ballistic and missile and space attack...and in what we need
to do here.
In both cases you are dealing with very low probability, but very
high
consequence events," Roberts said. "But now it's Mother
Nature throwing
things at us instead of a bad guy," he said.
The SAIC study did not suggest deflection or destruction
strategies for
fending off incoming objects. In his view, Roberts said, much
more data
about the physical makeup of comets and asteroids is urgently
needed. A
menacing object could be solid rock or a jumble of fragments.
Maybe a object
headed our way is just a fluffy snowball.
"We haven't got a clue...and we need to get a whole bunch of
clues," Roberts
said.
It's a "virtual certainty", Roberts said, that Earth is
going to be on the
receiving end of an asteroid or comet. "It is time to take
the next step. We
need to bring techniques, capabilities, information and
procedures together
that have been heretofore separated and segmented," he said.
"There is no question. It is a mathematical certainty. This
is the one point
in time...the one natural disaster that we can influence. I
believe our
study takes the right direction and is the right next step,"
Roberts
concluded.
Copyright 2002, Space.com
================
(12) RESEARCHER SEEKS TO MAKE OUTER SPACE EVENTS EASY TO PREDICT
>From Steve Koppes <s-koppes@uchicago.edu>
West Virginia University
1-Aug-02
Chemist Seeks to Make Outer Space Events Easy to Predict
Keywords: OUTER SPACE MARS ORBITS CELESTIAL BODIES ASTEROIDS
COMETS
Description: A West Virginia University chemist and five other
researchers
have taken a quantum leap in predicting the orbits of celestial
bodies,
research that could one day help scientists
accurately foretell if an asteroid or comet is headed for earth.
(Physical
Review Letters, 2-Jul-2002)
CONTACT: Charles Jaffe, Department of Chemistry
Phone: 304-685-0826; e-mail: cjaffe@wvu.edu
The Martian Chronicler
WVU Chemist Seeks to Make Outer Space Events Easy to Predict
MORGANTOWN, W.Va. -- A West Virginia University chemist and five
other
researchers have taken a quantum leap in predicting the orbits of
celestial
bodies, research that could one day help scientists accurately
foretell if
an asteroid or comet is headed for Earth.
Charles Jaffe, associate professor of chemistry at WVU, is part
of a team
that combined a near 70-year-old chemical transition state theory
and
celestial mechanics to predict the outcome of a simulation
involving Martian
asteroids.
"We wanted to test the application of transition state
theory to celestial
mechanics by comparing our results with those of a
simulation," Dr. Jaffe
said. "We chose as our simulation the escape
of asteroids from Mars because of our interest in the Martian
meteor found
in Antarctica a few years ago."
The research team's paper, "Statistical Theory of Asteroid
Escape Rates,"
made the cover of the July 2 issue of Physical Review Letters.
The paper is
also featured on the Physical Review Focus Web site at
http://focus.aps.org./v9/st31.html.
Co-authors were David Farrelly, a chemist at Utah State
University; T. Uzer,
an atomic physicist at Georgia Institute of Technology; Jerrold
Marsden, a
mathematician at California Institute of
Technology, and Shane D. Ross, his student; and Martin W. Lo, a
software
developer with Cal Tech's Jet Propulsion Laboratory.
Transition state theory, developed by chemists in the 1930s,
establishes a
brief stage in chemical reactions between reactant and product,
said Jaffe,
who has helped refine the theory for modern uses. Bottlenecks
between orbits
of celestial bodies resemble transition states in chemistry, he
added.
For their research, Jaffe and his fellow scientists developed a
computer-based simulation of asteroids orbiting Mars, then used
the
transition state theory to predict how many asteroids would
remain in the
red planet's orbit and how many would escape. The team then
calculated the
survival and escape rates by performing the simulation 107,000
times to
represent the asteroids' trajectories. There was a 1 percent
difference
between the simulation's results and the theory's predictions.
"This means the theory works and you don't need to run the
simulations,
which take several days," said Jaffe, who came to WVU in
1984 after
obtaining his doctorate from the University of Colorado and doing
postdoctoral work at the University of Toronto and Columbia
University.
Extending transition state theory to celestial mechanics could
one day help
scientists better predict such outer space events as asteroids
and comets
headed for Earth and solar storms capable of disrupting satellite
communications, Jaffe said.
Astronomers announced recently that they are monitoring a
recently
discovered asteroid that has a minimal chance of striking the
Earth in 2019.
Last month, scientists discovered an asteroid that narrowly
missed the
planet after it passed by.
Using transition theory, Jaffe explained, scientists could
determine which
group of asteroids is more likely to come close to Earth.
"What this will do is help us decide which space matter is
worth worrying
about," he said. "There is not enough time to look at
each asteroid. Using
transition state theory, instead of looking at individual things,
one can
look at classes of things."
The research is supported by the National Science Foundation,
American
Chemical Society, West Virginia NASA Space Grant Program
and NASA-ASEE
Summer Faculty Fellowship.
-WVU-
jd/7/29/02
WVU News on the Web: http://www.nis.wvu.edu/newsroom/
--
===============
(13) NEOS AT THE ACM
>From David Morrison <dmorrison@arc.nasa.gov>
NEO News (08/07/02) NEOs at ACM
The professional meeting "Asteroids, Comets, Meteors
2002" was held last
week in Berlin. Every three years, astronomers and others who
study
asteroids, comets, meteors, and meteorites get together to report
their
recent work and discuss the state of the field. More than 300
scientists
attended this meeting. Following are a few highlights from the
papers that
deal with Near Earth Objects (NEOs).
David Morrison
----------------------------------------------------------
1. NUMBER AND IMPACT FREQUENCY OF NEAS
As the discovery of NEAs (Near Earth Asteroids) has accelerated,
we have
much more complete data to use in estimating the numbers of NEAs
of various
sizes. However, these estimates are also complicated by an
increasing
awareness of the complexities of NEA dynamics. In particular, the
objects
that are the easiest to find are in general also those that come
closest to
the Earth and constitute the greater part of the impact hazard.
From the
perspective of the Spaceguard Survey, for example, we want to
focus on these
potentially hazardous NEAs. For other purposes, however, we may
want to look
at the total population.
Alan Harris (JPL) presented the major invited paper on NEA
populations,
focused on the question "Just how many Tunguskas are
there?" He reviewed
recent work that indicates that the number of
NEAs of diameter 1 km or greater (the primary targets of the
current
Spaceguard Survey) is 1100 +/- 100. The number of NEAs down to
the size of
Tunguska (60 meters diameter) is of order 100,000 but
considerably more
uncertain. Translating into impact frequency, Harris finds that
one Tunguska
size impact should take place at intervals of roughly 1000 years.
Some lunar
crater count data actually suggest that these impacts are as much
as a
factor of ten lower, but this seems to conflict with other data.
The
millennium timescale derived by Harris is also supported by an
estimate from
Roger Revelle (Los Alamos) that the average largest atmospheric
impact in a
year has energy of about 10 kilotons, for an equivalent diameter
of about 5
meters.
Robert Jedicke (Lunar & Planetary Lab) and Alessandro
Morbidelli (Cote
d'Azur Observatory) each discussed the distribution of NEOs from
the
perspective of meeting the Spaceguard Goal of finding 90% of NEAs
larger
than 1 km. Jedicke modeled the LINEAR survey, the most successful
current
NEA search, finding that if all NEAs are taken into account the
survey will
not be 90% complete until after 2020; however, if we focus on the
NEAs in
the most dangerous orbits, the goal will be met by 2010 (a result
that
Harris confirms from his models). Morbidelli and colleagues
carried out a
reassessment of the impact hazard as originally formulated by
Chapman and
Morrison (1994), finding in general that the hazard should be
lowered by
about a factor of 4 - their estimated interval for a 1 million
megaton
impacts is about 3.8 million years, somewhat lower than other
recent
estimates.
All these results are generally consistent in their evaluation of
the NEA
numbers and the associated risk. For Tunguska-size impacts, the
Chapman /
Morrison estimate of once in 300 years is now down to once in
1000 years.
For million-megaton impacts, the Chapman / Morrison estimate of
once in a
million years is now down to once in 2-4 million years. And
somewhat
coincidentally, the Chapman / Morrison estimate of 1500-2000 NEAs
larger
than 1 km is now down to 1100.
Curiously, while there is general agreement among astronomers,
others have
been arguing for a hazard a factor of ten or more higher. It is
not uncommon
to read that Tunguska-size impacts take place once a century, or
even more
often! One recent claim was for 3 Tunguska-size impacts during
the 20th
century. These claims are not consistent with the weight of
accumulating
astronomical evidence as reviewed at this meeting and at the 2001
asteroids
meeting in Palermo.
--------------------------------------------------
2. FUTURE ASTEROID SURVEYS
Recent United States National Academy of Sciences panels in both
astrophysics and planetary science have recommended the
construction of the
LSST, the Large Scale Synoptic Survey Telescope. One major
objective is the
extension of the Spaceguard Survey down to 300 meter NEAs. The
nominal LSST
design considered by the Academy panels is a single 6-8 meter
aperture
telescope.
At this meeting David Jewitt and David Tholen (University of
Hawaii)
announced that full funding of $40 million has just been received
from the
U.S. Air Force to construct an alternative version of the LSST
called Pan
Stars, based on multiple small telescopes. Although the design
has not been
finalized, one option would use 4 telescopes of 2-3 meter
aperture
constructed on Mauna Kea. Depending on how the system is
configured and
operated, Jewitt estimates that it can survey the entire sky to
visual
magnitude 24, with the prospect of finding 10,000 NEAs per year,
as well as
10,000 members of the Kuiper Belt per year and about 100,000
supernovas per
year.
-----------------------------------------------
3. ORIGIN OF NEAs
The NEAs are for the most part fragments of main belt asteroids
that have
been transported into Earth-crossing orbits. Two processes
contribute:
collisions or impacts among main belt asteroids, and a variety of
gravitational processes that can perturb these fragments into the
inner
solar system. Unfortunately, most recent studies have found that
these
effects are insufficient to account for the observed numbers of
NEAs. Recent
application of a third process - the Yarkovsky effect - has now
apparently
removed this discrepancy.
The Yarkovsky effect was postulated about a century ago as a way
to change
asteroid orbits by the absorption of sunlight followed by its
asymmetric
re-emission as thermal radiation. Although the forces are
extremely small,
they act continuously over many millions of years. The result is
to move the
asteroids or asteroid fragments until they reach a resonance,
where the more
conventional gravitational forces take over and complete their
perturbation
into the inner solar system. William Bottke (Southwest Research
Institute)
and several others presented highly convincing examples of the
Yarkovsky
effect at work. In addition to explaining the transport of
asteroids into
the inner solar system, the Yarkovsky effect also allows us to
understand
the evolution of families of asteroids in the main belt, and it
even
contributes to spinning up asteroid rotation and the formation of
some
binary systems.
A few NEAs may be small dead comets, but this has not been
demonstrated.
Most comets in the inner solar system are Jupiter family comets.
Paul
Weissman (JPL) reviewed the size, structure, and density of comet
nuclei. He
concludes that the Jupiter-family comets are derived from the
Kuiper Belt.
Weissman argued that they are fragments from a collisionally
evolved
population, with typical rubble-pile interiors and densities of
0.4 to 1.1
times the density of water. There is an apparent depletion of
small comets
(diameters less than about 2 km), which suggests that relatively
few survive
to become dead objects indistinguishable from NEAs.
----------------------------------------------------
4. NEA SURFACES
Several ACM papers by Marco Delbo (DLR), Allan Harris (DLR), Rick
Binzel
(MIT), Mike Nolan (Arecibo Observatory), and others dealt with
the physical
nature of asteroids, including NEAs. Radar observations of 22
NEAs were made
in 2001 - including multiple and binary objects, both fast and
slow
rotators, and both spherical and highly-elongated objects. A
number of
mechanisms were suggested that might lead to the accumulation of
a loose
high-porosity surface - overcoming some previous calculations
that small
asteroids would not have sufficient gravity to retain a dusty
regolith. One
of the results of recent work is the suggestion that for small
NEAs, the
albedo (reflectivity) increases with decreasing size. If this
reflectivity
trend is correct, then the faint NEAs currently being discovered
by LINEAR
and other search systems are actually smaller than has been
assumed from
their brightness - suggesting that there are fewer NEAs larger
than 1 km and
that we might be closer to achieving the Spaceguard Goal of 90%
completeness
at 1 km diameter than we have thought.
--
+++++++++++++++++++++++++++++++++++++++++++
NEO News is an informal compilation of news and opinion dealing
with Near
Earth Objects (NEOs) and their impacts. These opinions are the
responsibility of the individual authors and do not represent the
positions
of NASA, the International Astronomical Union, or any other
organization. To subscribe (or unsubscribe) contact dmorrison@arc.nasa.gov.
For additional information, please see the website:
http://impact.arc.nasa.gov.
If anyone wishes to copy or redistribute
original material from these notes, fully or in part, please
include this
disclaimer.
================
(14) RESEARCHER STUDIES FOLKLORE FOR CLUES ABOUT TSUNAMI
>From Associated Press, 12 August 2002
http://www.nandotimes.com/healthscience/story/496241p-3958410c.html
By ELIZABETH MURTAUGH, Associated Press
SEATTLE (August 12, 2002 9:41 a.m. EDT) - When scientists figured
out that
sea water drowned groves of tall trees up and down the coast of
Washington
state the same year a tsunami hit Japan, they theorized that a
massive
earthquake in the Pacific most likely triggered both events.
Based on Japanese records, scientists were able to pinpoint a
date - Jan.
26, 1700 - and estimate that the rupture of a long stretch of sea
floor had
caused a magnitude 9 quake, which would be the largest known
temblor ever to
strike what is now the contiguous United States.
But Ruth Ludwin, a University of Washington geophysics professor,
wanted
more. There appeared to be no accounts of cataclysmic
earth-shaking in the
stories and legends of the only North Americans who would have
been here to
witness the quake - Indians.
"When you talk about a very large earthquake in 1700, for
that to be really
convincing to me, I really need to have evidence from people who
were
there," Ludwin said. "I was looking for a more
comprehensive story."
Ludwin began to search obscure volumes of tribal folklore, where
she found
that, for centuries, Indians from British Columbia's Vancouver
Island to the
coast of Northern California had been telling strikingly similar
tales of
mudslides, of plains that suddenly became oceans and other
stories that
strongly suggest tribes bore witness to tsunamis like the one in
1700.
Many of the legends involve a mythic battle between a thunderbird
and a
whale.
One tale told by generations of Hoh Indians from the Forks area
of
Washington's Olympic Peninsula contains what Ludwin considers the
clearest
description of a concurrent earthquake and tsunami yet discovered
in tribal
legend.
As the story goes, Ludwin wrote in a research paper, "There
was a great
storm and hail and flashes of lightning in the darkened,
blackened sky and a
great and crashing 'thunder-noise' everywhere. ... There were
also a great
shaking, jumping and trembling of the earth beneath and a rolling
up of the
great waters."
The Makah Indians, whose reservation at Neah Bay sits at the
northwest tip
of Washington state, also have a version - one that ends with a
thunderbird
delivering a whale inland to the mouth of a river, giving the
giant beast to
a tribe that had been starving one winter thousands of years ago.
Although it's unclear exactly how long the story has been told,
it formed
the basis of the tribe's centuries-old whale hunt and could be
linked to one
of the seven "megathrust" quakes scientists believe
have occurred over the
past 3,500 years.
"I think it's really interesting that our cultural knowledge
can help
unravel some of these scientific mysteries," said Janine
Bowechop, director
of the Makah Museum. "I feel good that we can share
information and then
really have a better understanding for both worlds."
Many legends contain no time elements. Others that were never
written down
have been lost entirely, so Ludwin's work can seem like trying to
solve a
puzzle with most of the pieces missing. But she insists it's
worth it.
"The work that I've done is not extremely important from a
scientific point
of view, but it's important from the point of view of
understanding and
believing," Ludwin said. "It's another piece of the
puzzle."
The megathrust quake believed to have occurred in 1700 ruptured
the Cascadia
subduction zone, where two of the tectonic plates that form the
Earth's
crust - the Juan de Fuca and the North America plates - overlap.
From its
northern end, off the western coast of Vancouver Island, the
subduction zone
stretches about 600 miles south to Cape Mendocino in Northern
California,
then runs into the San Andreas fault.
It was the Japanese who first theorized that an enormous
earthquake in the
Pacific caused what they called their "orphan tsunami,"
so named because
there was no local temblor that accompanied the torrent of
6-foot-high waves
that crashed along 500 miles of coastline.
When they learned that groves of red cedars and Sitka spruces
along
Washington's coast had dropped several feet, drowning in
saltwater sometime
in the late 1600s or early 1700s, they theorized that one huge
quake must
have been responsible for both the Japanese tsunami and this
state's "ghost
forests."
Radiocarbon dating of spruce stumps narrowed the timeline of the
tree
drownings to somewhere between 1680 and 1720, said Brian Atwater,
a U.S.
Geological Survey scientist in Seattle.
That was too large a window, so scientists went back to one of
the estuaries
where roots of red cedars had survived and could be dated by the
rings in
the roots.
At that grove, near the Copalis River in Grays Harbor County,
tree-ring
dating showed the red cedars died sometime between August 1699
and May 1700.
"If we had found that those red cedars died in 1697 or 1703,
we would say,
'Well, we're not sure your tsunami came from our earthquake,'
" Atwater
said. "We knew there was an earthquake or a series of
earthquakes. The
question was how big and exactly when."
Although the geological evidence of the 1700 megathrust seemed
solid, there
were still some skeptics before Ludwin started finding Indian
tales that
supported the science.
Tribal folklore, Atwater said, "is important, because people
understandably
want human evidence as well as physical evidence."
Copyright © 2002 AP Online
==============
(15) SCIENTISTS BELIEVE DINOSAURS UNDER THREAT BEFORE ASTEROID
STRUCK
>From Ananova, 12 August 2002
http://www.ananova.com/news/story/sm_648741.html
Climate change may have begun killing North American dinosaurs
even before
an asteroid finished the job.
Researchers in southern Alberta suggest more than half the
dinosaurs that
flourished in the area had fallen victim to gradually cooling
temperatures
by the late Cretaceous period.
The study began last summer after researchers surveying a fossil
bed in the
Drumheller Valley realised many creatures and plant life had
vanished over
several million years.
David Eberth, curator of sedimentary geology at the Royal Tyrrell
Museum of
Paleontology in Drumheller, said: "It's telling us that
dinosaur communities
were under stress, at least in the northern reaches of North
America, well
before the asteroid impact.
"What we believe we have is the first solid evidence that
there was a
decline in dinosaur communities prior to the asteroid impact that
was the
final death knell for all of the dinosaurs."
The Calgary Herald reports the data is being compiled and will be
submitted
for publication within the year.
Researchers expect to have solid results by the end of the
summer, but the
project will continue for another two years.
Eberth says the geographic layers in Alberta's Badlands make it
the perfect
place for the investigation.
"There are very, very few places on the planet where you can
go to see a
continuous record back from the extinction event," he said.
By checking oxygen isotopes in the tooth enamel of meat-eating
dinosaurs,
researchers have found temperatures in Alberta dropped from about
25 C to 15
C.
Copyright 2002, Ananova
================
(16) THE PLANET X SAGA
>From Phil Plait's Bad Astronomy, July 2002
http://www.badastronomy.com/bad/misc/planetx/index.html
Doomsayers seem to pop up every few years. Last time, it was the
alignment
of the planets that somehow managed not to destroy the Earth in
May 2000.
Now, we have Planet X. A few people are claiming that a
heretofore unknown
planet in our solar system is on a very long, elliptical orbit.
In May 2003,
it will pass close enough to the Earth to affect it in some way,
causing it
to flip over (what many call a "pole shift") and spur
many other huge
disasters. The end result will be the deaths of many billions of
people.
There are a large number of web pages, chat rooms and books about
Planet X
and its horrible affects on the Earth. So the question is, does
this planet
exist, and will it come by in May 2003 and cause all this horror?
No, and no.
As much as I know anything in science, I know that there is no
Planet X as
described by this latest crop of Chicken Littles. How do I know
this? Well,
we'll have to look a little bit at the claims of the people doing
the
doomsaying, and why what they say is patently false. Along the
way, I'll be
talking about gravity, orbits, brown dwarfs, and why speculation
is a great
way to enflame emotions, but a terrible way to get the truth.
To make it easier to navigate, I have divided my arguments into
separate
pages. To find your way around, use the table of contents at the
top of this
page. There will be a link back to it at the top and bottom of
every page.
FULL STORY at http://www.badastronomy.com/bad/misc/planetx/index.html
©2002 Phil Plait. All Rights Reserved.
==============
(17) UFO REPORTS CAUSE A PANIC IN INDIA
>From MSNBC, 12 August 2002
http://www.msnbc.com/modules/exports/ct_email.asp?/news/793179.asp
Doctors say it's mass hysteria; police say bugs are
responsible
Brijesh Nishaad, 18, wears bandages on his face as family members
look on
Aug. 3, after he was allegedly injured by an unidentified flying
object
called "Moohnochwa," while sleeping outdoors in
Allahabad, India.
By Prajnan Bhattacharya
ASSOCIATED PRESS
SHANWA, India, Aug. 12 - It comes in the night, a flying
sphere emitting
red and blue lights that attacks villagers in this poor region,
extensively
burning those victims it does not kill. At least that's what
panic-stricken
villagers say. At least seven people have died of unexplained
injuries in
the past week in Uttar Pradesh state.
Survey results tallied every 60 seconds. Live Votes reflect
respondents'
views and are not scientifically valid surveys.
"A MYSTERIOUS flying object attacked him in the night,"
Raghuraj Pal said of
his neighbor, Ramji Pal, who died recently in Shanwa. "His
stomach was
ripped open. He died two days later."
Many others have suffered scratches and surface wounds, which
they say were
inflicted while they slept. In the village of Darra, 53-year-old
Kalawati
said she was attacked last week and displayed blisters on her
blackened
forearms.
"It was like a big soccer ball with sparkling lights,"
said Kalawati, who
uses only one name. "It burned my skin." "I can't
sleep because of pain,"
she said.
ALTERNATE EXPLANATIONS
Doctors dismiss the stories as mass hysteria.
"More often than not the victims have unconsciously
inflicted the symptoms
themselves," said Narrotam Lal, a doctor at King George's
Medical College in
Lucknow, the state capital. The police have another explanation:
bugs.
"It is a 3½-inch-long winged insect" that leaves
rashes and superficial
wounds, Kavindra P. Singh, a superintendent of police, told the
Press Trust
of India news agency.
Police drew this conclusion after residents of one village found
insects
they had never seen before.
VILLAGERS WORRIED
Villagers are unconvinced. In the most affected area, the
Mirzapur district,
440 miles (700 meters) southeast of New Delhi, people have
stopped sleeping
outdoors despite the sweltering heat and frequent power outages.
Villagers also have formed protection squads that patrol Shanwa,
beating
drums and shouting slogans such as, "Everyone alert.
Attackers beware."
Some accuse district officials of inaction and failing to capture
the
"aliens." One person died Thursday in nearby Sitapur
when police fired shots
to disperse a 10,000-strong crowd demanding that authorities
capture the
mysterious attackers.
"People just block the roads and attack the police for
inaction each time
there's a death or injury," said Amrit Abhijat, Mirzapur's
district
magistrate, who claims he has captured the UFO on film.
© 2002 Associated Press.
=============
(18) AND FINALLY: COSMOLOGISTS BAFFLED BY UNIVERSE'S 'MIRACULOUS'
WORKING
>From Andrew Yee <ayee@nova.astro.utoronto.ca>
[ http://www.nature.com/nsu/020812/020812-2.html
]
Tuesday, 13 August 2002
Is physics watching over us?
Our Universe is so unlikely that we must be missing something.
By PHILIP BALL
In an argument that would have gratified the ancient Greeks,
physicists have
claimed that the prevailing theoretical view of the Universe is
logically
flawed. Arranging the cosmos as we think
it is arranged, say the team, would have required a miracle [1].
An ever-more-rapidly expanding Universe is destined to repeat
itself, say
Leonard Susskind of Stanford University, California, and his
colleagues. But
the chances that such re-runs would
produce worlds like ours are infinitesimal.
So either space is not accelerating for the reasons we think it
is, or we
have yet to discover some principle of physics, the researchers
conclude.
Like a guardian angel, this principle would pick out those few
initial
states that lead to a Universe like ours, and then guide cosmic
evolution so
that it really does unfold this way.
The incomprehensibility of our situation even drives Susskind's
team to
ponder whether an "unknown agent intervened in the evolution
[of the
Universe] for reasons of its own". But
creationists should not rejoice: even a god such as this can't
explain how
things got so strange.
The problem stems from the observation in 1998 that the
Universe's expansion
seems to be speeding up. The most popular explanation for this is
that there
is a cosmological constant -- a repulsive force that opposes
gravity.
As things stand, other galaxies will eventually disappear as they
zoom away
from us faster than the speed of light. Then nothing that happens
in those
parts of the cosmos can affect us. Our world -- and everywhere
else -- will
be isolated behind a boundary called a de Sitter horizon.
This view holds that the Universe will fragment into a foam of
bubbles
separated by de Sitter horizons: a de Sitter space. Each bubble
would
eventually settle into a bland, lifeless uniformity. And that
would be the
end of history.
Here we go again
Or would it? Thermodynamics says otherwise, reckon Susskind and
his
colleagues. Wait long enough, and everything that can happen,
will. There is
nothing to stop a drop of ink dispersed in a glass
of water from gathering its molecules back into a single drop.
It's
incredibly unlikely but, with infinite patience, we'll see it
happen.
In the same way, a Universe driven to become a de Sitter space by
a
cosmological constant will, after an absurdly long time, return
to something
like its original condition, the researchers say. A new cosmic
history will
then unfold, including the reappearance of life. But the chances
that such a
cosmic recurrence will produce a Universe like ours are extremely
slim.
Cosmologists have a rejoinder to this kind of argument, called
the anthropic
principle. This says that, no matter how unlikely the Universe
seems, the
very fact that we are here to ask such questions resolves the
paradox. If
things were otherwise, life wouldn't exist and the question would
never
arise.
But Susskind's team show that the anthropic principle won't help,
because a
vast number of Universes would permit life and yet look quite
different from
this one. All of these habitable Universes would result from
'miraculous'
statistical events. But there are so many of them that they would
vastly
overwhelm a cosmos like ours.
Even if 'something' had set the peculiar initial conditions of
our Universe,
this would only apply for its first run. Subsequent recurrences
would
produce a quite different Universe.
In that case, we'd have to conclude that we are in the first
unfolding of
this carefully crafted Universe. This all seems too much like
special
pleading, the researchers say.
So either there is no cosmological constant after all -- in which
case, why
is the Universe accelerating? -- or we're missing something
fundamental.
References
[1] Dyson, L., Kleban, M. & Susskind, L. Disturbing
implications
of a cosmological constant. Preprint,
http://arXiv.org/abs/hep-th/0208013
(2002).
© Nature News Service / Macmillan Magazines Ltd 2002
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