PLEASE NOTE:


*

CCNet 58/2001 - 23 April 2001
-----------------------------


"Birthright aside, can a planet-sized object that fails to orbit a
star still be called a planet? The standards-setting International
Astronomical Union (IAU) recently issued a provisional answer -- no
way. Planets, by their new definition, must orbit a star. That definition
could be revised as more data come in and the group continues to meet. The
new definition, released in February, is the result of a sometimes
contentious months-long process. It was the IAU's first attempt to
give an official definition to the word "planet."
--Robin Lloyd, Space.com, 18 April 2001


"Near Earth Day 2001 is the first of what will be an annual event
occuring in conjunction with the better known "Earth Day" event
established by environmentalists years ago and celebrated this Sunday,
April 22nd.  Near Earth Day will be a day during which all are encouraged
to engage in activities and events which bring into clearer understanding
the opportunities and concerns related to the various "NEO's" or Near
Earth Objects that travel our Solar System."
Robert E. Strong, Director of the Near Earth Object
Foundation, 21 April 2001


(1) FIRST NEAR EARTH DAY OBSERVED
    Robert E. Strong <strongro@wlsc.wvnet.edu>

(2) FIREBALL STUNS SKY WATCHERS
    Australia Associated Press, 20 April 2001

(3) NEAR TEAM STUDIES SMALL SCALE FEATURES ON EROS
    Ron Baalke <baalke@jpl.nasa.gov>

(4) ASTEROID EROS: MOST DETAILED ANALYSIS OF UP-CLOSE IMAGES
    Space.com, 19 April 2001

(5) ORPHAN 'PLANET' FINDINGS CHALLENGED BY NEW MODEL
    Space.com, 18 April 2001

(6) DISTANT COMET TANGOES WITH SATELLITE
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(7) GLI IMPATTI COSMICI HANNO GIOCATO UN RUOLO FONDAMENTALE NELL'EVOLUZIONE
DELL'UMANITA
    Claudio Elidoro <claudio.elidoro@rccr.cremona.it>

(8) RUSSIAN SPACE EXPERT PREDICTS HUMAN MARS MISSION BY 2020
    Ananova, 22 April 2001

(9) A RESPONSE TO DUNCAN STEEL
    Ed Grondine <epgrondine@hotmail.com>

(10) AND FINALLY: UFO BUREAU SHUTS DOWN DUE TO LACK OF FLYING SAUCERS
     Michael Paine <mpaine@tpgi.com.au>

=============
(1) FIRST NEAR EARTH DAY OBSERVED

From Robert E. Strong <strongro@wlsc.wvnet.edu>

The Near Earth Object Foundation announces first observance of "Near Earth
Day"

Dateline; April 21st, 2001, Wheeling, West Virginia

Robert E. Strong, Director of the Near Earth Object Foundation
(neofoundation.org), a multidisciplinary group of scientists and concerned
citizens, announced the first observance of "Near Earth Day".

Near Earth Day 2001 is the first of what will be an annual event occuring in
conjunction with the better known "Earth Day" event established by
environmentalists years ago and celebrated this Sunday, April 22nd.  Near
Earth Day will be a day during which all are encouraged to engage in
activities and events which bring into clearer understanding the
opportunities and concerns related to the various "NEO's" or Near Earth
Objects that travel our Solar System.

The Near Earth Object Foundation in association with West Liberty State
College and the Space Studies Institute, recently dedicated the Sir Arthur
C. Clarke Near Earth Object Observatory in Warwood, West Virginia.

Future announcements for Near Earth Day will appear in the web site
http://www.neofoundation.org/nearearthday.htm

===========
(2) FIREBALL STUNS SKY WATCHERS

From Australia Associated Press, 20 April 2001
http://news.com.au/common/story_page/0,4057,1914638%255E1702,00.html

14:22 (AEST) A BRIGHT flash in the sky captivated scores of people across
Western Australia last night, who witnessed what may have been dust shed by
a comet thousands of years ago.

Perth Observatory astronomer Jamie Biggs said the event was seen as far
north as Dandaragan, 170 kilometres north of Perth, and as far south as
Albany, 410 kilometres south of Perth.

Dr Biggs said the specific incident was what's called a fireball - a bright
shooting star.

"We're not sure, but there is a meteor stream that the earth has just
started passing through last night, and this is the dust and junk that has
been shed by a comet, possibly thousands of years ago," Dr Biggs said.

"We're ploughing through what's left of its orbit, and so we get hit by all
this dust so we get an increase in meteor activity and it looks like it's
from one point in the sky.

"This object may have been one of those but it's hard to know.

"It was a lot brighter than what these things normally are."

About 100 people rang the Perth Observatory to report the event.

© News Limited Privacy Policy

=============
(3) NEAR TEAM STUDIES SMALL SCALE FEATURES ON EROS

From Ron Baalke <baalke@jpl.nasa.gov>

For Immediate Release
April 20, 2001

Media Contacts:
Helen Worth
Johns Hopkins University Applied Physics Laboratory
(240) 228-5113
helen.worth@jhuapl.edu

Michael Buckley
Johns Hopkins University Applied Physics Laboratory
(240) 228-7536
michael.buckley@jhuapl.edu

NEAR Team Studies Small Scale Features on Eros
Concludes Surface Topography the Result of Impacts

NEAR mission science team members have concluded that the majority of the
small features that make up the surface of asteroid Eros more likely came
from an unrelenting bombardment from space debris than internal processes.
Details of the research from NASA's Near Earth Asteroid Rendezvous (NEAR)
mission were published this week in Science and are based on the NEAR
Shoemaker spacecraft's Oct. 25-26, 2000, low-altitude flyover of asteroid
Eros that brought the spacecraft to within about 3 miles of the surface of
the asteroid.

"We think that impacts to the asteroid's surface have probably been the
single-most dominant process in shaping the surface texture of the
asteroid," says NEAR Project Scientist Dr. Andrew Cheng of the Johns Hopkins
University Applied Physics Laboratory in Laurel, Md., which managed the
mission for NASA. "We saw surface details such as regolith [surface dust and
debris], craters and fields of small boulders in incredible detail. We also
saw things that confound us, but we now have a more in-depth picture of Eros
that will help us to decipher the asteroid's history."

During the flyover, simultaneous observations were taken by the spacecraft's
multispectral imager and laser rangefinder over two tracks approximately 1
mile and 2.5 miles long that showed objects the size of a doghouse at three
to four times better resolution than previously obtained. The data revealed
an inordinate number of small boulders, a saturation of large craters and a
dearth of small ones, crater "ponds," and unknown erosion processes.

A vast number of large craters, 1,630 to 3,280 feet (500 to 1,000 meters) in
diameter, have been imaged, but there is a surprising scarcity of boulders
large enough to make such impacts. There is more than 100 times the number
of 10- to 12-foot (3- to 4-meter) boulders than there are impact craters in
this region. Some angular or slab-like features were imaged that could
indicate they are composed of stronger material than rounded objects. Some
boulder clusters are thought to be fragments of a larger projectile that hit
the asteroid.

The flyover also yielded evidence of an unusually low number of smaller
craters. "There could be some unknown process, possibly something like
seismic shaking following impacts, which is more likely on a small body such
as Eros," says Dr. Joseph Veverka of Cornell University, Ithaca, N.Y., who
heads the imaging team. "Other possibilities are processes that could erode
or erase smaller craters such as micro-cratering [the pummeling of the
surface by smaller objects] or thermal creep [the erosion of surface
material through normal seasonal heating and cooling of the asteroid] that
is eroding the smaller craters."

"We do know there is a substantial amount of regolith from erosion and
impacts that is covering blocks [boulders] and craters possibly to a depth
of several meters. So it could be that many smaller craters do exist but
they're buried under the regolith," says Veverka. "A thick covering of fine
dust that prevents us from seeing what lies beneath might also be part of
the answer to why the asteroid has little color variation. It is possible
that parts of Eros are covered in regolith as deep as a 10-story building."

The data also revealed ponds - flat surfaces at the bottom of craters -
formed by regolith deposits. These ponds are intriguing science team members
because of their extremely smooth surfaces. "The smoothness indicates that
there is an efficient process on Eros which is able to sort out the finest
component of the regolith from the coarser, more blocky portion and
concentrate this fine material into some low-lying areas such as crater
bottoms," Veverka says.

Moreover, the laser altimeter found that ponded deposits are not only smooth
but also extremely horizontal - level relative to local gravity - as if
formed by fluid-like motions. "It is astonishing that the total dry regolith
of an asteroid like Eros can apparently be mobilized like a fluid," says
Cheng. "There is no water on Eros, and there has not been any water, for
billions of years. However, seismic shaking caused by impacts may be able to
produce fluidized movement of regolith."

"Aprons" of debris at the base of some of the larger boulders indicate
another phenomenon the researchers are studying: efficient erosion or
disintegration of ejecta boulders (boulders forced out of a crater as the
result of an impact) after they have landed on the surface. But scientists
say they need to study higher resolution images to more definitively
interpret the various forms of regolith that the low-altitude images have
provided. "What causes this efficient disintegration remains a mystery,"
Veverka says. "But one we hope to solve over the coming months by studying
the wealth of data that the NEAR mission has provided."

More information on the NEAR mission can be found at the NEAR mission Web
site: http://near.jhuapl.edu.

============
(4) ASTEROID EROS: MOST DETAILED ANALYSIS OF UP-CLOSE IMAGES

From Space.com, 19 April 2001
http://www.space.com/missionlaunches/missions/eros_wrap_010419.html

By Robert Roy Britt
Senior Science Writer

If like a talented basketball player you had a strong vertical leap (say 36
inches, or just under 1 meter) you could jump a mile (1.6 kilometers) high
on Asteroid 433 Eros. But be careful, because you might also launch yourself
into orbit around the distant space rock.

But if you keep your footing, you'd have a clear view of a strange and
surprising world with house-sized boulders, inexplicable smooth spots and
very near horizons that in some directions loom like mountains on Earth --
all on a fairly firm but incredibly uneven and rocky surface coated with a
thin layer of dust.

If, by chance, you were also an asteroid expert, you'd be very surprised at
the lack of small impact craters on the otherwise heavily scarred, vaguely
shoe-shaped asteroid.

That's the picture painted by Cornell University researcher Peter Thomas,
who in an interview explained what's been learned by the most recent study
of detailed photographs sent back by the NEAR Shoemaker spacecraft.

NEAR landed on the asteroid Feb. 12, with the mission ending 16 days later.
All told, the craft returned more than 160,000 detailed pictures, and Thomas
said researchers will study them for many years.

But Thomas and a host of other scientists have now produced the first
comprehensive peer-reviewed analysis of Eros' small-scale features -- with
details shown down to 3 feet (1 meter). The study will be published in the
April 20 issue of the journal Science.

Lack of small craters

Eons of impacts have created at least 100,000 craters on Eros, which is
about 21 miles (33 kilometers) long, 8 miles (13 kilometers) wide and 8
miles thick.

But one puzzle revealed by the new study is a paucity of small impact
craters -- fewer in a given amount of surface area than are observed on the
Moon, Thomas said.

The lack of tiny divots is not due to a shortage of things to run into --
the "Asteroid Belt" between Mars and Jupiter where Eros roams is loaded with
millions of smaller rocks prone to taking pot shots at each other.

Something must be covering up or eroding small craters, researchers say. One
possible explanation is a phenomenon called seismic shaking. It goes like
this:

When another space rock slams into Eros, it sends shock waves, or sound
waves, reverberating through the asteroid, Thomas explains. This seismic
shaking causes small crater walls to crumble and settle, much like a mound
of flour in a bowl would level out upon shaking.

On an asteroid, seismic shaking would be enhanced by the low gravity, which
would allow small rocks and other debris to move around more freely than on
a more massive object like the Moon.

Larger craters would not be affected as significantly by seismic shaking.

But this shaking, or some other process, might also have created another
curious feature: smooth, flat areas at the bottom of several craters, large
and small. The flat spots, ranging from about 1 to 16 yards (1 to 15 meters)
across, appear to be made of the same material as the crater walls within
which they sit. This would rule out a process known to create similar flat
features on the Moon, when an impact carves out surface soil, exposing
different and often more solid material below.

House-sized boulders

Small boulders, up to the size of a house, are plentiful on Eros. In certain
areas, 25 boulders larger than 26 feet (8 meters) across sit on every square
kilometer, the study found. Researchers estimate there are about a million
such rocks total.

Clamoring up on one of these larger boulders, a visitor could in some
regions get a view of all horizons, which would fall away quickly on the
small rock. Researchers are nearly certain that dust or small pebbles coat
parts or all of the asteroid, but images are not of high enough resolution
to determine this with certainty. A decade ago, no one expected an asteroid
of this size to have enough gravity to retain small particles.

Smaller boulders, likely distributed over the eons during many collisions
with other space rocks, are everywhere. These boulders have been spotted
before, but the new study shows their prevalence.

Boulders 3 feet (1 meter) across or bigger are 500 times as plentiful as the
house-sized boulders.

In general, boulders on Eros appear to be buried in the asteroid's regolith,
or soil, to different depths. Researchers expect that older rocks are buried
deeper, and boulders that have been kicked up by more recent collisions sit
more fully on the surface.

Pile of rubble

Scientists have long wondered whether asteroids were solid rocks or large
collections of rubble. Figuring out how asteroids are structured has
potentially pragmatic uses: Properly destroying or deflecting an incoming
space rock, were one ever determined to be headed our way, would require
knowledge of the asteroid's composition and how well it is bound together.

Researchers have identified more than 350 near-Earth asteroids larger than 1
kilometer (about 0.6 miles) in diameter -- big enough to cause significant
regional or global damage in an impact. They estimate that the total is
likely between 500 and 1,000, and may be higher.

None are known to be on a collision course with Earth, but most experts
agree that an impact is inevitable, eventually.

Building on data published last September, the new analysis further shows
that the heart of Eros is solid, but the surface is clearly a scattered
collection of material. Eros' mass should be enough to create a solid core,
Thomas said, but closer to the surface this would give way to "progressively
fragmented rubble."

A solid core indicates that an asteroid has never been entirely broken up by
a collision, which means that its core, at least, has been around since the
early days of the solar system's formation.

Long grooves, previously spotted in lower-resolution images, have now been
found to be up to 33 feet (10 meters) wide and 82 feet (25 meters) deep.
These grooves appear to be created by cracks in solid material deeper within
the asteroid, and also show signs of collapsed edges that leave piles of
rubble within the grooves.

Beyond Eros

The images of Eros collectively represent by far the most detailed look at
an asteroid ever obtained. In fact, researchers say we have gotten a better
look at much of Eros than at many parts of Mars or the Moon.

And the new study did not examine the images taken at closest range.
Instead, because of the constraints required to publish a study, the
pictures reviewed were taken when NEAR zoomed down to within 4 miles (6.4
kilometers) of Eros in October 2000. Many more images were created later on
other close flybys and even as the spacecraft descended for landing.

One challenge researchers now face is simply absorbing and analyzing the
vast quantity of data and images.

"We solved mysteries, we unveiled more mysteries," said NEAR project
scientist Andrew Cheng shortly after the mission was completed in February.
"Now we're sharing the amazing amount of data that we collected with
scientists all over the world, to sort through and debate and hopefully to
help us discover facts about Eros and our solar system that no one knows
today."

Cheng, of Johns Hopkins, and other researchers contributed to the new
understanding of Eros with an analysis of laser data that is published in a
second paper in Science.

A map, and a benchmark

Thomas said efforts are underway to create a detailed "old-fashioned" global
map of Eros to pinpoint the many dips, mounds, protrusions and holes, as
well as understand how each feature was created.

He also said Eros would now serve as a benchmark against which researchers
could compare data on other asteroids, including ground-based observations.
The detail known about surface features could allow useful interpretations
to be made from other, less-detailed observations.

But Eros is just one asteroid, and researchers suspect others have different
makeups and histories.

"This is a small asteroid," Thomas said. "What a lot of us would like to do
is see a big asteroid up close and in detail."

Thomas said a favorite candidate is Ceres, which at about 620 miles (1,000
kilometers) wide was the first asteroid ever discovered. While other
asteroid missions have been proposed to NASA, currently none are firmly on
the drawing boards.

The NEAR spacecraft was operated by the Applied Physics Laboratory at Johns
Hopkins University, in cooperation with NASA. Those involved in the new
studies included researchers from these and several other institutions.

Copyright 2001, Space.com

==========
(5) ORPHAN 'PLANET' FINDINGS CHALLENGED BY NEW MODEL

From Space.com, 18 April 2001
http://www.space.com/scienceastronomy/astronomy/free_floaters_010403.html

By Robin Lloyd
Science Editor

Astrophysicists have struggled to develop a nomenclature for a handful of
recently discovered, small and orphaned celestial bodies. Now a new model
could spoil the party for planet hunters by proposing the free floating
Jupiter-sized objects are basically star fragments, not new worlds.

Scientists have discovered some 50 planets in the past five years orbiting
distant stars, along with some two dozen of these free-floaters, found in
the Orion Nebula. And the latter have divided some astrophysicists into two
camps -- planet believers and planet debunkers.

The new work by the Carnegie Institution's Alan Boss lands firmly on the
side of planet debunkers by recognizing the role that magnetic fields could
play in relaxing the gravitational gas collapses that are thought to yield
stars and then solar systems.

The low-mass, free floating objects form like stars, so they are not
planets, Boss said. Instead, they should be called sub-brown dwarfs --
objects that are smaller than typical brown dwarfs -- which are failed stars
too small to shine and burn their fuel.

"This model suggests that free floating planetary mass objects in Orion
could have formed in [the] same process as stars and just continued down to
lower masses," Boss said in an interview. "So they should be considered part
of the star-formation process rather than as being planets which have been
ejected from a protoplanetary disk."

If widely agreed on, the model could strike an intellectual blow to certain
scientists, including Patrick Roche of the University of Oxford and Philip
Lucas of the University of Hertfordshire, who have discovered such low-mass
bodies and labeled them planets. Findings like theirs tend to attract extra
attention from reporters and the public excited about the prospects for
worlds, and life, beyond our planet and solar system.

Too bad for the search for life

Boss's explanation for the free-floaters builds on his previous work and
introduces the new magnetic fields variable.

"Magnetic fields are a part of the puzzle that theorists like to leave out
because they complicate matters, but observers know they are there," Boss
said. "This is a first attempt to include them in a crude approximation."

Previous models of star formation suggest that the process could only yield
stars and other bodies with masses no less than 13 times the mass of
Jupiter.

In conventional models, planets (smaller, colder and incapable of burning
fuel or shining) form later around stars when a massive leftover dust disk
spins around a central star and cools, with small bodies eventually
coalescing, colliding and gaining mass to become planets.

In Boss' model, as the dust and gas of a protostellar disk collapses,
magnetic fields help stop the cloud from fusing into a single object at the
center of the cloud. The cloud remains distended and then breaks up into
smaller mass objects. On top of that, the magnetic tension helps the cloud
rebound from its center as it cools, again assisting the formation of
smaller objects, Boss said.

Four or more prestellar objects, each with a mass as low as Saturn, may form
in this way, he said. Eventually such an unstable system could eject single
fragments that would continue to gather a bit of mass to reach those
reported among the "Orion free-floaters."

"These little objects, if they form in a multiple system, won't become
stars," Boss said. "They are tossed out at such an early phase that they
lack the gas to become big stars. They are stellar embryos. They end up with
a mass you'd associate with planetary mass even though they form like
stars."

A planetary model fails too

More new research also points away from categorizing the Orion free-floaters
as planets. Geoff Bryden at NASA's Jet Propulsion Laboratory has modeled a
scenario that shows solar systems are unlikely to kick out objects with
masses similar to those of the free-floaters.

Instead, they might eject smaller objects, Bryden said.

"For this reason, our models do not account very well for observations of
young, free floating, 10-Jupiter-mass objects," he said. "There are
alternatives, such as the effect of other stars passing nearby, but probably
the most promising way to form such objects is along the lines of Boss'
paper."

Mark McCaughrean of the Astrophysical Institute in Potsdam, Germany, called
Boss's approach "perfectly reasonable."

But he questioned the observational data -- from Lucas and Roche and others
-- against which Boss is testing his new model, saying the free-floaters
could be quite a bit more massive than those researchers claim.

"We still have a lot of work ahead of us to prove whether or not such
objects [with masses below that of 13 Jupiters] really exist in star-forming
regions," he said. "In any case, this knocks another wooden stake through
the hearts of the P-word (planet) users: if fragmentation really can produce
objects [with the same mass as Jupiter] floating freely like this, then
there's even less justification for using the confusing P-word: 'sub-brown
dwarfs' will do very nicely."

A new working definition

Birthright aside, can a planet-sized object that fails to orbit a star still
be called a planet? The standards-setting International Astronomical Union
(IAU) recently issued a provisional answer -- no way. Planets, by their new
definition, must orbit a star. That definition could be revised as more data
come in and the group continues to meet.

The new definition, released in February, is the result of a sometimes
contentious months-long process that SPACE.com reported in November 2000. It
was the IAU's first attempt to give an official definition to the word
"planet."

Boss chairs the IAU working group that developed the definition and said he
remains neutral during discussions and keeps his research separate.

Copyright 2001, Space.com

===========
(6) DISTANT COMET TANGOES WITH SATELLITE

From Andrew Yee <ayee@nova.astro.utoronto.ca>

[Extracted from inScight, Academic Press,
http://www.academicpress.com/inscight/04192001/graphb.htm]

19 April 2001, 5 pm PST

Distant Comet Tangoes With Satellite
By GOVERT SCHILLING

Astronomers have discovered a satellite companion of a supercomet in the
Kuiper Belt, the part of the solar system beyond the orbit of Neptune. Until
now, Pluto, the outermost planet, was the only object in this region known
to have a satellite. The finding supports some astronomers'
contention that Pluto shouldn't be considered a planet.

The discovery was serendipitous, says team leader Christian Veillet of the
Canada-France-Hawaii Telescope (CFHT) in Mauna Kea, Hawaii. Still, the
existence of binary Kuiper Belt Objects wasn't unexpected. Astronomers had
already planned to search for them with the Hubble Space Telescope later
this year. "I think that probably nobody really thought that you could
actually see one from the ground on a medium-size telescope [such as Mauna
Kea's 3.6-meter CFHT]," says Veillet.

The satellite is at least 40,000 kilometers from its parent object, a
supercomet known as 1998 WR31, the researchers announced 15 April in an
International Astronomical Union circular. In the next few days, Veillet
hopes to precisely determine the satellite's orbit, using old photographs of
the pair. This will make it possible to calculate the mass of the comet and
its satellite. And if the two objects occasionally pass in front of each
other, as in an eclipse, the resulting brightness changes may be used to map
large features on their surfaces.

The discovery suggests that the binary nature of Pluto isn't exceptional for
its neighborhood. Indeed, such pairs are probably a fairly common result of
collisions in the Kuiper Belt, notes Alan Stern of the Southwest Research
Institute in Boulder, Colorado. That supports the popular view among
astronomers that Pluto should be considered a Kuiper Belt Object, albeit a
very large one. "Those who argue that Pluto is 'different' because it has a
satellite need to think again," says Benny Peiser of Liverpool John Moores
University, United Kingdom.

Related link:

* Christian Veillet's page on the discovery
  http://cfht.hawaii.edu/~veillet/WW31.html

© 2001 The American Association for the Advancement of Science

=========
(7) GLI IMPATTI COSMICI HANNO GIOCATO UN RUOLO FONDAMENTALE NELL'EVOLUZIONE
DELL'UMANITA

From Claudio Elidoro <claudio.elidoro@rccr.cremona.it>
http://www.geocities.com/elidoro/news/evoluzione.html

=============
(8) RUSSIAN SPACE EXPERT PREDICTS HUMAN MARS MISSION BY 2020

From Ananova, 22 April 2001
http://www.ananova.co.uk/news/story/sm_267828.html?menu=

Russia should be ready to send humans to Mars by 2020, the head of a leading
space science institute says.

Professor Anatoli Grigoriev, of the Institute of Biomedical Problems of the
Russian Academy of Sciences, says Russia has unmatched experience in space
flights lasting a year or more.

He says their experiences with Mir have also taught them how to keep crew
members sane 280 million miles away.

"Our engineers believe we can do this by 2020 and, from a medical point of
view, there are no big hurdles left to hinder such a mission," Prof
Grigoriev says.

He says Russia will produce a detailed plan for a manned Mars mission by
2005.

President Vladimir Putin has also recently promised to restore Russia's
prestige as a space power.

The Academy was founded in 1963 by Sergei Korolyev, architect of the Soviet
Union's early space triumphs. The Institute of Biomedical Problems was given
its name to confuse foreigners.

Other Russian experts claim Moscow could mount a manned Mars expedition for
as little as $10 billion, which equates to £6.9 billion, The Times reports.

Copyright © 2001 Ananova Ltd

============================
* LETTERS TO THE MODERATOR *
============================

(9) A RESPONSE TO DUNCAN STEEL

From Ed Grondine <epgrondine@hotmail.com>

Hello Benny -

Duncan Steel's recent note to the Conference (90 PERCENT OF WHAT? AND SOME
OTHER COMMENTS, CCNet 19 April 2001) raises some important issues which I
feel need to be commented on.

If I interpret Duncan's comments on the Siding Spring Observatory correctly,
it appears that he has accepted that the UK 3.5 meter telescope will not be
built by a government facing very large bills arising from both Mad Cow
Disease and the recent Hoof and Mouth epidemic. Indeed, the whole tone laise
common among researchers who have worked in this field for decades, the
belief that nothing serious will be done about the impact hazard until after
the next one hits.

As I myself have only been concerned about this problem for a very short
time, I have yet to give in to this despair, though comments from some
"space fantasists" here in the US have often made me groan in frustration.
When those feelings have surged, I have always comforted myself by
remembering the simple fact that since the US space agency, NASA, is
considering spending somewhere in the neighborhood of $20,000,000,000 on
something as realtively useless as a manned flight to Mars by a few
individuals, it is entirely likely that with carefully gathered evidence
they might be presuaded to increase NEO detection moneys somewhere above
last year's $7,000,000 level. I have also been aided in dealing with this
despair by the stoicism  I acquired through years of contact with my Russian
friends - note that while their economy is down now, that won't be the case
in the future; they remember Tunguska, they remember Sikote Ailin.

While Steel has always commented before about the arbitrariness of NASA's 1
kilometer goal, his note seems to show that for the while he has given and
accepted it: "The target of discovery then (that is, the NASA Spaceguard
target) is 90 percent of the 1 km (0.6 mile) plus objects of asteroidal
appearance in cis-jovian (short-period) orbits that approach that of the
Earth....The immediate aim, then, is to find 90 percent plus of the large
asteroids in short-period orbits."  In previous notes Steel has always
pointed out that 1 kilometer aim is NASA's aim, not "the" aim.

Steel also notes that "These comprise the majority of the impact hazard,
they are the easiest objects to find (barring the small number of active
comets that are simple to spot)..."

Besides giving in to NASA's rather arbitrary goal for asteroids, Steel
despairs of finding threatening comets: "That [i.e. NASA's] target excludes
the "frozen balls of ice and dust" (i.e. comets), and quite correctly at
this juncture. So far as I am aware the majority of very large objects on
Earth-crossing orbits observed over the history of astronomical research
have been comets, mostly in near-parabolic orbits. Finding 90 percent of
those is not feasible, because they spend most of their time near aphelion,
making it possible to find them only as they enter the planetary region."
Carolyn Shoemaker disagrees with him, and is seeking $170,000,000 for a
telescope for exactly this purpose. And while $170,000,000 may seem like a
large sum, compared to $250,000,000 for one Mars probe, it's clearly a
bargain - see the list of suspected impact deaths above.

Steel outlines our current understanding of the difficulty involved:
"Readers might care to note that [there] are around 100 million 1 km plus
comets per square degree of sky (almost all out in the Oort-Opik cloud and
of no concern to us)."  While he's right about the enormous number of
comets, he's also correct about most of these being of no concern. Those
very few which are of concern, in other words those comets on an inbound
course, will develop a coma, and this coma can be picked out by computer
image processing techniques, with the computer pitching out the data on the
enormous number of comets which are no concern.

Steel claims that even if we could find the next one of these comets which
will hit, we will be able to do nothing about it: "We do not at present have
the technology (in particular the propulsion technology) required to
intercept a near-parabolic comet even if found several years ahead of a
terrestrial impact,...". Several years back both the United States and the
Soviet Union developed nuclear thermal rocket engines for manned Mars
flight. Since these engines were capable of sending something as massive as
a manned vehicle, including its descent and ascent stages, to Mars, my first
order estimate is that they should have no problem moving something as light
as a 150 megaton nuclear charge to any place in the solar system where its
detonation might prove useful to mankind as a whole.

WHAT DO I EXPECT FROM THOSE WORKING IN THE FIELD?

I am not looking for excuses, I am looking for solutions. I am not looking
for rationalizations about what can not be done - I am looking for the
identification, design, and deployment of technologically feasable
solutions.

I am not looking for excuses about "budget constraints". Given the total
amount spent internationally on space research, clearly more of that can be
spent on NEO work instead of on less useful projects.

Immediately, I think it would be "nice" if future small impactors could be
detected early enough to either get people into shelters and away from their
blasts, or away from the coastal areas which will be submerged by the
tsunami resulting from their impacts. Based on my understanding of the
threat, my view is that there is nothing (except for the search for even
bigger asteroids) that NASA is now spending money on which could possibly
have a higher priority than this.

EP

=========
(10) AND FINALLY: UFO BUREAU SHUTS DOWN DUE TO LACK OF FLYING SAUCERS

From Michael Paine <mpaine@tpgi.com.au>

Dear Benny,

It seems that the extraterrestrial tourist trade has dropped off. Probably
our revised entry in The Hitchhikers Guide to the Galaxy didn't help: The
Earth - Mostly Harmless.

regards
Michael Paine

Sydney Morning Herald
http://www.smh.com.au/breaking/2001/04/23/FFXNDZ14VLC.html
UFO bureau shuts down due to lack of flying saucers

Source: AAP|Published: Monday April 23, 9:37 AM

The British Flying Saucer Bureau, which has been hunting for
extra-terrestrial activity for half a century, has closed its doors because
of a dearth of unidentified flying objects (UFOs).

The bureau, which at one time boasted 1,500 members worldwide, has over the
years received weekly reports listing up to 30 UFO sightings.

These days there are rarely any such reports, and the bureau's monthly
meetings have now been scrapped  because of a lack of participants.

Denis Plunkett, who was a co-founder of the bureau in 1953, says UFO
sightings are in the middle of a long trough.

He says there are not enough sightings to warrant continuing.

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