PLEASE NOTE:


*

CCNet 96/2001 - 31 August 2001
------------------------------


"I see two much more 'interesting cases' to which we may one day be
confronted: The first one is the next Tunguska, which, very likely, we
will not be able to detect beforehand. [...] The second one, also a
probable one, is when we will have a long lasting spot on the so far
immaculate Torino Scale, or in other words, when we will start a real
asteroid scare among even the normally brained public."
--Alain Maury, 31 August 2001


"Although calls to adjust the flawed IAU guidelines have been
mounting ever since, and despite assurances by NASA officials that
the procedures would indeed be modified, no concrete action or amendment
has taken place since. In short, the obstreperous guidelines remain valid
as if nothing has happened. In view of the indecisiveness and wavering by
the IAU, it should be plain that we are nowhere near from managing a
more serious impact threat 'crisis' as envisaged by Alain."
--Benny J Peiser, 31 August 2001



(1) TWO AMATEUR ASTRONOMERS TO SHARE THE 2001 EDGAR WILSON AWARD
    Ron Baalke <baalke@zagami.jpl.nasa.gov>

(2) WITNESSES SAY METEOR MAY HAVE LANDED IN LA GARITA MOUNTAINS
    Alamosa Valley Courier, 29 August 2001

(3) FALLING METEORITE TRACKED TO LA GARITA MOUNTAINS
    The Denver Channel, 29 August 2001

(4) STAR OF BETHLEHEM 'WAS TWO BRILLIANT METEORS'
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(5) SHEDDING LIGHT ON CHRISTMAS
    The Daily Telegraph, 30 August 2001

(6) COMMENT: WHAT WAS THE STAR OF BETHLEHEM?
    Mark Kidger <mrk@ll.iac.es>

(7) BRITAIN CAN'T GET ENOUGH OF DEEP IMPACT
    The Guardian, 29 August 2001

(8) ON DAMOCLOIDS & ASTEROID SCARES
    Alain Maury <alain.maury@obs-azur.fr>

(9) A WORD OF WARNING ABOUT FUTURE ASTEROID SCARES
    Benny J Peiser <b.j.peiser@livjm.ac.uk>

(10) HOTSPOT INFLUENCES GEOID
     Hermann Burchard <burchar@mail.math.okstate.edu>

(11) AND FINALLY: SURPRISING FINDS BUST THE THEORY OF WHEN HUMANS LEFT
AFRICA
     Archaeology Today, 29 August 2001

===============
(1) TWO AMATEUR ASTRONOMERS TO SHARE THE 2001 EDGAR WILSON AWARD

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

Public Affairs Department
Harvard-Smithsonian Center for Astrophysics

Contact Information:

Brian Marsden, Harvard-Smithsonian Center for Astrophysics
60 Garden Street Cambridge, MA 02138
bmarsden@cfa.harvard.edu
(617) 495-7244

Dan Green, Harvard-Smithsonian Center for Astrophysics
60 Garden Street Cambridge, MA 02138
dgreen@cfa.harvard.edu
(617) 495-7440

For Release: August 28, 2001

Release No.: 01-09

Two Amateur Astronomers from the Pacific Rim to Share the 2001 Edgar Wilson
Award for the Discovery of Comets

Cambridge, MA -- To some observers, comets are the dirty snowballs of the
solar system that only occasionally appear in the nighttime sky. To others,
comets are the "white whales" of the vast cosmic ocean. Recently, two
amateur astronomers separated by six thousand miles of a more familiar ocean
spotted the same cosmic whale, comet C/2000 W1 (Utsunomiya-Jones). For their
outstanding efforts they will share the "2001 Edgar Wilson Award for the
discovery of comets."

Established in 1998 and administered by the Smithsonian Astrophysical
Observatory, the Edgar Wilson Award promotes amateur cometary astronomy by
rewarding individual discoverers with a cash prize that could reach $20,000.


Few amateur astronomers regularly have the necessary time and skies free
from light pollution needed to discover new comets. Today, the receipt of
the Edgar Wilson award is especially notable because amateur astronomers
face fierce competition from professionals working with programs such as the
Lincoln Near Earth Asteroid Research (LINEAR) project and other CCD surveys.


The Wilson Award is funded by the Edgar Wilson Charitable Trust, established
upon the death in 1976 of the successful Lexington, Kentucky businessman who
was quite interested in promoting amateur astronomy. Bank One serves as the
Trustee.

This year's award is to be shared by comet hunter Syogo Utsunomiya of
Kumamoto, Japan, and Albert Jones, the dedicated variable star observer from
Nelson, New Zealand. Their co-discovery of comet C/2000 W1 is an example of
astronomical and international coordination. On the night of November 18,
2000, Syogo Utsunomiya was observing the southern constellation of Vela with
his 25x100mm binoculars when he spotted a fast-moving comet low on his
southern horizon. Utsunomiya dutifully noted the comet to be approximately 5
arcmin across, magnitude 8.5 and moving rapidly to the southeast. The fast
moving comet would soon be unobservable from his position. (The moon's
apparent size is about 30 arcmin across and objects about magnitude 8.5
require at least small telescopes and binoculars.)

On November 19, after confirming his observation, Utsunomiya relayed his
report to the Central Bureau for Astronomical Telegrams (CBAT) at the
Smithsonian Astrophysical Observatory. Soon afterwards, a description of the
comet and its predicted position was sent from CBAT to a few other observers
for confirmation. Despite the efforts of those astronomers, Utsunomiya's
fast-moving comet went unnoticed for almost another week. Then in the early
morning on November 26, the 80-year-old eagle-eyed Jones spotted what he
recognized as a comet with his 78-mm refractor, not knowing it to be one
that Utsunomiya had seen a week earlier further to the north. Jones had
chanced upon the comet as he was quickly moving from star to star or "star
hopping." He was actually trying to observe the variable star T Apodis
before the approaching morning sun ruined the sky. Jones' luck that morning
would earn him two more distinctions: he is now the oldest person to have
discovered a comet, and he has set the record for the longest time interval
between discovering comets at 54 years!

At the CBAT, Brian Marsden and Daniel Green both realized quickly that
Jones' comet was likely to be the same as Utsunomiya's comet, even though
only very rough visual positions were available from both observers. Under
this assumption, Green and Marsden contacted additional observers in the
southern hemisphere with a revised ephemeris predicting where the presumed
single comet might be. An answer quickly came from the New Zealand
astronomer Alan Gilmore at Mount John University Observatory on the South
Island with accurate positions obtained with a CCD camera attached to a
telescope with a 1-meter mirror: the comet was indeed present where it
should be if Utsunomiya's and Jones' comets were one and the same. The comet
was now secure, and the CBAT issued its IAU Circular No. 7526 on November 26
to tell the world, as is its customary practice with new comets, novae,
supernovae, and other interesting new "transient" astronomical objects in
its role as the worldwide clearinghouse for announcing such discoveries. The
computed orbital elements issued by the CBAT showed that the comet would
come closest to the sun exactly a month later at a distance from the sun of
about 30 million miles.

The SAO is a member of the Harvard-Smithsonian Center for Astrophysics and
its headquarters are located in Cambridge, Massachusetts. About thirty-three
other comets discovered with ground-based telescopes were announced by the
CBAT in the year encompassing the 2001 Wilson Award, but only one
amateur-discovered comet, C/2000 W1, was eligible for the award.

In 1999, seven amateur astronomers received Wilson Awards; in 2000 there
were four. This year's Wilson Award clearly demonstrates how individual
amateur astronomers can continue contribute to our understanding of the
solar system. 

Websites:

* Central Bureau for Astronomical Telegrams
  http://cfa-www.harvard.edu/iau/Headlines.html
* Wilson Award
  http://cfa-www.harvard.edu/iau/special/EdgarWilson.html

===========
(2) WITNESSES SAY METEOR MAY HAVE LANDED IN LA GARITA MOUNTAINS

>From Alamosa Valley Courier, 29 August 2001
http://www.zwire.com/news/newsstory.cfm?newsid=2282699
&title=Witnesses%20say%20meteor%20may%20have%20landed%20in%20La%20Garita%20Mountains&BRD=1190&PAG=
461&CATNAME=Top%20Stories&CATEGORYID=410

Aug 29 2001 12:00AM  By By TERESA L. BENNS  
 
By TERESA L. BENNS

LA GARITA - Geologists and star trackers are eagerly seeking the exact
landing field for a meteor they now believe fell near Storm King Campground
in the eastern La Garita Mountains.

The huge fireball was sighted by several Valley residents around 10:45 p.m.
Friday, Aug. 17, according to local officials.

Forty times brighter than a full moon, the meteor was seen as far away as
New Mexico, Wyoming and Idaho, according to a press release from Denver's
Nature and Science Museum.

The sighting sparked an influx of calls and e-mails to the museum.

Dr. Jack Murphy, a Nature and Science Museum geologist and Dr. Peter Brown
from Los Alamos National Laboratories in New Mexico estimate the meteor
weighed one metric ton on entry and was traveling 11.25 miles per second.

Eyewitness accounts

Saguache Deputy Richard Sutton, patrolling along Highway 17 at County Road H
saw a "really intense, bright light like lightning," sometime between 10:30
and 11 p.m.

"It lit up the entire Valley but it lasted five to six seconds," Sutton
said. The meteor was directly over his head, causing him to crane his neck
to follow it.

"I actually saw debris coming through the atmosphere, and smoke with golden
sparks trailing behind the meteor. These gold and yellow sparks went very
slowly," Sutton said.

"The meteor passed over the town of Center to the north, slowed down to a
crawl and went down low, fading slowly before it went dark."

Sutton says he saw no small explosions, and given the amount of burning, the
elevation, and the meteor's lowness in the sky, he feels a chunk of the
object could be lodged somewhere in Saguache County.

The deputy believes the meteor landed east of Storm King campground.

Monte Vista resident Mike Valdez was relaxing in his hot tub that night when
he saw the meteor.

"It was just plain awesome," Valdez said. "It's so hard to describe because
there's nothing to compare it to."

Valdez said the light "was so bright it dwarfed the intensity of the city
light in my backyard. It was bright white, and after it finished burning it
spread apart into two reddish-orange balls."

About 15 minutes later, Valdez said he heard noises "like low thunder."

Del Norte residents Lance and Deanne Andersen were camping near Summitville
that evening when they saw the meteor streak through the sky and disappear
over the mountains.

"It lit up the Valley like daylight," Andersen said. "I could see along way.
It was pretty impressive."

He watched the meteor until it disappeared somewhere over the La Garita
Mountains.

Location of impact not exact

Originally it was believed the meteor went down somewhere in the vicinity of
the San Juans in Conejos County.

Later the site was better pinpointed, after studying eyewitness reports, to
the Storm King area.

While coursing through the atmosphere, the light generated lends this
falling space mass the name meteor. Once on the ground, it is referred to as
a meteorite, because it has disintegrated into numerous fragments.

Hoping to locate and examine some of these fragments, Murphy came to the San
Luis Valley last week to interview eyewitnesses, among them Andersen and
Valdez.

"We're looking for people who were stationary or sitting down and actually
saw pieces falling from the sky," Murphy said. "If we have some landmarks,
like between a chimney and a telephone pole, we can line it up with compass
bearings."

The museum hopes to do a scientific study on the meteor and would like to
tell people how to identify meteorites, Murphy emphasized.

Meteorites found will not be confiscated, only examined. The space rocks
belong to private property owners if found on private land and to the
federal government, if found on BLM or national forest land.

Eyewitnesses may contact Murphy at 303-370-6445.

©Alamosa Valley Courier 2001

=========
(3) FALLING METEORITE TRACKED TO LA GARITA MOUNTAINS

>From The Denver Channel, 29 August 2001
http://www.thedenverchannel.com/den/news/stories/news-93810220010829-090836.html?subid=22100484

Some San Luis Valley Residents Reported Seeing Meteor Directly Overhead

LA GARITA, Colo. -- Geologists and meteorite hunters are looking for the
exact landing spot for a meteor they now believe fell near a campground
close to the San Luis Valley.

The huge fireball was sighted by many people around 10:45 p.m. Friday, Aug.
17.

Forty times brighter than a full moon, the meteor was seen as far away as
New Mexico, Wyoming and Idaho, according to a press release from Denver's
Nature and Science Museum.

The sighting sparked an influx of calls and e-mails to the museum.

Meteor or Meteorite?

A meteoroid is a piece of stony or metallic material which travels in space.

A meteor is a piece of stony or metallic material which enters the Earth's
atmosphere and burns up.

A meteorite is a meteor which doesn't burn up before hitting the ground.
 
Dr. Jack Murphy, a Nature and Science Museum geologist and Dr. Peter Brown
from Los Alamos National Laboratories in New Mexico estimate the meteor
weighed one metric ton on entry and was traveling 11.25 miles per second.

Saguache Deputy Richard Sutton, patrolling along Highway 17 at County Road H
saw a "really intense, bright light like lightning," sometime between 10:30
and 11 p.m.

"It lit up the entire valley but it lasted five to six seconds," Sutton
said. The meteor was directly over his head, causing him to crane his neck
to follow it.

"I actually saw debris coming through the atmosphere, and smoke with golden
sparks trailing behind the meteor. These gold and yellow sparks went very
slowly," Sutton said.

"The meteor passed over the town of Center to the north, slowed down to a
crawl and went down low, fading slowly before it went dark."

Sutton says he saw no small explosions, and given the amount of burning, the
elevation, and the meteor's lowness in the sky, he feels a chunk of the
object could be lodged somewhere in Saguache County.

The deputy believes the meteor landed east of the Storm King campground.

Monte Vista resident Mike Valdez was relaxing in his hot tub that night when
he saw the meteor.

"It was just plain awesome," Valdez said. "It's so hard to describe because
there's nothing to compare it to."

Valdez said the light "was so bright it dwarfed the intensity of the city
light in my backyard. It was bright white, and after it finished burning it
spread apart into two reddish-orange balls."

About 15 minutes later, Valdez said he heard noises "like low thunder."

Del Norte residents Lance and Deanne Andersen were camping near Summitville
that evening when they saw the meteor streak through the sky and disappear
over the mountains.

"It lit up the valley like daylight," Andersen said. "I could see along way.
It was pretty impressive."

He watched the meteor until it disappeared somewhere over the La Garita
Mountains.

It was first believed that the meteor went down somewhere in the vicinity of
the San Juans in Conejos County.

Later the site was better pinpointed, after studying eyewitness reports, to
the Storm King area.

Murphy traveled to the San Luis Valley last week to interview eyewitnesses,
among them Andersen and Valdez.

"We're looking for people who were stationary or sitting down and actually
saw pieces falling from the sky," Murphy said. "If we have some landmarks,
like between a chimney and a telephone pole, we can line it up with compass
bearings."

The museum hopes to do a scientific study on the meteor and would like to
tell people how to identify meteorites, Murphy emphasized.

Meteorites found will not be confiscated, only examined. The space rocks
belong to private property owners if found on private land and to the
federal government, if found on BLM or national forest land.

Eyewitnesses are asked to call Dr. Jack Murphy at (303) 370-6445.

Copyright 2001, The Denver Chanel
 
==========
(4) STAR OF BETHLEHEM 'WAS TWO BRILLIANT METEORS'

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

>From The Daily Telegraph, 30 August 2001
http://portal.telegraph.co.uk/news/main.jhtml?xml=/news/2001/08/30/nstar30.xml

Thursday, 30 August 2001

Star of Bethlehem 'was two brilliant meteors'
By Victoria Combe, Religion Correspondent

THE Star of Bethlehem that led the wise men to the infant Christ was two
brilliant meteors following similar paths, according to a study by Sir
Patrick Moore.

The astronomer has investigated theories about the nature of the star in the
east described in St Matthew's account of the nativity in the Bible.

In his book, The Star of Bethelehem, published by Canopus in October, Sir
Patrick dismisses previous scientific explanations for the star as
improbable. He claims the star was two meteors, or shooting stars, rising in
the east and crossing the sky in a westward direction, leaving a trail
visible for several hours.

"Meteors are the only natural objects which show definite movement across
the sky over a short period of observation," he writes. While not proposing
to have found the definite answer, Sir Patrick, 78, believes his theory
cannot be disproved.

He has tested other theories against the criteria that the star must have
been unusual and conspicuous to the wise men and it must have appeared
between 7BC and 4BC, the dates between which Biblical scholars believe
Christ was born.

For the star to have been noticed by the wise men, and not by everyone else,
it must have appeared for a short time and have moved in a way quite unlike
that of any other star or planet. Speaking from his home yesterday, Sir
Patrick said the sight of a procession of shooting stars would have been
spectacular, brighter than a full moon.

"If these had appeared in a very sparsely populated area only those looking
up at the same time would have seen it," he added. The study offers no
explanation for the "unmeteoritic behaviour" reported in Matthew's gospel of
the star stopping at the place where Jesus Christ lay.

"We will have to allow Matthew a sufficient degree of poetic licence,"
writes Sir Patrick. His book is devoid of any cynicism about the nativity
and he does allow for the possibility that the star was a message from God
and so "beyond science".

The star is mentioned four times in Matthew's gospel, with little detail,
and not once in Luke's account of the nativity. The gospels of Mark and John
do not mention the nativity.

Mark Kidger, an astrophysicist who has been interested in the star of
Bethlehem for 20 years and last year published a book on the subject, is not
convinced by Sir Patrick's theory of the two meteors.

"A bright meteor you see for one or two seconds and in exceptional cases as
much as 10 seconds," said Mr Kidger. "It would have appeared and disappeared
so quickly the wise men would have had to have had jet propelled camels to
have followed it."

© Copyright of Telegraph Group Limited 2001.

================
(5) SHEDDING LIGHT ON CHRISTMAS

>From The Daily Telegraph, 30 August 2001
[ http://portal.telegraph.co.uk/news/main.jhtml?xml=/news/2001/08/30/nstar130.xml ]

Shedding light on Christmas
By Roger Highfield, Science Editor

TWO thousand years after it was first seen by the wise men, the Star of
Bethlehem has led us to an interesting array of theories.

There are many rival explanations for this herald of the birth of Christ: a
comet, the birth or death of a star, a conjunction of planets, or even the
sighting of Uranus, which was unknown at the time.

When I researched the origins of the Bethlehem star for my book on the
science of Christmas I was struck by two things: the meagre evidence for the
star in the Bible and how the objective perspective of a modern astronomer
may be inadequate.

Sir Patrick says "we must always bear in mind the purely astrological
significance of the star, and we must accept that the wise men were
astrologers first and foremost".

Dr Michael Molnar, a rival star theorist who bases his on the mindset of the
Wise Men, argues: "It is precisely his experience and training as an
astronomer that is the Achilles' heel of this book. It is one thing to
speculate about the rarity and brightness of astronomical events. It is
another to claim that ancient people interpreted these the same as modern
people."

The Magi would not have been impressed by a routine event such as the
appearance of a shooting star, he added.

Dr Molnar's study of ancient astrology suggests that the "star" was Jupiter
when, in 6BC, it emerged "in the east" as a morning star and underwent a
close conjunction with the moon in the sign of the Jews -- Aries. "By my
theory, Jesus would have been 2,000 years old on April 17, 1995."

© Copyright of Telegraph Group Limited 2001.

==================
(6) COMMENT: WHAT WAS THE STAR OF BETHLEHEM?

>From Mark Kidger <mrk@ll.iac.es>

Dear Benny 

The fact that three books can come out about the Star of Bethlehem in less
than two years, each by a reputable author and each coming to a completely
different conclusion and all are taken seriously gives readers an idea of
the problem.

I've read Sir Patrick's book very carefully and Michael Molnar's work is
well known as a genuinely original contribution to the study of the problem.
Astronomically, there is probably very little more that can be done. Just
about all the  even minimally plausible phenomena that can be considered
candidates have been identified. When preparing my book, one of the referees
looked at the chapter on different theories and made a couple of comments on
the lines of "why is this one even included?". One man's meat in this case
is very definitely another man's poison. The list of phenomena is
essentially complete and the last important apportation was the
identification by Michael Molnar of the lunar occultations of Jupiter.

There are a bewildering number of ideas. The fact that people still argue
shows that by pure logic and astronomy there will never be a  solution that
will convince everyone. Other approaches are needed. The areas where things
are very weak are now others. The most obvious hole is that of the Magi
themselves. Who were they? How may were there? Where did the come from? Were
the Jews or Gentiles? Very few books on the Star have seriously dedicated
themselves to this isssue and without knowing the Magi it is very hard to
talk of their motivation and identify what might have been a significant
sign in the sky for them. Without knowing their culture it is harder still
to take the step of deciding whether or not they could have been aware, just
by calculation, of an unobservable phenomenon such as the occultation of
Jupiter by the Moon just a few degrees away from the Sun. 

It is quite likely that the Star was something that meant something special
to the Magi, but not to ordinary people. The masses may well have observed
it, but without seeing any special sigificance and those who did see the
sigificance may well not have wanted to be the messenger who passed the bad
news too Herod. Most authors, and I think that here Sir Patrick follows the
current, tacitly assume that the Magi were Babylonian. This theory has
always been the line of least resistence. Interestingly, one of the few
surviving Babylonian astronomical records is of the 7BC Triple Conjunction
of Jupiter and Saturn that is one of the most popular Star of Bethlehem
theories. The Babylonian description of this, supposedly highly significant
event, is so low-key that it one does wonder how interested the Babylonians
really were.

In my own book I proposed that the Magi were more likely to be Persian than
Babylonian (what very little circustantial evidence that we have does point
to the Persians), although this creates a lot more problems. At least we
have some knowledge of Babylonian astronomy and astrology, of the Persians,
almost nothing is known, so their motivations are even harder to decipher!
The other areas of weakness are semantic and chronological.

The few lines of Matthew's Gospel have been analysed to death. Despite this,
part of the meteor theory is based on a common and very  popular
misconception. The movement of the Star is only mentioned as the Star going
before them on the very short road due south from Jerusalem to Bethlehem.
When first sighted the Star was a fixed object seen "at its rising". The
account in Matthew really makes most sense if you take the simplest
interpretation, that it was a normal astronomical object that was in the
south (probably at dawn) at the time that the Magi had finished their
business in Jerusalem. This really is the description of an ordinary object
that rises 4 minutes earlier each night and in 2-3 months (a reasonable time
for a long desert journey) would pass from being in the east at dawn to
being in the south! Do we need to make things more complicated? Similarly,
most authors forget that Luke publishes a similarly detailed, but totally
contradictory version of the Nativity. The only event common to Matthew and
Luke is the birth of Jesus. Luke presents a series of chonological issues
that were for many years considered insoluable. Which was the census
referred to by Luke? The famous 8BC census appears to have been "Roman's
only" and Joseph was not a Roman. Was it taken when Quirinius was Governor
of Syria? Or more than 10 years earlier when he was Governor's Legate? This
is one reason why some people deny that the Star ever existed  and was just
added by Matthew for artistic effect. One really does need to study and
consider the  chronology with great care. 

If these issues can be resolved the Star of  Bethlehem mystery will probably
be closed as much as it  ever can be. I for one consider the meteor theories
to be among the less likely exotic theories. Ordinary meteors just won't do
and very spectacular bolides that leave a trail for hours are so rare that
any one person seeing two in a few months is almost impossible (quite apart
from that EVERYONE would have seen and commented a really brilliant bolide).


Michael Molnar's work I really do like. He has made a real effort to be
original. His problem with the lunar occultation of Jupiter is the lack of
visibility - it would have been difficult to see even  with a small
telescope. This is the issue that holds it back. You have to demonstrate
that the Magi would have known about the occultation without seeing it and
show that this particular one was so important that it was THE event. Lunar
occultations of Jupiter, even limited to a single constellation  like Aries
are not at all rare over the centuries, particularly if you include
invisible ones. A sceptic might point to several nicely visible lunar
occultations of Mars, high in the night sky from the Near and Middle East,
around the same date and ask "why Jupiter and not Mars?".

Mark

=============
(7) BRITAIN CAN'T GET ENOUGH OF DEEP IMPACT

>From The Guardian, 29 August 2001
http://www.guardian.co.uk/Archive/Article/0,4273,4247170,00.html

BBC1 movie makes Deep Impact
Jason Deans

BBC1's repeat showing of asteroid disaster movie Deep Impact got the
better of ITV's Beech is Back last night.

Deep Impact had 6.4m viewers and a 32% audience share between 8.05pm and
10pm, according to unofficial overnights. ...

The BBC is certainly getting its movie assets to sweat a bit more these
days - it was Deep Impact's second BBC1 outing this year.

The movie drew 10.5m viewers and a 38% audience share on its terrestrial
premiere on BBC1 on January 3. [...]

Guardian Unlimited © Guardian Newspapers Limited 2001 

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

(8) ON DAMOCLOIDS & ASTEROID SCARES

>From Alain Maury <alain.maury@obs-azur.fr>

Benny,

I do not share Duncan's point of view concerning the importance of
Damocloids in the impact hazard. An object with a period of 49 years, and an
inclination on the ecliptic of 80° simply does not represent the same danger
as a low inclination, short period, Q~1 object. Of course it
is an apollo object, and in the population counts for a full object. But as
far as the risk is concerned, there are some type of orbits which are much
more dangerous.

This questions the validity of the curve giving the number of earth grazing
asteroids versus absolute magnitude as a valid tool to apprehend the impact
hazard. In this curve, objects are mathematical points, without respect for
their individual impact probability or the physics
involved (absolute magnitude is far from kinetic energy).

If I go a little bit further, I now feel that NASA's Spaceguard survey goal
is a pragmatic and academic answer to a real problem. Pragmatic for
eventhough it were obvious to everybody that we should survey small
asteroids first, i.e. the most dangerous on a short time scale, it is
simply not possible to run a survey on a few large telescopes with a 3
millions dollars per year budget. Academic for the 1km bodies are indeed the
ones which will create the highest number of casualty over a large period
(say 10 millions years), but not on the shorter time scale. If we
were able to travel 10,000 years ahead in time (and for civilisation, that
is a heck of a long time) and count all the impact-induced casualties, we
would see that they result mainly of 200m type objects, not 1km ones. If
asteroid searches were to stop once we feel we have catalogued 90% of the
1km objects, we would not have eliminated the impact hazard on what a normal
human (i.e. not academic) would call a relatively long time scale unless in
the very highly improbable case
where we would indeed be due for a very large impact in the coming century.
So let's hope that the people in charge of the NASA Spaceguard Survey will
be able to find a political way to go around the fixed goal once it is
reached. Technology may help us if the trend in low cost
microsatellites and new technology ground based telescopes continues.

On another recently discuted matter, one way I think some people may have
been overdoing it is by taking into account some looney web pages to
describe another impact scare that wasn't. I don't think "we" are making a
mistake when some idiot takes correctly presented information and distorts
it. If people are willing to call a one in a million probability a "very
high impact probability", it is their responsability, not ours. Our
responsability is to disclaim this false
information, but we cannot do much to prevent it. Whatever efforts we make
to improve our communication, it will never work with apocalypse retailers.

I have come to think that these "impact scares" are not really relevant to
our activity. I see two much more "interesting cases" to which we may one
day be confronted: The first one is the next Tunguska, which very likely we
will not have been able to detect beforehand. Even though it is beyond our
goal, and even non economically wise to do so, it will give a completely
different perspective to our business. We can already see the type of
accusation when some press article talks about an object which has been
discovered one week _after_ it grazed past the Earth. "What were the
astronomers doing ?". Since we are astronomers, in the eyes of the public we
are of course using no less than 8 meters telescopes to peer through the sky
in order to find the next impactor before it is too late. The second one,
also a probable one, is when we will have a long lasting spot on the so far
immaculate Torino Scale, in other words, when we will start a real asteroid
scare among even the normally brained public. In this regard, I think that
announcing the current short lasting, very low probability alerts is very
mundane. By now, our procedures and responsible and informed journalists
should be able to take care of these objects (or so I hope).

Nature has been kind enough so that in our field, time works with us. While
it is likely that we are now cataloging large and for the time being
completely harmless asteroids, we should still have ample time to create a
nice catalog, until the next, very likely small, short period and low
inclination object falls on Earth, as well as ample time to improve our
communication on non important objects (including damocloids), of course,
with the people with whom we can communicate.

Alain Maury

============
(9) A WORD OF WARNING ABOUT FUTURE ASTEROID SCARES

>From Benny J Peiser <b.j.peiser@livjm.ac.uk>

In his comment in today's CCNet, Alain Maury plays down recent asteroid
scares and foreshadows, instead, of two more worrisome eventualities we
might encounter in the foreseeable future:

"I see two much more 'interesting cases' to which we may one day be
confronted: The first one is the next Tunguska, which, very likely, we
will not be able to detect beforehand. [...] The second one, also a
probable one, is when we will have a long lasting spot on the so far
immaculate Torino Scale, or in other words, when we will start a real
asteroid scare among even the normally brained public."

One could even add a third plausible scenario, one in which a Tunguska-sized
object is actually spotted before before it enters the Earth atmosphere.
Interestingly, Alain does not discuss the measures and procedures the NEO
community should adopt in the event of any such unpleasant incident. That is
not surprising since the NEO community is not only not prepared for such
eventualities, but has been extremely reluctant to address past predicaments
or to learn the lessons from previous PR fiascos.

It is only half a year ago, that the IAU and NASA released an impact threat
announcement which claimed that the Earth might face a small risk of being
hit by a small extraterrestrial object in 2030. The next day, NASA and the
IAU had to retract their initial announcement because within hours of their
statement observational data of the object taken more than 18 months earlier
had neutralised the initial impact risk calculations.

The unnecessary and rushed public announcement was in actual fact due to IAU
guidelines, which request that the calculations of a "significant impact
risk" (i.e. NEOs that score level 1 or higher on the Torino Scale) should be
made public after 72 hours if verified. Although calls to adjust the flawed
IAU guidelines have been mounting ever since, and despite assurances by NASA
officials that the procedures would indeed be modified, no concrete action
or amendment has taken place since. In short, the obstreperous guidelines
remain valid as if nothing has happened (see the IAU Working Group on NEO
webpage at http://web.mit.edu/rpb/wgneo/TechComm.html).

In view of the indecisiveness and wavering by the IAU, it should be plain
that we are nowhere near from managing a more serious impact threat 'crisis'
as envisaged by Alain.

But Alain's comment gives me the opportunity to answer the remarks by two
observers, Larry Robinson and Carl Hergenrother, who recently commented on
the 2001 PM9 scare (CCNet 24 August 2001).

I fully agree with Larry that it is important to ensure that information
about a "virtual impactor" is readily available to astronomers who are in a
position to confirm or deny the calculations, by means of new,
post-announcement observations, through the recognition of images on
archival photographs, or both. The crucial question is how this can be best
achieved. This is why I also agree with Carl Hergenrother's main concern:
"The question at hand is what is the best way to get the word out and more
importantly, can we do better?"

Can we handle the announcement dilemma better? Yes, I think we can - if we
are willing to understand what the fundamental problems are we are dealing
with.

In the case of 2001 PM9, the problem was not an official IAU or NASA
announcement, but the deceptive manner in which impact probabilities were
published by NEODyS and then widely distributed by the Spaceguard Central
Node (SCN). While the information about  a "kilometer-sized PHA [which]
shows a bunch of solutions with non-zero probability of collision [...] in
2005 and in 2007 [in] the order of one part on a million" is intelligible in
its context for the experienced astronomer, the same is not true for the
untrained but interested non-professional.

Should we care about how to general public may misconstrue professional
impact threat calculations published on the internet? I think we should. Can
we prevent scaremongers from abusing NEO information? I don't think we can.
But many people who monitor the NEODyS Risk Pages are genuinely interested
layperson who are simply hoodwinked by the limited and unbalanced
information presented. Yes, the NEO community has a responsibility to
present its data and calculations in a reliable and faithful way so that the
interested public is not given a misleading impression about an impact risk.
In short, it should be presented in a way that minimises any conceivable
kind of sensationalism.

Unfortunately, this didn't happen in the case of 2001 PM9. What was clearly
missing in both the NEODyS and SCN announcements was a unambiguous
clarification that a) the impact solutions were only due to the extremely
short span of observations, and b) that additional observations would almost
guarantee that this object would be no threat whatever!

Given the very short arcs across the sky subtended by the thousands of
main-belt asteroids that are detected each lunation, possible Earth-impact
trajectories could be drawn through many of them. Yet it would definitely
not be appropriate to send out any sort of announcement every time we
calculate such a remote impact risk as this.

After all, the chances are pretty good that a large number of newly
discovered PHA are "virtual impactors", of course only if you raise the
alarm early enough, i.e. in the first couple of days. Now that experience
tells us that this is the case, why raise the alarm every time a PHA's short
arc shows an impact solution?

Carl Hergenrother writes:

"Unless further observations are known to be forthcoming, the impact
announcement should be released immediately. A delay could result in the
losing of an object as it fades or as the moon brightens the sky. It's
never too early to study and prepare for a potential natural disaster."

But was there any looming risk that 2001 PM9 would be lost? Not at all!
There was no risk that 2001 PM9 would not be followed up, and it was very
probable that the follow-up would cause the initial, rather immediate impact
probabilities to go away. 

Given that 2001 PM9 was observable for another month or so, it was almost
certain that additional data would eliminate the initial impact solutions.
In short, a specific impact threat announcement on MPML was unnecessary. In
this as in many other cases, it would have been much wiser to wait for a
couple of days or a week in order to monitor whether or not the object is
followed up. Only in the unlikely case that a virtual impactor is not
followed up, and only if there is a genuine risk that the object might soon
become invisible, could an announcement assist in alerting observers to
obtain additional observational data.

The fact of the matter is that we have ample experience and evidence now
that, just as 2001 PM9 dropped from the risk page, this will be the case in
almost all future cases. I believe it is the responsibility of NEODyS and
SCN to make this point absolutely clear when posting future impact threat
announcements. Would such a disclaimer/clarification serve as discouragement
for observers? I don't think so. But it would provide some helpful
counterbalance to the often 'sensationalist' impact probabilities.

The main question I am addressing here is how we deal with these
hypothetical impactors in public and what language we use. Given that we
know that almost every single "VI" will be deleted from the risk page sooner
or later, we should say so unmistakably. A look at the current design of the
NEODyS Risk Pages does not provide that sort of reassurance despite the fact
that we know better. What is worse, all the public can catch sight of are
those Virtual Impactors still listed - what they can't find out (and thus
fail to understand) is that most objects in this category have been (and
will be) eliminated.

To come back to Alain's worries, it should be stressed that even if the
impact probability should remain nonzero for a prolonged period of time or,
worse still, if the virtual impactor is no longer observable for a certain
period of time, the chances are still extremely high that we won't have a
problem, particularly if we're talking about something as low as one in a
million.

However, the real problem we may be facing in the future is another one of
our own making. Alan has already point out that it is fairly probable that
the NEO community might "start a real asteroid scare" if only a virtual
impactor would "have a long lasting spot on the so far immaculate Torino
Scale."

Far from being perfect, the Torino Scale has become a potential debacle for
addressing the impact hazard in a realistic and responsible manner. In fact,
we could in the future have cases of newly discovered PAHs reaching Torino
level 6 or 7. In view of the information provided on the Torino Scale (a
level 6 impact threat reads as: "A close encounter, with a significant
threat of a collision capable of causing a global catastrophe"; and level 7
"A close encounter, with an extremely significant threat of a collision
capable of causing a global catastrophe"), it would be almost impossible not
to frighten the living daylight out of a petrified public. Just imagine this
scary scenario if, as Alain foretells, the object would remain on this level
for days!

The real public dismay at our mishandling of yet another premature impact
threat announcement, however, would hit us when this object plummets (as
expected!) to zero as soon as extra data allow the object's orbit to be
calculated more precisely. Let nobody say afterwards we weren't aware of the
predicament.

Benny J Peiser

============
(10) HOTSPOT INFLUENCES GEOID

>From Hermann Burchard <burchar@mail.math.okstate.edu>

Dear Benny,

hotspots have been mentioned in recent research news (Mount Etna in today's
issue of NATURE, etc). Known also as mantle plumes, super volcanoes, or
resurgent calderas, these probable impact remnants have their abode at great
depth several K km in the interior of the planet in the mantle, as opposed
to other features such as craters and flood basalts which are found either
on top of the crust or buried under a few km of sediments or volcanic
eruptives.

Nonetheless, a hotspot such as the one under Yellowstone National Park in NW
Wyoming can have a major effect on the crust in that it disturbs the geoid
-- that equipotential surface roughly corresponding to sea level. An
impressive illustration is provided on the University of North Carolina web
pages:

   http://www.geolab.unc.edu/classes/Geo15/Geo15.html
   http://www.geolab.unc.edu/classes/Geo15/geoid.gif

It appears from this that the hotspot is the center of an uplifted area
roughly the size of Texas. This is not just a localized little well sunk
down into the mantle rocks. The corresponding impact structure (early
Miocene 20 Ma) is surmised to be located in SE Oregon, 900 km to the West.

Best regards,

Hermann

============
(11) AND FINALLY: SURPRISING FINDS BUST THE THEORY OF WHEN HUMANS LEFT
AFRICA

>From Archaeology Today, 29 August 2001
http://www.archaeologytoday.net/web%20articles/082901-dmanisi_skulls.htm

The explanation seemed straightforward: After a few million years of
evolution in Africa, hominids developed a new technology - an advanced stone
toolkit called Acheulean - about 1.6 million years ago. Better tools led to
more efficient hunting and scavenging, which allowed early humans to march
out of Africa and begin colonizing the world.

Then came Dmanisi. Now both the timing and the explanation for that first
critical step out of Africa must be rewritten - for here were hominids on
the edge of Europe 1.75 million years ago, well before Acheulean tools were
developed in Africa.

The Dmanisi site, in the Republic of Georgia in the Caucasus Mountains, sits
on an isolated, triangular spur of basalt. A medieval settlement called
Dmanisi prospered for a time as a trading center, though it was eventually
abandoned. Archaeologists explored the medieval ruins for decades. Then, in
1983, while excavating a deep storage pit originally dug by the medieval
inhabitants, investigators happened upon curious stone artifacts.

The artifacts had unequivocally been produced by humans and were associated
with the bones of mammals, such as elephant and rhinoceros, that were long
extinct in this region. Paleontologist Abesalom Vekua, after analyzing the
faunal remains, estimated the age of the archaeological horizon as more than
one million years.

That began years of meticulous excavations, the analyses of the
archaeological finds, and - above all - the collaboration of an
international team. These years of endeavor were rewarded in 1999, when two
almost-complete human skulls were discovered. These finds throw new light
not only on human evolution, but also on the first settlement of Eurasia.

The Georgian-German Research Project Dmanisi officially began in 1991. Prior
to this, David Lordkipanidze of the Georgia State Museum had spent several
months at the Palaeolithic Research Institute of the Römisch-Germanisches
Zentralmuseum Mainz in Neuwied, Germany.

But the ball was really set rolling by Gerhard Bosinski of the
Römisch-Germanisches Zentralmuseum, who visited Georgia to take a closer
look at several sites. After studying all the Lower Paleolithic artifacts
from Dmanisi, he was convinced this was an important site from the earliest
period of human history. He proposed a joint effort between the research
institute and the Archaeological Centre of the Georgian Academy of Sciences
- a difficult undertaking for both sides, as this coincided with the
collapse of the Soviet Union.

Toward the end of that first excavation season, a mandible with full
dentition from a 20- to 25-year-old human was found. Its anatomy, such as
the robust, narrow jawbone and absence of a chin, showed that it belonged to
an early human. The mandible rekindled discussion of the hominid migration
out of Africa, but it was not conclusive.

We spent the next five years excavating and interpreting the upper levels of
the site, where the bulk of the stone artifacts were found. In 1997, we
finally returned to the lower find level where the mandible was discovered,
this time moving some 25 meters (82 feet) from the trench that had yielded
the mandible. Our excavations in this area revealed a concentration of
animal remains and, under these, a human metatarsus (a foot bone).

The large-scale excavation clearly showed the lower levels were far more
complex geologically, with tunnel-like formations formed by water. The level
was capped and the erosion ceased when a calcite crust formed and sealed the
site.

The age of our find horizon has, however, been quite accurately assessed.
Our colleagues Paul v. d. Bogaard and Carl C. Swisher III agree that the
basalt underlying the horizon dates to about 1.85 million years ago. This is
based on the argon-40/argon-39 dating method, which utilizes the decay of
radioactive potassium-40 to argon-40 as a time-scale. Additional
paleomagnetic analyses were undertaken by Swisher, who concluded that the
intruding sediments must have been deposited around 1.75 million years ago.

The antiquity of the find was further confirmed for the more than 2,000
animal remains identified as species belonging to the "Villafranchium"
faunal complex, which includes ancestral mammoths, Etruscan rhinoceros,
giraffes, stenonid horses, gazelles, and large and small forms of
saber-toothed cats. It is typical of the period from 2 million to 1.6
million years ago.

Armed with this information, we finally began to investigate the areas close
to where the mandible had been found. Once again, we were incredibly lucky.
Even as the site was being prepared for the 1999 excavation, Gotcha Kiladze
found the first human skull. Almost the whole cranium, from the brow ridges
to the foramen magnum (where the spinal cord enters), had been preserved.

Only two meters (6.5 feet) from this fossil, Georgi Nioradze found a second,
better-preserved skull. Parts of the maxilla (the upper jaw) were recovered
with the second skull, which was surrounded by animal bones, as was the
mandible discovered in 1991.

As Abesalom Vekua was preparing the finds in the laboratory in Tiflis, he
found four teeth in the maxilla bones. The teeth were not comparable, either
in size or wear, to those in the mandible; the mandible and the second skull
do not belong to the same individual. Whether the mandible belongs to the
first skull or represents a third individual will be determined by further
analysis of all the human remains by anthropologist Leo Gabunia.

Although the study of these fossils has only just begun, most parallels can
be found in African Homo erectus forms, especially the early form described
as Homo ergaster. The age of these early Homo forms is estimated at about
1.8 to 1.5 million years, which compares well with the age of the find-level
at Dmanisi. The fact that so far only a handful of fossils described as Homo
ergaster have been found in the whole of Africa and facial bones are
preserved on only two of these finds underscores the great importance of our
discovery.

The results of the excavations at Dmanisi have shown that the first wave of
human expansion took place at an earlier date than previously thought, with
simple tools similar to "Oldowan" technology used in Africa for 750,000
years before these humans reached Dmanisi. If it was not new technology that
let humans leave Africa, perhaps it was new biology. Time will tell.

Antje Justus is a scientist in the Paleolithic Department of the
Römisch-Germanisch Zentralmuseum Mainz in Neuwied, Germany. Medea Nioradze
is head of the Department of Prehistory in the Archeological Centre of the
Georgian Academie of Science.

Copyright 2001, Archaeology Today

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