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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