CCNet DIGEST, 24 August 1998

    Torben Risbo <>

    Duncan Steel <>

    BBC Online Network

    Jonathan TATE <>

    Mike Baillie <>

    Andrew Yee <>

    Rolf Sinclair/NSF Physics Division <>


From Torben Risbo <>

Dear Benny Peiser

Following is a contribution for the CCNet. This is some genuine
stuff for consideration on the Greenland event. For further
information in the future contact the sources given below.

T. Risbo


The expedition to the target area on the Greenland ice sheet border
zone near Frederikshaab Isblink returned to Copenhagen on August 19
after having spent 4 weeks searching for the remnants from the bright
bolide observed over Southern Greenland in the early morning of
December 9 1997.

The task for the search was divided into two parts of equal weight:

1. Search for fine grained remnants in the snow cover from the last  
2. Visual search for macroscopic remnants in the fall area.

The fall area was determined by analysis of the Nuuk video recording
of the event and about 10 usefull visual observations from people
living in the towns of Nuuk, Fiskenaesset, Pamiut, Qaqortoq and
Narsarsuaq, supplemented by observations from trawlers operating in
the waters East, West and South of Greenland. Observations from
satellites supported the findings. Analysis of the video was done by
Holger Pedersen and Torben Risbo, Niels Bohr Institute AFG,
University of Copenhagen, the solution for the trajectory was
obtained in collaboration with Zdenek Ceplecha, Chech Academy of
Sciences. Eye witness reports were obtained by H. Pedersen on his 3
week travel to Greenland in January. The sighting of the Nuuk video
was documented also. The solution for the trajectory pointed to an
incoming track from the West at an inclination of approx. 35 degrees
to the horizon. The target area was initially given by a circle with
a diameter of 8 km centered on 62.39 N 49.07 W located in the border
zone of the ice sheet.
An precursor expedition in the target area was conducted by T. Risbo,
H. Pedersen and Kim Pedersen, Kangerlussuaq and a TV crew from Radio
Denmark with helicopter support from Greenland Air. This expedition
supplied an overview of the conditions on the ice to be met by the
main expedition to be launched in July. But most important a number
of snow samples were recovered for quick analysis for possible
microscopic fall out be expected from the an explosive terminal phase
of the meteorite due to its unusual large velocity.

40 snow samples of 2-3 kg were recovered representing the fall out
from the last winters snow. The samples subjected to a preliminary
analysis by T. Risbo at the Copenhagen University Arctic Station,
Qeqertarsuaq. The analysis suggested that some coloured mineral
grains of submillimeter size may be have been deposited in the snow
following the Greenland event. This was based on their glassy
appearance, likely of beeing fragments from an explosion. Some grains
have melted surfaces and even stumps from which glassy threds have
been separated by melting. Colours were bright red, blue and brown.
The distribution of this population over the target area was
different from the obvious geological material which have been blown
into the ice surface from nearby nunataks and the surrounding rocky
landscape. Atmospheric transportation of vulcanic glasses to the area
is excluded due to the size of the grains.

The findings of the main expedition support this view. Aprox. 200
snow samples have been collected each containing 10 kg of snow. In
addition a "production platform" was put up on a site well away from
land. This consisted of a long black plastic sheet and it delivered 1
ton of melt water through a filter. The preliminary microscopic
inspections in the field of these samples confirm the early findings of
the precursor expedition of June.

Analysis of this material is about to be organized and is to be taken
care of by the Geological Museum of Copenhagen University in close
collaboration with the Geophysical Department of Niels Bohr Institute
AFG. No statements on the possible meteoritic origin of the material
are possible at the moment. 

The second task of the expediton did not result in collecting any
macroscopic remnants. The search area was entended to the north and
some 800 km**2 of ice surface have been surveyed from low level
helicopter flights. Small selected areas were covered by the menbers
on foot. No large search and coverage on foot was possible due to the
very heavy crevassed ice surface. It is very difficult to assess the
probability of finding a fragments of a given size. Very big
fragments like house sized objects are not present. Golf ball sized
objects cannot be excluded.

As a comparison the Vaca Muerte meteorite fall in the Atacama Desert
of Chile was searched and collected by one of us (H. Pedersen). The
fall area was represented by an ellipse of area 12 km**2 and 130
pieces representing some tons of material were collected in 120 field
days in a terrain very easy to access and cross by a car.
The trajectory is under refinement following reanalysis of the video
frames now separated into half frames. The atmospheric intrance
velocity is constrained by analysis of the Nuuk video sequence. The
full light phenomenon of the bolide is contained in 100 video frames
representing 4 seconds of real time. The video system is PAL running
at 25 frames per second (50 half frames interlaced). Many visual eye
witnesses confirm that the light phenomenon was over within very few
seconds. Satellite data are going to be incorporated into the
trajectory solution and should also confirm the fastness of the
phenomenon. No final solution for the trajectory is available at the
moment. Evidence points to an entrance velocity in excess of 50
km/sec. A simple pedestrian estimate based on the  duration of the
light and the geometry of the track also supports such a number.
The name of Kangilia is coined for the Greenland meteorite event in
case that remnants are veryfied. Nunata Kangilia is the piece of
solid land closest to the target area and given a name on the map.
"Nunatak" is a land surrounded by the ice, "kangilia" means most
eastward of most remote. The chairman of the Greenland Home Rule mr.
Jonathan Motzfeldt suggested the name upon inspection of the 
beautifully coloured microscopic possible remnants at the Arctic
Station, Qeqertarsuaq.
Information on analysis of video and the trajectory:

Holger Pedersen, Niels Bohr Inst:
Torben Risbo          -         :

Information  on analysis of samples.
Torben Risbo, Niels Bohr Inst.  :
Asger Ken Pedersen: Geolog. Museum

Information on the Greenland event general: (Holger Pedersen)

Some pictures of "glassy" grains from the precursor expedition:  (Denmark Radio-
online) (CNN-

Information on the field work general:

Torben Risbo
Coordinator of the Greenland Meteorite Search &
Member of Expedition Steering Committee.
Niels Bohr Institute AFG, Geophysical Department,
Juliane Maries Vej 30, DK 2100 Copenhagen O, Denmark +45 35320585, +45 35320602 (sekr.)


From Duncan Steel <>

Dear Benny,

Regarding the 'interstellar meteorite lands in Greenland' story:

>Calculations based on the video frames of the meteorite's descent,
>which lit up the night sky over Greenland on Dec. 9, put its velocity
>at 35 miles per second, or one and a half times the maximum speed of
>any known meteorite in our solar system, Christensen said.

This is nonsense. 35 miles per second is equivalent to about 56 km
per second. The limiting speed is actually about 74 km per second.
This is easily calculated as follows.

At any heliocentric distance r an object with semi-major axis a has a
speed (v) given by

v^2 = (GM/1 AU) ((2/r) - (1/a))

(GM/1 AU) is about 29.8 km/sec; the Earth's speed various between
about 29.3 km/sec (in early July) to 30.3 km/sec (in early January)
because for our planet r varies between 1.0167 and 0.9833 AU

The highest value of a which is possible for an orbit bound to the Sun
(i.e., a parabolic orbit at the limit, eccentricity e=1) results from
having a ==>> infinity, thus 1/a = 0.  Thus the maximum speed is
root(2) times the terrestrial speed.  Doing the sums when the Earth
is at perihelion (0.9833 AU), for an object with inclination 180
degrees and also having q=0.9833, it meets us head-on.  Thus the
relative speed would be:

v_rel = (1 + root(2)) * 30.3  = 73.15 km/sec

The actual impact speed (say, the speed at h=100 km before any
appreciable atmospheric deceleration has occurred) is the above v_rel
added in quadrature (sum the squares and take the square root) with
the terrestrial escape speed of about 11 km/sec, the answer being
close to 74 km/sec.

On the other hand, it is also possible for hypothetical objects from
interstellar space to meet the Earth at speeds WELL BELOW the above:
it all depends upon their radiant (e.g., an object with i = 0 degrees
but q=0.9833 would catch the Earth up from behind, thus having
v_rel = (root(2) - 1) * 30.3 km/sec

However, if all one has to go on is a speed, then 74 km/sec is the

Some useful background on this is given by, for example, Marsden &
Steel in the 'Hazards Due to Comets and Asteroids' book (ed. T.
Gehrels), and also the paper by myself you cited in a CCNet posting
last week:

D.I. Steel, 'Distributions and moments of asteroid and comet impact
speeds upon the Earth and Mars,' Planetary & Space Science, 46,
473-478 (1998).

or in:

D.I. Steel, 'Collisions in the solar system -V. Terrestrial impact
probabilities for parabolic comets,' Monthly Notices of the Royal
Astronomical Society, 264, 813-817 (1993).

The problem of identifying interstellar meteoroids is discussed in
the NATURE paper by Taylor, Baggaley & Steel I cited before, plus
(more extensively) in the papers referenced therein.

(Lots of other people have published on these topics over the years, 
but of course I have my own papers to hand listed in my CV)

In short: the media reports seem daft, perhaps based upon comments by
people unfamiliar with the relatively simple physics involved (as

Duncan Steel


From the BBC Online Network

Meteors and comets have been worshipped for centuries

In Turkmenistan, the fall of two meteorites within a month is being
seen as a holy happening, causing a flurry of interest in the small
desert state.

The latest fell on a village just over 100km from the site of the
first, reportedly crashing through the roof of a house.

News of the second meteorite, which fell at the end of July, is only
just emerging as villagers refused to report the incident.

They believed the small object from the skies, weighing about a
kilogramme, to have religious significance. 

It has been taken to the capital, Ashkhabad, for study by scientists. 

The second "holy stone" follows the fall of one of the largest
individual meteorites in history - weighing 820 kilogrammes - near a
spiritual site in eastern Turkmenistan.

The BBC Central Asia Correspondent, Louise Hidalgo, says Turkmens 
hailed its arrival near the old capital of the ancient state of Khorezm
as an auspicious event as it coincided with the sixth anniversary of
the election of their leader, President Niyazov.

Witnesses who saw the meteorite fall spoke of a bright light and
tremendous noise, and earth tremors which were felt up to a 100km away..

And the meteorite, now on show in a museum, is to be named "leader of
the Turkmens" in honour of the president.

Copyright 1998, BBC


From Jonathan TATE <>

I have finally been to see what is probably the most harangued movie in
scientific history!  Having read the postings on various astronomically
orientated news groups I arrived at the cinema ready to be wildly
disappointed, and annoyed by the lack of accuracy that I had read so
much about. What I am about to say will probably condemn me as a
heretic, but what the hell!

Well, a science lesson it is certainly not. There are countless
"nit-picks", some truly "nit", and some actually elephantine!  But the
film was made to entertain, not to educate.  So, did it entertain?  You
bet! As a good rip-roaring adventure story it is excellent; there is
plenty of daring-do, a nice, but not overpowering love interest and
masses of great special effects. The plot doesn’t take a genius to
predict, but the same applies to most films these days.

Many people have been disappointed by the lack of scientific accuracy,
indeed some have been positively "anoraky" in their criticism. There is
no doubt that more accuracy could have been incorporated, but it
wouldn’t have taken much to introduce a "yawn factor", killing the film
stone dead. The general public want to be entertained, not educated in
a cinema. After seeing "Armageddon" most will come away with a pink
fuzzy feeling, and an increased awareness of the impact threat. They
might not know as much as some, but they will know that the hazard
exists. That is half of the battle won.

Now, it would be very easy to pontificate about the scientific
gaffs,(aren’t I clever - I know more than you), and become an instant
bore.  Let’s face it, most science IS boring to the uninitiated, so it
would be a huge error of judgement to spoil one of the few media events
dealing with the impact threat for the sake of some esoteric quibbles. 
If "Armageddon" raises the public perception of the impact threat, and
generates some interest then the errors can be forgiven - never let the
truth get in the way of a good story. I am a professional soldier, but
if I picked holes in every war film that I saw I would truly be Mr
Boring (my wife is convinced that this has already happened). The same
applies to most occupations - what about "Casualty", "ER", "The Bill"
or "Frost"?  You don’t see other professions getting heated about
technical errors in films or TV programmes, they just revel in, and
take advantage of the publicity.

"Deep Impact" and "Armageddon" are very different films, but both
portray the threat from asteroidal or cometary impacts in a fairly
responsible and tolerably accurate fashion. We should concentrate on
using the positive aspects of both for our purposes, and trying to
avoid becoming terminally boring about their shortcomings.

Bottom line? Go and see "Armageddon" with a big pack of popcorn, and
prepare for a roller-coaster ride! Watch out for the Paris bit -
tee-hee! (Apologies to our French members, but remember the Battle of

Jay Tate


From Mike Baillie <>

By a quirk of fate I happened to have the Feb 13 1996 copy of the
Weekly World News which carried the "Hubble Finds Doomsday Comet (and
it's speeding towards Earth)" story. Interestingly the comet was the
"size of Europe" even in 1996 but otherwise inflation has clicked in. 
Then it was $2.6 billion emergency expenditure, now it's $4 billion;
then it was an estiated 2 billion dead, now it's 3 billion.  However,
the expert Dr Clemson is almost the same, in 1996 he was Dr Cremson. 
The big change, consistent with reality, is that in 1996 they were
confidently working towards shooting it down with a NASA rocket adapted
to carry a nuclear payload ("to vaporize the comet while it is still
safely out in space"), now they're basically saying that won't work,
but we might as well try anyway, as nothing is to be lost. So, even in
the lunatic fringe, the message is moving in the right direction. They
are recognising that we can't do anything about a directly approaching
comet, and the casualty figure has risen to one half of the real
figure. It looks as though we still have to get the message over that
size is important.

Mike Baillie
Palaeoecology Centre
School of Geosciences
Queen's University, Belfast


From Andrew Yee <>

Public Relations
University of Cincinnati

Contact: Chris Curran
(513) 556-1806 (O)

August 20, 1998

UC Geologist Finds Evidence That Mass Extinctions Are Not Unique in
Affecting Global Diversity Trends

Cincinnati -- The dramatic effects of the mass extinctions recorded in
Earth's geologic record have led many geologists to view them as a
distinct class of events -- so powerful that they swamp out normal
evolutionary processes. Others have argued the opposite, that over
geologic time, mass extinctions have had little effect on global
diversity trends.

University of Cincinnati geologist Arnold Miller argues in a review
paper in the August 21 issue of Science that the truth is somewhere in
the middle of those extreme views. Miller's evaluation of global marine
diversity patterns through the Phanerozoic, in light of recent
research, indicates that mass extinctions are simply the most globally
extensive of a continuum of abrupt transitions that combine to affect
overall global diversity. The Phanerozoic covers the pasts 540 million

That view is in contrast to Stephen Jay Gould and others who have
viewed mass extinctions as an over-arching tier of evolutionary
processes, distinctly different than the processes which occur in the
intervening time periods.

"While I agree that mass extinctions are the largest and most important
of a class of 'catastrophes,' I would argue that they are not
fundamentally different as an evolutionary mechanism from what causes
diversity change in the intervals between them," said Miller. "The
so-called background intervals are also built of catastrophes that are
more local or regional in scope, but can have the same profound effect
on a local biota that a mass extinction has on a global biota."

As an example of an abrupt regional change, Miller discusses the
diversification of a group of organisms known as "biological
bulldozers," which dig into deposited sediments to find food. The
geologic record includes cases where the bulldozers replaced another
group known as ISOSS (immobile suspension feeders on soft substrates).
Previously, researchers believed the biological bulldozers out-competed
the ISOSS organisms. Miller suggests an alternative explanation.

"Many deposit-feeders favor muddy, nutrient-rich sediments as a
substrate to occupy. Just such sediments were provided during key
intervals as a consequence of eroding areas uplifted during
mountain-building. Quite apart from the action of the bulldozers, many
of the incumbent immobile types would not have liked this kind of
habitat. So I am suggesting, as an alternative to the above
'competitive' scenario, that the transition happened because of major,
physical changes to habitats."

In fact, previous research reported by Miller and others on the
Ordovician Period showed that diversification of certain groups was
favored in areas where active mountain-building took place.

As for those who argue that mass extinctions are actually minor
contributors to global diversity patterns, Miller has used his database
of Ordovician fossil occurrences to demonstrate that regional and local
bursts of diversification occur at different times around the world.
Over time, the bursts add up to present what Miller believes is a
misleading picture of diversification trends a smooth, gradual change
over geologic time.

"The global pattern does not match any localized pattern," said Miller.
"The global diversity trend is misleading for what it says about the
rates of transition and perhaps even for what causes them."

Miller's research is supported by NASA's Program on Exobiology.


From Rolf Sinclair/NSF Physics Division <>

Dear Colleague:

With this note, we wish to inform you of the up-coming Second International
Conference on
to be held 7-14 January 1999 on The Mediterranean Island of Malta
[ Website ]

The sky makes up half of mankind's world; the Earth around us makes up
the other half. This meeting will explore mankind's fascination with
the astronomical phenomena that  define the sky -- the lights in the
sky, by day and by night -- which have been a strong  and often
dominant element in human life and culture. Scholars from a variety of 
disciplines (including Anthropology, Archaeology, Art, Classics,
History and Prehistory, Mythology and Folklore, Philosophy, the
Physical Sciences, and Religion) will attend "INSAP II"  to discuss the
impacts astronomical phenomena have had on mankind.  Presentations by 
attendees will be grouped under four main topics: Literature; Art; Myth
and Religion;  History and Prehistory.

Invited presentations will include (tentatively):

Albert Boime (Art History, Univ. of California-Los Angeles): "The
Artistic Portrayal of Starry Skies";
Madanjeet Singh (UNESCO, Paris): "The Sun, Symbol of Power and Life";
John David Mooney (artist, Chicago): "Chicago: Vega and Horizon Astronomy"
Charles Camilleri (composer, Univ. of Malta): "Space and Music
Inspiration" (world premier).

Other presentations submitted include:

Imad A. Ahmad (Bethesda, Maryland): "Astronomical Inspiration in the
Rubayyat of Umar Khayyam"
Mats Bjorkin (Stockholm Univ.): "Shooting Stars: Cinema and
Astronomical Imagination"
Alberto Cappi (Osservatorio Astronomico di Bologna): "The Cosmology of
Edgar Allen Poe"
Sharon Daniel (Univ. of California-Santa Cruz): "Computer-Based
Interactive Art"
Harald Gropp (Univ. Heidelberg): "The Nearly-Forgotten Calendar of Coligny"
John Hatch (Univ. of Western Ontario): "Models of the Universe and their
Role in the Development of 'Abstract' Art"
Christopher Impey (Univ. of Arizona): "Reacting to the Size and Shape of
the Universe"
Daniel Oberti (Sculptor, Sebastopol, California): "Sundials and Moon
Adrian Otoiu (University of the North, Romania): "When the Stars
Go Astray"
Daniel Varisco (Hofstra Univ.): "The Mystical Symbolism of the Lunar
Stations in Medieval Islamic Cosmology"
Skawomira Zeranska-Kominek (Univ. of Warsaw): "Possession and
Inspiration: The Musician Between Day and Night"

The Conference will allow the attendees to address the many and
variegated cultural impacts of the perceptions of the day and night
skies, providing a mechanism for a  broad group of artists, historians,
philosophers, and scientists to meet, compare notes,  and have the
chance to ask those questions of each other about their work which may
have  been lying fallow for decades. Attendance will be by invitation
from among those applying. Full information on the Conference and an
application form can be obtained by contacting  the Organizing
Committee, or from our Website
( Although the nominal
deadline has passed, the selection committee will be happy to receive
applications while they are deliberating over those on-hand. The
absolute close-off date will be, however, 25 August 1998; even with the
use of Email, the committee needs a little time to devise a program out
of the pile of applications!

This Conference is the second to be held on this general theme. Details
of the first meeting (held at Castel Gandolfo, Vatican State, 27 June-2
July 1994), and the  publication references that include many of the
papers presented there, may be found at .

This Conference is sponsored by the OTS Foundation and the Vatican

Please circulate or post this announcement.

The Organizing Committee:
Professor Raymond E. White, Steward Observatory, University of Arizona
(Chair) (
Rev. George V. Coyne, S. J., The Vatican Observatory: (
Dr. Rolf M. Sinclair, National Science Foundation, Arlington VA
Prof. Frank Ventura, Malta (

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