PLEASE NOTE:


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CCNet DIGEST, 9 July 1999
--------------------------

     MALCOLM MILLER'S THOUGHT FOR THE DAY
    
     DIRTY SNOWBALL?

     Halley's Comet. I'm one of those who've seen it.
     Almost a generation's passed since it was here,
     A modest cosmic windsock, quite hard to see
     Against the light of even this small city's glare,
     And almost universally decried -  'is that all?'
     I watched it for a year, quite unspectacular,
     But bringer of a special thrill. He saw it, Edmund,
     And before him how many millions saw it
     Each three quarter century in star-dark skies?
     I wonder who of those alive this day
     Will see it back again in twenty sixty,
     Or if they'll even care about what Halley guessed?

     Malcolm Miller
     <stellar2@actonline.com.au>


(1) GREAT BALLS OF FIRE
    Joel Schiff <j.schiff@auckland.ac.nz>

(2) OBSERVATORY ON TRAIL OF FIERY SPACE ROCK
    New Zealand Herald, 9 July 1999

(3) PREPARING FOR DEEP IMPACT
    ABC NEWS ONLINE, 9 July 1999

(4) WHAT CAUSED THE DESERTIFICATION OF THE SAHARA
    Doug J Keenan <dj.keenan@virgin.net>

(5) IMPACTS RATES
    Timo Niroma <timo.niroma@tilmari.pp.fi>

(6) DNA ON THE ROCKS
    INSCiGHT, 8 July

=================
(1) GREAT BALLS OF FIRE

From Joel Schiff <j.schiff@auckland.ac.nz>

Dear Benny,

Like with most fireball events, there are a lot of spurious media
reports that are bandied about and this recent New Zealand event is no 
exception. Speaking to the media over the telephone is an especially
dangerous activity. When I told a New Zealand Herald reporter that
since the object had detonated in the atmosphere, if people were to
search to ground for any meteorite fragments they could be pea to apple
size, but instead, it came out that the object in space was this size,
a matter I certainly would not have speculated on. To a reporter these
are incidental matters, and perhaps that is why they are not
scientists.

There were also reports that fragments came down over Napier which is
over on the East coast (North Island), but the trajectory data so far
points to a fall area over Taranaki on the West coast (North Island). At
the moment this area is 100 km long and half of it is out to sea.
Further eyewitness reports are being coordinated by Dr Ian Griffin of
the Auckland Observatory in order to refine the trajectory.

So far there has not been one fragment recovered from this event
although I have already seen a number of volcanic rocks, a road stone
with tar on it, etc.

Joel Schiff

===============
(2) OBSERVATORY ON TRAIL OF FIERY SPACE ROCK

From New Zealand Herald, 9 July 1999
[http://www.nzherald.co.nz/nzherald99/story.cfm?theStoryID=10070]

Friday, July 9, 1999

Observatory on trail of fiery space rock
By Philip English

The Auckland Observatory is confident of plotting the path of the
meteorite that blazed over central New Zealand on Wednesday.
A dealer in New York offered $US25,000 ($47,465) for its remains
yesterday. 

Staff of the observatory at One Tree Hill were on the job at 4 am,
collating observations of the meteorite's course in a tracking exercise
that could take several days.

By late yesterday the director of the observatory, Dr Ian Griffin, said
the impact area had been narrowed to a 100km-long strip in Taranaki,
perhaps half in the sea and half on the land.

"It is a long and drawn-out process but we are slowly working it through."

Dr Griffin said observers were being questioned to define the area more
specifically for scientific purposes.

The observatory had no clues to how big the meteorite was.

As it travelled through space, it could have been anything up to the
size of a chair.

Coming through the atmosphere at 60km to 80km above Earth, it would
have broken into fragments, perhaps too small to see on the ground
after being consumed in the fireball.

Depending on the geography of the land, there could be a chance of
finding a fragment, said Dr Griffin.

"If there was a big enough crater, you might see it."

Institute of Geological and Nuclear Sciences seismographs picked up the
boom of the meteorite as it crashed through the atmosphere, evidence
likely to be used by the observatory in the tracking exercise.

The editor of Meteorite magazine, Dr Joel Schiff, of the University of
Auckland maths department, was inundated with calls from people
believing they had parts of the meteorite or earlier meteorites.

A dealer he knew in New York had offered $US25,000 for the meteorite.

"He has put this money up front. I think he is serious."

A truck driver in Hawkes Bay whose windscreen was cracked by something
when no other traffic was around produced a rock the size of a 5c
piece.

"It looked like a piece of road metal to me," said Dr Schiff.

"It had some black stuff on it which instead of being fusion crust
looked like tar."

Copyright 1999, NZ Herald

=============
(3) PREPARING FOR DEEP IMPACT

From ABC NEWS ONLINE, 9 July 1999
http://abcnews.go.com/sections/science/DailyNews/deepimpact990709.html

PREPARING FOR DEEP IMPACT
Spacecraft to Fire 1,100-Pound Bullet at Comet’s Core

By Matthew Fordahl
The Associated Press

L O S   A N G E L E S,   July 9 — A spacecraft named Deep Impact will
fire a 1,100-pound copper bullet at the nucleus of a comet, blasting
out a crater the size of a football field and as deep as a seven-story
building.

The radical $240 million mission, approved Wednesday by NASA 
administrators, may sound more like fiction than science, but its
primary purpose will be to study the makeup of comets.

It’s a coincidence that the project has the same name as last summer’s
disaster movie Deep Impact, which was about a comet smacking Earth,
mission planners said Thursday.

“The name was selected prior to the movie,” said James Graf, Deep
Impact’s project manager at NASA’s Jet Propulsion Laboratory in
Pasadena, Calif. “It wasn’t inspired by it.

Studying the Inside

Deep Impact is scheduled to be launched in January 2004 and will arrive
at comet Tempel 1 on July 4, 2005. The projectile will separate from
the spacecraft and hit the comet at 22,300 mph.

Shortly after impact, the craft will come within 300 miles of the comet
surface and send back data and pictures of the debris and crater. It
will eventually zoom off into space.

Comets are believed to be remnants from the early days of the solar
system, and several missions are planned to observe them close-up. Deep
Impact’s projectile, however, will be the first to crash into one. 
Deep Impact will allow scientists to study the inside of a comet by
observing the debris ejected from the crater.  “It can give us an
understanding of what the solar system looked like during its
formation, and what contributions comets may have made to our life here
on Earth,” Graf said.

Visible from Earth

The impact should be visible from Earth — 83 million miles away — with
the aid of a telescope. The mission poses no threat to Earth, Graf
said. The impact crater will be small compared with the overall size
of the comet’s nucleus.

NASA’s approval of Deep Impact was made less than two weeks after the
space agency pulled the plug on another mission to the same comet.
Space Technology 4/Champollion would have landed on Tempel 1 and
drilled beneath the surface.

NASA administrators decided to favor Deep Impact because it was focused
solely on science and fit into existing budget plans, said Doug Isbell,
a NASA spokesman in Washington, D.C.

Copyright 1999 The Associated Press.
===========
(4) WHAT CAUSED THE DESERTIFICATION OF THE SAHARA

From Doug J Keenan <dj.keenan@virgin.net>

Hi Benny,

In the July 8th CCNet Digest item on the desertification of the 
Sahara, it says that copies of the original paper can be obtained
from Harvey Liefert at AGU. The paper is now available directly on
the web at the following addresses (in HTML and PDF formats,
respectively).

   http://www.agu.org/GRL/articles/1999GL900494/GL905W01.html
   http://www.agu.org/GRL/articles/1999GL900494/GL905W01.pdf

I had a look at it. The paper is not really about the 4K BP event:
the event is mentioned only briefly, and none of the main work on the
event is cited.

The paper is about the permanent shift in Saharan climate and
vegetation that occurred about 6000 years ago. The paper presents
good evidence that atmosphere-vegetation feedbacks can greatly
amplify other climate forcings. The (external) climate forcing
considered is orbitally-modulated insolation; in principal, though,
it might also be a comet, volcano, etc. (assuming other aspects of
the climate system permitted multiple equilibria).

Cheers,
Doug Keenan

============
(5) IMPACTS RATES

From Timo Niroma <timo.niroma@tilmari.pp.fi>

Dear Benny,
Dear Michael,

Michael Paine wrote that a Canadian webpage did not contain any
craters of a size larger than some meters during the last 50,000
years. Here is a list of the last 7,000 years of craters exceeding
50m. Theoretically, the list cannot be complete, given that a new
crater is found every few years even in this category. Practically
the list can't be complete because there are many craters whose age
has not yet been determined. And last but not least, my list was
compiled in 1997, so there may be later identifications to add
yo this list. Please do so, if you know of any new discovery.

I looked at the Canadian website. It was under construction, it even
changed during the period I looked at it.

So the list of craters dating from the last 7000 years is as follows:

Mache (or Macha) (Russia) 7000BP or 5000BC 300m
Henbury (Australia) 5000BP or 3000BC 157m
Boxhole (Australia) 5000BP or 3000BC 170m
Campo del Cielo (Argentina) 4000BP or 2000BC 50m
Rio Cuarto (Argentina) 4000BP or 2000BC several in a row, the
    greatest 4.5 km
Kaalijarvi (Estonia) 4000BP or 2000BC 110m
Wabar (Saudi-Arabia) most probably AD, 100m

We can see that during the late Holocene the Rio Cuarto crater(s) are
by far the greatest (known). It may be one of the causative agents to
the happenings in 2000-2500 BC.

Regards,
Timo Niroma

PS. Look at the great heap 5000-4000 years ago.

============
(6) DNA ON THE ROCKS

From INSCiGHT, 8 July
[http://www.academicpress.com/inscight/07081999/graphb.htm]

8 July 1999, 5 pm PST

DNA on the Rocks
By Lone Frank

Scientists say they have, for the first time, extracted DNA from
ancient ice core samples in northern Greenland. The success may usher
in a worldwide hunt for ancient microbes trapped in ice.

A team led by evolutionary biologist Peter Arctander of Copenhagen
University used the polymerase chain reaction (PCR) to amplify
fragments of well-characterized genes in ice cores dated to 2000 and
4000 years ago. After sequencing the recovered fragments, they compared
them to known sequences in a database and found that the ice cores held
the remains of a surprising diversity of life forms: at least 57
distinct organisms, including several types of fungi, algae, protists,
and a class of conifer, they report in the 6 July issue of Proceedings
of the National Academy of Sciences.

"No one expected such a variety of fungi to be present," says Andrea
Gargas of the University of Wisconsin, Madison, a specialist on fungal
DNA. "We have found samples trapped under glaciers that were only from
two different fungal groups," she says. "You always think of [that]
environment as a bit more sterile because it's so remote and because of
the lack of nutrients." And there's more to come, says Arctander: So
far they've only toted up the eukaryotic organisms -- those with
nuclei. The number of bacterial species, he says, should be far greater.

Previously, the study of ancient microbial life in ice cores was mostly
limited to the identification of plant pollen and spores, says
Arctander. But PCR has opened up a wealth of new possibilities.
Co-author Anders J. Hansen now plans to look at the DNA of plant
material in 6000-year-old Greenland ice, to see which plants were
available around the time the first humans are thought to have migrated
there from northern Canada. And his colleague Eske Willerslev plans to 
sample ice cores from Siberia, Canada, and Antarctica to compare
microbial life and find out how long DNA can stay intact.

DNA analysis will also enhance climate studies, says Henrik Brink
Clausen of The Niels Bohr Institute in Copenhagen. Adding biological
information to atmospheric data from ice cores, he says, "will provide
a much more accurate picture of climate and changes over time."

1999 The American Association for the Advancement of Science

[Extracted from INSCiGHT, Academic Press.]

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*

UK TASK FORCE TO STUDY ASTEROID THREAT

From Graham Richard Pointer <grp1@st-andrews.ac.uk

Dear Dr Peiser,

I saw this on the Daily Telegraph site

http://www.telegraph.co.uk:80/et?ac=000627142853006&rtmo=3qwxBHwM&atmo=F
FFFFamX&pg=/et/hupdate.html#go6

Yours sincerely,
Graham Pointer.

Task force to study Asteroid threat

THE GOVERNMENT is considering what  can be done to prevent the "serious"
risk of earth being hit by an asteroid, it emerged today.

After a meeting with Liberal Democrat MP Lembit Opik, Science Minister Lord
Sainsbury has agreed to consider putting together a group of experts to
study the threat from "near earth objects".

"It produces in most people a fairly good giggle factor and people say it's
not an issue. But it is an issue," warned Lord Sainsbury. "It is one of
those issues which has a very low probability of happening.
We are talking about something that could happen, say once every 100,000
years, so I have got to say I don't stay awake at night worrying about it,"
Lord Sainsbury told BBC Radio 5 Live's Breakfast Show.

Claiming that someone was 750 times more  likely to die in an asteroid
impact than win the lottery this weekend, Mr Opik said: "There are at least
1,500 objects which could hit us and over time something
definitely will." He suggested a network of telescopes around the world to
see if anything was heading for Earth.

Copyright 1999, the Daily Telegraph



CCCMENU CCC for 1999

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