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(meteorobs) Excerpts from "CCNet DIGEST, 9 July 1999"
------- Forwarded Message
From: Benny J Peiser <b.j.peiser@livjm.acdot uk>
To: cambridge-conference@livjm.acdot uk
Subject: CCNet DIGEST, 9 July 1999
Date: Fri, 9 Jul 1999 09:42:16 -0400 (EDT)
CCNet DIGEST, 9 July 1999
======================================
(1) GREAT BALLS OF FIRE
Joel Schiff <j.schiff@auckland.ac.nz>=20
(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
[...]
(5) IMPACTS RATES
Timo Niroma <timo.niroma@tilmari.pp.fi>=20
[...]
======================================
(1) GREAT BALLS OF FIRE
>From Joel Schiff <j.schiff@auckland.ac.nz>=20
Dear Benny,
=20
Like with most fireball events, there are a lot of spurious media=20
reports that are bandied about and this recent New Zealand event is no =
exception. Speaking to the media over the telephone is an especially=20
dangerous activity. When I told a New Zealand Herald reporter that=20
since the object had detonated in the atmosphere, if people were to=20
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,=20
a matter I certainly would not have speculated on. To a reporter these=20
are incidental matters, and perhaps that is why they are not=20
scientists.
There were also reports that fragments came down over Napier which is=20
over on the East coast (North Island), but the trajectory data so far=20
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.=20
Further eyewitness reports are being coordinated by Dr Ian Griffin of
the Auckland Observatory in order to refine the trajectory.=20
So far there has not been one fragment recovered from this event=20
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=3D10070]
Friday, July 9, 1999
Observatory on trail of fiery space rock
By Philip English=20
The Auckland Observatory is confident of plotting the path of the=20
meteorite that blazed over central New Zealand on Wednesday.=20
A dealer in New York offered $US25,000 ($47,465) for its remains=20
yesterday. =20
Staff of the observatory at One Tree Hill were on the job at 4 am,=20
collating observations of the meteorite's course in a tracking exercise =
that could take several days.=20
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,=20
perhaps half in the sea and half on the land.=20
"It is a long and drawn-out process but we are slowly working it =
through."=20
Dr Griffin said observers were being questioned to define the area more =
specifically for scientific purposes.=20
The observatory had no clues to how big the meteorite was.=20
As it travelled through space, it could have been anything up to the=20
size of a chair.=20
Coming through the atmosphere at 60km to 80km above Earth, it would
have broken into fragments, perhaps too small to see on the ground=20
after being consumed in the fireball.=20
Depending on the geography of the land, there could be a chance of=20
finding a fragment, said Dr Griffin.=20
"If there was a big enough crater, you might see it."=20
Institute of Geological and Nuclear Sciences seismographs picked up the =
boom of the meteorite as it crashed through the atmosphere, evidence=20
likely to be used by the observatory in the tracking exercise.=20
The editor of Meteorite magazine, Dr Joel Schiff, of the University of=20
Auckland maths department, was inundated with calls from people=20
believing they had parts of the meteorite or earlier meteorites.=20
A dealer he knew in New York had offered $US25,000 for the meteorite.=20
"He has put this money up front. I think he is serious."=20
A truck driver in Hawkes Bay whose windscreen was cracked by something=20
when no other traffic was around produced a rock the size of a 5c=20
piece.=20
"It looked like a piece of road metal to me," said Dr Schiff.=20
"It had some black stuff on it which instead of being fusion crust=20
looked like tar."=20
=A9 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=92s Core=20
By Matthew Fordahl
The Associated Press
L O S A N G E L E S, July 9 =97 A spacecraft named Deep Impact will =
fire a 1,100-pound copper bullet at the nucleus of a comet, blasting=20
out a crater the size of a football field and as deep as a seven-story=20
building.
The radical $240 million mission, approved Wednesday by NASA =20
administrators, may sound more like fiction than science, but its=20
primary purpose will be to study the makeup of comets.=20
It=92s 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.=20
The name was selected prior to the movie,=94 said James Graf, Deep=20
Impact=92s project manager at NASA=92s Jet Propulsion Laboratory in=20
Pasadena, Calif. =93It wasn=92t inspired by it.=20
Studying the Inside=20
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=20
the spacecraft and hit the comet at 22,300 mph.=20
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=20
will eventually zoom off into space.=20
Comets are believed to be remnants from the early days of the solar=20
system, and several missions are planned to observe them close-up. Deep =
Impact=92s projectile, however, will be the first to crash into one. =20
Deep Impact will allow scientists to study the inside of a comet by=20
observing the debris ejected from the crater. =93It can give us an=20
understanding of what the solar system looked like during its=20
formation, and what contributions comets may have made to our life here =
on Earth,=94 Graf said.=20
Visible from Earth=20
The impact should be visible from Earth =97 83 million miles away =97 =
with=20
the aid of a telescope. The mission poses no threat to Earth, Graf=20
said. The impact crater will be small compared with the overall size
of the comet=92s nucleus.=20
NASA=92s approval of Deep Impact was made less than two weeks after the =
space agency pulled the plug on another mission to the same comet.=20
Space Technology 4/Champollion would have landed on Tempel 1 and=20
drilled beneath the surface.=20
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.=20
Copyright 1999 The Associated Press.=20
======================================
(5) IMPACTS RATES
>From Timo Niroma <timo.niroma@tilmari.pp.fi>=20
=20
Dear Benny,
Dear Michael,
=20
Michael Paine wrote that a Canadian webpage did not contain any=20
craters of a size larger than some meters during the last 50,000=20
years. Here is a list of the last 7,000 years of craters exceeding=20
50m. Theoretically, the list cannot be complete, given that a new=20
crater is found every few years even in this category. Practically=20
the list can't be complete because there are many craters whose age=20
has not yet been determined. And last but not least, my list was=20
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=20
changed during the period I looked at it.
=20
So the list of craters dating from the last 7000 years is as follows:
=20
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=20
greatest 4.5 km=20
Kaalijarvi (Estonia) 4000BP or 2000BC 110m
Wabar (Saudi-Arabia) most probably AD, 100m
=20
We can see that during the late Holocene the Rio Cuarto crater(s) are=20
by far the greatest (known). It may be one of the causative agents to=20
the happenings in 2000-2500 BC.
=20
Regards,
Timo Niroma
=20
PS. Look at the great heap 5000-4000 years ago.
======================================
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