PLEASE NOTE:
*
CCNet DIGEST, 18 March 1999
---------------------------
Asteroid 1999 FA, the 167th Potentially
Hazardous Asteroid, was
discovered by LINEAR on 16 March 1999.
(http://cfa-www.harvard.edu/mpec/J99/J99F08.html)
(1) COSMIC WINTER: HOW IMPACTS CAN TRIGGER ABRUPT CLIMATIC
CHANGES
C.S. Cockell*) & M.D. Stokes, CARNEGIE
INSTITUTE WASHINGTON
(2) DEEP SPACE 1 BOUND FOR ASTEROID FLYBY
FLORIDA TODAY, March 17, 1999
(3) THE BJURBOLE METEORITE
Timo Niroma <timo.niroma@tilmari.pp.fi>
(4) FOUR HUNDRED YEARS ASTRONOMY ON MERSEYSIDE
Peter D Hingley <pdh@RAS.ORG.UK>
(5) TREE-RING EVIDENCE FOR TEMPERATURE CHANGES AFTER VOLCANIC
EVENTS
R.D. DArrigo & G.C. Jacoby, LAMONT DOHERTY
EARTH OBSERV
========================
(1) COSMIC WINTER: HOW IMPACTS CAN TRIGGER ABRUPT CLIMATIC
CHANGES
C.S. Cockell*) & M.D. Stokes: Polar winter: A biological
model for
impact events and related dark/cold climatic changes. CLIMATIC
CHANGE,
1999, Vol.41, No.2, pp.151-173
*) CARNEGIE INSTITUTE WASHINGTON, DEPT PLANT BIOL, 290 PANAMA ST
STANFORD, CA, 94305
Models of the climatic perturbation caused by a large scale
extraterrestrial impact predict an injection of dust into the
stratosphere. This would cause the onset of environmental
conditions
whose two principal characteristics are a prolonged period of
darkness
and reduced global temperatures. Similar scenarios follow large
scale
volcanic eruptions, wildfires and they are predicted for a
nuclear
winter following a protracted nuclear exchange. A significant
drop in
temperature and solar insolation are also characteristics of the
polar
winter. In this paper the onset and emergence from the polar
winter is
examined as a potential biological framework for studying
immediate
biological effects following transition into and out of a
dark/cold
catastrophe. Limitations of the conceptual model, particularly
with
respect to the fact that polar organisms are well adapted to a
regular
and severe dark/cold climatic change (which the rest of the
Earth's
biota is not) are discussed. The model has implications for the
poles
as an extinction refuge during such climatic changes. Copyright
1999,
Institute for Scientific Information Inc.
==================
(2) DEEP SPACE 1 BOUND FOR ASTEROID FLYBY
From FLORIDA TODAY, March 17, 1999
http://www.flatoday.com/space/today/031799c.htm
By Robyn Suriano
CAPE CANAVERAL, Fla. - A NASA spacecraft is headed for the
closest
encounter ever with an asteroid after successfully completing a
crucial
engine firing Tuesday.
Its next stop: A July rendezvous with a space rock called 1992 KD
to
take pictures and study the remnant of the solar system's
formation.
The Deep Space 1 spacecraft was launched from Cape Canaveral in
October
on a $152 million mission to test a dozen new technologies,
including a
futuristic ion engine that runs on charged atoms.
The engine fired at 2:15 a.m. EST (0715 GMT) Tuesday, allowing
the
craft to begin to close the 90 million miles between it and the
asteroid.
"The engine came to life just as it was supposed to,"
said Marc Rayman,
the spacecraft's chief engineer and deputy mission manager at
NASA's
Jet Propulsion Laboratory in Pasadena, Calif.
Fueled by charged atoms instead of traditional chemicals such as
hydrazine, the engine overcame an early glitch and ran
successfully for
850 hours before NASA turned it off in December.
It will now have to be fired periodically through April 26 to put
Deep
Space 1 on course for the asteroid. If all goes will, it will
come
within six miles of the rock.
In addition to the engine, other new technology aboard includes a
navigation system that guides the craft without human help and a
"thinking" computer that makes decisions without input
from
controllers.
"All the experiments are going on quite well, and we are
learning a
lot," said Guy Man, an engineer on the NASA team developing
the new
technologies. "A number of (the innovations) will have a lot
of use in
the future."
NASA plans to use an ion engine to power a mission set for launch
in
2003, when a probe is to explore a comet by landing on its
surface.
Copyright 1999, Florida Today
===================
(3) THE BJURBOLE METEORITE
From Timo Niroma <timo.niroma@tilmari.pp.fi>
Dear Benny,
We recently commemorated here in Finland a rare centenary. 100
years
ago, on the 12 March 1899, a huge meteorite penetrated 1 meter of
ice
and proceeded 8 meter deep into the mud on a shallow bay near the
coast
in Bjurbole just south of the town of Porvoo, 50 km east of
Helsinki.
At the time, the event was the main news in the leading
newspapers for
almost a week and aroused much discussion because virtually
everyone
who was awake in the southern Finland had seen the light that for
a
moment made the night look like day. Besides, the roar was so
loud that
people run out onto the streets in fear and panic, not knowing
what was
happening. The amount of people reading this newspaper story was
so
great that already the next day it was identified as a meteorite.
Due
to the many eyewitnesses the meteorite was found two days later.
The event is interesting from several viewpoints. The meteorite
was
stony, but did not explode - it only fragmented. It lit up the
whole
Baltic sea area when it came in (it was 21:30 Finnish time and
deep
dark night). The time 22:30, mentioned in many books is in error,
because the report that was published in Germany in 1902 had this
typing(?) error. It was seen in Stockholm, it was seen in St.
Petersburg, it was even seen in Byelorussia.
This object was no tennis ball, the biggest fragment weighed a
little
over 80 kg, and all fragments that were found weighted 328 kg
altogether. It can thus be estimated that the meteorite weighed
over
400 kg when it hit the ground. Finnish scientists understood
immediately its great scientific value and media interest. In
fact,
the Bjurbole meteorite was the focus of attention in the Finnish
pavilion of the Paris World Exhibition which took place the
following year (1900). But only few know about this secret: the
original was never sent to Paris, but there was an exact copy of
it at
the World Exhibition. The original 80kg main body was kept and
still is
at Helsinki University.
What lesson does this event provide us? First of all we can learn
that
even a stony meteorite can survive the penetration through
the atmosphere - if it comes in the right angle. The right angle
saved
the Apollo 13 astronauts, a wrong angle killed the Russian
cosmonaut
Komarov. A "wrong" angle caused the Tunguska meteorite
to explode, a
"right" angle allowed the dinosaur-killer to be so
devastating.
A second lesson I would like to send to the US National
Transportation
Safety Board. There is growing suspicion among some interested
observers that the TWA Boeing that exploded on July 17, 1996 near
New
York, might have been hit by a meteor. One of the main arguments
against the meteor theory has been that stony meteors either
explode or
lose their cosmic speed before reaching the altitude of 4.5 km,
where
the plane had already climbed after leaving NY airport. Yet the
Bjurbole meteorite had still a speed of about 1 km/sec and came
down in
relative great pieces. After going through the CD-ROM data sent
to me
by the NTSB, I'm more than ever convinced that a meteorite
penetrated
into the central wing tank (CWT) and cause the explosion there. I
can't
find any other plausible explanation. And Bjurbole proves that
the
theory is at least possible. It could have been a
tennis-ball-size one,
one fragment of a larger meteor that detonated outside the plane.
If
extra amount of 21% Fe, 18% Si, 15% Mg, 1.2% Ca, 1-2 % Al, 2% S,
1% Ni
(the general element content of stony meteorites found in
Finland)
could be found in the structure of CWT, they would have the
cosmic
fingerprints.
A third lesson goes to the search expeditions of the December
1997
meteorite impact in Greenland. It would appear that its size and
speed
was very similar to the Bjurbole meteorite. If that's the case,
it is
most likely buried up to 10 meter deep in snow and ice. All its
traces
might have been buried by heavy winds into the snow in a few
weeks.
One really should know the place of impact within a few meters
of accuracy or would have to start searching only few days after
the
incident.
The Bjurbole meteorite did not explode - it fragmented. This
caused
a large roar when the pieces flew at supersonic speed over
Helsinki
towards Porvoo and Bjurbole. This effect reminds me of the
Sumerian
Gilgamesh epos which mentions heavenly bulls which roar before
causing havoc on earth by means of fire and flood. In the
Bjurbole
case, the actual 'damage' was due to scaring people whose
buildings in
Helsinki trembled, when the "great electronic bulb"
(indeed, Finland
was already then a forerunner in electronics, electric light was
spreading in use, as today mobile phones and internet) flew over
towards east. When the roar was heard, many thought that the
heavy
artillery in Viipuri (a frontier town between Finland and Russia,
west
of St. Petersburg) fired against this heavenly bulb (like the
heavenly bull in the Sumerian legend...).
Regards,
Timo Niroma
==================
(4) FOUR HUNDRED YEARS ASTRONOMY ON MERSEYSIDE
From Peter D Hingley <pdh@RAS.ORG.UK>
Dear Colleagues,
I am sending this message on behalf of Jeff Hall; I
hope you will
find the planned conference interesting and attractive.
Peter D Hingley
400 Years of Astronomy on Merseyside
Merseyside Maritime Museum, NMGM, Liverpool
Saturday 16th October 1999
Programme:
09.30 Registration
09.45 The Telescopes of William Lassell Jeff Hall,
University of
Liverpool.
10.10 Isaac Roberts, Philip Pennington, University of Liverpool.
10.35 Solar Eclipse Observations, Dr Eric Jones, Proudman
Oceanographic Laboratory
11.00 Coffee
11.30 The Mars Observations of Dawes and Lassell Dr Patrick
Moore
12.30 Lunch
13.40 Astronomy at Bidston Observatory Martin Suggett, NMGM
14.05 George Higgs and the Solar Spectrum Alan Bowden, NMGM
14.30 Liverpool to Leeds and Preston to Chester: The
English Corridor
of Astronomical Innovation, 1630
to the present day'. Dr Allan
Chapman, University of Oxford
15.30 Tea
15.50 The Astrophysics Research Institute, the Liverpool
Telescope and
modern Astronomy on
Merseyside Prof. Mike Bode, John Moores
University
16.50 Plenary discussion and concluding remarks
17.30 End of Conference
The cost is pounds 15 per delegate, payable in
advance, including
lunch and tea / coffee
Contacts are Phil Pennington (tel 01744 739959)
or e-mail ggastro@liverpool.ac.uk
==================
(5) TREE-RING EVIDENCE FOR TEMPERATURE CHANGES AFTER VOLCANIC
EVENTS
R.D. DArrigo & G.C. Jacoby: Northern North American tree-ring
evidence
for regional temperature changes after major volcanic events.
CLIMATIC
CHANGE, 1999, Vol.41, No.1, pp.1-15
LAMONT DOHERTY EARTH OBSERV,TREE RING LAB,ROUTE
9W,PALISADES,NY,10964
Maximum latewood density data from trees at thirteen
temperature-sensitive sites along the northern treeline of North
America are used to evaluate the spatial patterns of response to
four
known volcanic events just prior to the period of modern
observations:
in 1640, 1783, 1815 and 1835. A previously unknown event is also
postulated for 1699. This tree-ring density parameter is used
because
it shows a stronger and more consistent short-term,
temperature-related
volcanic signal than ring width. Normalized density departures
following these events vary in sign and magnitude from region to
region, with the coldest summer conditions inferred for the
Northwest
Territories in 1641, Alaska in 1783, Quebec and Labrador in 1816
and
the Northwest Territories in 1836. For these as well as other
events,
low density values are often among the most extreme on record at
their
respective locations. We suggest that these regional variations
in tree
growth reflect cooling induced by volcanism and the distribution
of
cooling influenced by atmospheric circulation patterns. Copyright
1999,
Institute for Scientific Information Inc.
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