PLEASE NOTE:
*
CCNet, 84/2000 - 6 September 2000
----------------------------------
"Whatever the proportion of the
impact hazard, though, the
discovery of 1999 XS35 does add another
consideration into the
pot. It also indicates that there are
things we have yet to
understand. [...] If 1999 XS35 were such
a comet-derived beast,
then one might imagine that, given the
way that a typical comet
(if there is such a thing) behaves, then
the solitary known object
1999 XS35 might not be the only one in
that orbit. It might have
10 or 100 siblings from earlier
disintegrations. And all of them
would have orbits passing very close by
the Earth. Thus the
physical nature of 1999 XS35 would be a
very useful thing to know.
Do we?"
-- Duncan Steel,
6 September 2000
"I believe the waves in both cases
were caused by meteor impacts
at sea. I also believe that safety
officials play down these
incidents, feeding the public any excuse
but the truth. Why?
Because we have no defense or warning
systems to deal with meteor
impacts. Our government justifies
spending billions of tax dollars
on missile defense systems, and yet a
missile attack is less of a
threat than the debris flying around in
local space. The reality
is that even if an imminent impact were
predicted, there is
nothing we could do about it."
--
Gene Floersch, Florida Today, 5 September 2000
(1) IMPACTS, NOT STORMS, BLAMED FOR MYSTERIOUS TSUNAMIS
Christian Gritzner <christian.gritzner@mailbox.tu-dresden.de>
(2) DISASTER MANAGEMENT AND NEO IMPACTS
Michael Paine <mpaine@tpgi.com.au>
(3) THE YEARS WITHOUT SUMMER: A.D. 536 AND ITS AFTERMATH
Joel D. Gunn <jdgunn@mindspring.com>
(4) EVIDENCE FOR ABRUPT CLIMATE CHANGE IN PREHISTORIC CHILE
Andrew Yee <ayee@nova.astro.utoronto.ca>
(5) LONG-PERIOD EARTH-CROSSING ASTEROIDS
Duncan Steel <D.I.Steel@salford.ac.uk>
(6) 2000 QW7 AND SPACE WAETHERING
Kelly Beatty <kbeatty@skypub.com>
(7) ASTEROID/COMET WORKSHOP AT THE ISDC 2001
Andy Smith <astrosafe@yahoo.com>
(8) MEDIA ATTENTION GOOD FOR PUBLIC EDUCATION
Daniel Spires <DSpires@wcom.net>
(9) SEARCHING FOR HISTORICAL IMPACTS IN NORTH AMERICA
Ben L. Moon <benlmoon@wans.net>
(10) AND FINALLY: FIXING THE HOLE IN THE NORTH POLE
Nando Times, 4 September 2000
===================
(1) IMPACTS, NOT STORMS, BLAMED FOR MYSTERIOUS TSUNAMIS
From Christian Gritzner <christian.gritzner@mailbox.tu-dresden.de>
Hi Benny,
here is a story about a 'meteor' splashing into the ocean and
causing 'big waves'.
http://www.floridatoday.com/news/columnists/milt/090500milt.htm
From Florida Today, 5 September 2000
Sept. 5, 2000
Meteor, not storm, blamed for big waves
By Milt Salamon
A FLORIDA TODAY column
"I'd be willing to bet that if you had the weather maps of
the
Atlantic Ocean on those days, you'd find no wave-generating storm
off Africa," wrote Gene Floersch of Melbourne Beach. He was
referring to a suggested cause of the mysterious huge waves we've
been writing about.
They suddenly invaded the beach north of Fort Lauderdale on a
clear, sunny, wind-free day in early March 1962 and frightened
onlookers. One, Mary Swanson, now an Indialantic resident, said
she'd moved to Arizona soon after the event and never knew what
caused it.
She hoped our readers could tell her. We've been reporting their
responses, which mostly blame the waves on far-off storms, as
distant as Africa.
Gene contrasted the nature of the waves described by Mary to the
storm-generated ocean swells that "every good surfer
knows" - like
the ones he surfed that year in Daytona Beach ("no mystery
waves
there," he said).
"Any storm powerful enough to send waves clear across the
Atlantic
would have affected the whole Florida coastline . . . and would
also have first devastated the Bahama Islands," Gene said.
However, he added, "there was a more recent incident of
'mystery
waves' that did hit Daytona Beach on an evening when the sea was
flat, swamping beach-parked cars and scaring a lot of tourists at
the boardwalk. Officials claimed these waves were generated by a
'sand slide' out on the continental shelf, but there was no
geological activity registered by seismic sensors along the east
coast.
"Some weeks later a local news channel ran a report about
the
operators of a shrimp boat off the coast witnessing a huge splash
in the distance and then almost being swamped by massive swells.
"I believe the waves in both cases were caused by meteor
impacts
at sea. I also believe that safety officials play down these
incidents, feeding the public any excuse but the truth.
"Why? Because we have no defense or warning systems to deal
with
meteor impacts. Our government justifies spending billions of tax
dollars on missile defense systems, and yet a missile attack is
less of a threat than the debris flying around in local space.
The
reality is that even if an imminent impact were predicted, there
is nothing we could do about it."
Copyright 2000, Florida Today
==================
(2) DISASTER MANAGEMENT AND NEO IMPACTS
From Michael Paine <mpaine@tpgi.com.au>
Dear Benny,
A recent issue of Space Policy (Vol 16 (2000) 213-222) includes a
paper
by Victoria Garshnek, David Morrison and Frederick Burkle 'The
mitigation, management and survivability of asteroid/comet impact
with
Earth'. It covers the threat and consequences of a NEO impact and
the
disaster management implications. The Journal homepage is
http://www.elsevier/locate/spacepol.
So far I have not found an online copy of the paper.
I was pleased to see the analysis that I did for impact-tsunami
risk
referenced (and used) in the paper. The paper refers to my web
page
http://www1.tpgi.com.au/users/tps-seti/spacegd7.html
but the analysis is
also contained in the paper I wrote for The Science of Tsunami
Hazards
(vol 17 (3) Dec 2000). That issue contains a couple of
NEO-related
papers - a 9.4Mb PDF copy can be downloaded from
http://epubs.lanl.gov/tsunami/
(abstracts of all issues are at
http://www.ccalmr.ogi.edu/STH/abstracts.html
)
I have not got around to comparing the fatality estimates on my
tsunami
webpage (first prepared in 1998) with those generated from the
computer
simulation associated with your AAAS presentation this year (John
Lewis's software tends to generate more fatalities from smaller,
but
unusual, objects than those from 'typical' impacts). In any case,
there
is a high degree of uncertainty about the estimates but the
conclusion
of Garshnek and co-authors is not affected: 'An impact disaster
may be
many orders of magnitude greater than any disaster the human
species
has ever experienced'.
regards
Michael Paine
==================
(3) THE YEARS WITHOUT SUMMER: A.D. 536 AND ITS AFTERMATH
From Joel D. Gunn <jdgunn@mindspring.com>
Dear Benny,
I have been following Ed Grondine's studies of impacts in the
Southeastern United States and look forward to the rest of his
installments. On a related topic, I am happy to announce to those
following Ed Grondine's discussion of impacts in the Southeastern
United States, and also to the many CCNET readers who have
inquired
about it, that THE YEARS WITHOUT SUMMER: A.D. 536 AND ITS
AFTERMATH is
currently in print and should be available momentarily. The book
is
composed of 16 chapters about half of which are by Southeastern
United
States archaeologists. These chapters are joined by a worldwide
span of
regional specialists interested the the problem of a coordinated
global
scale climate event and how it shows up in the historical and
archaeological records. The following is a note from David
Davidson of
Archaeopress on the status of the volume.
NOTE FROM DAVID DAVIDSON OF ARCHAEOPRESS
The book will come out in the course of August and will be
available
for purchase immediately.
It will be BAR International Series 872, ISBN 1 84171 074
1. We don't
yet have the price, but shall sent that to you as soon as we can.
The distributors are Hadrian Books Ltd, 122 Banbury Road, Oxford
OX2 7BP,
Tel/fax +44 1865 316916. They take Visa, Mastercard and
Access.
Unfortunately they do not run a web site, but a printed catalogue
goes
out three times a year. The details of the book will soon appear
on our
Archaeopress web site. The book will also be available from Oxbow
Books
<oxbowbooks.com> / David Brown Books Co in North America
<david.brown.bk.co@pop.snet.net
> and they will soon get the details into
their catalogues. Of course in any event the book can be ordered
at
'any good bookshop'.
A RESUME OF THE CONTENT AND SOME OF THE ISSUES
ADDRESSED IN THE BOOK
THE YEARS WITHOUT SUMMER: A.D. 536 AND ITS AFTERMATH
Gunn, Joel D. (editor and contributor) (2000) The Years Without
Summer:
A.D. 536 and Its Aftermath. Archaeopress, Oxford.
The Years Without Summer contains examples from around the world
of
personal and cultural reactions to the events surrounding A.D.
536 and
subsequent centuries. Authors of 16 chapters address the issue of
cultural consequences of global change in the past by examining
evidence from Eurasia, Africa and North America. Given the
growing
attention that rapid climate change and its impact on societies
has
justly demanded in recent years, the question has been raised
among
students of prehistory and history as to what they might
contribute to
understanding such events.
Archaeologists have studied the impact of long
term changes in the
environment on humans intensively since the middle twentieth
century,
and at least incidentally since the 1700s. Historians such as
Leroy
Lauderie, and geographers such as Ried Bryson, along with many
others,
have likewise extended understanding of changing environments on
the
human condition.
In recent decades a new scale of perception
has been added to the
mix of growing understanding of the multicausal matrix of human
activity. The geographic scale of human actions has exploded from
purely local concerns to a world-wide perspective captured in the
term
"earth system." The earth system, thanks in part to the
advent of space
photography and sophisticated models of geophysical, atmospheric,
biological, and cultural systems, has come to be understood as a
wholly
interactive entity. By processes that have yet to be understood
in
their entirety, the earth system maintains itself through
biological
and physical processes in a space environment that would
otherwise be
hostile to carbon-based life forms. An important questions in
this new
context is how established disciplines fashioned to understand
the
human condition in a compartmentalized context, should
accommodate
themselves to the realities of a fully integrated earth system.
In a
practical perspective, how should they contribute to the
understanding
of that system in a world that may be headed for extreme
environmental
changes precipitated by human activities?
Of course, the first question is, what do
students of human history
have to contribute that cannot be gained by other means.
Said most
simply, their contribution would seem to lie in interpreting past
centuries when the world was hotter or cooler than any years
observed
in this century by instrumental means. What measures did humans
from
different geographies and cultural backgrounds take to adapt to
those
conditions?
In The Years Without Summer we take part of
this problem to task.
The part is colder global conditions, a time when the world was
largely
cooler than it is now. During the first millenium A.D., there are
no
instrumental observations of global temperatures. There is,
however,
plenty of evidence of extreme conditions. The Nile froze in A.D.
826.
Crops were extremely poor in Europe during the years A.D.
760-840,
apparently due to cold winters. According the best measures of
environment through this period, however, the most extreme period
was
in the decades following A.D. 536.
These measures are tree rings, which have been
studied intensively
in Europe for the last 30 years, and in fact around the
world. The
European tree rings imply the coldest conditions in the last
6,000
years in the decade following A.D. 536. We take the global scale
of the
A.D. 536 event as an opportunity to tune in on the existing
capabilities of historians and archaeologists in a time of
extreme
conditions. Because of the scope of the A.D. 536 event, which was
a
major atmospheric disturbance that resulted in diminished
sunlight and
reduced food supplies for many peoples of the world, it provides
a
venue from which to observe the ability of students of the past
to
contribute to current issues of human adaptation to extreme,
rapidly-changing environments at an earth system scale.
The book is divided into two parts. Part
I presents the
convincing, even overwhelming, historical evidence from literate
societies in Africa, Eurasia, and Mesoamerica that A.D. 536 was a
watershed year in the history of the world. Some historians are
proposing that it was the breakline between Classical and Modern
times.
Part II focuses on the effects of the event in subregions of
Southeastern United States. Chapters engages the question of how
archaeologists with less resolved time scales can make useful
contributions to the understanding of precisely timed events. The
answer is found more in the aftermath, in this case 300 years
following, than in definition of the moment. One of the authors,
however, points out that archaeologists' ability to cope with
more
refined time scales are promising. Much of the book, in fact, is
pointed toward extracting promises from old but resolute data.
======================
(4) EVIDENCE FOR ABRUPT CLIMATE CHANGE IN PREHISTORIC CHILE
From Andrew Yee <ayee@nova.astro.utoronto.ca>
News Services
University of Arizona
Tucson, Arizona
Contact Information:
Julio L. Betancourt, 520-219-6531, jlbetanc@usgs.gov
Jay Quade, 520-629-9455 ext. 1,jquade@geo.arizona.edu
Claudio Latorre (in Santiago, Chile), 562-6787323, clatorre@abello.dic.uchile.cl
Jason Rech, 520-629-9455 ext. 7, jrech@geo.arizona.edu
Kate A. Rylander, 520-670-6821 ext. 117, katydid@usgs.gov
Aug 31, 2000
Scientists Find Long History of Tropical Monsoon in World's
Driest
Desert
By Lori Stiles
Scientists have used techniques developed to reconstruct climate
history in the American Southwest in reconstructing the past
22,000
years of climate in the world's driest desert with striking
results.
Fossil rodent middens and paleospring deposits from the heart of
the
Atacama Desert in northern Chile document millennia-long wet and
dry
climate regimes that are linked to changes in tropical monsoons
far
removed from the region.
Julio L. Betancourt of the U.S. Geological Survey, Claudio
Latorre of
the University of Chile, Jason A. Rech and Jay Quade of the
University
of Arizona, and Kate.A. Rylander of the USGS report on it in the
current issue of Science (Sept. 1).
Their article, "A 22,000-year record of monsoonal
precipitation from
northern Chile's Atacama Desert," fuels a growing
realization that the
tropics play a more pivotal role in global climate change than
previously thought. Their research is funded by the InterAmerican
Institute, National Geographic and the National Science
Foundation.
"It may seem paradoxical to try to reconstruct large-scale
changes in
tropical rainfall from the driest desert in the world,"
Betancourt
said. But in places like the Amazon Basin, geologic evidence of
climate
change is either buried under jungle vegetation or has been
washed away
by meters of annual rainfall, he added.
"The Atacama Desert, in the rainshadow of the central Andes,
is at the
tail end of the tropical rainfall belt, where annual
precipitation
wanes to zero," said Betancourt, an adjunct research
associate in the
UA geosciences department. Betancourt and his colleagues are part
of
the USGS - UA Desert Laboratory, a unique facility for
paleoenvironmental research on Tucson's Tumamoc Hill.
The researchers refer to the Atacama as "absolute"
desert -- desert
that more resembles the surface of Mars than the Sonoran Desert.
It may
not rain in the desert for years or decades. Yearly precipitation
at
some of their study sites averages 20 millimeters, less than an
inch,
less than falls during a single, one-hour monsoon storm in
Tucson.
"It is desert that makes Death Valley look lush," said
UA geoscientist
Jay Quade.
But it is hyperaridity that makes the Atacama so useful for
studying
changes in tropical rainfall, Betancourt explained. Any extra
moisture
from the Amazon Basin to the Pacific slope of the Andes creates
an
amplified hydrological and biological response that the
geoscientists
can expertly measure using radiocarbon dated fossil rodent midden
and
wetland deposit techniques they honed in the American Southwest.
During wetter periods, more moisture from the Amazon Basin over
the
Pacific slope of the Andes increases the snowpack and raises the
regional water table, which discharges in springs along the
foothills.
The spillover also brings more rains to the lower elevations,
causing
vegetation, rodents and other organisms to expand into what is
now
Absolute Desert.
Hyperaridity preserves rodent "middens," or rodent
urine-hardened nests
rich in plant remains, for 40,000 years or more. Midden records
are
like snapshots of flora through time, Betancourt said.
He and others have led the North American midden research effort,
collecting and analyzing more than 2,000 packrat middens from
western
North America over the years.
The researchers identified many plant remains in rodent middens
as
summer-flowering grasses. "Because summer temperatures are
not limiting
at these elevations in the Atacama Desert, we can specify that
any
climatic changes are due to changes in monsoonal moisture. This
may
seem trivial, but we know of few geologic records anywhere in the
world
that specify the season of moisture and preclude temperature
effects,"
he said.
Quade and Rech reconstructed water table heights from ancient
spring
deposits left high and dry in canyons and lowlands of the Atacama
Desert.
"Think of them as bathtub rings," said Quade of the
Desert Lab, an
expert in analyzing such wetland deposits. "When the water
table was
high, it left a ring on the canyon wall. It's the same stuff you
get on
your pipes or the bottom of your water cooler."
The combined data from middens and paleospring deposits provide a
detailed and replicated record of climatic change during the past
22,000 years, the researchers report in Science.
The record shows that the desert became increasingly wet between
16,200
to 10,500 years ago, with the wettest period during the past 22
millennia occurring from 11,800 to 10,500 years ago, at the end
of the
last Ice Age. Higher elevation shrubs and summer-flowering
grasses grew
as much as 1,000 meters lower than they do today.
Paradoxically, the late glacial/early Holocene pluvial period
coincided
with a time when the amount of solar radiation over this part of
the
Earth was at its minimum. (Variations in aspects of the Earth's
orbit
through time causes changes in the amount and distribution of
sunlight
reaching Earth's surface.) Scientists assumed decreased solar
heating
would have weakened monsoon storms over southern Amazonia and the
central Andes.
"Instead, we find evidence for intensified monsoonal
circulation that
spills more moisture over the rainshadow of the central Andes
onto the
Pacific slope and the highlands of the Atacama Desert,"
Betancourt
said.
In their paper, he and the others suggest that greater solar
radiation
over the Tibetan Plateau 10,000 to 12,000 years ago intensified
the
central Asian monsoon, and that, combined with atmospheric
circulation
involved in El Nino - La Nina oscillations, resulted in stronger
easterlies (east-to-west winds) over the Pacific Ocean. La
Nina-like
circulation enhances convection and precipitation over the
central
Andes.
"The moral of the story is that insolation (solar radiation)
may
operate on large-scale circulation and regional climates through
climatic teleconnections that are far removed from the region in
question," Betancourt said.
The scientists found that after 10,500 years ago, climate in the
Atacama dried abruptly. After 9,000 years ago, the water table
dropped
to near modern levels. From 9,000 to 8,000 years ago, and the
past
3,000 years mark perhaps the driest climate over the last 22
millennia.
"The climate changes (at around 10,500 years ago) might have
been
happening, basically, in a few decades," Betancourt said.
"This
question bears on our future. Is it possible within the current
regime
to get such rapid changes in climate?"
The midden-paleospring record also documents a previously
undetected
wet phase from 8,000 to 3,000 years ago. Other researchers have
documented that Lake Titicaca on the Bolivian Altiplano, the
extensive
high plateau of the central Andes, was 100 meters below its
modern
level during this period. Two possible reasons for the
discrepancy have
to do with sharp geographic variations in summertime climate in
the
central Andes and Atacama Desert or with complex responses of
such a
large, deep lake to long-term variations in climate, Betancourt
said.
[NOTE: Images supporting this release are available at
http://uanews.opi.arizona.edu/cgi-bin/WebObjects/UANews.woa/wa/SRStoryDetails?ArticleID=2101]
=============================
* LETTERS TO THE MODERATOR *
=============================
(5) LONG-PERIOD EARTH-CROSSING ASTEROIDS
From Duncan Steel <D.I.Steel@salford..ac.uk>
Dear Benny,
In perusing the list of Apollo asteroids I noted that 1999 XS35,
which
was discovered by the LONEOS team last December, seems to have
escaped
discussion in CCNet. This is an object of interest for the
following
reasons.
With perihelion distance of 0.948 AU and an orbit bringing it
very
close by that of the Earth, this asteroid is classed as
potentially-hazardous, although it will be another 76 years
before
it returns (cf. Comet Halley) because it has such a large
orbit/high
eccentricity (a=18.046 AU, Q=35.144 AU, e=0.948, i=19.5 deg). It
is
also quite large (H=17.2 so maybe 1.5-2.0 km in diameter).
David Asher and I discussed the possible existence of such
long-period
Earth-crossing asteroids soon after 1991 DA (now 5335 Damocles)
was
discovered; that large asteroid has an orbit which just crosses
Mars,
and we thought that it would be unreasonable to suppose that
there are
no such objects on Earth-crossing orbits. We suggested that these
might
pose a significant proportion of the impact hazard in the
following
paper:
D.I. Steel & D.J. Asher,
'The past and future orbit of (extinct comet?) 1991
DA,'
pp.65-73 in Periodic Comets (eds. J.A.
Fernandez & H. Rickman),
Universidad de la Republica, Montevideo, Uruguay
(1992).
Later this work was extended with Mark Bailey and Gerhard Hahn,
resulting in:
D.J. Asher, M.E. Bailey, G. Hahn & D.I. Steel,
'Asteroid 5335 Damocles and its implications for
cometary dynamics,'
Monthly Notices of the Royal Astronomical Society,
267, 26-42 (1994).
The final sentence of the abstract of that paper reads:
"It is suggested that Damocles may be the first of a
substantial
population of such bodies to be discovered which make a major
contribution to the flux of Earth impactors."
My reason for bringing this up is that it has implications for
future
NEO search strategies. Some people question whether the aim of
the
current NASA Spaceguard Survey (90 percent of 1 km NEAs, leaving
aside
the timeline here) is adequate. A rejoinder to that view is the
fact
that comets (long-period or otherwise) pose a component of the
impact
hazard of order 10 percent (some people would argue only 1-2
percent,
others would go for 30 or even 50 percent). Once one gets to 90
percent
of NEAs, though, any extra dent in the final 10 percent of NEAs
is of
reducing relevance: we need instead to pay attention to the early
detection of long-period comets, while they are still in the
outer
solar system, if we are to have time for ameliorative action
should one
be found heading our way.
The fact, though, that there are also asteroids on large orbits
adds in
another term to the equation. Although talk centers on "90
percent of
1-km plus NEAs" it is implicit that the aim includes only
short-period
NEAs, and indeed the Shoemaker report was explicit on that point.
For
"short-period" one may understand cis-jovian orbits
(aphelia closer to
us that Jupiter). Based upon only 5335 Damocles, David Asher and
I
estimated that asteroids on long- and intermediate-period orbits
might
comprise 10 percent of the impact hazard. The confirmation that
such
objects exist adds to that view.
Whatever the proportion of the hazard, though, the discovery of
1999 XS35 does add another consideration into the pot. It also
indicates that there are things we have yet to understand. For
example,
when we (in the above cited papers) were looking at Damocles, we
were
thinking in terms of it being an extinct or dormant comet. It
might be
difficult, although not impossible, to get an asteroid from the
main
belt into its large, high-e orbit. If 1999 XS35 were such a
comet-derived beast, then one might imagine that, given the way
that a
typical comet (if there is such a thing) behaves, then the
solitary
known object 1999 XS35 might not be the only one in that orbit.
It
might have 10 or 100 siblings from earlier disintegrations. And
all of
them would have orbits passing very close by the Earth. Thus the
physical nature of 1999 XS35 would be a very useful thing to
know. Do
we?
These thoughts add weight to the view that the NASA target (I
won't
repeat it again) is sensible given what we don't yet know; that
is,
there is no sense at this stage in aiming for 99 percent rather
than
90 percent. On the other hand, our previous knowledge of
long-period
comets (not brightening until they cross Saturn's orbit at least)
and
now asteroid 1999 XS35 indicates the need for a phasing-in of a
search
programme using rather larger apertures. Of course, they will
find
large(r) numbers of cis-jovian NEAs smaller than 1 km, but
vis-a-vis
the 1-km plus objects capable of causing a global impact
catastrophe,
their primary aim would be discovering such targets whilst they
are
still in the outer solar system. We need to be looking to develop
search systems with apertures of 3 metres or more, and conducting
follow-up (not just astrometry, but also
spectrophotometry/spectroscopy
with 4-metre class systems.
Duncan Steel
================
(6) 2000 QW7 AND SPACE WEATHERING
From Kelly Beatty <kbeatty@skypub.com>
Benny...
>Can anyone please tell me what all the fuss is about asteroid
2000 QW7?
From the perspective of amateur astronomers, QW7 was/is an
Earth-approacher bright enough to be seen telescopically and
nothing
more. See our note about it at http://www.skypub.com/news/news.html.
And while you're there, note that this same page from which John
Wagoner lifted my writeup about the S-type/OC link (your item
#5). I'm
gratified that he sent it to you, but it would have been nice to
acknowledge where he got it.
I'm sorry we didn't have more time to chat in Manchester -- next
time
perhaps.
Kelly Beatty
===============
(7) ASTEROID/COMET WORKSHOP AT THE ISDC 2001
From Andy Smith <astrosafe@yahoo.com>
Hello Benny,
It is good to see the resumption of the CCNet flow (we missed it,
a
lot)and to see the many manifestations of interest and expertise
in
planetary defense and asteroid/comet emergency preparedness, on
the
Internet and the Web. I am positive and encouraged.
Many good things are happening and many important doors are
opening.
The NEO discovery rate continues to grow and Brian Marsden and
Gareth
Williams seem to be keeping-up with it (and we are all very
grateful to
them). There is general awareness of the need for an orbiting
early-
warning capability, in addition to our excellent and maturing
terrestrial observatory network. NEAR-SHOEMAKER is successfully
spinning around and studying EROS. Several good new
asteroid/comet
spacecraft are in development. The Russians continue to report
impressive studies of the dynamics of interception and
deflection, on
their SPACE SHIELD Web page. This excellent forum needs to be
enlarged
and we should all take advantage of their offer to host an open
global
forum. They are doing an outstanding job.
It is also great to see a number of private programs getting
underway,
in mining development and in impact prevention and preparedness
research.
We are making great progress, Benny. We have a long way to go (to
be
sure), but we are moving toward the goal. We still have only
about 1%
of the NEO data we need, but we are moving and the discovery rate
is
climbing, dramatically. We have no quick-reaction emergency
response
capability (and it would take at least two years to put-togeather
a
system, today) but we are moving toward a global program. We have
no
civil emergency preparedness programs (and this need is
especially
acute for the coastal cities), but we are moving toward one. A
global
tsunami preparedness program is already underway.
I am impatient and I find it very frustrating to watch us moving
so
slowly, but we are moving and things are improving. We pray
(as I am
sure do many of you), that we will be given the time we need to
prepare.
At the next International Space Development Conference (ISDC
2001),
which is being held in Albuquerque, next May (24-28), we plan to
devote
a day (Saturday, 25 May) to a review of global planetary defense
and
emergency preparedness progress (to include mining development
plans).
The meeting is being jointly sponsored by the National Space
Society
(NSS) and the American Institute of Aeronautics and Astronautics
(AIAA). It was the AIAA that developed the landmark 1990
Planetary
Defense Policy Statement, following the near-miss by 1989 FC,
that
started the chain of events which led to the Spaceguard Study,
the
Planetary Defense Workshop (Livermore, CA in 1995) and the
U.S.Congressional hearings, on this vital subject. This important
statement (and the 1995 follow-up statement) can be seen on the
AIAA
Web Site.
The meeting registration fee is very reasonable. The deadline for
the
submission of abstracts is in mid-October. We cordially invite
the
CCNet community to participate and to attend. In addition to the
Asteroid/Comet Workshop, an outstanding Astrogeology Symposium is
being
organized.
As the Program begins to take shape, we will send you updates and
we
will summarize the Sessions, following the Conference.
Cheers
Andy Smith
===============
(8) MEDIA ATTENTION GOOD FOR PUBLIC EDUCATION
From Daniel Spires <DSpires@wcom.net>
Good morning, Benny (a globally relative term at best).
As long as you're asking why:
I seriously believe that, in this particular case, those who know
better about NEA 2000 QW7 should keep mum. The impactor threat
for the
planet Earth is very real, with new NEAs continually being found,
and
until mass and trajectory can be determined, all possess an
identical
impact value -- that being 'catastrophic'.
The 'great impactor' of the modern age does exist, and it has
been
heading our way since the dawn of time.. Will it be discovered
tomorrow,
driving toward us on its unalterable course? This is an unknown.
NEA defense will exist, but only with the support of government
agencies. As it stands these agencies are slowly beginning to
take the
impactor threat seriously -- but very slowly. What is required to
speed
the process is public awareness. The average person on the street
knows
little astronomy. They realize that the Earth has a Sun and Moon,
that
there are other planets such as Mars and Venus, but not much
beyond
this. The public needs to be educated, but the only way to do
this is
to inform them that there is something deadly out there that they
need
to know about. It will be up to the people to vote for a defense
against the great impactor threat, but they must first know about
it.
Personally, I like the PR that 2000 QW7 has received and I hope
that it
will continue. This is not misinformation, but rather productive
education. Many may take a hard swallow at allowing the public to
become concerned about 2000 QW7, but I trust that concern will
become
extended toward the need of a viable defense plan.
Thank you,
Dan Spires
dspires@uu.net
=================
(9) SEARCHING FOR HISTORICAL IMPACTS IN NORTH AMERICA
From Ben L. Moon <benlmoon@wans.net>
Ed Grondine's digressions are interesting in their point of view,
somewhat like a modern-day de Tocqueville.
--Ben L. Moon, Carrollton, Georgia
==========
(10) AND FINALLY: FIXING THE HOLE IN THE NORTH POLE
From Nando Times, 4 September 2000
http://www.nandotimes.com/healthscience/story/0,1080,500247028-500366989-502170760-0,00.html
Copyright © 2000 Nando Media
Copyright © 2000 Scripps McClatchy Western Service
By DOUG O'HARRA, Anchorage Daily News
(September 4, 2000 2:48 p.m. EDT http://www.nandotimes.com) -
"The
North Pole is melting," The New York Times declared in a
lead story two
weeks ago.
In a story that surprised readers across the nation, the Times
reported
that "an ice-free patch of ocean about a mile wide has
opened at the
very top of the world, something that has presumably never before
been
seen by humans. ... The last time scientists can be certain the
pole
was awash in water was more than 50 million years ago."
The paper characterized the observation, made by scientists and
tourists on a July trip to the Pole aboard a Russian icebreaker,
as
evidence of global warming's relentless acceleration in the
Arctic.
Not exactly, the paper admitted a week later.
Open water at the North Pole isn't that unusual. And the
condition of
the Arctic Ocean's ice cap and its relationship to global climate
change are more complex than the Times first reported. A later
story,
published Aug. 29 in the Times' Science section, admitted as much
and
went into extensive details with satellite photos.
The original Times story was based on interviews with
internationally
respected scientists who saw the open water but who do not study
the
Arctic Ocean full time. That caveat frustrated some Alaska and
Washington researchers, who say the journalist and the
scientists,
while well-meaning, overreacted.
Not only has open water been observed at or near the North Pole
many
times, said Doug Schneider, public information officer of the
Alaska
Sea Grant College, but the prevalence of open leads in the polar
ice
cap has far more to do with ocean currents and wind patterns than
global warming.
Still, it's true that the ice cap thinned as much as 40 percent
between
the 1960s and the 1990s, according to researchers at the
University of
Alaska Fairbanks and the University of Washington. In addition,
average
temperatures have risen in the Arctic over the past decades. But
local
scientists say it's not clear whether these changes are natural
cycles
or a consequence of global warming.
The whole issue began with the Aug. 19 story by noted science
journalist John Noble Wilford. His story was based on accounts by
several scientists who had just returned from the North Pole.
They
included oceanographer James McCarthy, director of the Museum of
Comparative Zoology at Harvard University and a leader of a
United
Nation's panel on climate change.
McCarthy and other scientists didn't see thick ice on their route
north, which surprised them, a feeling he expressed Aug. 25 on
National
Public Radio.
Among those amazed at the thinness of the ice was the captain of
the
icebreaker, who was making his 11th visit to the region.
When the group found the lead of open water over the Pole, they
were
stunned.
"I don't know if anybody in history ever got to 90 degrees
north to be
greeted by water," Malcolm McKenna, a paleontologist at New
York's
American Museum of Natural History, told the Times.
McKenna's photograph of the slate-gray lead, rimmed by thin pale
ice,
graced the cover of the Times. The story went on to link the open
water
to global warming.
But Alaska scientists and others quickly called the
interpretations
premature, if not wrong.
Arctic Ocean ice thickness appears to be governed by a 60-to
70-year
cycle that may be triggered by a complex process in the North
Atlantic
Ocean, according to Igor Polyakov, a physical oceanographer at
the
International Arctic Research Center in Fairbanks.
So what about the report of open water?
On any summer day, as much as 15 percent of the Arctic Ocean
remains
ice-free, according to UAF physical oceanographer Mark Johnson.
Johnson
told Schneider that the 6-mile-long lead reported by the polar
excursion was normal for midsummer.
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