PLEASE NOTE:
*
CCNet 123/2002 - 28 October 2002
-------------------------------
"The earth is going to get hit, it's just a question of
time. Maybe
our generation won't have to deal with it but some future
generation is
definitely going to have to deal with this."
--Doug ReVelle, Los Alamos National Laboratory
"We've heard how large asteroids devastate the Earth every
few
hundred thousand years or so. One wiped out the dinosaurs and
Hollywood's even made movies about one wiping out us. But
Australian
scientist Ted Bryant says it's not the infrequent big space rocks
we really
should be concerned about it's the smaller ones. Bryant takes
Catalyst
reporter Graham Philips to the cliff tops of the coastline around
Wollongong and finds geological features that he claims were made
by
Tsunami's that in turn were caused by asteroid impact. Whilst
these
impacts may not be big enough to cause global damage, when one of
these
splashes down into the ocean it produces a massive tsunami, which
will
devastate nearby coastlines. And Bryant says further tsunamis are
in
store for us. Every 120 years the Earths obit passes through the
trail of
a broken up comet causing the meteorites rain down on the
planet."
--ABC, 24 October 2002
(1) TSUNAMI DEVASTATED SEATTLE AREA IN 900 AD
Nature Science Update, 28 October 2002
(2) ASTEROID TSUNAMI IN 1500 AD?
ABC, 24 October 2002
(3) FORCES OF NATURE: EVIDENCE FOR MILLENNIAL-SCALE STORM
DISASTERS
Andrew Yee <ayee@nova.astro.utoronto.ca>
(4) WAITING FOR THE LEONIDS
Astronomy.com, 27 October 2002
(5) VOM HIMMEL HOCH
Die Welt, 26 October 2002
(6) MARTIAN ROCK 'DOES CONTAIN LIFE' - BUT IT MAY BE TERRESTRIAL
BBC News Online, 23 October 2002
(7) FREQUENCY OF KILO- AND MEGATON IMPACTS
Roberto Gorelli <md6648@mclink.it>
(8) HERE COMES THE RIO SCALE
Michael Paine <mpaine@tpg.com.au>
(9) SCIENCES & AVENIR
Hermann Burchard <burchar@math.okstate.edu>
(10) AND FINALLY: MYSTERY FIREBALL PHENOMONON A DAMP SQUIB
Reuters, October 22, 2002 09:34 AM
ET
===========
(1) TSUNAMI DEVASTATED SEATTLE AREA IN 900 AD
>From Nature Science Update, 28 October 2002
http://www.nature.com/nsu/021021/021021-10.html
Wave devastated Seattle area: Ancient tsunami provides clues to
future
threat.
28 October 2002
TOM CLARKE
Around 1,100 years ago, a tsunami devastated the northwestern
coast of North
America where the city of Seattle now stands, computer modelling
has
revealed. The research could help planners reduce damage and loss
of life in
the event of a future giant wave1.
About 900AD, a shallow but powerful earthquake shook Seattle's
harbour, the
Puget Sound, a 2,329 square-kilometre inlet of the Pacific Ocean.
The quake,
produced by the still-active Seattle fault, would have sent a
tsunami
throughout the sound, the study shows.
Combining clues from silty deposits around the sound2 with modern
computing
power, Shunichi Koshimura, of the Disaster Reduction and Human
Renovation
Institution in Kobe, Japan and colleagues have recreated the
tsunami's
spread. "It's a complex detective story," says one of
team, Harold Mofjeld
of the Pacific Marine Environmental Laboratory in Seattle,
Washington.
They calculate that the tsunami reached heights of 3 to 7 metres.
It
travelled at 30 to 45 kilometres per hour, and swept at least 300
metres
onto shore in some places. Two areas bore the brunt of the wave:
Cultus Bay
and West Point.
Excavation at West Point has revealed a Native American fire pit
beneath
sand swept onshore by the wave. "Many people were probably
living by the
water's edge," says Mofjeld. According to the model the wave
took only three
minutes to get from the middle of the Sound to West Point.
"It happened so
fast," says Mofjeld, escape was very unlikely.
Hazard warning
Monitoring of the Seattle fault indicates a similar tsunami could
hit the
Puget Sound again - though it's almost impossible to predict
when. Today
over 3 million people live and work in the Seattle area. Damage
would be
"substantial", says Mofjeld, especially because the
wave would arrive just
minutes after a powerful earthquake.
A wave the size of the one modelled by Koshimura can lift cars.
Combine that
with gas lines severed after a quake, "and you've got the
makings of a
disaster," agrees tsunami researcher Emile Okal, at
Northwestern University
in Evanston, Illinois.
The latest model will be incorporated into hazard maps, which
predict where
tsunami risk is the greatest in terms of how far waves can travel
inland, or
where they will be most powerful. These maps, an idea borrowed
from Japanese
planners, form part of the National Tsunami Hazard Mitigation
Program that
covers the US West Coast, Alaska and Hawaii.
Being a young city in a geologically active region, most of
Seattle's newer
buildings are designed to withstand earthquakes and would fare
better
against a tsunami too. It is no stranger to small tsunamis,
caused by
landslides into water after earthquakes.
Signposts and public-awareness programs advise residents on
exposed shores
to head for high ground as quickly as possible following a
'quake. "The
earthquake serves as Seattle's tsunami warning," says
geologist Brian
Atwater of the US Geological Survey at the University of
Washington in
Seattle.
References
Koshimura, S., Mofjeld, H. O., González, F. I. & Moore, A.
L. Modelling the
1100bp paleotsunami in Puget Sound, Washington. Geophysical
Research
Letters, published online, doi:10.1029/2002GL015170 (2002).
|Homepage|
Atwater, B. F. & Moore, A. L. A tsunami about 1000 years ago
in Puget Sound,
Washington. Science, 258, 1614 - 1617, (1992). |Homepage|
© Nature News Service / Macmillan Magazines Ltd 2002
=============
(2) ASTEROID TSUNAMI IN 1500 AD?
>From ABC, 24 October 2002
http://www.abc.net.au/catalyst/stories/default.htm
We've heard how large asteroids devastate the Earth every few
hundred
thousand years or so. One wiped out the dinosaurs and Hollywood's
even made
movies about one wiping out us.
But Australian scientist Ted Bryant says it's not the infrequent
big space
rocks we really should be concerned about it's the smaller ones.
Bryant
takes Catalyst reporter Graham Philips to the cliff tops of the
coastline
around Wollongong and finds geological features that he claims
were made by
Tsunami's that in turn were caused by asteroid impact.
Whilst these impacts may not be big enough to cause global
damage, when one
of these splashes down into the ocean it produces a massive
tsunami, which
will devastate nearby coastlines.
And Bryant says further tsunamis are in store for us. Every 120
years the
Earths obit passes through the trail of a broken up comet causing
the
meteorites rain down on the planet.
Full Program Transcript:
Narration: A comet breaks up. It creates a cloud of rock, dust
and ice in
the solar system. The Earth now periodically orbits through
it...and every
few hundred years pieces of it crash down, splash into the ocean
and cause
giant waves...deadly tsunamis. That's the theory of this
Australian
geologist Ted Bryant. And his evidence is that tsunamis have hit
this
coastline every few centuries, he says. One washed over the
Wollongong area
in 1500 AD. It wasn't big enough to destroy civilisation like in
the movies,
but the film Deep Impact does give a feel for what happened 500
years ago
Graham Phillips: So if we were standing here in 1500 AD looking
out to sea
what would we have seen?
Associate Professor Ted Bryant: You would see the horizon
starting to lift
up. And within about a minute you'd see it moving towards you.
And at this
headland you'd probably see a wall of water 20 metres high or
more.
Narration: Hollywood got the idea of an asteroid creating a
tsunami right,
but they did make a classic blunder, says Ted. The tsunami
wouldn't have
actually broken onto the shore.
Associate Professor Ted Bryant: I can remember the scene of the
wave coming
into Cape Padders and breaking at the height of the Statue of
Liberty. It
doesn't do that. It swamps .... It doesn't come in as breaking
wave.
Narration: And that fact that it doesn't break gives the tsunami
its power -
enough power to heave those boulders behind us out of the water
and up on to
the ledge, says Ted...evidence for the 1500 tsunami.
Associate Professor Ted Bryant: It's very difficult for storm
waves to move
boulders this size because storm waves break off shore. And
another thing
these boulders are aligned. They're aligned like dominos and they
all point
back in that south-east direction.
Graham: That's the direction the wave came from
Associate Professor Ted Bryant: That's the direction they come
from.
Associate Professor Ted Bryant: And finally, when we walk along
cliff tops,
down at Jervis Bay especially, we find these boulders up on the
cliff tops,
lined up to the south-east.
Narration: And these potholes are further evidence says Ted. From
the shape,
they must have been carved into the rocks in just minutes, he
says, by the
churning waters of the tsunami.
Associate Professor Ted Bryant: We know that if the water moves
fast enough
it has air bubbles in it and they're very unstable and they
instantly
collapse at 30,000 atmospheres pressure and when they collapse
they can just
chew through solid bedrock. But the flows moving so you get these
snakelike
features that have been carved into the bedrock as well.
Narration: And the tremendous force of the flow even carved a new
bay in the
headland.
Associate Professor Ted Bryant: It's gone in a counter-clockwise
direction
and gouged out this circular embayment here.
Graham Phillips: So you're telling me the vortex could carve
through all
that depth of rock there.
Associate Professor Ted Bryant: We believe we're looking at 20
metres depth
of erosion - instantaneous - and that was carved out in less than
a minute.
Narration: Ted's certain all this happened in 1500 because he's
carbon-dated
the tiny pieces of shell washed up by the big waves. But the next
step his
proof needs is evidence that 300-metre-wide chunks of that comet
do fall
down every few hundred years. And that comes from an unusual
source...this
network of listening devices across America...used by scientists
at Los
Alamos military laboratories to pick up nuclear bomb detonations.
But they
also hear the explosions of incoming meteors.
Dr Doug ReVelle: We pick up objects that penetrate deeply into
the
atmosphere and are able to generate a shock wave by virtue of
their very
high velocity and that shock wave then decays and travels to
earth where we
pick it up as a signal."
Narration: And judging from Doug Revelle's signals, meteors the
size Ted
needs arrive once every 120 years or so. That's spot on. Other
scientists at
Los Alamos are showing how the falling fragments create the
tsunamis, by
mathematically modelling them on one of the world's most powerful
supercomputers.
Associate Professor Ted Bryant: They don't drop in like dropping
a pebble
directly into the ocean and then a big splash and a lot spray and
that spray
is 5000 degrees Celsius. So it would incinerate us.
Narration: And surprisingly, it's not that initial big splash
that creates
the tsunami. Rather, the impact shoots a jet of water kilometres
into the
air and as that jet falls down it gives birth to the deadly
tsunami. And the
Los Alamos researchers have even thought up new disaster
scenarios from that
broken up comet. Even if the fragments don't land in the ocean.
Take that
famous impact above Siberia in 1908. Flattening 2000 square
kilometres of
forest and even producing a rising mushroom cloud, it looked like
a nuclear
blast. If something like that happened these days - an event as
Doug calmly
calls it - it could be mistaken for a nuclear attack and trigger
a
retaliation.
Dr Doug ReVelle: Yes, there was a very interesting event that is
not totally
public knowledge yet. This event fell out over the Mediterranean
just to the
west of Crete is where it ended and had that event fallen over
Israel or
Syria or Jordan or that part of the world just a little bit
further east
there might have been some very, very tense moments.
Narration: An event needn't even make it to the ground to be
dangerous.
Dr Doug ReVelle: Certainly every year we get dozens of objects
that
penetrate down to the 20 kilometre height range which are just
above where
aeroplanes fly and if there happens to be low turbulence in the
atmosphere
and this dust just kind of hangs there for a while and an
aeroplane were to
draw that into their jet engine there would be big trouble.
Narration: The final sting is, these relatively small pieces of
comet rubble
are too tiny for astronomers to track.
Associate Professor Ted Bryant: We're picking up the small
objects after
they pass the earth. So we'd get absolutely no warning of this.
Dr Doug ReVelle: The earth is going to get hit, it's just a
question of time
maybe our generation won't have to deal with it but some future
generation
is definitely going to have to deal with this."
Copyright 2002, ABC
=============
(3) FORCES OF NATURE: EVIDENCE FOR MILLENNIAL-SCALE STORM
DISASTERS
>From Andrew Yee <ayee@nova.astro.utoronto.ca>
University Communications
University of Vermont
Burlington, Vermont
Author: Lynda J Majarian
Email: Lynda.Majarian@uvm.edu
Phone: (802)656-2005 Fax: 656-3203
Release Date: 10-23-2002
Forces of Nature: UVM Geologists' Storm and Flood Research
Featured in
Premier Science Journal
Is New England headed for troubled waters? Significant storms and
floods may
be ready to wreak havoc, according to geologists at the
University of
Vermont. Their study of storm and flood patterns in the Northeast
over the
past 13,000 years will appear in the Oct. 24 issue of the journal
Nature,
the world's premier information resource for biological and
physical
sciences.
Funded by a National Science Foundation Career grant, Paul
Bierman,
professor of geology, led a team of colleagues and students in a
four-year
project to collect and study core samples from 21 lakes in
Vermont and the
Adirondacks. Among their conclusions: periods of intense
storminess have
peaked in the North Atlantic region roughly every 3,000 years
over a
13,000-year period.
"The last big group of storms was -- you guessed it --
almost 3,000 years
ago," says Bierman, who co-authored the Nature paper with
Anders Noren,
former graduate student of geology at UVM; Andrea Lini, assistant
professor
of geology; and colleagues in Washington and California. While
they cannot
predict exactly when the next big storm will hit, the regional
patterns they
were able to establish are red flags to emergency planners, who
rely on
early detection to quickly evacuate people to higher ground when
waters
rise.
There was no time for warnings, preparations or escape when
record rainfall
overflowed rivers and partially submerged several Vermont towns
in 1927,
killing 55 people and destroying $30 million in property. But
that disaster,
says Bierman, was merely a drop in the bucket compared to earlier
-- and
future -- hydrologic hassles.
"If this cycle continues, the frequency and severity of
intense rainstorms
that can cause massive flooding should continue to increase for
the next
several hundred years," agrees Noren, who is lead author of
the Nature
article. He joined Bierman's research team as a graduate student
and wrote
his thesis on the project, building on the thesis of another
geology
graduate student, Sarah Brown. In a laborious process he calls
"a wintry
dance," Noren spent long, cold days helping to collect
sedimentary archives
by hammering 20-foot pieces of 3-inch diameter PVC pipe into the
bottom of
frozen lakes and extracting core samples that were later sliced,
photographed and painstakingly analyzed.
"In each of the cores we looked for sandy layers of sediment
that were
washed into the lakes during rainstorm-induced floods," he
explains. During
"nor'easters," cyclones and hurricanes, material stored
in upland streams
and basin hill slopes is eroded and transported to lake basins.
"By getting
radiocarbon dates on the organic materials in and around these
layers, we
were able to determine when floods occurred," Noren notes.
The study's main
conclusions were culled from an analysis of the flood
chronologies of all
the lakes.
"There may be much bigger floods than the 1927 disaster
lurking out there,"
Bierman says. "But the most important thing to come out of
this research is
that, for the first time, we know the history of stormy periods
in New
England over the past 13,000 years." The storm rhythms
observed in the UVM
study are consistent with those recorded in the Greenland ice
sheet, which
carries signals in its chemical and physical properties that
reflect an
upswing in storminess over the past 600 years. It is suspected
that the
impact of human activity, especially the emission of atmospheric
greenhouse
gases, could speed up storm cycles.
Bierman has conducted additional research on alluvial fans, which
collect
debris from hill slopes and landslides. Those results support the
data
collected on regional storms, and will appear in the next issue
of the
Geological Society of America bulletin.
Noren graduated from UVM in May with a master's degree in
geology. He has
returned to his native Minnesota and currently is a research
technician at
the Limnological Research Center at University of Minnesota in
Minneapolis.
Read the Nature article, titled "Millennial-scale storminess
variability in
the northeastern United States during the Holocene epoch,"
online at
http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v419/n6909/abs/nature01132_fs.html
=============
(4) WAITING FOR THE LEONIDS
>From Astronomy.com, 27 October 2002
http://www.astronomy.com/Content/Dynamic/Articles/000/000/001/077wtrbd.asp
Professional meteor watchers predict and prepare for this year's
Leonid
display.
by Pamela L. Gay
On November 19, early risers in North America will (weather
permitting)
start their day with a spectacular sky show. That morning, Earth
will pass
through debris trails left by Comet Temple-Tuttle. As flecks of
cometary
dust and debris streak through Earth's atmosphere they will burn
up or
explode, collectively creating a meteor shower called the
Leonids. This
natural fireworks display is certain to draw the attention of
millions of
people around the world. Scattered among starry-eyed kids and
captivated
adults will be astronomers who view the Leonids as a grand
laboratory
experiment for testing their understanding of comets, meteor
shower
intensities, and our atmosphere.
Scientists like Rob Suggs, leader of the Space Environments Team,
will be
out counting. He'll be in New Mexico with his colleagues
recording meteors
with video cameras as part of a larger effort to protect
satellites from
meteor showers.
Some groups of scientists have studied Comet Temple-Tuttle's and
Earth's
orbits to predict when we should pass directly through the
comet's debris
trails. When this happens, we experience meteor storms with tens
of meteors
streaking through the sky each second. By keeping counts of how
many meteors
appear per minute, scientists can determine when we actually
passed through
the debris trails and confirm or refine their predictions.
The three leading prediction teams forecast an initial peak at
approximately
4:00 Universal Time (UT) on November 19 (11 pm EST November 18)
when we pass
through a debris trail left in 1767. This peak will be most
striking for
observers in Europe. American viewers will lose much of this
display to
moonlight, and the meteors they do see will appear low on the
eastern
horizon. The second peak will be at 10:30 UT (5:30 am EST)
November 19 while
traveling through debris deposited in 1866. This shower is
ideally timed for
North American observers. The radiant will be high in the
southeast and the
moon will be sinking in the west.
Not all Leonid counters will be confined to Earth, though.
"The ISS will be
flying over Europe during the first outburst," explains
Suggs. "Then it will
pass over North America during the second outburst. Perfect
timing!"
Astronauts looking out the space station's windows could spot
more meteors
than anyone else.
Another set of flying observers will be tracking the meteor
shower over
Spain. Peter Jenniskens will be leading a NASA team in a mobile
science
mission called the Multi-Instrument Aircraft Campaign (MAC).
Flying in two
NASA aircraft, MAC scientists will observe the storm from above
the clouds.
Keeping their planes 100 kilometers (62 miles) apart, they will
monitor the
storm from two angles and obtain a three-dimensional perspective
on how
meteors pass through our atmosphere. Using an arsenal of
spectrometers,
cameras, and counters (for meteor flux measurements), they will
study how
meteors burn up, and what (if any) of the meteors' organic
material
survives. "Meteors dominated the supply of organics to the
early Earth if
organic matter survived this pathway efficiently,"
Jenniskens notes.
"Understanding these processes relies heavily on empirical
evidence that is
still very limited."
If you would like to contribute to this year's meteor shower
studies, find a
dark location and prepare to record your counts. Amateurs are
encouraged to
keep logs of how many meteors they see per minute (or every 5 or
15 minutes)
during the night. You can help the MAC team by reporting your
counts. You
can also report observations to organizations such as the
International
Meteor Organization, North American Meteor Network, and the
American Meteor
Society. Or you could share your reports with others in
Astronomy.com's
Discussion Forums or send your meteor photos to gallery@astronomy.com.
To find out when the Leonids should peak in your area and later
compare your
observations with the predictions, visit this NASA website or the
MAC
mission's flux estimator page.
For more information about the Leonids and how to observe them,
see the
November issue of Astronomy magazine.
Copyright © 1996-2002 Kalmbach Publishing Co.
=========
(5) VOM HIMMEL HOCH
>From Die Welt, 26 October 2002
http://www.welt.de/daten/2002/10/26/1026astr364594.htx
... da kommen sie her, die Asteroiden. Damit sie dort auch
bleiben und uns
nicht vernichten, dachte neulich ein Weltkongress über Methoden
nach, sie
unschädlich zu machen
Von Ulli Kulke
Wir sind umzingelt. Allan Harris kann es auf seinem Monitor
zeigen. In der
Mitte, auf schwarzem Grund, lässt der Astrophysiker am Zentrum
für Luft- und
Raumfahrt (DLR) in Berlin-Adlershof die Erde und die anderen
inneren
Planeten zirkulieren, in ruhiger Bahn. Doch etwas weiter
draußen, zwischen
Mars und Jupiter, da lauern sie vieltausendfach, umkreisen das
Zentrum
unseres Planetensystems wie ein Schwarm Haie seine Beute: grüne
Punkte, so
dicht, dass sie zu einer homogenen Masse verschmelzen: die
Asteroiden.
So lange die gefährlichen Brocken aus Stein oder Erz mit gut
30.000 Sachen
in ihrem Hauptgürtel durchs Universum jagen, sind sie für uns
uninteressant.
Doch auf Harris' Monitor tummeln sich auch Punkte im Innern
unseres
Planetensystems, mal hier, mal da kreuzen sie die Bahn von Mars,
Venus,
Merkur - und der Erde. Was tun, wenn so ein Klumpen, wenige Meter
oder
mehrere Kilometer groß, auf unseren Planeten zu stürzen droht?
Die Frage
stellten sich kürzlich 70 Wissenschaftler aus aller Welt in
Arlington
(Virgina) auf einem Workshop über gezielte Abwehrmaßnahmen.
FULL ARTICLE AT
http://www.welt.de/daten/2002/10/26/1026astr364594.htx
============
(6) MARTIAN ROCK 'DOES CONTAIN LIFE' - BUT IT MAY BE TERRESTRIAL
>From BBC News Online, 23 October 2002
http://news.bbc.co.uk/2/hi/science/nature/2354533.stm
By Dr David Whitehouse, BBC News Online science editor
The strange shapes seen in a rock from Mars that some researchers
say are
fossilised bacteria really are tiny microorganisms, say American
researchers.
But while they are confident the Mars rock contains fossilised
life they
cannot quite bring themselves to say it comes from the Red
Planet, it might
be Earthly contamination.
Despite the uncertainty about their origin establishing that the
small
structures really were living things, and not just mineral
globules, would
be an advance in a field that has
sharply divided opinions.
Lawrence Taylor of the University of Tennessee told BBC News
Online that
so-called "nannobacteria" found on Earth resemble those
found in the Mars
rock." The next task is to find a way to determine if they
really came from
Mars.
Life on Mars?
Since the dramatic announcement in 1996 by Nasa scientists that
there were
several lines of evidence that suggested rock ALH84001, picked up
from
Antarctic ice but originally from Mars, contained evidence of
life,
scientific opinion has been divided between those who wanted to
be
persuaded, and those who did not.
Since then the rock has been extensively analysed and many papers
written,
but few have shifted their viewpoints.
One camp has looked at magnetic grains in the microfossils saying
that they
appear identical to magnetic grains found in some terrestrial
bacteria.
Another group of researchers looked at indications of how carbon
deposits in
the rock were formed looking to see if they were deposited at low
enough
temperatures so they could be by-products of life.
Rival researchers have argued that the very small size of the
purported
microorganisms make it unlikely that they were living things
because they
are too small.
In the past few years however some researchers, principally
Robert Folk of
the University of Texas, have put forward evidence that
terrestrial
nannobacteria do exist and add significantly to the Earth's
biomass.
The latest study, by Robert Folk and Lawrence Taylor, casts doubt
on the
lower size limit for life viewpoint. Some of the larger bacteria
found in
ALH2004 are actually close in size to the smallest terrestrial
organisms.
But if the case for the fossilised microorganisms in ALH84001 is
strengthened somewhat the big question remains: where did they
come from?
"We conclude that the nanobodies that are so abundant in
ALH84001 are indeed
nannobacteria. However whether these bodies originated on Mars,
or are
Antarctic contamination remains a valid question," say the
researchers.
Copyright 2002, BBC
============================
* LETTERS TO THE MODERATOR *
============================
(7) FREQUENCY OF KILO- AND MEGATON IMPACTS
>From Roberto Gorelli <md6648@mclink.it>
Dear Benny,
I read in CCNet 118/2002 (9 October 2002), the DPS Press Release
of Alan W.
Harris on the impact frequency of "Tunguska-sized"
events. I would like to
express some considerations on his arguments.
When I developed my catalogue of megatonic events I inserted also
the
Tunguska event, but in effects the class of megatonic events for
definition
would have to comprise only events from
0,5 to 5,0 megatons. The Tunguska event with its credited value
of 12.5 +/-
2.5 megatons is in the decamegatonic class: from this work I
obtained the
frequency of an event every 10 years
on all the Earth and one every 30 -35 years on mainland for the
of megatonic
class events.
The events of the order of 1-10 kilotons happen with a frequency
of
approximately 10 to the year: calculations of Shoemaker, from
those most
recent ones of Harris (of which I have only read extracted) and
others
indicate for the events with analogous power to that one of the
Tunguska
values of the order of an event every 350 years or more.
The events, between 0.1 and 10 megatons can truly happen in the
next tens of
years and during our life, (on February, 1st 1994, the US
President was
woken up during the night as sensors had detected a high energy
signal above
the Pacific, following a method of calculation of the energy
emitted in the
infrared the event could to have approached a 1 megaton of
power).
It is necessary to reflect on a point: the kilotonic events in a
generalized
manner do not produce damages and in any case only locally. While
the
Tunguska events are of concern, they must be considered as
"unprobable
event" with the meter of the duration of the human life, the
ettokilotonic
and megatonic events are instead in my opinion those of which we
must mainly
preoccupy in how much even if the damages that they produced are
not
comparable with events as Tunguska their force are not get
exhaustedded in
the atmosphere like for the kilotonic events, moreover if they
had to happen
in determined areas of the planet could provoke an equal
number of victims to those expectable by Tunguska events. Do we
want to be
worried of this class of events or should be better ignore
them?
Regards
Roberto Gorelli
==============
(8) HERE COMES THE RIO SCALE
>From Michael Paine <mpaine@tpg.com.au>
Dear Benny
There may be some lessons here for the NEO community
regards
Michael Paine
International SETI Launches New Detection Scale
http://www.spacedaily.com/news/seti-02c.html
Little Ferry - Oct 23, 2002
A new scale designed to give the public an expert view of any
claimed
detection of extraterrestrial intelligence has been launched
today by the
International Academy of Astronautics' Search for
Extraterrestrial
Intelligence Permanent Study Group at the World Space Congress in
Houston.
The Rio Scale was initiated by Drs. Ivan Almar of Hungary and
Jill Tarter of
the SETI Institute in California to give the media and the public
an idea of
the credibility and importance -- as determined by a panel of
SETI
scientists -- of any claim that intelligence elsewhere in the
universe has
been detected.
To demonstrate the Rio Scale, Dr. Seth Shostak of the SETI
Institute and
Almar have authored a paper for the World Space Congress
assessing fictional
and past non-fictional SETI events.
>From the realm of fiction they include the films Contact, The
Arrival,
Independence Day, The Sphere and 2001: A Space Odyssey and books
including
The Listeners, The Sparrow and The Coming. The non-fiction claims
include
the "face on Mars" and a SETI hoax involving the star
EQ Peg.
So what Rio Scale rating would they get? The scale runs from zero
(for
non-credible claims of detection) to ten (for a completely
reliable
detection.) The SETI type detection in the movie Contact gets
high marks
near 10 because of the confirmations by telescopes around the
world.
On the other hand a claim of a real detection in the EQ Peg hoax
reaches
only 3-4 on the scale during the claim, dropping to zero when a
large radio
telescope proves the signal is false.
"Hollywood has been rather inventive about scenarios
involving contact with
extraterrestrial societies, and their stories are well
known," says Shostak.
"Some of these films make good 'lab rats' for testing out
the Rio Scale, and
testing is definitely desirable. After all, if SETI researchers
picks up a
signal, it will be very useful to have a scheme in place for
assessing the
importance and reliability of the discovery."
Copyright 2002, Space Daily
=============
(9) SCIENCES & AVENIR
>From Hermann Burchard <burchar@math.okstate.edu>
Dear Benny,
from SCIENCES & AVENIR online, octobre 2002 - N° 668,
Inventaire des
astéroïdes qui menacent la Terre, a tabulation of potential
impactors this
century, "de 27 astéroïdes géocroiseurs connus", min
dist in AU:
(4179) Toutatis 29 septembre 2004 0,01036
2000 UG11 9 novembre 2008 0,009096
1999 AQ10 18 février 2009 0,01183
1999 MN 2 juin 2010 0,007625
1998 HH49 17 octobre 2023 0,007852
1999 AN10 7 août 2027 0,002652
2001 WN5 25 juin 2028 0,004367
(35396) 1997 XF11 26 octobre 2028 0,006228
2000 QK130 15 mars 2036 0,01157
2002 NY40 11 février 2038 0,007548
2001 WN5 26 juin 2039 0,001485
2001 AD2 3 avril 2046 0,01125
1999 DB7 28 février 2048 0,007903
1988 TA 1er octobre 2053 0,01030
2002 CY9 25 janvier 2055 0,01019
(4660) Nereus 14 février 2060 0,008011
1999 RQ36 22 septembre 2060 0,005548
2001 QQ142 13 décembre 2062 0,01107
(2340) Hathor 21 octobre 2069 0,006598
2002 LV 3 août 2076 0,007149
1999 JU3 6 décembre 2076 0,01047
2002 CU11 31 août 2080 0,004270
(2340) Hathor 21 octobre 2086 0,005973
1999 VP11 22 octobre 2086 0,006027
2000 WO107 30 novembre 2093 0,007877
1998 SC15 8 avril 2095 0,01064
(35396) 1997 XF11 27 octobre 2095 0,01146
http://www.sciencesetavenir.com/tempsfort/p668/a26129.html
See also
Astéroïdes De plus en plus près
http://www.sciencesetavenir.com/tempsfort/p668/a26127.html
Regards,
Hermann
==============
(10) AND FINALLY: MYSTERY FIREBALL PHENOMONON A DAMP SQUIB
>From Reuters, October 22, 2002 09:34 AM ET
http://reuters.com/news_article.jhtml?type=humannews&StoryID=1613089
By Orathai Sriring
NONG KHAI, Thailand (Reuters) - Almost half a million people
flocked to
witness the annual rising of fireballs from the Mekong where the
river
snakes between Thailand and Laos, but the phenomenon turned out
to be a damp
squib.
A four-hour downpour from twilight on Monday put the dampers on
the show for
most of the crowd camped out along a 10-km (six-mile) stretch of
river bank
opposite the Laotian capital of Vientiane.
Usually thousands of reddish-pink balls of light are said to
shoot up into
the sky above the Mekong, which runs through five nations before
flowing out
to sea in Vietnam.
But this year only a few dozen balls were seen.
The fireballs, called "bung fai phaya naga," or
"naga fireballs," after a
mythical giant serpent, have never been proved scientifically,
but some
speculate they are the result of natural gases rising from the
river bottom.
Others say they are a hoax, while local myth tells of an ancient
waterworld
beneath the brown waters of the Mekong. Locals say the phenomenon
has been
occurring for half a century.
They happen during the full moon of the eleventh lunar month in
Nong Khai
province, 600 km (360 miles) northeast of Bangkok.
"This is terrible," complained a disgruntled
grandmother, who spent hours on
traffic-clogged roads to see the event.
"The fireballs weren't that spectacular and my grandchildren
were crying and
starving."
The fireballs this year drew more than four times the usual crowd
because a
recent movie on the same subject.
"Usually we get around 100,000 visitors, but the crowd this
year is
estimated at 450,000-500,000 because of the movie," said
Saroch Laowilai, a
spokesman for the Nong Khai provincial administration.
All 30 hotels and inns in the town of Nong Khai were fully booked
and
several hospitals and Buddhist temples offered room and board,
officials
said.
Thousands also camped along highways and the river bank.
But despite the disappointment from out-of-towners, locals
enjoyed the show.
"I don't how they happen," said Poon Matawong, a
72-year-old fisherman who
says he first saw the fireballs when he was 20.
"But I believe that the waterworld exists."
Copyright 2002, Reuters
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