PLEASE NOTE:
*
CCNet DIGEST 25 June 1998
-------------------------
(1) ELECTROPHONIC FIREBALL SOUNDS
Colin Keay phcslk@cc.newcastle.edu.au
(2) NUKES AND US
Bob Kobres <bkobres@uga.edu>
(3) SPACEGUARD TM
Jonathan TATE <fr77@dial.pipex.com>
(4) UPCOMING ASTEROID DOCUMENTARY ON THE EVE OF TUNGUSKA
ANNIVERSARY
Paul Almond <novel@compuserve.com>
(5) METEORITE MAY REVEAL CLUES TO SOLAR SYSTEM'S EARLY DAYS
Albuquerque Journal
http://www.abqjournal.com/scitech/1sci6-24.htm
(6) DEFLECTING EARTH-COLLIDING ASTEROIDS WITH NUCLEAR EXPLOSIVES
S. Yabushita, KYOTO UNIVERSITY
(7) ISOTOPIC COMPOSITION OF PRIMITIVE METEORITES
E. Zinner, WASHINGTON UNIVERSITY
(8) THE PUZZLING DETECTION OF WATER IN COMET HYAKUTAKE
C.B. Cosmovici et al., CNR,IST FIS SPAZIO
INTERPLANETARIO
(9) THE EVOLUTION OF COMETARY ICE SURFACES
W.J. Markiewicz et al., MAX PLANCK INST AERON
(10) CHEMICAL PROCESSING IN THE COMA AS THE SOURCE OF COMETARY
HNC
W.M. Irvine et al., UNIVERSITY OF
MASSACHUSETTS
==================
(1) ELECTROPHONIC FIREBALL SOUNDS
From Colin Keay phcslk@cc.newcastle.edu.au
Dear Dr Peiser:
The following excerpt from the 23/06/98 CCNet Digest has been
drawn to
my notice:
>"Electrophonic sounds have never been validated
scientifically,
>and their origin is unknown. Currently, the most popular
theory is the
>potential emission of VLF radio waves by the fireball,
although this
>has yet to be verified."
With great respect may I point out that the above statement is
untrue,
as the published (fully peer reviewed) literature attests. The
VLF
radiation has been detected at least twice to my certain
knowledge. My
model (published in SCIENCE in 1980) was immediately validated by
V A
Bronshten in Moscow. Laboratory tests have verified that VLF em
fields
can be transduced into sounds. There are two distinct origins for
the
VLF: continuous sounds (hissing, etc) are from VLF produced by
trapped
geomagnetic field in the turbulent fireball trail; and sharp
sounds
(popping, etc) arise from explosive events in the bolide itself
by a
similar mechanism to the VLF produced by atmospheric nuclear
explosions.
The method of production of electrophonic sounds from VLF
radiation
generated by very large fireballs is now accepted by meteor
fireball
experts and I believe the CCNet Digest renders its readers a
disservice
by suggesting otherwise. And I trust the AMS will not promulgate
such
misinformation.
May I draw to your attention my web-pages which present an
outline of
the work done in this area and provides a bibliography of my work
on
the problem. They may be found at:
http://users.hunterlink.net.au/~ddcsk
or it can be located quite readily by search engines such as
Yahoo,
using my name and/or the word "electrophonic".
Colin Keay.
*********************************************************************
* Dr Colin Keay
::::::: ~ ~ To
achieve anything really
* Physics Dept
~
::::: ~ worthwhile in
research it is
* Newcastle Univ
~ :::\ | / necessary to
go against the
* NSW, AUSTRALIA 2308 ~
~ - o - opinions of one's
fellows.
* phcslk@cc.Newcastle.edu.au
/ | \ ~ "Where the Wind Blows"
*
www2.hunterlink.net.au/~ddcsk
~
~ - Fred Hoyle *
*********************************************************************
=====================
(2) NUKES AND US
From Bob Kobres <bkobres@uga.edu>
Nuclear reaimament is what I called the potential to convert
nuclear
weapon technology to the task of Earth-defense. Let’s face
it, the
genie is out of the bottle. See:
http://abob.libs.uga.edu/bobk/1908.html
While there is no way to ensure that this knowledge will not
again be
used to destroy life and property there are ways to make it less
likely
for that to happen. Rather than rehash the steps that could be
taken,
I’ll point the reader to earlier documents that express some
still
pertinent ideas:
http://abob.libs.uga.edu/bobk/nucreaim.html
http://abob.libs.uga.edu/bobk/rma.html
I'm no advocate of large-scale Earth-based nuclear use. All
we’ve
managed to do with nuclear energy technology is boil water with a
vengeance, creating a good deal of waste heat plus nuclear waste
storage problems. With nuclear weapons we've actually blown
adversaries
to smithereens and threatened to do so again, ultimately leading
to
various strategic plans of MAD (suicidal vengeance). In other
words the
nuclear-power-genie is a beast in the biosphere—better to
banish what
we’ve made to the Moon! By verifiably removing weapon grade
nuclear
material from Earth, in conjunction with international
cooperative Space
development aimed at reducing the need of high grade energy
within the
biosphere, we can greatly reduce the potential for conditions
that might
cause a reactionary mess on our planet.
In particular for Mr. Isobe (JAPANESE OBJECTIONS TO THE USE OF
NUCLEAR
DEVICES IN PLANETARY DEFENSE, CCNet 6/22/98), I suggest that he
consider how much Japan could benefit from becoming a pioneer in
developing solar-power-satellite technology. This also
includes ocean
based ‘refineries’ of such concentrated sun-energy,
which could supply
our civilization with hydrogen as a non-polluting portable fuel
as well
as increasing the supply of potable water.
As I’ve said many times—YES—we can mess ourselves
up with nuclear
technology, BUT—we don’t have to. An impact,
however, WILL get us
unless we learn how to avoid this otherwise inevitable natural
phenomenon.
Ultimately it is the general regard we have for one another,
coupled
with the dominant vision of our future, that will determine
whether we
continue to advance through knowledge or fall back to a state of
fear
and superstition.
A dozen years ago Joseph V. Smith, Louis Block Professor of
Physical
Sciences at the University of Chicago, in his article, THE
DEFENCE OF
THE EARTH, which appeared in the British Journal NEW SCIENTIST
(17
April 1986), stated the following:
"Although we have known about the dangers of nuclear war for
40 years,
they continue to increase as technology develops, driven by
divisive
bickering over social, political, nationalistic and religious
matters.
"How are my proposals related to the dangers of war,
especially the use
of nuclear weapons? At the simplest level, huge expenditure on
nuclear
and other weapons eats up technical resources that we could
better use
elsewhere. We could apply some of these resources to the
programmes I
propose here, some for the enrichment of education, and the rest
for a
host of other needs including exchange programmes to promote
interactions between people with different histories and
philosophies.
The fewer the scientists and engineers working on weapons, the
slower
the pace of development, and the better the chance that
diplomatic
negotiations can achieve success. In addition, if fewer people
worked in
weapons factories, and more on building instruments to study
asteroids,
comets, volcanoes and earthquakes, conventional and nuclear wars
might
also cause less damage. At a deeper level, there is the hope that
a
worldwide collaboration of scientists and engineers, working
together in
groups organised in a diplomatic consensus, will set an example
of
harmony that will lead us away from present disputes. Instead of
acting
like primitive tribes hunting heads, we might develop a feeling
that we
belong to one race irrespective of colour, religion and
historical
grouping.
"The genuine dangers of nuclear war have overshadowed the
threat to
humankind from natural hazards--hazards that few people fully
recognise. Such dangers have become obvious over the past 20
years to
geologists and astronomers.
"We can now propose sensible methods to prevent or mitigate
them. Given
worldwide cooperation over the next century, we could kill two
birds
with one stone if we reduced expenditure on weapons, and engaged
the
scientists, engineers and manufacturers in new programmes to
defend
people from natural hazards. All scientific and engineering
developments have the capacity for good or evil. Let us choose
Dr.
Jekyll over Mr. Hyde."
Choice is the real crux of the matter. Nuclear weapons will
be around
as long as people fear another group might attempt to gain
control of
them or their resources. We can expand our collective resource
base and
cause covetousness to diminish by electing to convert PHOs to
BROs
(benign resource objects). We can actively build trust between
disparate cultures by choosing to work together to accomplish
this
necessary for long-term-survival goal. We could also just hope
for the
best and decide to talk about doing something for a couple of
more
decades. Remember, the only certainty is change--better to steer
toward
a positive ideal than drift into chaos. In my view, Earth-defense
is not
just about comets and asteroids, it is rather more about our
attitude
toward our future.
Still hopeful.
bobk
Bob Kobres
=================
(3) SPACEGUARD TM
From Jonathan TATE <fr77@dial.pipex.com>
Re: "Spaceguard" TM
After seeking, and receiving support and agreement from Arthur
Clarke, the name "Spaceguard UK" and the SGUK logo were
registered as
UK trademarks. Both the name and logo are becoming quite well
recognised in the UK, and it only seems sensible to protect the
membership from cowboys!
For those interested, membership now stands at:
Patrons - 4
Associates - 28
Visiting - 21
General - 103
Jay Tate
Spaceguard UK
=====================
(4) UPCOMING ASTEROID DOCUMENTARY ON THE EVE OF TUNGUSKA
ANNIVERSARY
From Paul Almond <novel@compuserve.com>
Dear Benny,
You might want to alert those members who have access to TV sets
in
the US:
"Ends of the Earth: Doomsday Asteroid" is a one-hour
special which
will air on The Learning Channel this Monday, June 29th at
9:00PM.
We explore the peril our planet faces from a future impact from a
comet or asteroid by speaking to the following experts in the
field:
Don Yeomans and Steve Ostro from JPL
Jack Hills and Gregory Canavan at Los Alamos National Lab
Paul Almond - Filmmaker/author
Astronomers Clark Chapman, Duncan Steel, Alan Hildebrand, John
Mosely
Grant Stokes - Manager of LINEAR asteroid tracking project
Peter Ward of the University of Washington
Best wishes, Paul
Almond.
================
(5) METEORITE MAY REVEAL CLUES TO SOLAR SYSTEM'S EARLY DAYS
From the Albuquerque Journal
http://www.abqjournal.com/scitech/1sci6-24.htm
Tuesday, June 23, 1998
Any rock that falls from space is uncommon, but one that fell in
Portales may be extremely rare
By John Fleck
A football-sized rock that slammed into a Portales art teacher's
yard
June 13 appears to be a rare type of meteorite that could offer
clues
to the early days of our solar system, scientists say.
At 37 pounds, it's the largest meteorite ever found in New
Mexico. But
its unusual mix of metal and minerals is what really sets it
apart,
said Adrian Brearley, a University of New Mexico meteorite expert
who
got his first look at the rock Tuesday.
"It's a very unusual kind of meteorite," Brearley said.
Any rock from
space falling in your back driveway -- which is what happened to
Nelda
Wallace -- would probably count as "unusual," but
Wallace's rock is
even more special than that, Brearley said Tuesday. Wallace toted
it in
a bowling ball bag to UNM's Institute of Meteoritics on Tuesday
so
Brearley could figure out what it is.
"He has one of the best facilities to do that," Wallace
explained.
Wallace retains ownership of the rock, but has agreed to let
Brearley
cut small samples from it for analysis. The mixture of
minerals and
metal in Wallace's meteorite is rare, leading the scientists to
guess
that it's a kind of meteorite called a "mesosiderite",
according to
Horton Newsom of the Institute of Meteoritics. Mesosiderites are
special for what they lack, said Alan Rubin, an expert in their
study
at the University of California-Los Angeles.
Minerals like olivine that make up a big part of the asteroids
from
which meteorites come are largely missing from mesosiderites.
Rubin
believes the only way that can happen is in a rare type of
low-velocity
collision between big space rocks 4.5 billion years ago.
If Newsom's and Brearley's preliminary diagnosis is right, it's
one of
only 30 such meteorites ever found, and could provide important
clues
to those collisions, Rubin said.
It's not the minerals themselves that are important, but what
they can
tell scientists about the history of the rock. The tortures of
time
have eliminated all but the most rudimentary of clues on Earth
about
the conditions when the planet was forming. That leaves
scientists like
Rubin and Brearley to piece together circumstantial evidence
about what
was going on back then by looking at different types of
meteorites, and
mesosiderates are useful because their history is so unusual.
"That
tells us a lot about what happened early in the solar
system," Rubin said.
News of the find has raced through the close-knit community of
meteorite scientists. "It's pretty exciting,"
said Allan Treiman of
the Lunar and Planetary Institute in Houston. Neither Wallace nor
Brearley would put a number on the rock's value, but with both
museums
and private collectors interested, it could be worth a pile of
money to
Wallace, who owns the rock by virtue of the fact that it fell on
her
property. Meteorites of similar size are frequently advertised in
collectors' publications for tens of thousands of dollars.
"It's an
unusual one and therefore its value is probably fairly
high," Brearley
said.
Wallace said she has already been approached by collectors, but
she
said she has stopped them before they named a price. John Wasson,
a
meteorite expert at the University of California-Los Angeles,
suggested
a group of research institutions also might try to raise the
money to
buy it for study. Wasson said scientists have to compete with
collectors trying to buy meteorites.
Wallace's rock is apparently the largest of a cluster of at least
10
that fell over a several mile area of eastern New Mexico the
morning of
June 13, according to Brearley. Already three have been sold to
collectors, Brearley said. The scientists believe they all came
from
the same space rock.
Wallace said she and her brother-in-law were drinking their
morning
coffee when they heard two booms. They went to the door, heard a
noise
like a freight train, and Wallace grabbed her shoes and went out
to see
what was going on. What she saw was a rock slam into her back
driveway,
burrowing a hole 10 inches deep.
"It was so hot you could not touch it," she said. What
Wallace likely
heard was explosions as either a single rock from space or a
small
cluster of them exploded as they entered Earth's atmosphere, said
Mark
Boslough, a Sandia National Laboratories scientist who studies
meteorite impacts.
When the rock hit the ground, it was likely traveling several
hundred
miles per hour, Boslough said. Before that, however, the rock was
shredded by its high-speed encounter with Earth's atmosphere.
"It's
torn apart very violently by the air," he said. Boslough
said he's
interested in contacting anyone in the Portales area who might
have
photographs of the rocks entering the atmosphere, which he could
use to
calculate the meteorite's trajectory.
Copyright © 1997, 1998 Albuquerque Journal
===================
(6) DEFLECTING EARTH-COLLIDING ASTEROIDS WITH NUCLEAR EXPLOSIVES
S. Yabushita: On the transfer of radiation at asteroidal surfaces
in
relation to their orbit deflection. MONTHLY NOTICES OF THE ROYAL
ASTRONOMICAL SOCIETY, 1998, Vol.296, No.3, pp.662-668
KYOTO UNIVERSITY, DEPT APPL MATH & PHYS, KYOTO 606, JAPAN
One of the methods discussed in deflecting the orbit of an
Earth-colliding asteroid is the use of nuclear explosives. In
assessing
its feasibility, apart from political considerations, it is
important
to quantify how effective it is in orbit deflection. The transfer
of
radiation incident at the surface is governed by a non-linear
diffusion
equation. For low-yield explosions with a slab geometry (S-0
similar or
equal to 10(8) kJ mu s(-1)), the temperature at depth x and time
t is
well approximated by a similarity solution of the form T(x, t)=
T(0)f(xi), xi=x/(T(0)(n)t)(1/2), with T-0 given by
(S-0/sigma)(1/4),
where sigma is the Stefan-Boltzmann constant, n is an index that
specifies the radiation transfer and f(xi) is the solution of a
non-linear differential equation subject to the condition f(0) =
1 and
lim(xi-->infinity)f(xi)= 0. For high-yield explosions (S-0
similar or
equal to 10(10) kJ mu s(-1)), numerical solutions to the
non-linear
diffusion equation can be obtained. These solutions have
properties
similar to the case of low-yield explosions. If the duration of
the
explosion is d x 10(-8) s, where d is close to 3, the fraction of
energy absorbed by the surface is found to be 7, 12 and 23 per
cent for
S-0 = 10(8), 10(9) and 10(10) kJ mu s(-1) respectively. Copyright
1998,
Institute for Scientific Information Inc.
=======================
(7) ISOTOPIC COMPOSITION OF PRIMITIVE METEORITES
E. Zinner: Stellar nucleosynthesis and the isotopic composition
of
presolar grains from primitive meteorites. ANNUAL REVIEW OF EARTH
AND
PLANETARY SCIENCES, 1998, Vol.26, pp.147-188
WASHINGTON UNIVERSITY, MCDONNELL CTR SPACE SCI, ST LOUIS, MO,
63130
Primitive meteorites contain grains of stardust that originated
from
stellar outflows and supernova ejecta prior to the formation of
the
Solar System. The study of these grains in the laboratory provide
new
information on stellar evolution, nucleosynthesis, mixing in
supernovae, galactic evolution, and the age of the galaxy. Grains
whose
isotopically anomalous compositions indicate a stellar origin
include
diamond, silicon carbide, graphite, corundum, and silicon
nitride. Most
silicon carbide and corundum come from red giant and asymptotic
giant
branch stars (low-mass stars at the end of their evolution), and
carry
the isotopic signatures of H burning in the core and later of H
and He
burning in thin shells. Diamond carries a supernova isotopic
signature
in its Xe, and low-density graphite and silicon nitride, as well
as a
subgroup of silicon carbide, show evidence for a supernova origin
in
the form of extinct Ti-44 and large Si-28 excesses. Copyright
1998,
Institute for Scientific Information Inc.
=====================
(8) THE PUZZLING DETECTION OF WATER IN COMET HYAKUTAKE
C.B. Cosmovici*), S. Montebugnoli, A. Orfei, S. Pogrebenko, S.
Cortiglioni: The puzzling detection of the 22 GHz water mission
line in
Comet Hyakutake at perihelion. PLANETARY AND SPACE SCIENCE, 1998,
Vol.46, No.4, pp.467-470
*) CNR,IST FIS SPAZIO INTERPLANETARIO,AREA RIC TOR
VERGATA,I-00133
ROME, ITALY
We observed Comet Hyakutake C/1996 B2 during the period 26
April-4 May
1996 around perihelion searching for the 22 GHz neutral water
line by
using a fast multichannel spectrometer coupled to the 32 m dish
of the
Medicina radiotelescope. We report here not only the first
certain
detection of this radio spectral line in a comet and the unique
detection of water in a celestial body at a distance of 0.23 AU
from
the Sun, but also strong physical anomalies in the behavior of
the
water molecule velocities. The line is split into two clear and
bright
components and is positively shifted with respect to the comet
rest
velocity at velocities varying from 22 to 44 km/s during the four
days
of observation. As far as we know, a similar behavior of neutral
molecules in comets has never been observed before as the outflow
velocity should normally not exceed 1 km/s. A qualitative
analysis of
the data seems to support sublimation of excited water molecules
from
accelerated icy grains which form an extended source around the
nucleus. The strong coronal activity observed by the SOHO
spacecraft in
the same period may have contributed to the acceleration
mechanism. A
future quantitative analysis would be very useful for the study
of the
complex plasma-grain interaction problem and of the cometary
activity
at very close distances from the Sun. (C) 1998 Elsevier Science
Ltd.
All rights reserved.
=======================
(9) THE EVOLUTION OF COMETARY ICE SURFACES
W.J. Markiewicz*), Y.V. Skorov, H.U. Keller, N.I. Komle:
Evolution of
ice surfaces within porous near-surface layers on cometary
nuclei.
PLANETARY AND SPACE SCIENCE, 1998, Vol.46, No.4, pp.357-366
*) MAX PLANCK INST AERON, MAX PLANCK ST 2, D-37191 KATLENBURG
DUHM,
GERMANY
The small-scale structure of a cometary surface layer determines
to a
large extent the way in which cometary activity develops. The
strong
temperature variations on a rotating cometary nucleus and the
corresponding sublimation and condensation processes make it
probable
that the surface is rough, with many caverns,cracks, and pores on
size
scales from meters down to the sub-millimeter range. Present work
describes first results of theoretical models able to describe
some of
the aspects of the ''shape-forming'' processes active on a
cometary
nucleus. Monte Carlo simulations and analytical methods are used
to
study the gas flow within a porous surface layer. Dust pores with
sublimation from ice filled bottoms as well as ice covered walls
are
considered. It is found that the erosion of an ice-filled channel
embedded in a matrix composed non-volatile material is
effectively
limited by the gas recondensing at the bottom due to the back
flux of
molecules reflected from the side walls. Inhomogenities of the
sublimating bottom tend to be leveled out, resulting in a
sublimation
surface of slightly parabolic shape. Hence it is correct to use
Clausing formula for far flux out of porous media modelled by a
bundle
of tubes, even if the shape of the sublimating surface bottom of
each
tube is a priori not known. (C) 1998 Elsevier Science Ltd. All
rights
reserved.
=====================
(10) CHEMICAL PROCESSING IN THE COMA AS THE SOURCE OF COMETARY
HNC
W.M. Irvine*), D.A. Bergin, J.E. Dickens, D. Jewitt, A.J. Lovell:
Chemical processing in the coma as the source of cometary HNC.
NATURE,
1998, Vol.393, No.6685, pp.547-550
*) UNIVERSITY OF MASSACHUSETTS, FIVE COLL RADIO ASTRON OBSERV,
619
LGRC, AMHERST, MA, 01003
The discovery of hydrogen isocyanide (HNC) in comet Hyakutake
with an
abundance (relative to hydrogen cyanide, KCN) similar to that
seen in
dense interstellar clouds raised the possibility that these
molecules
might be surviving interstellar material(1). The preservation of
material from the Sun's parent molecular cloud would provide
important
constraints on the processes that took place in the protostellar
nebula. But another possibility is that HNC is produced by
photochemical processes in the coma, which means that its
abundance
could not be used as a direct constraint on conditions in the
early
Solar System. Here we show that the HNC/HCN ratio determined for
comet
Hale-Bopp varied with heliocentric distance in a way that matches
the
predictions of models of gas-phase chemical production of HNC in
the
coma, but cannot be explained if the HNC molecules were coming
from the
comet's nucleus. We conclude that HNC forms mainly by chemical
reactions in the coma, and that such reactions need to be
considered
when attempting to deduce the composition of the nucleus from
observations of the coma. Copyright 1998, Institute for
Scientific
Information Inc.
----------------------------------------
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