PLEASE NOTE:
*
CCNet 52/2002 - 22 April 2002
-----------------------------
"Where were the people carrying the "Down With
Asteroids" signs
during this past weekends protests against everything in
Washington?
Why isn't the World Wildlife Federation demanding that Congress
do
something to end this threat to world wildlife? Why didn't Al
Gore
denounce President Bush for failing to counter the threat from
above during
his 35th or so coming-out speech in Florida? Probably because
anti-asteroid activism doesn't pay the bills or procure the
votes."
--Charles Rousseaux, Washington Times, 22 April 2002
(1) U.S. SPACE COMMAND NOW IN COMMAND OF ORBITAL DEBRIS TRACKING
Andrew Yee <ayee@nova.astro.utoronto.ca>
(2) THE NEAR EARTH OBJECTS INFORMATION CENTRE
www.nearearthobjects.co.uk
(3) PERILS BEYOND EARTH'S 2002 ORBIT
Washington Times, 22 April 2002
(4) HOW LIFE ORIGINATED IN SPACE
Andrew Yee <ayee@nova.astro.utoronto.ca>
(5) Re: AGE OF EMPEROR HAWAII CHAIN
Hermann Burchard <burchar@mail.math.okstate.edu>
(6) THE TERM ATMOSPHERE
Bob Kobres <bkobres@arches.uga.edu>
(7) AND FINALLY: SENDING EMOTIONAL E-MAILS IS GOOD FOR YOUR
HEALTH
Ananova, 22 April 2002
==============
(1) U.S. SPACE COMMAND NOW IN COMMAND OF ORBITAL DEBRIS TRACKING
>From Andrew Yee <ayee@nova.astro.utoronto.ca>
[ http://www.upi.com/view.cfm?StoryID=19042002-125008-8371r
]
Friday, April 19, 2002, 3:31 PM EDT
NASA axing orbital debris research program
By IRENE BROWN, UPI Science Correspondent
JOHNSON SPACE CENTER, Texas (UPI) -- Budget overruns are
prompting the
National Aeronautics and Space Administration to end its
23-year-old Orbital
Debris Program Office on Oct. 1, space agency officials admitted
on Friday,
even though orbital debris is acknowledged as a serious problem
for the
space shuttle, International Space Station and satellites in
low-Earth
orbit.
At 17,500 mph, even a fleck of paint can be dangerous for
spaceships and
satellites in orbit. A four-inch chuck of metal flying at the
space shuttle
could be fatal for any human in its path.
NASA as well as commercial and scientific satellite operators
still have the
U.S. Space Command tracking data for debris large enough to be
spotted by
optical and radar telescopes on the ground. The military
currently tracks
about 10,000 objects daily that are bigger than 4
inches in diameter so satellite operators can move their
spacecraft to avoid
being hit.
But clouds of smaller fragments born in rocket explosions, as
well as other
small objects hovering in near-Earth orbits, will be left largely
unstudied
as a result of the NASA office closing, reportedly for
cost-cutting reasons.
"There were nine explosions in orbit last year and each
creates more and
more debris," said Nicholas Johnson, head of the Johnson
Space Center
Orbital Debris Program Office, which since its founding in 1979
has been
modeling the small particle debris environment, issuing
forecasts,
recommending preventative measures and assessing risks.
"Radars cannot track small debris in the same manner as
larger objects. We
do a statistical evaluation, based on optical observations of
particles as
small as two millimeters. We can see them, but we don't know
where they'll
be tomorrow. We do assessments of probabilities of how many
particles are at
what altitude," Johnson said.
The analysis is one factor NASA takes into consideration when
setting launch
dates and times for the space shuttle. The research also has been
key to
identifying sources of orbital debris and setting national and
international
guidelines for debris prevention and mitigation.
"We're sitting here hoping that someone will find a
solution," said Johnson.
"This is a problem that's been coming for a long time. We're
terminating a
key capability."
A NASA safety advisory panel issued a report earlier this year
calling for
the agency to reconsider its decision.
"Over the last several decades, NASA has led an
international effort to
understand how the space environment is impacted by the presence
of
micrometeoroid/orbital debris," wrote the Aerospace Safety
Advisory Panel.
"This work ... has provided a growing ability to track such
objects and to
maneuver spacecraft, including the space shuttle and
International Space
Station to avoid collisions ... Proposed budget cutbacks would
eliminate
funding for the activities of this group, (depriving) the shuttle
and
station programs of updated knowledge on debris risks."
Scientists warn that the orbital debris environment may become
even more
dangerous if the United States proceeds with plans to develop a
space-based
missile defense system -- whether from testing the system in
space or in
actual conditions of a missile attack.
"In science fiction movies like 'Star Wars' there are
constant explosions,
but a few seconds later the screen is clean. It's not going to
work that way
near a planet," said physicist Joel Primack, with the
University of
California, Santa Cruz.
"The space debris aspect of a 'Star Wars' missile system is
just not talked
about in the public arena," said Primack, who was scheduled
to present a
paper on Friday at the United Nations Educational, Scientific and
Cultural
Organization headquarters in Paris.
"If we do this, we're going to create a terrible problem
there's no easy
solution for," Primack said.
Copyright © 2002 United Press International. All rights
reserved.
===============
(2) THE NEAR EARTH OBJECTS INFORMATION CENTRE
www.nearearthobjects.co.uk
Over the past forty years scientists have discovered that
asteroids and
comets have collided with the Earth throughout its 4.5 billion
year history.
The impact of these Near Earth Objects with our planet can be
catastrophic
still represents a natural hazard today.
The NEO Information Centre provides services to the public,
educators, media
and scientists to encourage understanding and advancement of NEO
science.
Our virtual exhibition and online activities allow users to learn
about the
nature of NEOs and the hazard they pose, find out what efforts
are being
made to detect NEOs and what could be done to overt a collision.
We keep you
informed with the latest news on NEO issues and enable you to
voice your
opinions through discussion forums and special events. We provide
materials
for educators, information and contact services for the media,
and support
for NEO scientists in communicating and conducting their work.
OUR MISSION
Our goal is to increase public awareness and understanding of
impact hazards
so that everyone, whatever their background knowledge, can make
informed
decisions on NEO issues. We aim to provide a platform by which
NEO science
is communicated to the public and media in an accurate and yet
understandable way. Our services also providing a resource by
which the
media can find the information and experts they need.
Through an active programme of events and discussion we aim to
enable the
public and scientists to voice their opinions on NEO issues and
ensure that
these are heard by policy makers. At the same time we aim to
clearly explain
current policy and existing research programmes.
ABOUT US
The NEO Information Centre was established by the UK Government
in response
to the recommendations of the Task Force Report on potentially
hazardous
Near Earth Objects to provide accurate and level-headed
information on Near
Earth Objects to the public and media and to support the
international NEO
science community.
The Centre is operated by a consortium lead by the National Space
Centre in
Leicester. Additional members of the consortium are the Natural
History
Museum, Queen Mary and Westfield College, Queen's University
Belfast, the
Royal Observatory Visitors Centre, the University of Leicester,
the UK
Astronomy Technology Centre and W5. Regional exhibitions will be
housed with
many of the consortium members.
The Centre is advised by an academic network of leading
scientific NEO
experts and is administered by the British National Space Centre
for the UK
Government.
OUR PARTNERS
Our partners are organisations involved in NEO research and the
communication of science to the public and media. Together we
provide
accurate and understandable information on NEO issues to a wider
and more
diverse audience.
Key partner organisations of the NEO Information Centre are:
The British National Space Centre
The BNSC is the UK government department charged with ensuring a
safer
near-earth environment. It co-ordinates with other agencies on
the threat
from Near Earth Objects.
The Minor Planet Centre
The Minor Planet Centre plays a crucial role in NEO observation
programmes
by cataloging new observations of asteroids and comets. The MPC
ensures that
astronomers can obtain the information they need to follow up new
observations
WHO WE ARE
The NEO Information Centre is operated by a consortium of
organisations and
is led by the National Space Centre in Leicester. The management
team
comprises:
Ms Alex Barnett (Project Manager) (more info...)
alexbarnett@nearearthobjects.co.uk
Mr Kevin Yates (Project Officer) (more info...)
kevinyates@nearearthobjects.co.uk
Dr Matthew Genge (Web Manager) (more info...)
matthewgenge@nearearthobjects.co.uk
The Academic Network which advises the NEO Information Centre
comprises:
Prof Iwan Williams (Astronomer, Queen Mary's and Westfield
College)
Dr Alan Fitzsimmons (Astronomer, Queen's University, Belfast)
Dr Matthew Genge (Planetary Scientist, Natural History Museum)
Dr Monica Grady (Planetary Scientist, Natural History Museum)
Dr John Davies (Planetary Scientist, UK Astronomy Technology
Centre, Royal
Observatory)
===============
(3) PERILS BEYOND EARTH'S 2002 ORBIT
>From Washington Times, 22 April 2002
http://www.washtimes.com/commentary/20020422-24158344.htm
Charles Rousseaux
On this 32nd anniversary of Earth Day, it's important to remember
that the
Jeremiahs of the environmental movement actually do have it
right. One day,
life as we know it will be wiped off the Earth.
It has happened before, and it will again, not as a consequence
of evil
corporate capitalism, but rather devastating orbital dynamics.
There are
about 1,000 large asteroids capable of hitting the Earth flying
around the
solar system at a speed and recklessness that defy comparison.
They hit
hard, too. About 65 million years ago, a chunk of space rock hit
near the
Yucatan Peninsula, exterminating 75 percent of the life forms
living on
Earth at the time, including all the dinosaurs (except for Fidel
Castro).
Other asteroids have had similarly deep impacts on the Earth's
ecology.
Alarmingly, NASA scientists recently calculated that a fairly
large rock
innocuously named 1950 DA has a chance of ruining the weekend
plans of
everyone on Earth.
So where is the outrage? Where were the people carrying the
"Down With
Asteroids" signs during this past weekends protests against
everything in
Washington? Why isn't the World Wildlife Federation demanding
that Congress
do something to end this threat to world wildlife? Why didn't Al
Gore
denounce President Bush for failing to counter the threat from
above during
his 35th or so coming-out speech in Florida?
Probably because anti-asteroid activism doesn't pay the bills or
procure the
votes. NASA scientists consider 1950 DA "a greater hazard
than any other
known asteroid," but calculate that its chances of causing
an Armageddon are
only 1 in 300. Besides, that close encounter that won't come
until 2880, a
distant threat that is death to fund-raising and ballot-box
appeal. Instead,
environmental activists and Democratic operatives will spend
today attacking
big producers, big polluters and big Republicans, who, if you
believe the
rhetoric, have nothing better to do than kill spotted owls, drop
arsenic
into the water and breathe sulfur dioxide into the air.
However, the quality of the U.S. environment has never been
better,
according to the "Index of Leading Environmental Indicators
2002," a study
just released by the Pacific Research Institute. Authors Steven
Hayward and
Julie Majeres noted that the total emissions of six
"criteria" pollutants
regulated by the Clean Air Acts have declined by almost a third
since 1970,
even though the U.S. economy has grown by almost the same amount
since then.
Water quality is up, releases of toxic chemicals are down, and
supplies of
energy are still abundant, despite the best efforts of Senate
Democrats.
That shouldn't be surprising, since most Americans want a clean,
safe
environment, even if they don't bother to join the Sierra Club.
Yet most of
them also realize that neither they nor their children can be
protected from
all hazards at all costs.
Last year, NASA spent $4.5 million on the Near Earth Object
Program, which
is designed to identify and discover 90 percent of the 1
kilometer and
larger asteroids in near-Earth orbit by 2008. That's .03 percent
of it's $15
billion annual budget, two-ten thousandths of a percent of the
$2.13
trillion budget for fiscal year 2003 that President Bush sent to
Congress.
The NASA scientists I talked to seemed to think the level of
funding was
about right, based on the low-risk nature of the threat.
Defense got a much bigger chunk of our tax dollars, and
rightfully so. After
all, Osama bin Laden probably isn't hiding in the asteroid belt.
A less
distant, but also less certain threat is global warming,
allegedly caused by
industrialized countries' increased emissions of carbon dioxide.
Those
releases could be cut by an infinitesimal amount by following the
strictures
of the Kyoto Protocol, but only at a catastrophic price.
According to
skeptical environmentalist Bjorn Lomborg, the $150 billion cost
of one
year's worth of compliance with the Kyoto treaty would be almost
enough to
buy every inhabitant of the Third World basic access to
sanitation, water,
health and education - twice.
Those sorts of cost-benefit calculations are supposed to be a
basic part of
political decision-making. Yet ironically, many of the same
politicans and
activists who apply a pragmatic approach to procuring votes and
demanding
dollars will spend today demanding environmental protection at
all costs.
Still, there's still reason for optimism this Earth Day. After
all, the sky
isn't scheduled to fall until 2880.
Charles Rousseaux is an editorial writer and an editor for the
Commentary
pages of The Washington Times.
© 2002 News World Communications, Inc.
================
(4) HOW LIFE ORIGINATED IN SPACE
>From Andrew Yee <ayee@nova.astro.utoronto.ca>
Informnauka (Informscience) Agency
Moscow, Russia
Contact:
E.A. Kuzicheva, N.B.Gontareva
Institute of Cytology
Russian Academy of Sciences
St. Peterburg
+7 (812) 247-18-29, nnnik@dcc.cyt.ras.spb.ru
Natalia Reznik, Informnauka (Informscience) Agency
textmaster@informnauka.ru,
7-095-2675418
12.04.2002
HOW LIFE ORIGINATED IN SPACE
The eternal question about the origin of life on the Earth has no
answer so
far. One of the theories assumes that life on the Earth might
have
originated in space. Russian scientists successfully reproduced
the
experiment carried out by Nature three and a half billion years
ago.
Life originated on the Earth more than 3.5 billion years ago.
However, the
scientists are still disputing over the possible sources of the
life origin.
The matter is that life on our planet evolved from the molecular
level to
the level of bacteria organisms within 0.5 - 1 billion years,
this period
being very short for such an important evolutionary step. The
researchers
are still racking the brains over this mystery. One of the
popular
hypothesis asserts that some germs of life have been brought to
the Earth
from space. But what exactly could have been brought from space
and how
could the germs have originated in space?
E.A. Kuzicheva and N.B.Gontareva, research assistants from the
Institute of
Cytology, Russian Academy of Sciences, have confirmed a
possibility of
abiogenous synthesis of complex organic compounds (monomeric
units of
nucleic acids) on the surface of comets, asteroids, meteorites
and
space dust particles in the outer space. Therefore, it is
possible that the
above monomeric units of nucleic acids could have got to the
Earth and thus
could have significantly reduced the time period of the evolution
process.
On the surface of space bodies the scientists have found all
kinds of
various organic molecules (amino acids, organic acids, sugars
etc.) and the
components required for their synthesis. Obviously, it is there
that organic
substances are being synthesised, but the researchers can not be
sure of
this fact, until the experiments confirm their assumptions.
The scientists from St. Petersburg reproduced synthesis of one of
the DNA
components -- 5'-adenosine monophosphate (5'-AMP) under the
conditions
specially designed to simulate the space environment. In order to
synthesise
5'-AMP it is required to combine adenosine and inorganic
phosphate.
On the Earth the reaction goes in the solution, but there are no
solvents
whatsoever in space, therefore the researchers dried them in the
air and got
a pellicle. Synthesis requires energy. The major source of energy
in the
outer space both at present and in the prebiotic period of the
Earth history
has been the solar ultraviolet radiation of different
wavelengths.
Therefore, the pellicles were irradiated by a powerful
ultraviolet lamp.
Naturally, the synthesis was carried out in vacuum, and the
researchers used the lunar soil,
delivered to the Earth by the 'Moon-16' station from the Sea of
Abundance,
as a model of the comet, meteorite, interplanetary or cosmic
dust. The soil
represented basaltic dust of the dark-grey colour, the diameter
of its
particles being less than 0.2 millimetres.
After 7-9 hours of ultraviolet irradiation of the dry pellicles
the
scientists acquired several compounds, mainly 5'-AMP, one of the
DNA/RNA
monomers. The energy of radiation does not promote synthesis
alone, it also
facilitates decomposition of the initial and newly-synthesised
compounds,
the more powerful the radiation is, the more extensively the
decomposition
goes. However, the lunar soil provided some protection. It has
appeared that
a small pinch of the lunar soil protects organic substances from
the destructive ultraviolet
impact -- the lunar soil helps to increase the 5'-AMP yield by
2.7 times.
The researchers have made a conclusion that the organic compounds
synthesis
could have happened in the outer space environment. The synthesis
could have
taken place on the surface of space bodies at the initial phases
of the
solar system formation, along with that the chemical evolution
(formation
and selection of complex molecules) could have started in space.
By the time
the Earth was formed the chemical evolution might have approached
the phase
to be followed by the biological evolution. That implies that
life on the
Earth most probably did not start from the elementary organic
molecules
synthesis, but commenced from the polymers formation phase or
from a further
stage. Hopefully, the above assumptions will help the scientists
to deeper
penetrate into the mystery of the accelerated development of life
on the
Earth when the latter was quite a 'young' planet.
============================
* LETTERS TO THE MODERATOR *
============================
(5) Re: AGE OF EMPEROR HAWAII CHAIN
>From Hermann Burchard <burchar@mail.math.okstate.edu>
Dear Benny,
in Robert D. Brown's latest (Hawaii: Tombstone of the
Dinosaurs", CCNet
2002-4-19), he would seem to again imply that Detroit Seamount,
aged 81 Ma,
is not a portion of the Emperor-Hawaii chain but has a separate
origin, as
in his AGU Spring Meeting Abstract S32A-11 (CCNet 2002-4-17)
where he
promotes the idea of an "Hawaiian impact site circa 65
Ma".
By contrast, in recent work geologists Tarduno and Cottrell (U.
of
Rochester, NY) appear to routinely assign the Detroit Seamount
(and Meiji)
to the Emperor chain. This is well illustrated in an
abstract (see below,
Appendix 1, following my signature) from the web pages of Rory
Cottrell,
paleomagnetist on ODP Leg 197, who did Ph.D. work on the motion
of the
Hawaii hotspot directed by John Tarduno. Tarduno was
co-chief scientist on
ODP Leg 197. Recent data on the geochemistry (in which I am
not expert) can
be found in the Leg 197 preliminary report, 1 July-27 August 2001
(to which
Brown refers):
http://www-odp.tamu.edu/publications/prelim/197_prel/197toc.html
Extensive remarks on the hypothesis of contact at ~80 Ma between
the hotspot
and a spreading ridge are included in the report (see below,
Appendix 2,
beneath signature).
But there is no support in the report for Brown's idea of an
"Hawaiian
impact site circa 65 Ma", or of any specific effect on the
seamount chain by
events at 65 Ma. A map included with the report
http://www-odp.tamu.edu/publications/prelim/197_prel/figf1.html
clearly shows there is complete continuity in the chain from SE
of Nintoku
Seamount (56 Ma) and Suiko Seamount (65 Ma) all the way NW to the
large
Detroit Seamount platform (81 Ma). For this reason, there
is no relevance
in the details shown by the NOAA close-up images of the seamounts
near the
cusp of the Aleut and Kamchatka subduction trenches:
http://www.ngdc.noaa.gov/mgg/image/2minrelief.html
These images scarcely can lend support to Robert Brown's attempt
of finding
a significant connection between an impact 65 Ma ago and the
Hawai'ian
Islands. It hardly matters whether he is right or wrong in
his supposition
that
"interested readers... can see for themselves that
Detroit and Meiji
ride atop a standard oceanic ridge that runs roughly
parallel to and
south of the Aleutian Chain, a reality that readily
explains their
measured isotopic composition(s)."
He is here clearly accepting the age > 80 Ma of the two
mounts, but still
attempts to implies a separate origin for them.
It may be noted also that the "ridge that runs roughly
parallel to and south
of the Aleutian Chain" is much different in structure in its
two parts
formed by intersection with the Emperor chain: To the W of the
chain the
ridge has a solid appearance and seems to be a part of the
seamount chain.
This feature could be a signature of the resistance of the
hotspot track to
subduction. This resistance is easy to understand in terms
of the deep
mantle roots of the track and it is also evident in, and the
presumptive
cause of, the remarkable cusp formed by the two trenches at this
point.
To the E of the seamounts the ridge differs and looks more ragged
-- among
possible explanations this could be a part of a MOR close to the
hotspot
at ~80 Ma discussed by numerous authors mentioned in the Leg 197
Report
(see quote below).
Interestingly, the NOAA images also may show the hotspot track
continuing on
the Sibirian mainland in linear parallel ridges trending E-W,
even on the
floor of Shelekhov gulf N of the Sea of Okhotsk.
Regards,
Hermann
= = = = = = = =
Appendix 1, from Rory Cottrell's web page:
http://www.earth.rochester.edu/pmag/rory/index.html
Paleolatitude of the Detroit Seamount: Implications for the
Motion of the
Pacific Plate and Hawaiian Hotspot
Recent data sets available from ocean drilling have allowed a
general
reconsideration of Pacific plate motion and relative motion
between
hotspots. We examine here a new data set collected from Ocean
Drilling
Program Site 884 (51.5o N, 168.3o E) drilled on Detroit Seamount
(81 Ma)
of the Hawaiian-Emperor Seamount chain. Thirteen lithologic
units, equaling
87 m of massive and pillow basalt flows, can be distinguished
based on the
presence of chilled margins and changes in crystallinity.
Detailed thermal
demagnetizations (50-675oC at 25o C increments) of 97 azimuthally
unoriented
basalt samples were performed. Orthogonal vector plots of the
thermal
demagnetization data showed near univectorial decay of most
samples
analyzed. Unblocking temperatures (525-580o C) suggest that the
magnetic
mineralogy has a compositional range from low Ti titanomagnetite
to
magnetite. Average Hcr/Hc and Mr/Ms values, 2.51 and 0.31
respectively,
support this interpretation. Preliminary analysis of
inclination-only data
suggests 9 distinct inclination groups, from which a
paleolatitude of 36.3o
+/- 4.9o N was derived. Estimated angular dispersion (S) from the
inclination-only average is 16o, only slightly higher than values
quoted for
rocks of this age and paleolatitude, suggesting that secular
variation has
been adequately sampled. The colatitude of these basalts does not
correspond
with other Campanian pole positions for the Pacific plate and
apparently
contradicts prior suggestions of fast apparent polar wander
between 66-81
Ma. In addition, preliminary examination of these new data
suggests ~18o of
southerly offset of the Hawaiian hotspot since the formation of
the Detroit
Seamount.
= = = = = = =
Appendix 2, from the TAMU Leg 197 Prelim. Report:
http://www-odp.tamu.edu/publications/prelim/197_prel/prel6.html#234089
As an example, the Sr isotope ratios of tholeiitic basalt from
the Hawaiian
hotspot track show a systematic trend through time (Fig. F6).
These ratios
are approximately constant along the Hawaiian Ridge (out to the
43-Ma bend)
then decrease steadily northward along the Emperor Seamounts to
Suiko
Seamount. This decrease has been attributed to a decrease in
distance
between the hotspot and the nearest spreading ridge (Lanphere et
al., 1980).
Only the tholeiitic basalt from the shield phase of volcano
construction
show this trend because only these magmas appear
to have escaped contamination by the oceanic lithosphere (Chen
and Frey,
1985). Keller et al. (2000) have extended this analysis to
Detroit and Meiji
Seamounts, and they find that Sr isotope ratios continue to
decrease
northward, with a minimum value at Detroit Seamount well within
the range of
compositions for Pacific mid-ocean-ridge basalt (MORB). This
composition
(confirmed with other isotopic and elemental ratios) is
unprecedented in the
Hawaiian hotspot-produced volcanism to the south, but is
consistent with the
interpretation from plate reconstructions that the
hotspot was located close to a spreading ridge at ~80 Ma. The
seamount
magmas, then, appear to be derived from a mixture of plume
("enriched") and
predominantly aesthenosphere ("depleted") mantle
sources. The plume
end-member is more like the "Kilauea" than the
"Koolau" component of the
modern hotspot.
Plate reconstructions (e.g., Mammerickx and Sharman, 1988;
Atwater, 1989)
place a spreading ridge close to the Hawaiian hotspot at ~80 Ma.
In other
locations where a plume is close to a ridge (Galapagos Islands,
Easter
Island, and Iceland) the isotopic compositions of hotspot
products extend
toward MORB values. Several processes may lead to this effect.
The nearby
spreading ridge could have provided a higher temperature and
lower viscosity
and density regime, leading to significant entrainment of
aesthenosphere
within the rising plume. Thinner lithosphere near the ridge would
promote a
longer melting column in the plume, leading to greater degrees of
partial
melting and homogenization of geochemical heterogeneities (M.
Regelous et
al., unpubl. data). Also, younger, hotter lithosphere may be more
readily
assimilated by the ascending plume melts.
Thus, the thickness of the lithosphere could determine how much
aesthenosphere contributes to hotspot volcanism or how possible
isotopic
heterogeneities within the plume itself are expressed through
partial
melting. The (deep mantle?) region where the Hawaiian plume
acquires its
geochemical characteristics has probably not been homogeneous and
static.
But the degree of geochemical variability at given sites within
the Emperor
Seamounts has not been established on the basis of the few
analyses reported
so far."
============
(6) THE TERM ATMOSPHERE
>From Bob Kobres <bkobres@arches.uga.edu>
It seems that Duncan and I have an interesting dynamic concerning
the term
atmosphere--I use the word in perhaps too loose (--or is that to
lose?;^)
http://abob.libs.uga.edu/bobk/ccc/cc020101.html
#7) of a fashion and Duncan
corrects me. This happened earlier with regard to some conjecture
I was making about
events with more burn than blast:
http://abob.libs.uga.edu/bobk/discd.html
http://abob.libs.uga.edu/bobk/iceoxy.html
I had originally said something like 'an oxygen enhanced
atmosphere,' which
was sloppy and misleading. What I meant was a small temporary
volume of
oxygen enhanced air, although I now lean more toward ball
lightning type
phenomena to explain these burns. In this latest missive
regarding dark
objects I intended the term atmosphere to be inclusive of
anything that can
envelope Earth--sort of the opposite of how I messed up before
(actually I
was conceptually including the Magnetosphere). The Exosphere is
pretty far
out though and I still may have a chance to get by on the loose
definition
of just how far out that sphere extends:
http://daac.gsfc.nasa.gov/CAMPAIGN_DOCS/ATM_CHEM/exosphere.html
http://www.miamisci.org/youth/unity/Unity2/jerry/Our%20Atmosphere/
http://ssdoo.gsfc.nasa.gov/education/lectures/magnetosphere.html
The point that I was really trying to make however is that we are
still
pretty ignorant about how Solar System weather affects what we
observe from
a terrestrial perspective--along the same line as this earlier
submission
that focused upon events of 1737:
http://abob.libs.uga.edu/bobk/ccc/cc110499.html
#4
In the archive I did add back the observation snippets that did
not make the
mailing on the 18th:
http://abob.libs.uga.edu/bobk/ccc/cc041802.html
#12
Among these is a description of an April 9, 1879, destructive
fireball event
that occurred in Chicago; this may be related to the April
fireball
observations described by Pavel Spurny via Jiri Borovicka's
submission:
http://abob.libs.uga.edu/bobk/ccc/cc041902.html
#9
There are also a couple of recently published descriptions of
high energy
ball lightning, which may be more often associated with accretion
events
than is currently accepted.
Also, Duncan's comments caused me to think about the following
question
(from a few years back) about comet dust. I started to reply to
this at the
time but never actually sent the response because I was a
bit uncertain
about my way of calculating what might happen. Perhaps
Duncan could provide
a more informed opinion on this?
(4) SERIOUS DOUBTS ABOUT COMETARY DUST LOADING
>From Roy Tucker <tucker@noao.edu>
At 12:32 PM 11/8/99 -0500, this was in CCNet:
[ http://abob.libs.uga.edu/bobk/ccc/cc110899.html
]
"Actually his interpretation of the
evidence is more closely
aligned with the suggestion published by Fred
Hoyle and N. Chandra
Wickramasinghe in 1978 that the dinosaur
extinction was due not to
a cometary impact but rather to a close call.
The logic is
impeccable. The Earth is a tiny target, so for
every strike there
are thousands of close approaches. For
asteroids, only impacts
count. But for comets, a flyby results in our
planet passing
through the cometary coma, which can be larger
than the Moon's
orbit. In such an event, we would accumulate a
mass of dust, which
takes years to settle out of the atmosphere.
These crossings must
occur on millennial time scales. (Napier and
Wickramasinghe are
currently investigating the climatic
effects.)"
Dear Dr. Peiser,
The notion that the passage of the earth through a cometary coma
can deposit
sufficient dust in the atmosphere to have significant
environmental
consequences stretches credulity. A major volcanic eruption can
introduce
many cubic kilometers of silicate particles into the atmosphere,
perhaps a
volume exceeding the dimensions of the average cometary nucleus.
Even if a
cometary nucleus consisted entirely of silicate dust and was
totally
disrupted to fill the volume of the coma, the earth would sweep
up only a tiny
fraction of this material even during a central passage.
Let's assume a twenty kilometer diameter cometary nucleus made
entirely of
densely packed silicate particles with a mass of about 10^19
grams. Let us
disperse this material uniformly within a spherical volume with a
diameter
equal to the moon's orbit. The density of material will be about
2 x 10^-13
grams/cubic cm. A cylindrical 'core' with a diameter equal to
that of the
earth through the center of this spherical volume will contain a
total of 2
x 10^16 grams of material. This equal to about 7.4 cubic
kilometers of the
original comet nucleus.
Mount Pinatubo injected about 5 cubic kilometers of material into
the
atmosphere and produced some beautiful twilight colors. Krakatau
produced 18
cubic kilometers. Long Valley spewed 600 cubic kilometers and the
Yellowstone caldera dispersed 2000 cubic kilometers
(http://quake.usgs.gov/VOLCANOES/LongValley/sizes.html).
I think a little more information is required about their
hypothesis. Simple
introduction of dust into the atmosphere doesn't seem to be a
compelling
argument for environmental devastation from the skies.
Best regards,
- Roy Tucker
~~~~~~~~~~~~~~~~~~~~~~~~~~~
OK, an impact with a mass of 2x10^13 kg traveling at 30 km/sec
will
(according to E = 1/2 mv^2 ) liberate 9x10^21 joules or 8.5x10^18
Btu, which
equals a bit over 14 hours of solar radiation intercepted by
Earth. One ton
of TNT can release about 4.15x10^9 joules so the TNT equivalent
would be
2,168,674,698,795 tons of TNT or around a 2.2 million MT event.
Now the
diameter of the Moon's orbit around Earth is about 765,000 km so
our planet,
traveling at 30 km/sec, takes around 25,500 seconds to move this
far. So
while Earth is traversing Roy Tucker's hypothetical comet coma it
is
absorbing the equivalent of 85,046,067 tons of TNT or 85 MTs of
energy per
second for 425 minutes or SEVEN hours. I would expect that this
type of one
sided roasting might not be too good for the biosphere. Then of
course there
is the added dust from such an encounter--not a pretty picture!
A trip through an actual comet coma that brought us close to its
nucleus
would not be nearly this straight forward. The spacing of coma
material,
which would include water, would decrease as the nucleus neared
and then
increase upon leaving; there are also likely to be some large
lumps and
clumps of comet stuff orbiting about. In addition, there is apt
to be a
significant amount of organic matter within the coma soup and
these carbon
combinations probably play nasty tricks with atmospheric
norms. Billions
and billions of Bucky-balls? ;^)
What we really need to learn is more about the makeup of comet
nuclei and
the dynamics of the materials they shed. Volcanoes can produce a
pretty
respectable mess but they aren't very good at launching stuff
into
Space--most of the fall-out is local. Comets clearly have the
upper
advantage in depositing slow-to-settle aerosols into the topmost
layers of
Earth's atmosphere.
From:
http://rredc.nrel.gov/biomass/doe/rbep/we_agres/agres_bio.html
The total solar energy striking the earth's atmosphere is
estimated to be
5.2 x 10^21 Btu/yr (EJ/y).
Later.
bobk
Bob Kobres
Main Library
University of Georgia
Athens, GA 30602
bkobres@arches.uga.edu
http://abob.libs.uga.edu/bobk
===================
AND FINALLY: SENDING EMOTIONAL E-MAILS IS GOOD FOR YOUR HEALTH
>From Ananova, 22 April 2002
http://www.ananova.com/news/story/sm_572301.html?menu=news.scienceanddiscovery
A new study claims sending emails about how you feel is good for
your
health.
University students who wrote emotional emails were healthier
than those who
wrote non-emotional emails or didn't send them.
Texas University psychologists say they had less time off sick
then those
who didn't write emails about their feelings.
Psychologist Erin Brown says writing stops people internalising
stress.
The research showed students benefited from writing about their
reactions to
traumatic events like the September 11 attacks.
Prof Brown told The Daily Telegraph: "Sure, email is a fast
and convenient
form of communication and even a method for proliferating corny
jokes and
outrageous hoaxes. But results showed that even when administered
through
email, emotional writing still produced positive health outcomes.
"People have always known that talking or writing about
their problems helps
them feel better. This study provides empirical evidence that
written
emotional expression is beneficial to physical health, even when
conducted
through email."
Copyright 2002, Ananova
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