PLEASE NOTE:
*
CCNet 61/2003 - 1 September 2003
--------------------------------
"However, Ryskind ignores the possibility of a collision
with an
extraterrestrial object, which Wagner says is the generally
accepted
cause of the demise of dinosaurs 65 million years ago. But
[Peter]
Wagner doesn't rule out the possibility that both might occur at
the
same time.
"The asteroid doesn't say to itself, 'This planet's in
enough trouble, I
won't hit it.'"
--Art Golab, Chicago Sun-Times, 29
August 2003
(1) ANOTHER K-T EXTINCTION THEORY: "DID METHANE EXPLOSIONS
WIPE OUT
DINOSAURS?"
(2) WEATHER OF MASS DESTRUCTION
(3) ORB-DEV TO CHALLENGE U.S. GOVERNMENT ON ASTEROID PROPERTY
RIGHTS
(4) WHAT HAS COPERNICUS TO DO WITH NEOS?
(5) SPACE DUST FLOODING OUR SOLAR SYSTEM
(6) ASTEROIDS - NOW FOR THE GOODS NEWS
(7) PLANETARY SCIENCE MEETING: ASTEROID ABSTRACTS
(8) 35TH LUNAR AND PLANETARY SCIENCE CONFERENCE
(9) AND FINALLY: BOLT FROM THE BLUE IS NOT A GOOD BET
===========
(1) ANOTHER K-T EXTINCTION THEORY: "DID METHANE EXPLOSIONS
WIPE OUT
DINOSAURS?"
Chicago Sun-Times, 29 August 2003
http://www.suntimes.com/output/news/cst-nws-methane29.html
BY ART GOLAB Staff Reporter
Explosions of methane gas erupting from beneath the ocean floor
with a
force 10,000 times more powerful than the world's stockpile of
nuclear
weapons could explain the mass extinction of more than 70 percent
of
life that occurred on Earth 250 million years ago.
And similar, lesser eruptions of methane over time could account
for
other, more recent mass extinctions and climactic changes,
including
Noah's flood, says Northwestern University Professor Gregory
Ryskind in
a paper published in September's issue of the Journal of Geology.
Ryskind, a chemical engineer, makes the point that methane,
continuously
produced beneath the ocean floor, can saturate the water to the
point it
becomes unstable enough to explode every 100,000 to 1 million
years.
Conditions are ripe for this to occur especially in deeper,
stagnant
waters that were prevalent in the oceans of 250 million years
ago.
"There, the methane is not oxidized, so it remains
combustible and
explosive," said Ryskind. "It can be released in an
extremely fast
fashion--you have a huge explosion, a conflagration, it's like
hell on
earth."
The stagnant Black Sea also fit the bill in the age of Noah,
Ryskind
says, and the Book of Genesis' account of the Great Flood
describes it
as coming from deep within the sea: "All the fountains of
the great deep
burst forth and the floodgates of the heavens were opened."
However, it is unlikely we will see such an event in our
lifetimes. For
one thing, the oceans are far less stagnant. Still, Ryskind
believes
that smaller methane eruptions occur every 100,000 years and
larger
events every million years.
"These time scales are so large that it would be unlikely to
happen
right away or in the next few years," Ryskind said.
"But on the other
hand, assuming the hypothesis is proven correct, there is no
doubt that
this will happen again."
Ryskind's paper cites research on ice cores and geologic
formations that
show periodic spikes in methane levels.
"I have listed seven very different pieces of observational
evidence,"
he said. "Each of these pieces could be explained by some
other
mechanism, but I am not aware of any mechanism which could
explain all
of them at once."
Except methane explosions.
"It's a perfectly likely explanation," said Peter
Wagner, associate
curator of invertebrate paleontology at the Field Museum.
"It certainly
has an advantage over some theories because it does explain why
land and
sea life goes extinct at the same time. That's the Achilles heel
in some
of the other hypotheses; they only explain one or the
other."
However, Ryskind ignores the possibility of a collision with an
extraterrestrial object, which Wagner says is the generally
accepted
cause of the demise of dinosaurs 65 million years ago.
But Wagner doesn't rule out the possibility that both might occur
at the
same time.
"The asteroid doesn't say to itself, 'This planet's in
enough trouble, I
won't hit it.' "
Copyright 2003, Chicago Sun-Times
==============
(2) WEATHER OF MASS DESTRUCTION
Australian, 28 August 2003
As It Happened: The Day the Earth Nearly Died 8pm, SBS (2.30am,
Perth)
THINK of the wonderful profusion of life on Earth today. Then
imagine 95
per cent of it dying in a terrible cataclysm. As this program
from the
BBC's Horizon series tells us, it's not a fantasy, it happened
250
million years ago, bringing the Permian period, with its myriad
strange
life-forms, crashing to an end and sending evolution into an
abrupt
reverse.
The Permian mass extinction dwarfed the demise of the dinosaurs,
caused
by an asteroid strike 65 million years ago, when 60 per cent of
species
were destroyed.
But 250 million years ago, something happened that wiped almost
every
trace of life from Earth. We know this, because suddenly in the
rock
strata from that time, the Permian fossils disappear leaving just
a
layer of blank rock -- the dead zone, as it's called tonight.
What this killer was and why it came, no one knew. There were
apparently
no clues in the Permian rocks, which are so old and eroded
they're hard
to study.
Then, in the early 1990s, one man stumbled on the significance of
something in Siberia that started others thinking. Tonight's
program
traces the scientific detective work that has finally fingered
the twin
culprits that visited our planet with such destruction.
The process began when Frenchman Professor Vincent Courtillon
realised
the importance of hundreds of thousands of square kilometres of
lava
buried under the frozen wastes of a part of Siberia known as the
Traps.
Some 250 million years ago, it split apart in a giant volcanic
eruption
that lasted millions of years.
Would the resulting climate change have wiped out almost all
life?
Courtillon said yes. But others said no.
What about a meteor strike, as had killed the dinosaurs? This
idea was
considered, then discounted.
Then, in the late '90s British geologist Paul Wignall travelled
to
Greenland -- which has the best preserved Permian rocks -- to
look for
new clues.
It's fascinating how he and others were able finally to piece
together
the story of the Permian mass extinction from one basic clue -- a
puzzlingly high level of carbon-12 in Greenland's Permian rocks.
The story goes like this: The Siberian eruption warmed the Earth
by some
five degrees, over time killing many species. But it also caused
a
gentle rise in sea temperature, eventually releasing frozen
methane from
the watery depths into the atmosphere. This, in turn, caused an
additional five degrees of global warming -- enough to take life
on
Earth to the brink.
Copyright 2003, Australian
===============
(3) ORB-DEV TO CHALLENGE U.S. GOVERNMENT ON ASTEROID PROPERTY
RIGHTS
Space Daily, 28 August 2003
http://www.spacedaily.com/news/asteroid-03k.html
Carson City - Aug 28, 2003
Orbital Development reports that it has received an official
response
from the United States Department of State in regard to that
company's
"Eros Project" which was initiated to establish
official respect for
property rights in Space.
Orbital Development, in the course of its Eros Project, has
claimed and
owns Asteroid 433 Eros since 03 March, 2000. On 12 February, 2001
the
United States landed the NEAR-Shoemaker spacecraft on the
privately
owned planetoid, prompting OrbDev to send an invoice to NASA for
parking
& storage fees totaling $20.00 for one hundred years storage.
After a
lengthy exchange of letters with NASA's chief lawyer, its General
Counsel, NASA refused to pay OrbDev's invoice.
On 13 Feb 03, OrbDev sent an official and legal Notice to the
United
States Department of State stating that NASA had exceeded it
authority
in this matter and the Department of State should clarify the
United
States' Executive Branch position on the critical issue of
individual
property rights in Space.
In a letter dated 15 Aug 03, Ralph L. Braibanti, the Director of
Space
and Advanced Technology in the Department of State's Bureau of
Oceans
and International Environmental and Scientific Affairs, wrote,
"We have
reviewed the "Notice" dated February 13, 2003, that you
sent to the U.S.
Department of State. In the view of the Department, private
ownership of
an asteroid is precluded by Article II of the Treaty on
Principles
Governing the Activities of States in the Exploration and Use of
Outer
Space, including the Moon and Other Celestial Bodies.
Accordingly, we
have concluded that your claim is without legal basis."
Orbital Development continues to dispute this controversial
conclusion
by the Department of State and will file suit in Federal court
for a
definitive decision that will be binding on the U.S. government.
OrbDev's President, Gregory Nemitz, stated, "America's
Founders valued
individual property rights second only to freedom of religion.
This U.S.
Department of State opinion is at odds with the Bill of Rights'
Ninth
and Tenth Amendments to the Constitution of the United States of
America.
OrbDev question's the government's ability to abrogate any
individual's
inalienable rights via international treaties and believes that
the U.S.
government has no Constitutional authority to abridge an American
individual's inalienable Rights; thus the treaty Mr. Braibanti
refers to
can only restrict States which are a party to that treaty, and
cannot
restrict an American Citizen who is rightfully acting as
sovereign."
OrbDev maintains that official recognition of property rights to
natural
objects in space is the key issue for opening the space frontier
to
development and the extraction of the nearly unlimited resources
which
are available in Space.
Copyright 2003, Space Daily
===========
(4) WHAT HAS COPERNICUS TO DO WITH NEOS?
Tumbling Stone, August 2003
http://spaceguard.ias.rm.cnr.it/tumblingstone/issues/current/eng/cop1.htm
by Andrea Carusi - President of the SGF
It may seem rather strange that a magazine such as Tumbling
Stone, which
is mainly devoted to NEO research and related topics, should
publish a
series on the history of science. In fact the readers should not
be
surprised, because the scientific study of NEOs (and also, of
course, of
the threat that they may pose to us) involves the use of two
fundamental
tools: astronomical observations, and orbit computations.
Astronomical observations in the modern sense (i.e. with the
abstract
purpose of studying the Universe, and not to search for the
hypothetical
influences that it could have on human vicissitudes) were started
by
Galileo Galilei at the beginning of the XVIIth century. On the
other
hand, the computation of orbits is based on the theory of
universal
gravitation as delineated by Isaac Newton, and published towards
the end
of the same century. However, neither Galileo nor Newton were in
the
position of building without foundations. Their lines of research
and
their successes were, to a large extent, a consequence of the new
intellectual climate established in Europe in the XVIth and
XVIIth
centuries. In particular we note the major transformations in
such study
that originated from the publication of the book De
Revolutionibus
Orbium Coelestium by Mikolaj Kopernic (Nicolaus Copernicus) in
1543.
The changes induced by that book are correctly termed the
Copernican
Revolution: it was a revolution that not only involved all
aspects of
the study of nature, giving rise to "science" as we
know it, but also
unhinged the basis of an entire philosophical system and produced
fundamental modifications in the relationships between man and
nature,
man and society, and man and divinity. This was the most drastic
change
in human thought to occur in the last two millennia, with many
consequences eventuating.
I am not a philosopher, nor a science historian, but I am a
scientist
and - most important - a scholar of dynamics and celestial
mechanics.
Therefore, I can try to address this question from an
"internal" point
of view, and the path that I follow in this short series of
articles is
simply the way in which a student of the motions of celestial
bodies
reflects on the birth of his own science.
The Copernican Revolution started with a scientific problem.
However,
its consequences went well beyond the solution of this problem,
disrupting the underlying basis of society in the Middle Ages. By
the
end of the Revolution nothing remained as it was before.
The "Ariadne's thread" leading from the earliest stages
of human history
through to the epoch of science has indeed been the understanding
of
planetary motion. The starting point was a "fact", as
always in the
investigation of the physical world. This fact was to hand, in a
natural
way to those who observed the sky, but it would not have had any
great
significance unless men learned to ponder the facts of nature,
and thus
search for an understanding of how the world works.
The fact in question is deceptive in its simplicity: while most
celestial objects visible in the sky do not change their relative
positions from night to night, some of them move with respect to
the
others. This simple observation has originated a line of thought
that
through the centuries has given rise to astrology, to myths and
religious beliefs, to cultural debates and political contests,
quite
apart from providing the foundations for the development of
modern
science, as explained here.
The main difficulty facing the first critical observers of the
heavens
was the irregular motion of these objects. All stars move, with
respect
to a terrestrial observer, as if they were fixed to an enormous
sphere
centered on the Earth. Exceptions are, of course, the Sun, the
Moon, and
the planets. [Indeed in ancient Greek the word
"planets", which
originally included both the Sun and the Moon, means
"wanderers".]
However, the motion of the Sun is fairly regular and so, to a
lesser
extent, is that of the Moon. To the contrary, as the planets move
across
the sky they display continuous changes in their apparent speeds,
and
sometimes also in their directions of motion. From the time of
the
Babylonians, about 25 centuries ago, it was possible to predict
with
considerable precision, limited only by the instruments
available, the
position of a star for many years into the future; the
corresponding
computations of the positions of the Sun and the Moon were more
complex,
but still feasible, to the point that the Babylonians were able
to
predict eclipses to some extent. However, the exact prediction of
the
positions of the most brilliant planets was a challenge for all
geometric and mathematical models, and remained an unsolved
problem
until the XVIIth century.
From a technical viewpoint an important reason for this
difficulty was
an erroneous choice of the reference frame. Since the Earth moves
around
the Sun like all other planets (something unknown to the ancient
observers), it does not represent a good reference point to use
as the
origin of celestial coordinates. All geocentric reference systems
(horizontal, equatorial, ecliptical) suffer from the same
drawback, and
the ancient mathematics was not able to handle conditions of such
complexity. Certainly some Greek scientists (Aristarchus in
particular)
supported the hypothesis that it is the Earth that goes around
the Sun,
and not the contrary, but this idea was counter-intuitive and
clashed
with the experience of absolute immobility that the human body
"feels"
when it is at rest with respect to the ground; nor was it
possible to
elaborate a mathematical theory able to explain it. Moreover, we
must
take into account that several great philosophers, from Eudoxus
to
Aristotle, built on the geocentric hypothesis a great
cosmological
theory which was perfectly acceptable to most: the few observed
discrepancies therefore had to be resolved in the framework of
the
existing theory and were not considered a sufficient reason to
alter the
global picture. To these "scientific" motivations we
must add those of a
philosophical, religious, and political nature. A mobile Earth
was
simply judged "unnatural", and contrary to the required
perfection of
the celestial sphere.
Quite apart from the above, the real cultural misunderstanding
that
prevented, until the XVIth century, the elaboration of a complete
and
coherent theory was to think that the celestial bodies followed,
in
their motion, rules different from those governing terrestrial
objects.
Nobody would dare to maintain that there is no difference between
the
heavens (the domain of the gods, and of perfection) and the Earth
(the
abode of men, and of corruption). We must remember that the idea
of
Nature as a whole, always and anywhere subject to the same
universal
physical laws, is a very modern concept, known in the
astrophysical
domain as the cosmological principle. It is an assumption, not a
theoretical demonstration: a reasonable axiom derived from
experience.
In our path through the upset caused by the Copernican Revolution
we
will move from the situation of planetary astronomy just before
the
publication of De Revolutionibus Orbium Coelestium (1543). We
will then
examine quickly the contribution by Copernicus and his followers,
and in
the end we will compare it with the image of the physical world
contained in the Philosophiae Naturalis Principia Mathematica by
Newton
(1687). We will see that a profound change in the intellectual
environment occurred during that interval, modern science then
being
built on the resulting new understanding. We will face, with
Johannes
Kepler, the problem of predicting the motion of planets and the
definition of the two basic concepts of mass and force; we will
confront
the difficulty that led Galileo Galilei to "invent" the
experimental
method and to formulate, even if only partially, the first laws
of
motion; and finally, we will follow the sometimes tortuous path
through
which Isaac Newton establish the foundations of the differential
calculus, the analytical method that allowed him to treat
uniformly the
problem of motion. At the end we will find the scientia nova (new
science), now equipped with all the tools necessary to describe
the
world using only mental reasoning and Galileo's sensate
esperienze
(meaningful experiments).
Astronomy at the time of Copernicus (Part I)
When Copernicus wrote his important book, De Revolutionibus
Orbium
Coelestium (1543), the status of planetary astronomy in Europe
did not
differ too much from that in Ptolemy's time, more than a thousand
years
before. Copernicus himself was a Ptolemaic, both because of his
education in astronomy and because of a sincerely-held
conviction. The
modern concepts of mass and force, on which the Newtonian
dynamical
theory is based, were totally foreign to him, and Copernicus's
mathematical methods were not greatly different from those used
by his
predecessors. His biggest merit, that makes him the real
instigator of
the scientific Revolution, was the ability to leave aside
non-scientific
considerations and to base his reasoning on the deepest
intellectual
honesty. This position is very explicitly clarified in the
preface
letter that Copernicus published with the De Revolutionibus,
addressing
it to Pope Paul III:
"It is easy to forecast, most Holy Father, that somebody, as
soon as
they learn that in these books... I ascribe certain movements to
the
terrestrial globe, will soon ask with loud voices that, because
of this
opinion, I should be banned...Therefore, I do not want to conceal
from
Your Holiness that I have been induced to think with a different
method
of computation of the motion of spheres, only because I am
convinced
that the mathematicians have no clear ideas about these
movements...
As a matter of fact[they] were unable to establish with certainty
any
system definitely corresponding to the phenomena..."
The fundamental point expressed by Copernicus, underlined in the
above
quotation, is that the Ptolemaic astronomy did not solve, nor
could it
ever solve, the problem of planetary motion. Therefore, the basic
structure of Ptolemy's theory had to be wrong. This apparently
drastic
conclusion was based on the evidence that the many astronomical
models
following that of Ptolemy (first through the Arabic and then the
Mediaeval European traditions), all based upon the geocentric
hypothesis, had produced a "monster", described by
Copernicus in this
way:
"What happened to them [the ancient mathematicians] was what
would
happen to a painter collecting hands, feet, head and other parts
of the
body from different models, then painting them in an exquisite
manner
and yet not as a single body and, since all these parts do not
harmonise
with each other, the result is a monster, and not a man."
So Copernicus, unlike many contemporary astronomers, was
conscious of
the fact that the Ptolemaic theory of the heavens, as well as its
subsequent modifications, was based on a belief that is
fundamentally
incorrect. But this realisation was, so to speak, based only on
principle, because the astronomical data on which Copernicus
based his
reform were insufficiently precise. Some of them were simply
wrong,
while others did not correspond to anything real, or were
misprinted
while copying. No astronomical theory, past or future, would have
been
able to fit with the available data.
The success of the Copernican theory
It is said that Copernicus was given the first copy of his book
on his
deathbed, in 1543. The book, therefore, was published and first
distributed after its author had disappeared from the scene. In
consequence the diffusion of Copernicus's ideas was very tardy.
What is
most surprising, however, is not so much this initial slowness in
the
spread of the book, but rather the delay in the onset of
reactions to
its content. One of the many reasons that have been identified
for this
delay is that De Revolutionibus is a technical work, written for
specialists. It was difficult read, even for the best educated
people of
the time, unless they had specific training in astronomy and
mathematics. Furthermore, all the texts used in academic
education in
that era, including that of Copernicus himself, had been written
many
years earlier and were invariably based on Ptolemy's theory.
Copernicus's ideas therefore became known rather slowly, and even
then
only in a rather limited professional circle. The wider reaction
exploded, in an impressive crescendo, only at the beginning of
the
XVIIth century, more than 60 years after the publication of the
book.
But, why did this reaction occur? Why was it so harsh? And, last
of all,
why did Copernicanism win in the end?
In fact, the reaction in the Protestant domain was fairly rapid,
such
that in 1539, even before the book's publication, Luther
criticised
rudely a "twopenny-halfpenny astrologer, who has tried to
demonstrate
that it is the Earth to turn, and not the sky and the firmament,
the Sun
and the Moon...". Luther's leading disciple, Melanchthon,
echoed his
words: "...somebody...has established that the Earth is
moving; and
maintains that both the eighth sphere and the Sun are at
rest...Well: it
is a lack of dignity to publicly maintain such concepts, and the
example
is dangerous."
The ideas of Copernicus had, from the beginning, a difficult time
also
in the scientific sphere. The colleagues of Copernicus, all
educated
with the Ptolemaic system, were rarely converted to this novel
hypothesis, mainly because the new concepts were not supported by
convincing proofs. The inertia of the scientific world towards
innovations has always been strong: it is a very conservative
field of
endeavour. To change one's opinions implies an admission that you
had
maintained an incorrect stance and taught wrong - or at least
obsolete -
doctrines. This requires a personal effort of revision, very
difficult
to do especially if you are of an advanced age.
The astronomers, however, soon realised that the Copernican
theory was
extremely useful, at least because it allowed them to compute the
positions of the planets in a much simpler and more accurate way.
This
is proven by the Prutenicae Tabulae published by Erasmus Reinhold
in
1551, based on the Copernican method. These tables were
extensively used
in reforming the calendar in 1582, under Pope Gregory XIII: the
Catholic
world had not yet come to the stage of regarding Copernicus as
being a
danger.
The most violent reaction, therefore, was not caused by
scientific
motivations. As Thomas Kuhn has much more recently explained,
"...if the choice between the traditional and the Copernican
universes
were a matter of concern only for astronomers, most probably the
Copernican solution would have acquired gradually and smoothly
the
victory. This choice, on the contrary, was not exclusively, and
not even
principally, a competence of astronomers, and when the debate
extended
outside the astronomical circles, it became highly stormy."
Knowledgeable persons of that era, without a strong scientific
background, found the Copernican ideas absurd and at odds with
common
sense. Cautiously supported by the professionals, but always from
some
distance, while being opposed and mocked by scholars in other
fields,
the theory had its strongest opponents in religion and politics.
We have already noted that the first reactions came from the
Protestants. They were opposed to the Copernican statements
concerning
the "truth" of the Holy Scriptures, particularly some
verses in the Book
of Ecclesiastes. Today, it is clear (or, perhaps I should say,
should be
clear) to everybody, believer or not, that the statements of the
Bible
must be read with caution when they do not refer directly to
facts of
faith. At that time this was not true, and represented the major
obstacle to the self-defence of Galileo. The Copernicans were
accused of
being "infidels" and "atheists", sometimes
with impressive parallels to
some of the most integralist positions that still exist nowadays.
It
must be noted, however, that the Catholic Church did not
immediately
join the movement against Copernicus: this happened only after
1610,
following the first of Galileo's trials. In 1616 Copernicus and
his
followers were accused of heresy, and the De Revolutionibus was
included
in the list of prohibited books. But the battle was by then
already
effectively lost: the Copernican ideas, thanks largely to the
work of
Tycho Brahe, Johannes Kepler and Galileo Galilei, had been
substantially
accepted by the most influential professionals, and the adventure
of
science had begun.
To be followed...
Copyright 2003, Andrea Carusi
================
(5) SPACE DUST FLOODING OUR SOLAR SYSTEM
National Geographic News, 27 August 2003
http://news.nationalgeographic.com/news/2003/08/0827_030827_spacedust.html
John Roach
A flood of interstellar dust is breaching the sun's weakened
magnetic
shield and drifting into the solar system, according to European
astronomers.
The interstellar dust particles measure about one-hundredth the
diameter
of a human hair. The bits are thought to supply the building
blocks of
all solid bodies in the galaxy, including the planets and humans.
"All atoms in Earth were in interstellar grains before the
solar system
formed," said Donald Brownlee, an astronomer at the
University of
Washington in Seattle. The dust is believed to be composed of
heavy
elements such as carbon, magnesium, iron, and calcium.
The dust grains pose no serious threat to the planets. But they
could
chip away at the solar panels on spacecraft, causing a gradual
loss of
power, and knock particles off asteroids, filling the solar
system with
even more dust. On Earth, stargazers may observe a greater number
of
shooting stars.
"All these effects are not yet observed...but they are
expected," said
Markus Landgraf, an astronomer with the European Space Agency in
Darmstadt, Germany. Landgraf discovered the influx of dust using
data
from the agency's Ulysses spacecraft.
Since its launch in 1990, Ulysses has monitored how much dust
enters the
solar system from the interstellar space around it. Until ten
years ago,
astronomers believed that bits of interstellar dust could not
penetrate
the sun's magnetic field.
Weakening Field
Using data gathered by Ulysses, astronomers learned that stardust
can
enter the solar system. However, the flow of stardust is
regulated by
the sun's magnetic field, which is drawn out by the solar wind-a
flow of
ionized gas that expands away from the sun's surface and extends
out
beyond the edge of the solar system.
The field was thought to be strong enough to prevent the tiny
interstellar dust particles from entering the solar system.
"The dust grains are however about five times larger and one
hundred
times more massive than was thought before," said Landgraf.
"That's why
the force of gravity is about the same or even a little less than
the
solar radiation pressure."
When the magnetic field weakens, more grains of dust are able to
leak
into the solar system. The field weakens periodically during
phases of
intense sunspot activity as part of the sun's 22-year cycle.
These phases of intense activity are called solar maximums. The
intense
activity causes the magnetic field to become disordered as its
polarity
reverses, rendering it less effective as a shield against tiny
dust
particles floating around in interstellar space.
What surprised Landgraf and his colleagues at the Max Planck
Institute
for Nuclear Physics in Heidelberg is that the influx of dust has
continued to increase since activity on the sun calmed following
the
2001 solar maximum.
The scientists believe the continued influx is due to the way in
which
the polarity changed. Instead of reversing completely, flipping
north to
south, the sun's magnetic poles have only rotated halfway and are
now
more or less lying sideways along the sun's equator.
"Before the current solar maximum, the grains were deflected
out of the
vicinity of the sun. Now with a global solar magnetic field
weakened
during maximum conditions, we see more grains," said
Landgraf.
This weaker configuration of the magnetic field is allowing two
to three
times more stardust to enter the solar system than at the end of
the
1990s. This influx of stardust could continue to increase as the
field
further weakens until the end of the current solar cycle in 2012.
Independent of the variations in the solar magnetic field,
astronomers
expect the influx of interstellar dust to increase sometime in
the next
10,000 years when the solar system drifts into a galactic cloud
known as
the G-cloud.
Measurements of the G-cloud indicate it is full of gas. "And
where
there's more gas in the galaxy, there's more dust,
normally," said
Landgraf.
Building Blocks
Brownlee, the University of Washington astronomer, serves as the
principal investigator for NASA's Stardust spacecraft. Stardust
was
launched in 1999 to collect bits of interstellar dust and comet
fragments and return them to Earth for analysis. Brownlee said
the
discovery of increased interstellar particles makes his job
easier.
"In terms of Stardust collecting interstellar grains as part
of its
cruise, it makes us happier that the flux has increased recently
and the
particle sizes are bigger than estimated earlier," he said.
Stardust will deploy material called "aerogel" to
capture the particles,
which move at about 16 miles (26 kilometers) per second relative
to the
sun. When the particles hit the aerogel-a block of silicon-based
substance that is 99.8 percent air-they slow down as they
penetrate the
material, creating carrot-shaped tracks.
A paper by Landgraf and colleagues on the influx of interstellar
dust
will appear in the October 2003 issue of the Journal of
Geophysical
Research.
Copyright 2003, National Geographic News
==============
(6) ASTEROIDS - NOW FOR THE GOODS NEWS
The Australian Centre for Astrobiology
ACA COLLOQUIUM SERIES
http://aca.mq.edu.au/Colloquia/colloquium.html
Asteroids - now for the good news
MICHAEL PAINE
Mechanical Engineer, Vehicle Design and Research Pty Ltd, Sydney
+
MARK SONTER
Physicist, Mark Sonter Consulting P/L
When: 1:00pm Thursday 11th September
Where: Building E7B Room 100, Macquarie University (Sydney)
Who: Everyone welcome
The danger to life due to a large asteroid or comet striking the
Earth
has only been fully recognised over the past few decades.
However,
asteroid and comet impacts are not all bad news for lifekind.
This talk
will cover some of the good outcomes from having asteroids and
comets
pass through our region of the solar system.
1. Providing raw materials for space exploration. Asteroids are
likely
to provide most of the raw materials needed for serious space
exploration. Such raw materials are needed to avoid to
prohibitive cost
of launching everything from Earth. Some near earth asteroids are
easier
to reach and mine than the Moon.
2. Creating habitats. Impact craters can produce conditions that
assist
microbiotic life in gaining a foothold. Examples are the creation
of
hydrothermal systems and the generation of cracks in
"shocked" surface
rocks that become habitats for early photosynthesizers.
3. Transferring life between planets. From time to time
microbe-bearing
rocks have almost certainly been blasted from the surface of the
Earth
by an impact and launched into interplanetary space. Some must
have
reached Mars and might have seeded that planet with Earth-life.
Estimates have recently been made of the chances of life jumping
between
stellar systems via this mechanism of transpermia and the odds
are not
at all good.
==============
(7) PLANETARY SCIENCE MEETING: ASTEROID ABSTRACTS
Michael Paine <mpaine@tpg.com.au>
Dear Benny
Next week is the American Astronomical Society/Division for
Planetary
Sciences (DPS) meeting, hosted by NASA Ames Research Center,
Moffett
Field, Calif. http://dps03.arc.nasa.gov/
see link for abstracts: Microplanet titles from DPS2003
http://dps03.arc.nasa.gov/
regards
Michael Paine
===============
(8) 35TH LUNAR AND PLANETARY SCIENCE CONFERENCE
Ron Baalke <info@jpl.nasa.gov>
http://www.lpi.usra.edu/meetings/lpsc2004/lpsc2004.1st.html
35th Lunar and Planetary Science Conference
March 15-19, 2004, League City, Texas
'
FIRST
ANNOUNCEMENT
- September 2003 -
Conveners -
Dr. Stephen Mackwell,
Lunar and Planetary Institute Dr. Eileen Stansbery,
NASA Johnson Space Center
Sponsored by -
National Aeronautics and Space Administration,
Lunar and Planetary Institute,
NASA Johnson Space Center
We are pleased to invite your participation in the 35th Lunar and
Planetary
Science Conference to be held at the South Shore Resort and
Conference
Center in League City, Texas, March 15-19, 2004. This conference
brings
together international specialists in petrology, geochemistry,
geophysics,
geology, and astronomy to present the latest results of research
in
planetary science.
SPECIAL SESSIONS
You are encouraged to submit ideas and suggestions for plenary or
special
sessions to Mary Cloud (cloud@lpi.usra.edu)
by October 10, 2003, so they
can be considered, planned, and publicized. Organizers of these
sessions
should be prepared to serve on the Program Committee, or to have
a fully
empowered delegate serve on the Program Committee, if requested
by the Conference
Chairs. Authors of invited talks for special sessions must meet
the same
deadline for abstracts as authors of contributed papers (see
below).
Organizers who wish to have invited talks represented in the
conference
abstract volume should make the invited speakers aware of the
deadline
restrictions when inviting their presentation.
MEETING FORMAT
Participants may indicate a preference for oral, poster, or
print-only
presentation. The Program Committee will make all decisions on
the mode
of presentation to ensure a balance of as many important new
research
results as possible. Selection criteria will be based on the
relevance of the
subject matter to the conference and the quality of the science.
The
4.5-day conference will be organized by topical symposia and
problem-oriented
sessions.
ABSTRACT DEADLINE
To allow sufficient time and personnel to prepare for the program
committee meeting, we will have TWO separate deadlines for
electronic submission
of abstracts. The deadline for electronically submitting
abstracts in PDF
format will be 5:00 p.m. (CST) Tuesday, January 13, 2004. Authors
who
are unable to produce PDF files must submit their abstracts
electronically
by 5:00 p.m. (CST) Tuesday, January 6, 2004.
Authors who are unable to submit electronically will have to
request
special instructions (phone: 281-486-2142; fax: 281-486-2125;
e-mail:
publish@lpi.usra.edu).
Hard-copy submissions will be due at the LPI no
later than January 6, 2004.
Non-PDF submissions or hard-copy submissions that arrive after
January
6, 2004, will not be considered for the conference.
Detailed information regarding abstract preparation and
submission will be
available via the meeting Web page and will be included in the
second
announcement, to be posted on the conference Web site by the
middle of
November.
SUBMISSION RESTRICTIONS
There will again be a limit of TWO abstracts per first author for
oral
or poster presentation requests. If you submit two abstracts, you
will be
asked to rank them in order of preference.
As was the rule last year, print-only abstracts will be allowed,
but
ONLY from those authors who are NOT submitting an abstract for
oral or poster
presentation. In other words, if you're requesting a print-only
abstract, you cannot submit an abstract for any other type of
presentation.
Authors are limited to ONE print-only request.
The program committee will strictly enforce the above policies.
Abstracts submitted in violation of these policies will be
rejected. The only
exception will be for those who are invited to give a talk at a
special
session (e.g., the Masursky Lecture, or a special topical
session).
Those abstracts will not be counted against authors as one of the
two
abstracts they are allowed to submit.
FUTURE ANNOUNCEMENTS
More detailed information will be available in future
announcements
posted on this Web site (see schedule below). To be added to the
mailing list
to receive electronic reminders or special announcements via
e-mail, please
return the electronic Indication of Interest form by October 24,
2003.
(It is important that you provide us with a valid e-mail
address.)
CONTACT INFORMATION
For further information regarding conference logistics, contact
Mary Cloud
phone: 281-486-2143;
fax: 281-486-2125;
e-mail: cloud@lpi.usra.edu.
SCHEDULE
October 10,
2003
Deadline for suggestions on Special
Sessions
October 24,
2003
Deadline for Indication of Interest
forms
November 14,
2003
Second announcement posted on this Web
site
TUESDAY, January 6, 2004,
Deadline for hard-copy submission and
5:00 p.m. (U.S.
CST)
non-PDF electronic abstract submissions
TUESDAY, January 13, 2004, Deadline
for electronic abstract
5:00 p.m. (U.S.
CST)
submissions in PDF format
On or before February 3, 2004 Final announcement with
preliminary
program
and abstracts posted on this Web site
===================
(9) AND FINALLY: BOLT FROM THE BLUE IS NOT A GOOD BET
The (Sydney) Daily Telegraph, 1 September 2003
A STRAW poll of the office last week produced a most interesting
result.
The question posed was, if there was one thing you could ask of
science
what would it be?
Surprisingly, the only suggestion that featured more than once
was: what
are my chances of being hit by a meteorite?
It's a fair if rather odd question to ask and not one many
scientists
could answer.
However, and I have to admit to surprise when I discovered it,
someone
has actually calculated these odds.
In 1994, scientists at the Jet Propulsion Laboratory in Pasadena,
California, worked it out. Based on the number of meteorite
strikes in
China both large and small, somebody somewhere on the planet
should be
hit by a 100g meteorite once every 14 years.
NASA engineer Dave Morrison more recently estimated that the odds
of a
person being hit by a meteorite are about one in a million. The
odds of
winning Lotto range from one in five million to one in 80 million
depending on where you live. The odds of being hit by lightning
are one
in 300,000.
However, if a meteorite was 1km wide it could kill millions of
people
and a 10km wide meteorite would probably wipe out much of the
planet.
So, it's not so much a question of an individual being hit in the
head
by space junk. The real problem for insurance companies would
have to be
the odds of a giant meteorite or asteroid slamming into the
planet and
wreaking global devastation.
The earth's atmosphere is pounded by meteorites every day.
Fortunately,
most don't make it through and burn up in the atmosphere.
If you don't believe it, then go out to the country and look at
the
night sky for a while. You will probably see what we call a
shooting
star.
Of course these streaks of light across the sky are not stars at
all but
meteorites.
Or you could ask the people of the northern NSW town of Guyra,
who had
one come down in their water supply a few years back.
There was also a more recent incident in which a piece of space
rock
crashed through the roof of a North Coast house and landed in the
lounge
room.
Then there is the one that landed in the Gulf of Mexico and wiped
out
all the dinosaurs 65 million years ago.
Now, there is a 1km wide meteorite known as 1950AD which NASA and
many
of the world's leading astronomers have calculated has a
trajectory
which puts it on a collision course with earth in 800 years.
The odds of this happening they claim are about one in 300.
But this may not be as important as what would happen to us if it
did.
This stuff is not science fiction.
Copyright 2003, The Daily Telegraph
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