PLEASE NOTE:


*

CCNet 117/2001 - 9 November 2001
================================


"Suppose we find with certainty an object heading toward us, can we,
with the current technology, do anything to avoid the impact?
Unfortunately, the most likely answer to this question, in many cases, is:
No. Certainly we cannot hope to be able to move a 1-km object if the
future collision is discovered too late, nor can we hope to solve the
problem trying to destroy the impactor with nuclear explosives: celestial
mechanics works differently from ground military operations, and the
most probable consequence of a desperate, last minute attack would be to
have many impacts instead of one, with the additional problem of having
induced some radioactivity on the fragments."
--Andrea Carusi, Tumbling Stone, November 2001

 
"By the way, all these [deflection] methods were never tested or
applied for mitigation actions. They were only theoretically handled.
Besides, as already mentioned, the actual accomplishment of some of
these mitigation methods seems out of reach even in the distant
future, due to their insurmountable technical problems. Obviously, the hope
is that we would never need such remedies, but, as the old saying goes,
hope the best, get ready for the worse!"
--Germano D'Abramo, Tumbling Stone, November 2001
 

"These star-crossed lovers find themselves strangely handicapped by
the very intelligence that makes them such remarkable scientists. Dr.
Swift's star student, Denise, spent her youth absorbed in the sky,
an escape from the terrors of adolescence, but "her heart had little room
for anyone. It was too crammed with stars."
--Book review of Andrew Greer's debut novel "The Path of
Small Planets"


(1) ASTEROID DEFLECTION: WE ONLY NEED A LITTLE, GENTLE KICK....
    Tumbing Stone, November 2001

(2) EARTH-IMPACTOR MITIGATION METHODS
    Tumbing Stone, November 2001

(3) ALL IN THE FAMILITY: SCIENTISTS FIND MOTHER AND DAUGHTER ASTEROIDS
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(4) SLOAN IMPACT RISK SURVEY FALLOUT

(5) DISCOVERY OF BURIED IMPACT CRATERS ON MARS WIDENS POSSIBILITY OF ANCIENT
MARTIAN OCEAN
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(6) GEOLOGICAL MYTH BUSTING: EXTRATERRESTRIALS REALLY DON'T IMPACT
VOLVANOES?
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(7) ANOTHER SCIENCE MEDIA CENTRE LAUNCHES, BUT WILL IT DELIVER?
    Nature Science Update, 8 November 2001

(8) THE PRECAUTIONARY PRINCIPLE: A CRITICAL APPRAISAL OF ENVIRONMENTAL RISK
ASSESSMENT
    CATO Institute, November 2001

(9) THANKS TO THE SLOAN TEAM AND REMEMBER TAMBORA
    Andy Smith <astrosafe@yahoo.com>

(10) AND FINALLY: TERRESTRIAL BODIES LOOK TO THE SKY (BOOK REVIEW)
     The Christian Science Monitor, 8 November 2001

===================
(1) ASTEROID DEFLECTION: WE ONLY NEED A LITTLE, GENTLE KICK....

>From Tumbing Stone, November 2001
http://spaceguard.ias.rm.cnr.it/tumblingstone/issues/current/deflect.htm#carusi

by Andrea Carusi (*) - Copyright Tumbling Stone 2001

Discussions about the possibility to divert NEOs in route of collision with
the Earth have been going on for more than 10 years. The topic is
particularly difficult to address for many reasons. First, there is a lot of
concern about the means that should be adopted in order to move a mountain
in an adverse environment such as space; second, it is not clear at all what
would be the best strategy to achieve the desired goal; third, although
evereybody agrees that something should be done in case of a clear threat,
there is considerable debate about the timing, size and operational details
of a diverting maneuver.

In this number of Tumbling Stone we want to start addressing this important
issue: in the end, we are searching for NEOs that can collide with our
planet, and the final goal of our research is either to find that there is
no relevant danger for the near future (i.e., no sizeable objects on a
collision course in the next 100 years), or to detect a possible projectile
and to prepare countermeasures.

The first question that naturally comes to our mind is: suppose we find with
certainty (I'll come back to what "certainty" may mean) an object heading
toward us, can we, with the current technology, do anything to avoid the
impact? Unfortunately, the most likely answer to this question, in many
cases, is: No. Certainly we cannot hope to be able to move a 1-km object if
the future collision is discovered too late, nor can we hope to solve the
problem trying to destroy the impactor with nuclear explosives: celestial
mechanics works differently from ground military operations, and the most
probable consequence of a desperate, last minute attack would be to have
many impacts instead of one, with the additional problem of having induced
some radioactivity on the fragments. However, this is true for sizeable
bodies, while small objects could be moved or destroyed much more easily;
but we are very far, at the moment, from being able to detect a possible
impactor of any size, down to the Tunguska class.

The "warning time" is therefore a crucial parameter: this is usually defined
as the time lapse between the discovery of a future impact and the impact
itself. I will now address this point, showing the importance of an early
detection.

The path followed by asteroids and comets is dictated by two major forces,
originated by the solar gravitational pull (dict.) and by the perturbations
induced by the planets. Other forces, not due to gravitation, are also
active on relatively long time scales, but they are generally not relevant
in our context. If there were no planetary perturbations, these bodies would
move along an ellipse, following Kepler's laws (dict.). This is a perfectly
predictable situation, provided that the dynamical status of the object
(i.e., its orbital parameters (dict.)) are known with sufficient accuracy at
some time. Newton's universal gravitation (dict.), on the other hand, allows
us to compute the planetary perturbations with high precision, so that we
can be confident that our predictions will be accurate at least to the level
of accuracy of the object's orbital parameters. This is a crucial point
because it affects directly and dramatically our ability to predict "with
certainty" a future impact.

Suppose that you have an object that will impact Earth at some time in the
future, and suppose that you know "very well" its dynamical status. The
question is now: How much should we deviate this object in order to avoid
the impact? and when? We will see in a moment that "how much" and "when" are
two corners of the same problem.

The parameters of an orbit are determined by the position of the object in
space at a given moment and by the size and direction of its velocity with
respect to a given reference frame. Changing the size and/or direction of
the velocity vector would result in a change of orbit. This is what is
normally done to guide spacecrafts: maneuvers in space consist essentially
in rapid changes to the spacecraft velocity using rocket motors. There is of
course a direct relationship between the change in velocity (that is usually
called a "delta V") and the variation of the orbital parameters. For
instance, an increase of the velocity would translate in an increase of the
semimajor axis (the mean distance of the object from the Sun) and, thanks to
Kepler's third law, of the orbital period. This means that, after the
velocity variation, the object would take a longer time to arrive at a
specified point of its orbit, for example at the intersection with the
Earth's path, and this delay would grow with time. Since a delay in the
timing of the encounter is equivalent to a change of the minimum distance at
approach, our problem is to investigate what is the delta V to be provided
to the object so that, after a time lapse corresponding to the warning time,
the accumulated variation of minimum distance becomes greater than the
radius of the Earth or, in other words, the impact does not take place.

This computation has been done at the IAS (Carusi, Valsecchi, D'Abramo and
Boattini) using numerical integration of the orbital paths in a variety of
cases. The results confirm the preliminary evaluations made using very
simple analytical models, but also reveal the existence of specific
dynamical situations that may be of great relevance for the solution of this
problem.

Our simulations involved a few fictitious objects, whose orbits were very
close to the real ones. They have been forced to impact Earth, and their
path precisely determined in the 50 years preceding impact. We have then
applied a velocity variation at various moments during this time span,
searching for the minimum values of the delta V needed to avoid the
collision at the corresponding times before the anticipated impact. It is
quite intuitive that an early maneuver would require a smaller delta V, and
this is what has always been stated, but the shape of the delta V curve, and
its dependance on the dynamical characteristics of the involved bodies was
not known until now.

Let me present here only two cases, which are representative of two
completely different situations. The first refers to the asteroid 1996 JA1,
the second to 1997 XF11. Both are real asteroids, whose orbits have been
modified in our simulation to obtain an effective collision. The
corresponding delta V curves found with this method are shown in the figure:
in our simulation they impact Earth in 1996 and 2040, respectively.

click on the image to see it bigger
http://spaceguard.ias.rm.cnr.it/tumblingstone/issues/current/img/graf.gif
 
The case of 1996 JA1 is quite smple: at the beginning of the 50 years
interval, in 1946, the delta V needed to miss the Earth 50 years later is of
the order of 1 mm/s, or even less if the maneuver is applied at perihelion.
The difference in applying the maneuver at different position along the
orbit is shown by "waves" in the figure, whose lower points correspond to
perihelia. The size of this maneuver does not increase very much with time:
it is still of the order of 1 cm/s only 5 years before the impact date.

The case of 1997 XF11 is completely different. Here the delta V needed at
the beginning of the 50 years period, in 1991, is as small as 20-30 microns
per second, and decreases further in the following years, to rise again
until 2028 when the asteroid encounters the Earth very closely: this is the
close encounter that has been extensively reported by the press a few years
ago. Just after this encounter the delta V rises to about 1 cm/s, a value
very similar to that of 1996 JA1.

The reason for this discrepancy in the two cases must be searched for in the
phenomenon now known as "resonant return". The perturbations induced by the
Earth on 1997 XF11 at the encounter in 2028 have put the object almost
exactly in the 12:7 resonance with the Earth. The consequence of this event
is that 1997 XF11 impacts Earth exactly 12 years after that encounter. But
the interesting thing is that, as it is now known, the 2028 encounter acts
as an "amplifier" of the dynamical instability: there is considerable
difference in applying the delta V just before or just after the encounter
in 2028, a difference of about a factor of 130. In other words, when there
is a pre-impact encounter with the Earth, it is much easier to move the
object before than after that encounter.

This finding, already anticipated by analytical investigations, is of
extreme importance for our problem. It is true that the objects exhibiting
resonant returns, such as 1999 AN10 or 1997 XF11, are in principle more
dangerous, because they encounter the Earth repeatedly for an extended
period of time, but it is also true that these objects are the easiest to
deflect, provided that their orbits are known with high accuracy. This
demonstrates once again how important is the computation of very accurate
orbits for the most dangerous objects, once they are discovered.

There is another result from the computations done for this simulation. In
one case the relationships between the shape of the delta V curve and the
dynamical status are quite complex, being intimately connected to motion
close to resonances. We are just at the beginning of the exploration of this
important dynamical behaviour, and any discussion on deflection of incoming
objects must take into account that the timing and size of deflection
maneuvers must be studied with great care, after having investigated in
detail the possible dynamical evolution of the object.

Finally, one could use these results to analyse the relative merits of
various deflection techniques. An object of 1 km radius with a density of
2-3 g/cm^3, has a mass of about 10^15 g. If we want to accelerate it by 10
microns per second, it is sufficient to use kinetic energy because the
collision of a 5 tons projectile at 2 km/s of relative speed would do the
job. 5 tons is the weight of the Cassini spacecraft at launch. Furthermore,
we have studied only impulsive maneuvers, while for such small delta V's it
could perhaps be more convenient the use of more exhotic methods such as
solar sails or mass drivers. In any case, it is clear that an early
intervention would definitely resolve all problems related to the possible
use of nuclear devices.

Andrea Carusi (*) - president of the Spaceguard Foundation

Copyright Tumbling Stone 2001

=============
(2) EARTH-IMPACTOR MITIGATION METHODS

>From Tumbing Stone, November 2001
http://spaceguard.ias.rm.cnr.it/tumblingstone/issues/current/dabramo.htm

by Germano D'Abramo (*) - copyright TumblingStone 2001

The need to avoid the impact of an asteroid with the Earth has led to what
is now known as mitigation strategy. There are two basically different
approaches to the problem: the change of the asteroid's orbit (deflection)
or the asteroid fragmentation and its dispersal.

The fragmentation procedure appears to be risky and in some cases even
impossible for at least two reasons:

* it would require huge amounts of nuclear explosive to be put in orbit and
this cannot be done without some risk for the Earth environment.
* given our current knowledge, it is very difficult to predict the right
amount of energy required to completely fragment and disperse the asteroid,
and even if we succeed in this * operation we cannot exclude that the great
bulk of the asteroid's fragments falls on the Earth anyway (see actual issue
of T.S. "We only need a little, gentle kick ..." by Andrea Carusi.

Moreover, the fragmentation procedure is impossible in some cases, for
example:

* the asteroid is too big for the available nuclear explosive here on the
Earth (it is estimated that in order to fragment an asteroid 0.1, 1.0 and 10
km wide nuclear charges are necessary with energies of the order of some Kt,
Mt and Gt (dict.), respectively!).
* in order to produce optimum fragmentation, the charge should be buried in
the asteroid, with obvious (currently insuperable) technical difficulties.

Can a nuclear explosion be used to deflect an impactor?

Concerning the deflection procedure, it suffices to aptly modify the orbital
velocity of the impacting body along its revolution around the Sun. For the
sake of simplicity, we could say that the velocity change must lead the
asteroid gain ground (or lose it, depending on if we increment or decrement
its orbital velocity) with respect to the motion of the Earth during the
time span between the application and the predicted epoch of collision of an
amount of at least one Earth radius. Therefore, it is clear that the longer
the warning time before the epoch of the impact, the less the magnitude of
the velocity change required for the same deflection. Namely, in most cases
it is exactly an inverse proportion between warning time and magnitude of
velocity change, if we obviously ignore such peculiar cases like that
described by A. Carusi in this issue of T.S.

The velocity change can be impulsive or steady. It is impulsive if it is
delivered "instantaneously'', in one solution. The velocity change is steady
when a constant thrust is applied to the asteroid for a longer time span,
which could be even equal to the warning time before the impact.

Within the known mitigation strategies there are the following impulsive
methods:

Impactors: namely, space probes or specially designed projectiles which will
hit the asteroid at high velocity, spall off asteroid material, and will
therefore deliver an impulse (momentum dict.) able to change the asteroid
orbit (see the example of "We only need a gentle, little kick")

Asteroid-Asteroid collisions: this method consists in changing the orbit of
a small harmless asteroid so that it will collide with a larger asteroid on
collision course with the Earth and change its orbit.

Nuclear explosives: nuclear explosions could be used in two different ways:
(1) as a stand-off explosion at some distance from the asteroid surface; the
flash produced by the explosion vaporises the exposed side of the asteroid.
The surface material will therefore instantaneously spall away delivering an
impulse to the rest of the asteroid (see image above). (2) as an explosion
directly on the asteroid surface; such explosion excavates a huge crater and
ejects its material away from the asteroid. In this case, the deflecting
impulse is provided by the recoil from the ejected mass. As for the
fragmentation and dispersal strategies, some perplexities arise in these
cases: such ``energetic'' approaches to deflection seem to be very risky
because they are not so much controllable.

Among the steady mitigation methods there are:

Chemical, electric or nuclear propulsion: conventional chemical propulsion
system, electrical or nuclear fission engines could be attached to the
asteroids and fired when the thrust vector points to the desired direction
(due to the asteroid's own rotation).
Laser systems: in this case the asteroid surface is irradiated by an high
energy laser beam (ground-based or space-based). This beam would vaporise
surface material which will stream away from the asteroid producing thrust.

Mass drivers: mass drivers are devices which has to be installed on the
asteroid surface. They excavate and accelerate away from the asteroid
gravitational field small mass packages. The recoil produced by this
expulsion provides the thrust required to deflect the asteroid from its
pristine orbit.

Non-gravitational forces: this method consists, for instance, in covering
the asteroid surface partially or completely with some high-reflectivity
material (e.g. white powder, see T.S. number 5: "The sweet solution" by
Andrea Milani). This material would enhance the thrust given by the solar
radiation on the asteroid surface. Nevertheless, the effectiveness of this
approach is rather scanty, even with very small asteroids (e.g. of the order
of 10 meters), and pretty long warning times are needed to reach a sensible
deflection.

Mirrors and solar sails: for what concern solar mirrors, they essentially
act like laser system. A suitable mirror, orbiting around the asteroid,
collects solar radiation and focuses it onto the asteroid surface. This high
energy concentration vaporises the surface material creating a thrusting
stream. A different way to take advantage of solar radiation is to create
huge mirror sails and to attach them to the asteroid. In this case, the
thrust needed for deflection is provided by the solar light pressure. It is
pretty clear that this strategy suffers, more than others, from many
technical problems; for example, the sail area has to be at least in the
order of many square kilometers to provide a sensible thrust.

Solar panels, a mean of deflection?
 
By the way, all these methods were never tested or applied for mitigation
actions. They were only theoretically handled. Besides, as already
mentioned, the actual accomplishment of some of these mitigation methods
seems out of reach even in the distant future, due to their insurmountable
technical problems. Obviously, the hope is that we would never need such
remedies, but, as the old saying goes, hope the best, get ready for the
worse!

Copyright Tumbling Stone 2001

==========
(3) ALL IN THE FAMILITY: SCIENTISTS FIND MOTHER AND DAUGHTER ASTEROIDS

>From Andrew Yee <ayee@nova.astro.utoronto.ca>

Geological Society of America
Boulder, Colorado

Contact:
Ann Cairns, Director-Communications and Marketing
acairns@geosociety.org, 303-357-1056

Written by Kara LeBeau, GSA Staff Writer

FOR IMMEDIATE RELEASE: November 8, 2001

GSA Release No. 01-59

All in the Family: Scientists Find Mother and Daughter Asteroids

There are asteroids and there are asteroids. Most were once part of larger
"parent bodies" and some supply meteorites that plunge to Earth.

But how do you trace the family line of asteroids? Scientists compare
mineralogy of asteroids by analyzing their near-infrared spectra. They also
compare asteroids' orbits around the sun. And recently they found a perfect
match -- "uniting" in a scientific sense, mother and daughter asteroids.

"We determined the mineralogy of asteroid 1929 Kollaa and found that it was
once part of a larger asteroid called 4 Vesta. I was inspired to observe
these objects because they belong to the rare V-class of asteroids, and they
have orbits about the Sun that are very similar," explained Michael Kelley
from NASA's Johnson Space Center. "Vesta is the asteroid for which the
V-class was established. Until now, no mineralogical analysis had ever been
done on another V-type. In that sense, Vesta was unique until our recent
work was done. We found not only that this second V-class asteroid, 1929
Kollaa, was once part of Vesta, but that it is also related to a very
specific group of meteorites."

Kelley will present this new discovery on Thursday, November 8, at the
Geological Society of America's annual meeting in Boston.

Most planetary scientists believe that 4 Vesta is the source of howardite,
eucrite, and diogenite meteorites (HED) found on Earth, but Kelley points
out that it is not a direct process. "Vesta is located in a part of the main
asteroid belt that makes it almost impossible for it to deliver meteorites
directly to Earth. So there are probably intermediate asteroids, which were
once part of Vesta, located in more favorable orbits that provide delivery."


One of the ramifications of this discovery is that it will help scientists
build a geologic map of the asteroid belt and understand what forces have
acted on asteroids in the past. This information, along with asteroids'
mineralogy, would be crucial if there was ever a need to prevent an asteroid
from striking the Earth and causing a major disaster.

CONTACT INFORMATION

During the GSA Annual Meeting, November 4-8, contact Ann Cairns or Christa
Stratton at the GSA Newsroom in the Hynes Convention Center, Boston,
Massachusetts, for assistance and to arrange for interviews: (617) 954-3214.


The abstract for this presentation is available at:
     http://gsa.confex.com/gsa/2001AM/finalprogram/abstract_20247.htm

Post-meeting contact information:

Michael S. Kelley
NASA Johnson Space Center
Code SR
2101 NASA Rd. 1
Houston, TX 77058
E-mail: michael.kelley1@jsc.nasa.gov
Phone: 281-244-5119
Fax: 281-483-1573

Ann Cairns
Director of Communications
Geological Society of America
Phone: 303-357-1056
Fax: 303-357-1074
E-mail: acairns@geosociety.org

===========
(4) SLOAN IMPACT RISK SURVEY FALLOUT


--STUDY LOWERS LIKELIHOOD OF ASTEROID HIT
CNN, 8 November 2001
http://www.cnn.com/2001/TECH/space/11/08/asteroids.report.reut/index.html

--SURVEY LOWERS IMPACT RISK
BBC Online News, 8 November 2001
http://news.bbc.co.uk/hi/english/sci/tech/newsid_1644000/1644899.stm

--LESS REASON TO FEAR
ABC News, 8 November 2001
http://abcnews.go.com/sections/scitech/DailyNews/asteroidrisk011108.html

--KILLER ASTEROIDS MORE SCARCE THAN THOUGHT
New Scientist, 8 November 2001
http://www.newscientist.com/news/news.jsp?id=ns99991545

--ODDS OF EARTH BEING HIT BY BIG ASTEROID LOWERED
Houston Chronicle, 8 November 2001
http://www.chron.com/cs/CDA/story.hts/space/1124076

===============
(5) DISCOVERY OF BURIED IMPACT CRATERS ON MARS WIDENS POSSIBILITY OF ANCIENT
MARTIAN OCEAN

>From Andrew Yee <ayee@nova.astro.utoronto.ca>

Geological Society of America
Boulder, Colorado

Contact:
Ann Cairns, Director-Communications and Marketing
acairns@geosociety.org, 303-357-1056

Written by Kara LeBeau, GSA Staff Writer

FOR IMMEDIATE RELEASE: November 8, 2001

GSA Release No. 01-56

Discovery of Buried Impact Craters on Mars Widens Possibility of an
Ancient Martian Ocean

Soon after Mars was formed, it was bombarded by numerous large meteorites
and asteroids. Scientists have discovered an unexpectedly large grouping of
impact basins buried under Mars' northern plains that resulted from this
pounding. They used Mars Orbiter Laser Altimeter (MOLA) topographic data to
find them, because they can't be seen in images of the Martian surface.

Above these basins are thin young plains, but the lowland crust beneath them
is actually extremely old and was formed very, very early. According to
Herbert Frey of the Geodynamics Branch of NASA's Goddard Space Flight
Center, this is a radical departure from the popular
belief that the northern lowlands were formed later in Martian history,
perhaps by plate tectonic style processes.

Frey will discuss these findings on Thursday, November 8, at the Geological
Society of America's annual meeting in Boston, Massachusetts.

This discovery is a crucial piece to one of the greatest unsolved puzzles
about Mars-why does its surface have two distinct hemispheres: one that is
high and heavily cratered and one that is low and sparsely cratered? The
origin of this fundamental "crustal dichotomy" is uncertain both in terms of
how and when it formed. But this recent discovery of the numerous buried
craters may pin down the answer to when the lowlands first formed.

"The ancient age of the lowlands means whatever process produced them
occurred both early and relatively quickly," explained Frey. "Things like
plate tectonics may not work. Another ramification is that there have been
lowlands in the northern parts of Mars for essentially all of Martian
history. That means that at whatever early time conditions permitted liquid
water to exist on Mars, there was a northern lowland into which that water
could drain. So it is quite possible that a shallow ocean may have existed
on Mars very early in its history, as some have suggested based on
completely different data."

"The origin of the crustal dichotomy on Mars has been one of the main areas
of my own research for a long time, so anything that could tell us how old
the lowlands really were naturally was of interest," Frey said. "And of
course, the discovery aspects of 'seeing' (in elevation data) things that no
one else had ever seen or even guessed might be there is intrinsically
intoxicating. Not only has this work turned out to be very important, but
it's also been fun!"

CONTACT INFORMATION

During the GSA Annual Meeting, November 4-8, contact Ann Cairns or Christa
Stratton at the GSA Newsroom in the Hynes Convention Center, Boston,
Massachusetts, for assistance and to arrange for interviews: (617) 954-3214.


The abstract for this presentation is available at:
     http://gsa.confex.com/gsa/2001AM/finalprogram/abstract_25358.htm

Post-meeting contact information:

Herbert Frey
Geodynamics Branch
Goddard Space Flight Center
Code 921
Greenbelt, MD 20771,
E-Mail: frey@core2.gsfc.nasa.gov
Phone: 301-614-6468
Fax: 301-614-6522

Ann Cairns
Director of Communications
Geological Society of America
Phone: 303-357-1056
Fax: 303-357-1074
E-mail: acairns@geosociety.org

===============
(6) GEOLOGICAL MYTH BUSTING: EXTRATERRESTRIALS REALLY DON'T IMPACT
VOLVANOES?

>From Andrew Yee <ayee@nova.astro.utoronto.ca>

Geological Society of America
Boulder, Colorado

Contact:
Ann Cairns, Director-Communications and Marketing
acairns@geosociety.org, 303-357-1056

Written by Kara LeBeau, GSA Staff Writer

FOR IMMEDIATE RELEASE: November 8, 2001

GSA Release No. 01-52

Geological Myth Busting: Extraterrestrials Really Don't Impact Volcanoes?

The idea that volcanoes can erupt when the Earth is smacked by a large comet
or meteorite has become a popular idea in geology. But one challenger of
this idea says there's no proof to back it up.

"Not only is there not any firm evidence that an impact started a volcanic
eruption on Earth or on any other planet, there is no known mechanism by
which this can occur," explained Jay Melosh, professor of Planetary Sciences
at the University of Arizona. Melosh will present new research that
substantiates his case against this widely-held idea on Thursday, November
8, at the Geological Society of America's annual meeting, A Geo-Odyssey, in
Boston, Massachusetts.

"I will offer both evidence of the lack of impact-induced volcanism on other
heavily-impacted planets in our solar system and a theoretical analysis of
the conditions created by a large impact on Earth," he said. "This is new
research based on both observational studies of planetary images and
theoretical studies of the conditions surrounding an impact crater. It does
build on previous efforts by a number of researchers."

CONTACT INFORMATION

During the GSA Annual Meeting, November 4-8, contact Ann Cairns or Christa
Stratton at the GSA Newsroom in the Hynes Convention Center, Boston,
Massachusetts, for assistance and to arrange for interviews: (617) 954-3214.


The abstract for this presentation is available at:
     http://gsa.confex.com/gsa/2001AM/finalprogram/abstract_28367.htm

Post-meeting contact information:

Jay Melosh
Lunar and Planetary Lab-West
University of Arizona
Tucson AZ 85721 USA
E-mail: jmelosh@lpl.arizona.edu
Phone: (520) 621-2806

Ann Cairns
Director of Communications
Geological Society of America
Phone: 303-357-1056
Fax: 303-357-1074
E-mail: acairns@geosociety.org

==============
(7) ANOTHER SCIENCE MEDIA CENTRE LAUNCHES, BUT WILL IT DELIVER?

>From Nature Science Update, 8 November 2001
http://www.nature.com/nsu/011108/011108-13.html
 
London hub hopes to nurture science-media affairs.
HELEN PEARSON

Science journalists are being seduced in a new London club. The Science
Media Centre, which opens today, has ambitious plans to improve science news
coverage. But sceptics are concerned that the centre may benefit scientists
and the press more than the public.

Recent media controversies over health risks from genetically modified crops
and bovine spongiform encephalopathy (BSE) have left many researchers
peeved. They feel that more rapid, accurate communication of scientific data
and opinion might have allayed public fears.

"We are here to act as a portal," says Susan Greenfield, director of UK
academic society the Royal Institution, which is launching the 120,000
(US$175,000) centre. The centre hopes to become journalists' first call for
scientific contacts and information. It plans to provide rapid and sound
scientific response to breaking news through a database of experts or by
speaking on behalf of shy scientists.

Science communicators have long agreed that an informed public needs
researchers to open up to reporters. The very nature of research - giving
considered, informed judgement - is often incompatible with the quick
comment needed to meet press deadlines. "What they all fear is getting the
facts wrong," admits Greenfield.

Precisely how the centre will persuade reticent researchers to start giving
off-the-cuff comments is unclear, says Diane Stilwell, public-affairs
manager of the Institute of Physics, a learned society in London. "If
science and scientists want to be in the mainstream news they have to learn
to play by the news-gathering rules," she says. "We can't demand special
treatment."

How the media stand to gain from the centre is also vague. "It's not clear
to me that there's a demand," says Peter Briggs, chief executive of the
British Association for the Advancement of Science (BA), the UK's
science-communication organization. The BA and their US counterpart the
American Association for the Advancement of Science already offer databases
of experts as part of their online science press sites, AlphaGalileo and
Eurekalert!.

The US Media Resource Centre, a freephone referral service between
journalists and scientists, has been running since 1980. First-time
reporters are the ones who call, says co-ordinator Martin Baucom. Science
journalists, who mostly have their own contacts, only use them "once in a
while when they're really stumped".

Whether the media were sufficiently consulted before the launch has been
questioned. Discussion is a must to improve science coverage, thinks Briggs.
The ultimate aim would be to attain front-page stories from science
reporters and more scientifically informed stories from political ones, but
he says that "the age of pontification is over ... we should be sitting down
and talking with [the media]".

All things to all people

Greenfield's current plans for the centre are broad and ambitious for an
initial staff of three. "We want to be all things to all people," she says.
For the non-specialist media, the centre aims to explain scientific jargon
and methodology, such as control groups, statistical tests and peer review -
whether in person, print or online is not yet clear. For the scientifically
literate, they plan to build up interviews and surveys in anticipation of
newsworthy issues. "I'd like to get away from always being on the back
foot," she says.

Most agree it is a laudable first step towards improving the accuracy of
science news

The centre's goal to be an independent source of information without opinion
may be at odds with its parallel aims to be pro-active in releasing science
stories and raising awareness of science. The newly appointed head of the
centre, Fiona Fox, has a background in media relations; the hard science is
being left to the deputy head.

With broadcast facilities and plans for a restaurant and bar, the centre
also hopes to become a venue for science press conferences, broadcasts and
meetings - even a place to have coffee and "hang out", says Greenfield,
"like a science Groucho club".

Whether it becomes more than a scientist's clubroom only time will tell.
Most agree that it is a laudable first step towards improving the accuracy
of science news and that its role will evolve with time.

Opened on Wednesday evening by Cherie Booth, QC, the centre will begin
business in early 2002. Running costs of 200,000 a year for three years are
being sought from private and public sources, with each donation capped at
5% of the total to maintain independence.

Nature News Service / Macmillan Magazines Ltd 2001

=============
(8) THE PRECAUTIONARY PRINCIPLE: A CRITICAL APPRAISAL OF ENVIRONMENTAL RISK
ASSESSMENT

>From CATO Institute, November 2001
http://www.cato.org/cgi-bin/Web_store/web_store.cgi?page=precprinciple.html&cart_id

by Indur M. Goklany

The "precautionary principle"-the environmental version of the admonition
first, do no harm-is now enshrined in numerous international environmental
agreements including treaties addressing global warming, biological
diversity, and various pollutants. Some environmentalists have invoked this
principle to justify policies to control, if not ban, any technology that
cannot be proven to cause no harm. In this innovative book, Goklany shows
that the current use of the precautionary principle to justify such policies
is flawed and could be counterproductive because it ignores the possible
calamities those very policies might simultaneously create or prolong.

The precautionary principle, unfortunately, does not provide any method of
resolving such dilemmas, which are commonplace in the field of environmental
policy. To address that problem, Goklany develops a framework consistent
with the precautionary principle to resolve such dilemmas. That framework
ranks potential threats to the environment on the basis of their nature,
magnitude, immediacy, uncertainty, persistence, and the extent to which they
can be alleviated.

Applying that framework to three contentious environmental policy issues
facing humanity and the globe-DDT, bioengineered crops, and global
warming-Goklany shows that some popular policy prescriptions, despite good
intentions, are in fact likely to do more harm than good.

============================
* LETTERS TO THE MODERATOR *
============================

(9) THANKS TO THE SLOAN TEAM AND REMEMBER TAMBORA

>From Andy Smith <astrosafe@yahoo.com>

Hello Benny and CCNet,

Recognizing the pressing need to get larger telescopes involved in the hunt
for that one rock (with our name on it), which is still headed this way; it
was delightful to read the reports from the members of the Sloan Digital Sky
Survey (SDSS) team.

We continue to urge the large telescopes to take a more active roll in the
NEO hunt, while we still have the time....and no one would have been more
interested in seeing the Sloan telescope being used to help save the human
race, than Alfred P. Sloan, Jr. He was a gifted manager and electrical
engineer, who was the President of the General Motors Corporation, in 1934,
when he established his Foundation. He once said that, "Bedside manner is no
substitute for a good diagnosis" and he clearly favored getting important
data, as quickly as possible....especially when millions of lives are at
stake.

Global Disaster Threshold

Both Michael Paine and I have concluded that a Tambora-class terrestrial
explosion (1,000 megaton range) could cause a global disaster and that an impact
in the 200-300 meter range (mag 22-21) could provide this level of destructive energy.
The Tambora volcanic explosion, in 1815, produced the year-without-a-summer
(1816). There were millions of fatalities and most resulted from starvation.
The global disaster threshold is clearly much lower (or smaller) than
1km....probably in the 200-300 meter range (ACE#3-4).

Early Efforts

Many of us watched, during the 1990's, as a few of our courageous colleagues
built and operated the first asteroid early-warning telescopes.....starting
with film cameras and converting to CCD. We know that much of their support
was from volunteers and contributions and we greatly appreciate their
efforts.

However, with the lessons of the 90's behind us, it is now time to squarely
face the threat from the sky and to recognize that more than 95% of the
really dangerous NEO are smaller than a kilometer wide. We need to do all we
can to get larger telescopes and CCD cameras involved in the hunt and to
aggressively seek-out those tens-of-thousands of sub-kilometer NEO.

We need all of the excellent teams, who are now involved, as well as help
from the larger telescopes, which should report every sighting to one of the
teams. It is clear that they see asteroids all-the-time. It is also clear
that any one of those could be the one we are looking for....the one with
our name on it.

We are especially happy to see the development of the
Liverpool-JMU-Bisei-Faulkes team and we are hoping that this group will be
able to report all sightings to Dr. Isobe and his team, for further study
and the appropriate reporting to the MPC.

Tumbling Stone

The current issue of the Tumbling Stone, which is provided to the Web by the
Spaceguard Foundation and the NEO Dynamic Site (University of Pisa), is
especially interesting.  It is Issue 9:01/11/2001. See
http://spaceguard.ias.rm.cnr.it/tumblingstone/

In this issue, Andrea Causi, Germano D'Abramo, Andrea Milani and others
discuss NEO impact mitigation. We want to see Spaceguard address this
important matter and join with the Space Shield Foundation, the UN, the
AIAA, NASA, the ESA and the space and defense agencies of many countries, to
mount an effective global emergency preparedness program. We are also
encouraging the companies planning for space mining and tourism, to include
NEO emergency preparedness in their planning, since, until we have a
planetary defense system, they may be in the best position to respond
quickly.

Cheers
Andy Smith

============
(10) AND FINALLY: TERRESTRIAL BODIES LOOK TO THE SKY (BOOK REVIEW)

>From The Christian Science Monitor, 8 November 2001
http://www.csmonitor.com/2001/1108/p20s2-bogn.html

The cycles of a new comet provide the structure for this debut novel

By Ron Charles

For an astronomer, describing a single body in motion is simple. And
calculating the interaction of two objects is as easy as pi. But 300 years
after Sir Isaac Newton's equations on gravity, the interaction of three
bodies still baffles the best mathematicians.

For problems like that, call a novelist. They've been writing about the
interaction of bodies since the apple bonked Newton.
 
Perhaps none has blended the worlds of astronomy and romance so stunningly
as Andrew Greer. His debut novel, "The Path of Small Planets," traces the
lives of several scientists connected with a newly discovered comet.

We meet them in 1965, when Dr. Swift and his colleagues and graduate
students gather on a small island in the South Pacific to view his comet and
its attendant meteor shower. The warm air is thick with mosquitoes and
egotism. The scientists smirk at the natives and their primitive anxiety
about omens streaking across the sky.

Just as the first sparks appear above them, a young boy falls from the
observation deck to his death. For these students of physics, the accident
is an equation with brutal implications: "They were scientists," Greer
writes, "and could turn life into a laboratory setting, control every aspect
so that it pointed toward an answer. A crowd of artists, of dancers, of
poets could never have blamed themselves for terrible chance, but these
scientists thought they held chance firmly in their grip."

This inexplicable tragedy alters the trajectory of their lives in ways none
of them could predict. Greer's strategy for observing these changes is to
visit the scientists and their loved ones every six years, as they continue
to gather to celebrate the comet's appearance.

Survivors of "Same Time Next Year," take heart: In Greer's hands, this
periodic form seems entirely natural, even cosmic, placing us in the
position of that frozen ball of dust that races by the blue planet. Each
pass offers another sighting of brilliant people baffled by the calculus of
romance.

These star-crossed lovers find themselves strangely handicapped by the very
intelligence that makes them such remarkable scientists. Dr. Swift's star
student, Denise, spent her youth absorbed in the sky, an escape from the
terrors of adolescence, but "her heart had little room for anyone," Greer
writes. "It was too crammed with stars."

Now, at 25, she finds herself prone to the foolish, self-destructive
passions she should have worked out in her teens. "What could her life have
been?" she wonders. "Dances, coy looks, unwanted advances? Instead of
stars?"

Impulsively, she marries a pleasant but pedestrian novelist who can't share
her celestial interests or succeed in his own sphere. The person she truly
loves is Eli, her best friend's husband, a fellow astronomer who suffered
the same truncated childhood and accelerated maturity in the pursuit of
intellectual development.

Eventually, Denise and Eli have an affair under the guise of discovering
their own comet, but what they really discover is that a relationship
involving the betrayal of people who love them brings no lasting
satisfaction. The book's most moving passages follow the faint breezes of
resentment and loneliness that blow through a good marriage.

As the years pass, Greer moves on to the children of these scientists, young
people strangely wounded by the thin atmosphere of affection in their
scientific homes. Dr. Swift's daughter lives between the fear that she isn't
sufficiently intellectual and the dread of becoming like her father's nerdy
colleagues. Denise's son, like all the faculty children, must compete with
the stars.

Greer attracted critical praise last year for his first collection of short
stories, "How It Was For Me." This first novel displays the same startlingly
clever phrasing and a careful sensitivity with a wide range of characters -
young and old, male and female, scientists and their artistic spouses.

Despite his remarkably wise insight into the nature of marriage and
friendship, there's a certain chilliness to his portrayal that reminds us
that we're always looking at these characters through a microscope. His own
voice, polished to such luminescence, remains the most passionate object in
this haunting universe.

Copyright 2001, The Christian Science Monitor

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