CCNet, 034/2000 - 17 March 2000


     "These objects have been called preliminarily IEOs (objects
     Interior to Earth's Orbit) and should be as populous as at least
     60-70% of the current Aten population. These objects are important
     and should be taken into account when assessing the NEO impact
     risk and when planning discovery surveys. The major problem with
     IEOs, however, is that they are hardly observable from the ground,
     since they never reach large solar elongation angles. Therefore, a
     space-based facility seems most appropriate and needed if we want
     to find these objects."
        -- Alberto Cellino, Astronomical Observatory of Torino


    Larry Klaes <>

    Los Angeles Times, 16 March 2000

    M. Efroimsky*) & A. Lazarian, HARVARD UNIVERSITY

    A.A. Christou*) & K. Beurle, UNIVERSITY OF LONDON

    Alberto Cellino <>

    Richard A Muller <>

    Jeremy Tatum <UNIVERSE@uvvm.UVic.CA>

    Charles F. Peterson <>

     Bob Kobres <>

     Jeremy Tatum <UNIVERSE@uvvm.UVic.CA>



Donald Savage
Headquarters, Washington, DC                      March 16, 2000
(Phone:  202/358-1547)

Ann Hutchison
Johnson Space Center, Houston, TX
(Phone:  281/483-5111)

Jean-Claude Paradis
Natural Resources Canada, Ottawa, ON
(Phone:  613/992-9426)  

RELEASE:  00-41


     A meteorite that exploded over a remote area of northwest
Canada in January may offer "a new window into the universe before
the solar system was created," said a NASA scientist who has begun
analyzing some of the meteorite fragments.

     The very primitive composition and pristine condition of the
4.5-billion-year-old meteorite "offers us a snapshot of the
original composition of the entire solar system before the planets
formed," said Dr. Michael Zolensky, a cosmic mineralogist at
NASA's Johnson Space Center (JSC) in Houston.  "It tells us what
the initial materials were like that went into making up the
Earth, the Moon and the Sun."  The age of the solar system is
about 4.5 billion years.
     "These meteorite fragments are of immense scientific value
and interest," said Dr. Richard Herd, Curator of National
Collections for the Geological Survey of Canada.  "This rare find
potentially will contribute to a better understanding of the
nature of the universe."  He added that finding previously
undetected compounds in the fragments will have implications for
both planetary and biological sciences worldwide.

     The scientists described the fragments -- lumps of crumbly
rock with scorched, pitted surfaces -- as resembling partly used
charcoal briquettes:  black, porous, fairly light and still
smelling of sulfur.

     Several factors combined to make this meteorite a cosmic
bonanza for scientists.  First, it is a carbonaceous chondrite, a
rare type of meteorite that contains many forms of carbon and
organics, basic building blocks of life.  Carbonaceous chondrites,
which comprise only about 2 percent of meteorites known to have
fallen to Earth, are typically difficult to recover because they
easily break down during entry into Earth's atmosphere and during
weathering on the ground.  

     Zolensky said the last time a carbonaceous chondrite like
this fell to Earth and was recovered was 31 years ago.   "This is
probably the only time in my career this will happen," he said.

     The location and timing of the fireball also contributed to
the scientific value of the samples.  The fragments are part of a
meteor that blew apart over a remote area of the Yukon Territory
the morning of Jan. 18, 2000.  The resulting sonic booms startled
residents as far away as British Columbia and Alaska.  The frozen,
snow-covered ground of the remote Yukon provided near-ideal
conditions for preservation, Herd said. 

     The finder, a local resident who has requested anonymity,
collected the fragments in clean plastic bags and kept them
continuously frozen.  These are the only freshly fallen meteorite
fragments recovered and transferred to a laboratory without
thawing.  Keeping the fragments continuously frozen minimized the
potential loss of organics and other volatile compounds in the

     About 2 pounds of meteorite fragments have been recovered so
far.  Of those, Zolensky has about a pound of fragments provided
by the Canadian government and the University of Calgary.  The
finder loaned them to the university and to the National Meteorite
Collection of the Geological Survey of Canada, Natural Resources
Canada (NRCan) in Ottawa, which provided the still-frozen samples
to JSC for study and analysis.  NASA is working closely with NRCan
scientists and is providing results of the analysis to them.  "We
are very sensitive to the fact that these are Canadian
meteorites," Zolensky said.  Any future studies will be done in
cooperation with scientists worldwide.
     Scientific analysis of the fragments has just begun.  Tests
have been limited to two non-destructive activities: making a thin
section to analyze the mineralogy of the fragments, and measuring
induced radioactivity.  Tests for induced radioactivity, which are
being carried out by Dr. David Lindstrom of JSC, measure the
object's exposure to space radiation.  This can be used to
determine the size of the original meteoroid in space, estimates
of which range up to 50 feet in diameter, with a mass of more than
55 tons.

     The next step in the study of the fragments will be baseline
analyses of the organics in the meteorite.  This would require the
destruction of some samples, and negotiations are under way with
the finder for permission to do such tests.

     "The nice thing about having a sample like this is that you
don't really know what you're going to find or where it's going to
lead," Zolensky said.  "You can tuck samples away for the future
when new questions come along that people can't even think up


From Larry Klaes <>

From The Dallas Morning, 13 March 200

Geneticists help trace organisms' impact on planet

It's a match made on Earth. The rock jocks have found the gene scene.
Geologists and geneticists usually keep to themselves. But a marriage
may be on the horizon. New research in genetics promises a long and
fruitful future for geologists.

Scientists say genetic information can help explain how microscopic
living organisms have changed the land, water and atmosphere since Earth
formed 4.6 billion years ago.

"Various pieces of that story are going to be in the rock record, and
other pieces are going to be in the genetic data," said Chris House, a
geoscientist at Pennsylvania State University in University Park.
"Merging those two is going to give us a much better picture of the
diary of life on Earth."

Besides giving scientists a better picture of how Earth has changed,
combining genetics and geology could give scientists clues to conditions
that might support life on moons or other planets in the solar system.
Genetic studies should also help geologists who want to use microbes to
clean up the environment.

And Earth's past life can only get more interesting by studying
microbes, researchers say.



From Los Angeles Times, 16 March 2000

Despite previous reports that global warming could unleash epidemics or
other harms to health, a blue-ribbon scientific panel mandated by
Congress found no conclusive evidence to justify such fears. The
12-member panel analyzed existing data to predict the effects of a
slight rise in average global temperature on five possible outcomes:
future heat waves, extreme weather events like tornadoes, air
pollution, waterborne and food-borne illnesses, and infectious diseases
carried by insects and rodents.

Though the U.S.-funded panel, led by Jonathan Patz of Johns Hopkins
University School of Hygiene and Public Health, acknowledged that
various adverse health effects were possible, "the levels of
uncertainty preclude any definitive statement" about what is likely to
happen. Released Wednesday in the journal Environmental Health
Perspectives, the analysis also acknowledged the possibility that
global warming might have the seldom-heralded benefit of reducing
deaths from winter exposure to cold.

Copyright 2000, LA Times


M. Efroimsky*) & A. Lazarian: Inelastic dissipation in wobbling
SOCIETY, 2000, Vol.311, No.2, pp.269-278


Asteroids and comets dissipate energy when they rotate about any axis
different from the axis of the maximal moment of inertia. We show that
the most efficient internal relaxation happens at twice the frequency
of the precession of the body. Therefore earlier estimates that ignore
the double frequency input underestimate the internal relaxation in
asteroids and comets. We suggest that seismological data of the Earth
may poorly represent the acoustic properties of asteroids and comets as
internal relaxation increases in the presence of moisture. At the same
time, owing to the non-linearity of inelastic relaxation, small angle
nutations can persist for very long time spans, but our ability to
detect such precessions is limited by the resolution of the
radar-generated images. Wobbling may provide valuable information on
the composition and structure of asteroids and on their recent history
of external impacts. Copyright 2000, Institute for Scientific
Information Inc.


A.A. Christou*) & K. Beurle: Meteoroid streams at Mars: possibilities
and implications. PLANETARY AND SPACE SCIENCE, 1999, Vol.47, No.12,


In order to assess the possibility of meteoroid streams detectable from
the surface of Mars as meteor showers we have derived minimum distances
and associated velocities for a large sample of small body orbits
relative to the orbits of Mars and the Earth. The population ratio for
objects approaching to within 0.2 AU of these two planets is found to
be approximately 2:1. The smaller relative velocities in the case of
Mars appears to be the main impediment to the detection of meteors in
the upper atmosphere of that planet. We identify five bodies, including
the unusual object (5335) Damocles and periodic comet 1P/Halley, with
relative orbital parameters most suitable to produce prominent meteor
showers. We identify specific epochs at which showers related to these
bodies are expected to occur. An overview of possible detection methods
taking into account the unique characteristics of the Martian
environment is presented. We pay particular attention on the effects of
such streams on the dust rings believed to be present around Mars. (C)
1999 Elsevier Science Ltd. All rights reserved.



From Alberto Cellino <>

Hello Benny,

this is the first time I am sending a short contribution to the CCNet
discussion, since I must admit that I am only a desultory reader. I
write in order to express my appreciation of the letter by Duncan Steel
(CCNet, 16 March). I like his approach, and I agree with most of what
he said, mainly the general concept that nothing is straightforward in
the problem of NEO detection and appreciation of the impact risk.

In this context, I would like to point out that a paper has been
recently published by Icarus (the authors being P. Michel, V. Zappala`,
P. Tanga and myself, Icarus 143, 421-424), that shows that a class of
NEOs with orbits completely interior to Earth's must exist, and should
be fairly abundant. This conclusion follows from numerical integrations
of a large number of NEOs of different orbital classes. The
integrations show that these objects spend a significant fraction of
their lifetime in orbits having aphelion distances smaller than the
perihelion distances of the Earth. These objects have been called
preliminarily IEOs (objects Interior to Earth's Orbit) and should be as
populous as at least 60-70% of the current Aten population. These
objects are important and should be taken into account when assessing
the NEO impact risk and when planning discovery surveys.

The major problem with IEOs, however, is that they are hardly
observable from the ground, since they never reach large solar
elongation angles. Therefore, a space-based facility seems most
appropriate and needed if we want to find these objects. By the way, a
space-based facility would be in any case very useful in order to make
physical characterization of NEOs. We should not forget that we need
to know not only how many NEOs exist, but also how large they are,
their size distribution and general mineralogic composition. All this
is sorely needed not only for the purpose of evaluating the NEO impact
risk, but also to achieve a far better understanding of these objects
from the purely scientific point of view. Where are they coming from?
What about the parent bodies? What is their evolution? Is the NEO
population in a steady state or not?

All these are open questions deserving deep analysis. In turn, a
serious attempt at answering these problems requires a lot of physical
information that is currently severely missing, due to the need of
observing in thermal IR (to derive sizes and albedoes) to the lack of
dedicated suitable instruments and observing time, etc. Some of my
colleagues and I are convinced that a major effort should be produced
by the scientific community to improve the situation from the point of
view of NEO physical characterization, as well as from the point of
view of discovering IEOs.

Alberto Cellino
Astronomical Observatory of Torino


From Richard A Muller <>

Dear Benny Peiser,

I found many of Glickson's comments interesting and relevant. I will
reply only to those about which I have something to add.

He said,

> Due to the Moon-Earth gravity section of 1:1.4, Earth was more
> heavily bombarded and no 1:1 correlation can be drawn between lunar 
> and terrestrial impact history.

I disagree.. Although the stronger gravity of the Earth causes a
stronger gravitational focussing, this effect does not change with
time. We do not measure absolute impact rates, only the time behavior.
So the pattern of decrease and increase will be the same on the Earth
and the Moon, although the absolute rates (i.e. impacts per square
kilometer) will be different.

He said,

> 9. Whether an impact periodicity, variably suggested in the range of
> 26-35*10^6 years (Rampino and Stothers, 1984, Nature, 308, 709-712;
> Rampino, 1998, Celestial Mechanics and Dynamical Astronomy, Kluwer
> Academic Publ., 49-58), is confirmed or otherwise, this in itself
> does not resolve the question of the origin of such periodicity,
> alternatively interpreted in terms of (1) a "Nemesis" twin star
> (Muller, 1988, Nemesis - The Death Star, Weidenfeld and Nicolson, New
> York), and (2) Z-shaped solar system oscillations across the galactic
> plane with consequent disturbance of the cometary Oort cloud (Bachal
> and Bachal, 1985, Nature, 316, 706-708; Napier, 1998, Celestial
> Mechanics and Dynamical Astronomy, Kluwer Academic Publ., 59-76).

The proper reference to the Nemesis theory is not my popular book, but
"Extinction of Species by Periodic Comet Showers," Marc Davis, Piet
Hut, and R.A. Muller,  LBL-177298 (December 1983), Nature 308, 715-717
(1984).  The Rampino theory is not viable, since the oscillations of
the sun in the Galaxy are quite small, and the variations in density
experienced by the solar system are too small to affect impacts.  The
Nemesis theory has been attacked as having an unstable orbit, but that
conclusion is also incorrect; for references, see my web site. 
Moreover the various theories predict different periods for the impact
cycle: Rampino and Stothers predicts 36 Myr, not 26.

I have posted additional information on my web page,   
Please also check the press release issued by the Lawrence Berkeley


Richard Muller

Professor of Physics
University Distinguished Teacher
50-5032 LBL
University of California
Berkeley, California 94720
phone: (510) 486-7430


From Jeremy Tatum <UNIVERSE@uvvm.UVic.CA>

Concerning the recent correspondence concerning what spin parameter
is most significant about an asteroid, I was encouraged that Petr
Pravec suggested the ratio between centrifugal and gravitational
force, because just last week I made my students calculate exactly
that quantity (also including oblateness effects) for the major
planets Mercury to Neptune.  Not surprisingly, the effect is very
pronounced for rapidly-rotating oblate Jupiter  and negligible for
slowly-rotating spherical Venus.  Perhaps I should not get them to
repeat the same calculation for all 100,000 asteroids, or however
many there are.

I suppose it might also be argued that what causes an asteroid to
spin rapidly might be an oblique collision by an impactor.  In that
case, I think the asteroid experiences an impulsive torque, and the
time integral of that torque results in (indeed is equal to) a change
in the angular momentum of the asteroid.  From that point of view, I
suppose one could argue that the significant spin parameter would be
the asteroid's angular momentum - which is proportional to the
product of the linear speed at the equator, and the radius and the

In any case, rather than make my students calculate any of these
quantities for 100,000 asteroids, I shall torture them with another
one this morning:  A spherical asteroid is struck obliquely. Show
that the centre of the asteroid will move forwards if the impact
parameter is less than 40% of the radius; otherwise it moves


Jeremy Tatum


From Charles F. Peterson <>

Many thanks for Petr Pravec's prompt response. There is so much to
keep in mind, and there are so many exciting, new programs and
discoveries. Thank goddess for the internet and CCnet! Access to ask
questions...  access to answers...

Charles F. Peterson


From Bob Kobres <>

Impacts happen, volcanic outbursts happen, as do earthquakes and
variations in Sun dominated Space-weather. These high-energy events
can cause similar perturbations within our biosphere such as
flooding, violent storms, unseasonable temperatures, and
visually-unusual atmospheric phenomena. It is very risky to associate
handed down lore or observation with an impact event in general
because the traditions of various cultures can easily color their
interpretation of cause and effect.

In other words actually witnessing one or more environmentally
significant impact event and passing along the description of what
happened opens the possibility of later observers looking to the
stars to explain a plague or why their wine went sour.  Ed's list of
"observations" (CCNet, 3/14/00, A QUICK NOTE ON IMPACT EVENT RATES)
is a little loose for my standards (in particular: Rio Cuarto has not
been definitively dated yet!) but there is valid information to be
gained from handed down lore:

The pertinent point for us today is the possibility that we may be
able to eliminate what has been, and still could be, the most lethal
form of abrupt high-energy input to the biosphere. Regardless of what
we do to improve conditions for ourselves (Life) on Earth, one nasty
impact event could trump all prior effort. This is the bottom-line. 
No amount of PHO finding can rule out the possibility of a large comet
entering our region of the solar system, with little warning, in a way
that could harm us. We have observed one instance of short-notice
near-miss as recently as 1770:

Personally, I think that we should use this real possibility to
justify developing a Space based infrastructure in the shortest time
possible. This would provide us with numerous survival advantages in
addition to preventing future impacts on Earth.

The problem seems to be that various perceived authorities are
fixated on quantifying the likelihood of such an event so politically
powerful bean-counters can derive some form of cost-benefit analysis.
Has our artificial economic system distorted our view of the real
world to the point that we hesitate to do as much as we could to
protect ourselves from a potential species terminating event? 

Remember the only thing that is really new is our likely, but not yet
proven, ability to affect the orbit of a threatening object and this
possibility has been recognized since 1966:
A scientifically reasoned notion that a large celestial object slamming into
Earth would not be good for Life has been available since 1828:

So getting back to the point of this blurb: High energy events happen
and it's not often easy to tell what actually produced various
phenomena observed and recorded by our predecessors. An interesting
example of unusual observation occurred in 1737:
Even though the term meteor, as well as explosion, is used, the
observation is most likely to be of unusual aurora activity. 

Though it is a fascinating source of information that can inform us
that something interesting happened, there is no good reason to rely
upon handed down lore or reports as a rational for protecting
ourselves. Impacts occur and there is currently nothing (unless you
count luck) to prevent the next one from taking place. We can no
longer claim to be victims of a cosmic collision should one happen. 
It is a possibility allowed by ostensibly well-considered policy. 

I suspect that what really needs to be more openly discussed is the
apparent dilemma over the use of nuclear energy, as well as military
involvement, in a planetary defense system. If an international
agreement cannot be reached in these relatively peaceful times, the
likelihood of unilateral action will increase. Such independent moves
would be highly suspect as to actual motive and are not apt to take
place as long as no serious resource-control conflicts arise, but
given the history of international political relations in a resource
limited world, it is not a good bet that the pursuit of private
monetary profit will ensure cordial conditions ahead. 

We who see great promise in Space development need to focus public
attention on the rationale for rapidly developing a permanent,
internationally supported and run, Earth monitoring and defense
system, to the point where such a project actually gets underway. 
This type of positive, future-oriented, commitment and view is apt to
serve as a social glue between cultures.

Fixating on any one aspect of protecting Life on Earth tends to
distort the overview. We need to focus with as much depth of field as
possible on protecting and enhancing our situation into the future. 
The capacity to convert potentially hazardous objects (PHOs) into
benign resource objects (BROs) is a necessary step for developing
industrial capabilities in Space. Actively learning how best to do
this will obviously also teach us a great deal about dealing with an
actual threatening object, plus we gain a better perspective to
recognize a broader range of threats as well as opportunities. 

Trying to be hopeful.

On fire and brimstone:
And earlier dragons:

Bob Kobres
Main Library
University of Georgia
Athens, GA  30602


From Jeremy Tatum <UNIVERSE@uvvm.UVic.CA>

I would count it to be a quite remarkable achievement if a colony
of ants succeeded in building a termite's nest.

Andrew Glikson wrote: 
> It is said that "History is written by the winners".  There is an
> inherent inclination for Homo Sapiens to take its species name too
> literally, i.e. define intelligence in terms of the faculties in
> which it excels, compared to other creatures.  When a pilot flies
> a jet from London to New York, or an architect designs a building,
> these are defined as intelligent achievements.  On the other hand,
> when a Starling navigates from Greenland to the Cape of Good Hope,
> or an ant colony builds the most elaborate termite nest, these are
> attributed to "instinct" or to genetic codes - a clear double
> standard.
MODERATOR'S NOTE: Jeremy is quite right here. Termites are not ants.
They are most closely related to the cockroaches. Ants are related to
bees and wasps (the Hymenoptera). Termites belong to their own insect
group, the Isoptera. Hence, ants never build termite nests. In fact,
they are simply too stupid for such tasks even if they tried. Humans,
on the other hand, can do this simple job quite easily. This open-ended
skilfulness is why Homo sapiens is the only species that yields genuine
mastery over the forces of nature by means of scientific discovery,
invention and technology. According to the Baconian (i.e.
Judeo-Christian) philosophy of science, it is this unique endowment
that makes us both the masters over nature and the guardians of life
on Earth. Whether or not we like our role as chosen primate, it seems
obvious to me that we cannot escape our responsibility.

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