PLEASE NOTE:


*

CCNet, 008/2000 - 21 January 2000
---------------------------------


     QUOTES OF THE DAY

     "That influenza might be included amongst the impact hazards posed
     by comets is intriguing because if correct then there have been
     more than 20 million fatalities due to impacts (albeit of dust) in
     the last 100 years. This is significantly more than could be
     caused by even a number of 'well-aimed' Tunguska events. Perhaps
     then the most important task in mitigating impact hazards is not
     the development of next generation launch vehicles and
     thermonuclear devices but improved vaccines and hot water
     bottles."
        --Matt Genge, 20 January 2000


     "When Fred Hoyle and Chandra Wickramasinghe first came up with the
     idea that the main ingredients of life could form in space and
     then be carried around the universe by comets, the scientific
     community was distinctly unimpressed. But scientists in India have
     now come up with a computer model of a collapsing molecular cloud
     that shows that this is not just science fiction. DNA bases appear
     in abundance in their model and could have provided a genetic
     starter kit for life to evolve rapidly on Earth--and lots of other
     places too. So if you ever finally meet an alien from space don't
     be surprised if they are rather like you... "
        -- New Scientist, 20 January 2000


(1) ISO FINDS THE PRECURSORS OF LIFE IN SPACE
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(2) BUILDINGS BLOCKS OF DNA MAY COME FROM OUTER SPACE
    NEW SCIENTIST WEEKLY NEWSLETTER

(3) IMPACT HAZARDS FROM COMETS -  INFLUENZA?
    Matthew Genge <M.Genge@nhm.ac.uk>

(4) SPACEGUARD FOUNDATION: 1999 REPORT
    Andrea Carusi <carusi@ias.rm.cnr.it>

(5) MYSTERY ICEBALLS CLAIM FIRST VICTIM IN SPAIN
    YAHOO NEWS, 20 January 20000

(6) GREAT BALLS OF ICE - SORRY, NOT FROM SPACE
    Paulo Holvorcem <holvorcem@mpc.com.br>

(7) LEONID MAC WORKSHOP 2000
    Robert Hawkes <rhawkes@mta.ca>

(8) AND FINALLY: MAN-MADE OZONE-DEPLETION - ANOTHER ECO SCARE?
    NATURE 20 January 2000

=========
(1) ISO FINDS THE PRECURSORS OF LIFE IN SPACE

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

ESA Science News
http://sci.esa.int

20 Jan 2000

ISO finds the precursors of the complex organic molecules in space

The clouds of gas and dust grains in interstellar space contain complex
organic molecules made of hundreds of chained carbon atoms. The European
Space Agency's infrared space telescope, ISO, has detected these molecules
in many different environments and is now unveiling the chemical paths
leading to their formation in space. A group of Spanish astronomers have
detected for the first time outside the Solar System two molecules that
could be the precursors for the formation of the more complex organic
compounds. The newly found molecules, detected in two very old stars,
are diacetylene and triacetylene (C4H2 and C6H2).

The study of the complex organic molecules in space, the so-called 'PAH'
(Polycyclic Aromatic Hydrocarbons), is rapidly advancing with ISO.
Researchers from Canada and the US reported last week at the American
Astronomical Society meeting in Atlanta (US) that the making of PAH in
stellar envelopes can take as little as a few thousand years (see previous
story "Complex organic molecules form quickly in old stars",
http://sci.esa.int/newsitem.cfm?TypeID=1&ContentID=8831&Storytype=18).
Now, the finding by the Spanish team adds information about the
intermediate chemical steps that lead from one of the simplest organic
molecules, such as the acetylene, to the complex PAH.

"ISO has provided an important database for the study of these large and
complex organic molecules", says José Cernicharo, from the Centro Superior
de Investigaciones Científicas (CSIC) in Madrid. "This will allow us to
investigate their role in the chemistry of interstellar space, and to answer
important questions that remain open. For instance, how are these large
species formed?"

Using ISO, Cernicharo and co-workers observed two stars in the process
of dying, CRL618 and CRL2688, which have been blasting out huge amounts
of material over the last thousand years and thus have become the
central stars illuminating a large shell of gas and dust -- a structure
called 'a protoplanetary nebula'. The astronomers studied the chemical
composition of the gas around the stars and realised that many new
molecules had been synthesised. Many of these molecules are unknown,
but the researchers were able to identify at least two of them: C4H2
and C6H2, di- and tri-acetylene.

"The large number of unknown molecular bands revealed by ISO left us
astonished. Among them we quickly identified two new molecules, di- and
tri-acetylene, which are present in the planets of the Solar System but
had not been found before in the interstellar space. The unknown
molecular species and the di- and tri-acetylene might very well be the
'small bricks' that will combine to make the complex molecules like
PAHs", Cernicharo explains.

In the proto-planetary nebula CRL618 Cernicharo and Fabrice Herpin
(CSIC) have found also water (H2O) and OH, an unexpected result because
CRL618 is a carbon-rich object and those are oxygen-bearing molecules.
To the researchers, these are examples of how powerful the stars are
when it comes to the production of new molecules ... molecules that are
likely to end up in planets like the Earth.

As Cernicharo explains, "when an old star is volving towards the proto-
planetary phase, it produces violent phenomena such as high velocity winds
and high flux of high energy photons; these phenomena modify completely
the chemistry of the gas around the star, and allow the formation of
new molecules. With time, they will escape from the gravity of the
central star and will reach the interstellar medium, where they will
joint the molecular clouds out of which new stars will form. When a new
star with its planetary system is formed, highly complex molecular
species, many of them containing a large number of carbon atoms, are
already present to form part of comets and planets".

A paper about this findings will appear in the February issue of The
Astrophysical Journal Letters.

Footnote about ISO

The European Space Agency's infrared space observatory, ISO, operated
from November 1995 to May 1998, almost a year longer than expected. An
unprecedented observatory for infrared astronomy, able to examine cool
and hidden places in the Universe, ISO made nearly 30,000 scientific
observations.

Contacts:

Martin Kessler, ISO Project Scientist
mkessler@iso.vilspa.esa.es
+34 91 8131254

José Cernicharo, Consejo Superior de Investigaciones Científicas
cerni@astro.iem.csic.es
+34 91 5901611

USEFUL LINKS FOR THIS STORY
* ISO Science homepage
  http://www.iso.vilspa.esa.es/
* More about ISO
  http://sci.esa.int/iso

===============
(2) BUILDINGS BLOCKS OF DNA MAY COME FROM OUTER SPACE

From NEW SCIENTIST WEEKLY NEWSLETTER
22 January 2000

When Fred Hoyle and Chandra Wickramasinghe first came up with the idea
that the main ingredients of life could form in space and then be
carried around the universe by comets, the scientific community was
distinctly unimpressed. But scientists in India have now come up with a
computer model of a collapsing molecular cloud that shows that this is
not just science fiction. DNA bases appear in abundance in their model
and could have provided a genetic starter kit for life to evolve rapidly
on Earth--and lots of other places too. So if you ever finally meet an
alien from space don't be surprised if they are rather like you...
http://www.newscientist.com/news/news.jsp?id=ns222245

SEEDS OF LIFE

From NEW SCIENTIST, 22 January 2000
http://www.newscientist.com/news/news.jsp?id=ns222245

Seeds oif Life

Did interstellar clouds give a chemical kick-start to evolution?

THE building blocks of DNA could have formed in space before Earth was
born, providing a starter kit of genetic material for life to
evolve rapidly on Earth, claim astrochemists in India. Their computer
models of chemicals evolving in space may explain why life emerged
only 600 million years after the Earth formed 4.5 billion years ago.

The model also suggests that comets are packed with the building blocks
of life. If true, it backs up the idea that comets seed evolution when
they smash into planets.

Sandip Chakrabarti and his wife Sonali at the S. N. Bose National 
Centre for Basic Sciences in Calcutta modelled how chemicals would
evolve in an interstellar cloud collapsing under gravity. The model
began with a typical cloud 7 light years across, containing a dozen
elements including hydrogen, carbon, oxygen and nitrogen.

The model mimicked the cloud collapsing to 10 million kilometres
across, over a million or so years. The computer worked out the
variations in temperature and density of the cloud as this happened,
and calculated the rates at which different chemicals in the cloud
would react.

The Chakrabartis focused on a series of four reactions for making the
DNA base adenine from hydrogen cyanide, a compound abundant in
interstellar clouds. And at the end of the simulation, the cloud was
littered with adenine. In fact, the Earth would have been showered with
millions of tonnes of the DNA base if it had formed in a chemical
environment like this.

"DNA bases produced in the collapsing cloud could have contaminated the
Earth," the Chakrabartis will report in the journal Astronomy and
Astrophysics. "There should be many such planets in each galaxy where
DNA-based life should flourish."

But the idea remains controversial. Tom Millar of the University of
Manchester Institute of Science and Technology, whose database of
chemical reactions formed the basis of the new work, questions whether
there would be enough energy to drive the adenine reactions in the
chilly depths of space at just 10 degrees above absolute zero. Even if
adenine did form, it might break down again in some other process.

But Millar adds that the new results will prompt chemists to try their
hand at recreating the adenine-producing reactions in the lab. Sandip
Chakrabarti agrees that this is the way forward. "Everything hinges on
the reaction rates," he told New Scientist.

British researchers who suggested in 1977 that the ingredients of life
originated in space and were dispersed by comets are delighted by the
Indian findings. "It's yet another indication that the chemical
feedstock of life could be produced throughout the Universe, and
nothing on Earth would reproduce that grandeur of scale," says Chandra
Wickramasinghe of the University of Wales at Cardiff, who suggested the
idea along with his colleague Fred Hoyle.

Max Bernstein, an astrochemist at NASA's Ames Research Center in
California, agrees. "It is reasonable to suggest that this molecule
could have made the trip by having been preserved in a comet," he says.
He thinks the Indian study should give further impetus for lab
experiments to study the reactions, as well as searches for signs of
adenine in space.

Andy Coghlan

Copyright 2000, New Scientist

=================
(3) IMPACT HAZARDS FROM COMETS -  INFLUENZA?

From Matthew Genge <M.Genge@nhm.ac.uk>

That influenza might be included amongst the impact hazards posed by
comets is intriguing because if correct then there have been more than
20 million fatalities due to impacts (albeit of dust) in the last 100
years. This is significantly more than could be caused by even a number
of 'well-aimed' Tunguska events. Perhaps then the most important task
in mitigating impact hazards is not the development of next generation
launch vehicles and thermonuclear devices but improved vaccines and hot
water bottles.

It has been known for sometime that primitive carbon-rich solar system
materials such as the carbonaceous chondrite meteorites contain amino
acids and nucleic base acids generated inorganically in the
interstellar medium, in the solar nebula or on asteroidal parent
bodies. That such molecules occur in interstellar clouds seems also to
imply that they will occur in comet nuclei. These compounds are,
however, still far from being viral RNA. If a virus such as influenza
was present on comet nuclei would it survive for 4.5 billion years at a
few tens of degrees K in the Oort cloud or Kuiper belt?

Every year the Earth captures around 40,000 tonnes of interplanetary
dust from asteroids and comets, equivalent to around 10^16  one
microgram particles. Only a few percent of this material will survive
atmospheric entry heating to reach the Earth's surface and cometary
dust with its high geocentric velocities (e.g. Leonids 70 km/s) is even
less likely to survive than asteroidal particles. Of the dust particles
that reach settling velocity a significant proportion (>99%) will have
been heated to temperatures >300C during deceleration and the survival
of a RNA would seem unlikely. Consequently less than 10^11 particles in
which biomolecules survive will probably reach the Earth's surface each
year. Taking the average cross-sectional area of a human to be 0.5 m2
(as seen above and measured from a pretty average colleague) each of us
encounters 1 comet dust particle with surviving biomolecules once every
5,000 years. This means there are 1.2 million comet impacts with human
beings per year. Since the transmission of a virus from a comet dust
particle probably would only occur due to inhalation, the transmission
rate is probably exceedingly low and few cases could be attributed to
direct transmission from comet dust.

The 31 influenza pandemics that have occurred since 1580, including the
three this century in 1918, 1957 and 1968, are thought be due to major
changes in the viral antigenic proteins. These cause humans to have
little immunity to the altered strain. Smaller antigenic shifts occur
annually between influenza seasonal epidemics and are demonstrably due
to mutation. Current theories suggest that aquatic bird populations are
the main host for influenza genes and that transmission to other
species in particular pigs leads to antigenic shifts.

If influenza RNA exist on comet nuclei and can survive exposure to SEP
on dust particles in interplanetary space then it is entirely possible
that some viable biomolecules could survive atmospheric entry within
host dust particles to be transmitted to animals and humans. However,
if influenza pandemics were to be attributed to cometary RNA then the
shifts in antigenic proteins would be expected to reflect primary
genetic differences in cometary biomolecules rather than inter-species
transmission. Considering the background flux of cometary dust at the
Earth's surface, antigenic shifts would thus imply the appearance of a
new and distinct cometary source as opposed to the enhanced flux from
the existing interplanetary dust population related to sun spots or any
other phenomenon.

One test population of subjects exists that has a far higher exposure
to cometary dust particles than any other. I have worked as a cosmic
dust scientist for five years and I have been exposed to several
hundred particles a year (1.5x10^6 the exposure of the average human
being). In the last five years I have not had influenza. Perhaps I've
developed immunity.

Dr Matthew J. Genge
Researcher (Meteoritics)
Department of Mineralogy, The Natural History Museum
Cromwell Road, London SW7 5BD, UK.
Tel: Int + 020 7 942 5581
Fax: Int.+ 020 7 942 5537
email: M.Genge@nhm.ac.uk
Staff internet page http://www.nhm.ac.uk/mineralogy/genge/genge.htm


===============
(4) SPACEGUARD FOUNDATION: 1999 REPORT

From Andrea Carusi <carusi@ias.rm.cnr.it>

Dear Benny,

the Report to the members of the Spaceguard Foundation for 1999 is in
our web page. You can find it at the address:

http://spaceguard.ias.rm.cnr.it/SGF/reports/INDEX.html (case sensitive)

You may wish to put this notice on the CCNet for those who may be
interested in reading it.

Thank you

Andrea Carusi
IAS, Area Ricerca CNR Tor Vergata
Via Fosso del Cavaliere 100
00133 Roma, Italy
Phone: +39-06-49934447 Fax: +39-06-20660188
E-mail: carusi@ias.rm.cnr.it

==============
(5) MYSTERY ICEBALLS CLAIM FIRST VICTIM IN SPAIN

From YAHOO NEWS, 20 January 20000

Mystery iceballs claim "first victim" in Spain

MADRID (Reuters) - An elderly Spanish woman has claimed she was hit by a
falling iceball, apparently the first victim of a phenonmenon that has
been puzzling scientists for days, state radio reported.

Juana Sanchez Sanchez, 70, said she was knocked out briefly by a large,
flying, frozen object that hit her on the shoulder as she walked in a
street near her home in Almeria, southern Spain, the radio said.

A man in Seville escaped injury last week when a four-kilo (nine-pound)
iceball slammed into his car.

Scientists are examining a dozen specimens to establish their origin
amid speculation they could be frozen human excrement jettisoned by
high-flying aircraft or debris from comets, an explanation which some
space experts have ruled out.

A Spanish newspaper said on Thursday at least three of the mystery,
football-sized objects were fakes - - two turned out to be made of salt
and another came from a restaurant freezer.

Copyright 2000, Reuters

====================
(6) GREAT BALLS OF ICE - SORRY, NOT FROM SPACE

From Paulo Holvorcem <holvorcem@mpc.com.br>

Dear Benny,

I would like to make a few comments on the mysterious ice falls in
Spain, based on my recent experience a few years ago.

The suggestion that the ice balls are comet debris is highly
questionable, given that comet material is fragile and volatile, and
would not survive the passage through the atmosphere. The fall of a
large enough piece of comet material might conceivably yield ice
fragments which reach the ground, but then a big explosion (fireball)
would be expected; none has been reported. Then there is the question
of why these reports are coming from Spain only, and not from other
places on Earth.

I did some investigation on a similar event involving the fall of two
ice chunks weighing several kilograms on different days a few tens of
km from each other. This happened here in Campinas, Brazil, in
mid-1997. Local meteorologists speculated wildly about a supposed
confirmation of Lou Frank's small comet hypothesis (which was being
"revived" at that time with the data from the Polar satellite), the
fall of house-sized ice blocks from outer space (in our region *only*),
the supposed discovery of a new class of meteorite, dubbed
"hydro-meteorites", etc. Isotopic analysis of the ice showed no
difference with respect to local water. Almost certainly, it was not
human excrement falling from aircraft, although they might be related
to aircraft in some way which is not well understood. No fireball was
detected by defense satellites over the region in question on the dates
of the ice falls. The true nature of the ice was not discovered, but it
is very, very unlikely that it came from space.

Paulo Holvorcem
Universidade Estadual de Campinas
Campinas, SP, Brazil
holvorcem@mpc.com.br
http://www.ime.unicamp.br/~holvorce/astro/astro1.html

====================
(7) LEONID MAC WORKSHOP 2000

From Robert Hawkes <rhawkes@mta.ca>

LEONID MAC WORKSHOP 2000
Tel Aviv University, Tel Aviv, Israel
April 16-18, 2000.

You are cordially invited to participate in an international workshop
at Tel Aviv University, Israel, to discuss the recent Leonid observing
campaigns.

The Leonid meteor shower has offered unprecedented opportunity to
address outstanding issues in Planetary Astronomy, Astrobiology, and
the dynamics of the upper atmosphere, and issues that relate to the
satellite impact hazard of meteor storms. This workshop aims to bring
that science in focus, make a tally of observational data from the
recent November 1998 and 1999 observing campaigns, and make
recommendations for the next campaigns in November 2000-2002.

List of Sessions:

Session on comet grain ejection and meteoroid stream dynamics
Related issues: the activity of the shower in 1999,
size distributions, prediction models of meteor storms

Session on satellite impact hazard
Related issues: impacts on the Moon

Session on  meteoroid composition and structure
Related issues:  morphology and wake of meteoroids, composition of
meteoroids, composition of comets

Session on meteor-induced chemistry and physical phenomena
Related issues: meteor physics, sprites,
recondensed meteoric vapor, meteoric signature of stratosphere aerosols

Session on the role of meteors in creating the conditions for life s
origin on Earth
Related issues:  Astrobiology, atmospheric and surface conditions on the
early Earth, formation of planetesimals, iron catalysis, shock and impact
chemistry.

Plans and coordination for November 2000 and beyond: Leonid MAC and
ground-based campaigns
Related issues: outreach effort

Exciting results that will be discussed include:
* origin of life - the fate of organic matter in meteoroids
* the satellite impact hazard - the near-real time flux
        measurements of the 1999 meteor storm
* new meteor, meteor train, and meteor shower models
* sprites - observations during the storm, triggered by meteors?
* impacts of meteoroids on the Moon
* comet composition and ejection dynamics - the spectroscopy of
        meteors and meteor trains of bright fireballs
* laboratory studies that help explain the observed spectral
        features
* remote sensing - new techniques that may be deployed in future
        storms

In particular, the workshop will present the first results from the
Leonid Multi-Instrument Aircraft Campaign  and related ground-based
efforts during the Leonid storm of 1999.

This meeting is sponsored by NASA, the U.S. Air Force, and the Israel
Space Agency.

Registration with a brief outline of the matter that will be presented,
is due on March 1, 2000.

On line registrations and submission of abstracts can be done at:
http://leonid.arc.nasa.gov/workshops/

Information on the workshop is available at:
http://leonid.arc.nasa.gov/workshops/

The Chair of the Scientific Organizing Committee is Dr. Peter
Jenniskens, pjenniskens@mail.arc.nasa.gov.

==========
(8) AND FINALLY: MAN-MADE OZONE-DEPLETION - ANOTHER ECO SCARE?

From NATURE 20 January 2000
http://www.nature.com

Atmospheric methyl halides

Methyl chloride and methyl bromide are the most common
chlorine-containing and bromine-containing gases in the Earth's
atmosphere and they are produced in good part from natural sources.
While much attention has been focused on studying ozone-depleting
gases produced by human activity (notably chlorofluorocarbons), the
sources of methyl halides have received little attention until
recently. Although biological processes involving oceanic algae
and plankton have been identified as a source of these gases, they
alone cannot account for atmospheric levels of methyl chloride or
methyl bromide. Three papers in this week's Nature shed light on
this topic, revealing that salt marshes, forested coastal land in
the tropics, and organic matter in soil are responsible for
producing these and other halogenated gases. This week's web
feature provides free access to these three papers and to two
related pieces from Nature's online archive.

FULL PAPERS AT http://www.nature.com

Nature © Macmillan Publishers Ltd.

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