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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