PLEASE NOTE:


*

CCNet, 47/2000 - 11 April 2000
------------------------------


     "Will the sun and therefore the Earth ever become too warm to suit
     human activities? No one knows. From past changes, however, it is
     known that any such increase would likely occur gradually over
     many thousands of years. Moreover, should our distant descendants
     ever wish to adjust the Earth's thermostat, they could more easily
     adjust it downward, rather than upward. American scientists have
     pointed out that the Earth could be cooled relatively
     inexpensively by blocking solar radiation using present
     technology. Warming the Earth, however, is beyond the
     capabilities of modern science and engineering.”
        -- The American Spectator, April 2000


(1) BARREN GALAXIES
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(2) SEARCHING FOR FOSSIL LIFE ON MARS
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(3) LABORATORY ASTROPHYSICS IN SOLAR SYSTEM STUDIES
    D.P. Cruikshank, NASA,AMES RES CTR

(4) PAOLO FARINELLA REMEMBERED
    Luigi Foschini <foschini@tesre.bo.cnr.it>

(5) AURORA DISPLAY IN THE UK
    Neil Bone <bafb4@central.susx.ac.uk>

(6) COMET HYAKUTAKE BREAKS WIND
    Bob Kobres <bkobres@uga.edu>

(7) SOME LIKE IT HOT: HOW THE GLOBAL WARMING BUSINESS COULD  
    BANKRUPT EARTH
    American Spectator, April 2000

(8) AND FINALLY: SHOCK, HORROR - GLOBAL TEMPS GETTING COOLER
    YAHOO! News, 10 April 2000

=============
(1) BARREN GALAXIES

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

[http://helix.nature.com/nsu/000413/000413-4.html]

Monday 10 April 2000

Barren galaxies
By PHILIP BALL

The Universe is almost certainly full of stars that possess planetary
systems. So surely some will be like Earth, capable of supporting
intelligent life? Not necessarily, a group of researchers from the
University of Washington claimed this week.

Speaking at a meeting on 'astrobiology', the science of life's origins
on Earth and elsewhere, organized by the US space agency NASA at their
Ames Research Center at Moffett Field, California, Guillermo Gonzalez
and colleagues said: "It is possible that entire galaxies are devoid of
Earth-sized planets and complex life".

Ever since Copernicus suggested that the Earth revolves around the Sun
and not vice versa, we have come to abide by the 'Copernican
Principle': the idea that our situation in the Universe is not special
but typical. According to this principle, we are not at the centre of
everything but are simply an anonymous face in a crowded cosmos. We
must expect there to be plenty of planets like the Earth around other
stars -- and, in all probability, other worlds where life has arisen.

Indeed there is now good evidence that several nearby stars in our own
galaxy, the Milky Way, have orbiting planets. So far these are all
'giant planets' like our own Jupiter, because only such giants show up
to the current methods of detection. But at least some of these
Jupiter-like worlds might be accompanied by suites of smaller planets
-- just as Jupiter is by Earth, Venus and Mars -- which elude detection
from such a distance.

This may be true of nearby stars. But Gonzalez and colleagues suggest
that in more distant regions of our galaxy the conditions just aren't
right for making life-supporting Earth-like planets. In other words,
our part of the galaxy is rather special after all.

Certainly, we occupy a privileged position within the solar system.
Much closer to the Sun, and, like Venus, we would have been boiled.
Mars, on the other hand, which is slightly further from the Sun than we
are, is consigned to a deep freeze. The Earth sits in the so-called
'habitable zone', a ring around the Sun within which liquid water can
exist on a planet. Without liquid water, any kind of life is highly
unlikely.

Gonzalez and colleagues have now proposed that entire galaxies, which
contain millions of stars, also have habitable zones, beyond whose
boundaries life -- or, at least, advanced life -- can't get a foothold.
They say that the habitable zone of a spiral galaxy (like the Milky
Way) may encircle its centre, just as the habitable zone of the solar
system encircles the Sun. Inside or outside this band, a galaxy is
sterile.

It is easy enough to see why a star should have a habitable zone -- it
is simply a matter of being neither too hot nor too cold. But why
should a galaxy?

It is a delicate matter to make a planet like Earth. You need the right
materials: heavy, rock-forming elements like silicon and aluminium, and
iron for the core. Further out in a galaxy like the Milky Way, these
elements are scarcer, and so rocky planets would be smaller. They would
also be cooler, because there would be less of the heavy radioactive
elements that, in the Earth, warm up the interior by radioactive decay.

Without a warm interior, an Earth-like planet cannot have
plate-tectonic movements of the crust. This means that the planet can't
keep water circulating through its atmosphere, and so it is likely to
run down to a frozen state. That is what happened to Mars, which is
actually within the solar system's habitable zone, but froze because,
being smaller than the Earth, it cooled down too quickly and lost the
ability to maintain plate tectonics.

Further in towards the centre of the galaxy, other factors frustrate
the development of life. Stars are more densely crowded together, and
so things are stormier. Exploding stars -- 'supernovae', for instance
-- may bathe nearby planetary systems in hazardous radiation. And
planets are likely to suffer heavier bombardment by comets, which are
sent charging through a star's planetary system by the gravitational
pull of other stars. On Earth, the deadly effects of gigantic comet
collisions may have choked life several times on the young planet, and
so delayed the evolution of complex organisms. If this bombardment had
been more frequent, life might never have got going at all, or may have
been constantly prevented from evolving into complex forms.

So Gonzalez and his colleagues suggest that most galaxies might have
only limited regions where Earth-like planets could both form at all
and be able to support life: not too far out, not too central. In fact,
they say, because many galaxies have less heavy elements than the Milky
Way, their habitable zones might shrink out of existence, leaving no
room for life. The Universe might be peppered with galaxies that,
however brightly they glow, are as barren as the Moon.

(c) Macmillan Magazines Ltd 2000 - NATURE NEWS SERVICE

=============================
(2) SEARCHING FOR FOSSIL LIFE ON MARS

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

[http://helix.nature.com/nsu/000413/000413-3.html]

Monday 10 April 2000

White elephant
By PHILIP BALL

Future spacecraft missions to Mars will be looking for signs of life.
Not living organisms -- they now seem improbable on the Red Planet --
but perhaps fossil evidence that primitive life once evolved there.

But one of the prime candidate landing sites for a future robotic
explorer on Mars might not be a good bet after all. 'White Rock' may
not, as hoped, be a mineral deposited from salty water, and so is
unlikely to mark a spot where martian microbes might once have thrived,
Steven Ruff of Arizona State University told NASA's First Astrobiology
Science Conference at its Ames Research Center in California this week.

Mars has a history of laying false trails for Martian-seekers. In the
late nineteenth century, astronomer Percival Lowell thought he spotted
a system of artificial canals that turned out to be natural surface
markings, not the handiwork of a martian civilization.

The dark patches that advance and recede over the planet with the
seasons, thought until the 1950s to be vegetation, are just the result
of dust storms on a dry world. Even the signs of fossilized
bacteria-like forms reported in a martian meteorite in 1996 may be
nothing more than unusual mineral features. And recent close-up
pictures of the infamous 'face of Mars' rock formation seen by the
Mariner spacecraft in the 1970s reveal that the structure is not really
like a face at all once it is in focus.

Yet Mariner 9's discovery of river-like features on Mars's surface in
1972 revitalized hopes that life might exist -- or might once have
existed -- on the planet. It is hard to explain these sinuous valleys
and rivulet-like markings as anything but the remnants of water flowing
over the rock. They testify to the likelihood that, in Mars's distant
past, the planet was warmer and wetter. This implies that life might
once have arisen there, even if today Mars is utterly barren.

So when the Viking robotic landers were sent to Mars in 1976, some
researchers hoped that they might find signs of primitive life in the
soil samples they scooped up. Yet they found nothing of the kind.
Worse, they discovered that, lacking the protective screen of an ozone
layer, Mars's surface is sterilized beneath the harsh ultraviolet rays
of the Sun.

Now researchers hold out little hope of finding microbes alive on Mars.
But they do still dream of uncovering signs that organisms once existed
in the rivers and lakes that might have covered parts of the martian
landscape in the past. Indeed, at the NASA conference, Daniel McCleese
from the Jet Propulsion Laboratory in Pasadena, California, indicated
that the strategy for future searches for martian life is: Follow the
water.

Yet even the evidence for flowing water on Mars in the past is
indirect. The valleys don't look exactly like river valleys on Earth.
What scientists would really like to find are rocks that can only be
formed by the action of water. This might then provide a good
indication of where future Mars lander missions might be sent to look
for martian fossils.

A prime candidate for such a landing site appeared to be the region
spotted by Mariner 9 in the 1970s, known as 'White Rock'. Sitting at
the bottom of a crater, White Rock is a patch of terrain, about twelve
by fifteen kilometres, that stands out brightly from the surrounding
ground. It looks, from the spacecraft pictures, reminiscent of rock
deposits called evaporites that form at the bottom of dried-up salt
lakes on Earth.

Evaporites are essentially pure salt. Some are made of the same stuff
as table salt; others of the mineral gypsum, which can also precipitate
out of briny water as it evaporates. Evaporation of salty water is the
only known way for evaporites to form. So is White Rock the fingerprint
of a salt lake that once filled the crater?

Probably not, Ruff says. He has analysed measurements made by an
instrument called the Thermal Emission Spectrometer (TES) on board the
orbiting Mars Global Surveyor satellite. This instrument is able to
identify the composition of the surface material, and it seems to show
that White Rock is not, after all, so different from the surrounding
terrain. The bright feature seems to be a wind-blown deposit like a
huge sand dune, and its brightness is due to a difference in texture,
rather than composition, from the plain on which it sits.

Ruff points out that White Rock was widely regarded as representative
of several similar sites seen in spacecraft images of Mars, which were
also suspected of being evaporite-type features. So the new results
strike a blow to hopes for identifying promising landing sites for Mars
missions. But all is not lost. Ruff also announced that the TES has
found what appears to be a different kind of mineral, a type of iron
oxide, that is thought to require water for its formation. But it is
too early to be sure if this is indeed a marker of an ancient martian
lake.

(c) Macmillan Magazines Ltd 2000 - NATURE NEWS SERVICE

===============
(3) LABORATORY ASTROPHYSICS IN SOLAR SYSTEM STUDIES

D.P. Cruikshank: Laboratory astrophysics in solar system studies - An
overview. EARTH MOON AND PLANETS, 1998 (2000), Vol.80, No.1-3, pp.3-33

*) NASA,AMES RES CTR,MOFFETT FIELD,CA,94035

The compositions of the numerous bodies in the Solar System are
determined from remote sensing observations, most often spectroscopic,
and in some cases direct sampling. Laboratory studies of materials and
processes are an essential component of the analysis and interpretation
of all compositional data. Planetary atmospheres are composed of gases
and aerosols, while the surfaces of the terrestrial planets, asteroids,
comets, and planetary satellites are composed of minerals, ices, and
organic solids. The principal spectroscopic characteristics of each of
these materials are reviewed here. The tables present a synopsis of our
current knowledge of the compositions of the principal bodies in the
Solar System. Copyright 2000, Institute for Scientific Information Inc.

=============
(4) PAOLO FARINELLA REMEMBERED

From Luigi Foschini <foschini@tesre.bo.cnr.it>

Dear Benny,

On March 26th, just after the death of Paolo Farinella, I wrote some
memories about him, but in Italian. Today, I have ended the translation
in English. You can find these notes at the web page:

http://www-th.bo.infn.it/tunguska/paolo/paolo_en.htm

I hope that you and all the members of CCNet will like these memories
about Paolo.

Greetings,

Luigi


Dr. Luigi Foschini
Institute TeSRE - CNR
Via Gobetti 101, I-40129 Bologna (Italy)
Tel. +39 051.6398706 - Fax +39 051.6398724
Email: foschini@tesre.bo.cnr.it
       luifosc@tin.it (home)
Home page: http://tonno.tesre.bo.cnr.it/~foschini/

================
(5) AURORA DISPLAY IN THE UK

From Neil Bone <bafb4@central.susx.ac.uk>

I know this isn't strictly CCNet territory, but you may be interested
to know of a major auroral display, seen widely across the UK (and
presumably later from the US) over 2000 April 6-7. This is the first
truly major event of Cycle 23, and comes after a long quiet spell
during which many of us were beginning to wonder if we were ever
going to see a take-off in auroral/solar-terrestrial activity! e-mail
and other reports have so far come from Ayrshire, Edinburgh, Co.
Durham, Suffolk, Hampshire, Salisbury, Essex, Chichester, Kent, and
Leicester. In  broad detail, the event was already in progress at
dusk, when many were out looking at the planetary/lunar conjunction.
An early peak in activity occurred around 21h UT. Even from my
location at Chichester, West Sussex in the  south of England, red
rays were reaching past Polaris at this time. Tom McEwan at
Glengarnock, Ayrshire and David Gavine, Edinburgh, both report the
display as 3/4- to whole-sky at this stage! Activity appears to have
continued with occasional lulls essentially throughout the night.
Another peak occurred close to 01h UT, when even at Chichester the
display reached into the southern sky, forming a weak coronal
structure. The sky to Spica (140 degrees from the N horizon) was
suffused with a bright auroral veil, and patches of red light.
An awesome display - but watch out for the  UFO reports! Cause
putatively a CME seen on April 4, according to NOAA/SEC. A full and
detailed report will be assembled by Ron Livesey of the BAA Aurora
Section in due course. It looks, now, as if the long wait for
lower-latitude auroral activity in the current cycle may at last be
over!

Neil Bone
Sussex, 7th April 2000

=============
(6) COMET HYAKUTAKE BREAKS WIND

From Bob Kobres <bkobres@uga.edu>

Whole blurb at:
http://science.nasa.gov/headlines/y2000/ast06apr_2.htm

"This tail extends half a billion kilometers (more than 300 million
miles). That's more than three times the distance from the Earth to the
Sun," said Dr. Nathan Schwadron, of the University of Michigan in Ann
Arbor, a member of one of two Ulysses teams that made the discovery
independently of one another. Findings from both teams appear in the
April 6 issue of the journal Nature.

"This makes it the longest comet tail ever recorded," said Dr. Geraint
Jones from Imperial College, London, of the Ulysses magnetometer team.

Comet Hyakutake, one of the brightest comets of the 20th century, made
a dazzling nighttime appearance in the spring of 1996, when it made a
close pass by the Sun. While Ulysses was cruising through space
studying the solar wind on May 1, 1996, its data suddenly went wild for
a few hours. For example, the solar wind seemed to almost disappear and
was replaced by gases not normally found in the solar wind, and the
magnetic field in the solar wind was distorted. Since Ulysses
scientists were not looking for comets, they did not realize the
significance of the data right away. 
~~~~~~~~~~~~~~~~~~~~~~~~~~~

Do comet tails have other than the obvious portent potential?  How
unusual might aurora phenomena become in the wake of a comet?

~~~~~~~~~~~~~~~~~~~~~~~~~~~
From: THE FIRST CRUSADE AND THE IDEA OF CRUSADING, by Jonathan
Riley-Smith (1986), page 92

Their growing conviction that they were operating in a super-natural
context was heightened by the fact that, after a period of  calm, the
skies again became troubled, just as they began to move from Asia Minor
into Syria.  In early October 1097 a comet--one, incidentally,
well-documented in Chinese and Korean records--was seen with a tail
shaped like a sword.  As the ground shook in the earthquake of 30
December the heavens glowed red and there appeared a great light in the
form of a cross; this possibly an early reference to 'earthquake
lights'.  On the night of 13 June 1098 a meteor fell from the West on
to the Muslim camp outside Antioch. The night of 27 September seems to
have been extraordinary, with an aurora so great that it was seen in
Europe as well as in Antioch: it must have been visible over a large
part of the northern hemisphere.
~~~~~~~~~~~~~~~~~~~~~~~~~~~

If the "night of 27 September" was in 1097 rather than 1098, as seems
to be implied above, the extensive aurora might have been related to
the October 1097 comet, which was at perihelion within the orbit of
Earth around that time.   According to G. W. Kronk in COMETS (1984), p.
3: . . . An orbital calculation gave the perihelion date as September
22 (r= 0.74 AU).  It also indicated an approach to within 0.17 AU of
Earth between October 17 and 25.

Anybody in a good position to quickly nail the actual year of the 27
September aurora? 

Later.
bobk

=============
(7) SOME LIKE IT HOT: HOW THE GLOBAL WARMING BUSINESS COULD  
    BANKRUPT EARTH

From American Spectator, April 2000
http://www.spectator.org/archives/0004TAS/robinson0004.htm

The global warming business could bankrupt our Earth.

by Arthur B. Robinson and Noah Robinson

Everyone knows by now that the Earth is ill. It must be because its
temperature is reported to be rising. Well, it's not so simple. A
warming trend began about 300 years ago, during the Little Ice Age, but
this has nothing to do with human activity, or the release of carbon
dioxide into the atmosphere. The 300-year trend and the fluctuations
within it are closely correlated with solar activity.

Within this trend there are smaller cycles, up and down, and we don't
have enough information to know exactly where we are within such
cycles. Uncertainty about natural phenomena should not become the
excuse for governments to restrict the use of fossil fuels, but the
crazy fact is that if the sun continues its 300-year warming trend, in
the next few years environmentalists may succeed in closing down half
of humanity's energy supplies.

For this reason, research on atmospheric temperatures has taken on a
new urgency. Documenting the natural factors that affect the Earth's
temperature -- especially that of the sun -- will allow us to prevent
such political disasters. We are now in a race between the irrational
religion of pseudo-environmentalism and the truth about atmospheric
science.

The accompanying graph places all this in historical perspective.
Derived from isotope ratios in the skeletons of marine organisms
deposited in the Sargasso Sea, this record shows temperatures during
the past three millennia. Clearly seen are the Little Ice Age and the
much warmer period about 1,000 years ago known as the Medieval Climate
Optimum, so named because the recorded climate was unusually benign.
Earth temperatures are now near the 3,000-year average and
not unusual.

What will temperatures be during the coming century and beyond? No one
knows. Astronomers cannot yet predict future solar activity. If recent
trends continue, however, our environment will be much improved.
Already, plant growth and diversity -- from the forests and fields of
North America to the rain forests of South America -- have shown a
marked increase. This is the result of carbon dioxide fertilization.
Mankind is moving carbon from below-ground deposits of coal, oil, and
natural gas into the atmosphere, where it is then used to make more
plants and animals.

Studies indicate that North American forests are growing so fast that
they are storing all of the human-released carbon from North America.
According to the U.S. Forest Service and the Department of Agriculture,
the total amount of large-tree standing timber in the United States
alone has increased by 30 percent since 1950. Because they use plants
for food, animals have also increased. When this biological miracle
stabilizes within one or two centuries, the plant and animal population
of the Earth may have doubled. Farm production is already increasing
from carbon dioxide fertilization. Wheat crops in dry areas are growing
10 percent faster as a result of atmospheric carbon dioxide increases
during the twentieth century (from 280 parts per million in 1900 to 360
in 2000). Trees are more strongly affected. Young orange trees and pine
trees are growing more than 25 percent faster. Measurements of South
American rain forests show similar accelerations.

Gradual, natural changes in the environment have been distorted by
politicians. Both Interior Secretary Bruce Babbitt and Vice President
Al Gore visited Glacier National Park to bewail the current diminution
of its glaciers. Geologists know, however, that those glaciers have
come and gone many times as Earth's temperature has risen and fallen
during past millennia.

Will the sun and therefore the Earth ever become too warm to suit human
activities? No one knows. From past changes, however, it is known that
any such increase would likely occur gradually over many thousands of
years. Moreover, should our distant descendants ever wish to adjust the
Earth's thermostat, they could more easily adjust it downward, rather
than upward. American scientists have pointed out that the Earth could
be cooled relatively inexpensively by blocking solar radiation using
present technology. Warming the Earth, however, is beyond the
capabilities of modern science and engineering.

FULL STORY at
http://www.spectator.org/archives/0004TAS/robinson0004.htm

=============
(8) AND FINALLY: SHOCK, HORROR - GLOBAL TEMPS GETTING COOLER

From YAHOO! News, 10 April 2000
http://dailynews.yahoo.com/h/nm/20000410/ts/environment_warming_1.html

Global Temps Cooler Than Normal in March-Report

WASHINGTON (Reuters) - Global temperatures were cooler-than-normal in
March, continuing a year-long trend linked to the La Nina weather
phenomenon, researchers said on Monday.

John Christy and Roy Spencer, space scientists working on a joint
project by NASA and the University of Alabama in Huntsville (UAH), said
the past year has been the coolest recorded since the 12 months ending
August 1994.

Average global temperatures from April 1999 through March 2000 were
0.17 Fahrenheit 0.095 degrees Celsius below seasonal norms culled from
a 20-year average between 1979 and 1998.

The scientists said La Nina, a large region of cool water in the
eastern equatorial portion of the Pacific, cools the tropics in a broad
band that surrounds much of the Earth.

The 1994 cool spell was the result of the lingering effects from
the 1991 eruption of the Mount Pinatubo volcano in the Philippines.

North America experienced warmer temperatures in March, but overall,
the globe's temperatures last month were 'pretty typical' for this time
of year, Christy said.

Global composite temperatures for the month were 0.2 F 0.11 Celsius
below the 20-year average for March.

Data for the NASA-UAH report is gathered by monitoring weather
satellites. The equipment allows accurate temperature readings for
almost all of the Earth, including remote desert, rain forests and
oceans, the researchers said.

Copyright 2000, Reuters

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