PLEASE NOTE:


*

CCNet, 046/2000 - 7 April 2000
------------------------------


      "But is it possible that tiny creatures from another world
      somehow hitched a ride on a comet, crash-landed on Earth, then
      began to multiply and conquer the planet? The idea is known as
      panspermia - the theory that microscopic life was delivered to
      Earth billions of years ago from outer space. First proposed in
      1865, panspermia has gained widespread support in recent years
      with the discovery of organisms that thrive in extreme  
      environments like those found elsewhere in space - boiling or
      freezing temperatures, extreme acidity and even heavy doses of
      radiation."
            -- Mark Shwartz, Standford University



(1) SCIENTISTS PONDER EXTRATERRESTRIAL ORIGIN OF LIFE
    Stanford News Service <stanford.report@forsythe.stanford.edu>

(2) EROS' AGING CRATERS
    Ron Baalke <BAALKE@kelvin.jpl.nasa.gov>

(3) AH, FOLLOW-UP OBSERVATIONS INVALIDATE PROTOPLANET CLAIMS
    NASANews@hq.nasa.gov

(4) DETECTING SUNSPOTS ON THE FAR SIDE OF THE SUN
    PHYSICS NEWS UPDATE <physnews@aip.org>

(5) ASTROD ORBIT SIMULATION
    D.W. Chiou*) & W.T. Ni, NATL TSING HUA UNIVERSITY

(6) ANALYTICAL SOLUTION TO THE KOZAI RESONANCE
    H. Kinoshita*) & H. Nakai, NATIONAL ASTRONOMICAL OBSERVATORY

(7) GEOLOGICAL UNITS ON VENUS: EVIDENCE FOR GLOBAL CORRELATIONS
    A.T. Basilevsky*) & J.W. Head,  RUSSIAN ACAD SCI

(8) AND FINALLY: A TIMELY CLARIFICATION
    Leon Jaroff <NEONLEO@aol.com>



=========
(1) SCIENTISTS PONDER EXTRATERRESTRIAL ORIGIN OF LIFE

From Stanford News Service <stanford.report@forsythe.stanford.edu>

04/06/00

CONTACT: Mark Shwartz, News Service (650) 723-9296;
                       e-mail mshwartz@stanford.edu
For NASA illustration: http://nai.arc.nasa.gov/press.cfm?page=gallery

Scientists ponder the extraterrestrial origin of life

The question of whether life exists elsewhere in the universe left the
realm of science fiction this week, as NASA hosted the galaxy`s first
Astrobiology Science Conference.

The event was held April 3-5 at the NASA Ames Research Center in
Mountain View, Calif.

The conference brought together researchers from Stanford and dozens of
other institutions to discuss new developments in the burgeoning field
of astrobiology, which NASA defines as ``the study of the origin,
evolution, distribution and destiny of life in the universe.``

While several authors submitted papers on the search for
extraterrestrial intelligence, most focused on the question of whether
simpler life forms, such as bacteria, exist elsewhere in our solar
system or in other galaxies.

Christopher F. Chyba, associate professor (research) of geological and
environmental sciences, co-authored a study showing that life-giving
organic molecules could have arrived on Earth and other planets aboard
fast-moving comets.

"Life as we know it requires organic compounds, liquid water and a
source of energy," wrote Chyba and Elisabetta Pierazzo of the
University of Arizona. 

"Few places in the solar system appear to satisfy these requirements,"
they noted, except Earth, Mars and Jupiter`s moon, Europa.

Previous studies showed that comets contain organic compounds such as
amino acids, the building blocks of proteins.

Using computer simulations, Chyba and Pierazzo concluded that certain
amino acids could have survived "large cometary impacts" billions of
years ago, becoming part of a primordial soup that eventually gave rise
to single-celled organisms on Earth - and perhaps on Mars and Europa.

But is it possible that tiny creatures from another world somehow
hitched a ride on a comet, crash-landed on Earth, then began to
multiply and conquer the planet?

The idea is known as panspermia - the theory that microscopic life was
delivered to Earth billions of years ago from outer space.

First proposed in 1865, panspermia has gained widespread support in
recent years with the discovery of organisms that thrive in extreme
environments like those found elsewhere in space - boiling or freezing
temperatures, extreme acidity and even heavy doses of radiation.

One NASA Ames researcher pointed to recent experiments with a species
of worm called C. elegans that is only a millimeter long.  Miniature
worms were placed in a centrifuge then spun at 10 Gs, or 10 times the
gravitational force felt on Earth.

The little creatures survived four days of spinning - no surprise to
Stuart Kim, associate professor of developmental biology at Stanford.

"These worms will live at 100,000 Gs," said Kim, who is conducting
additional studies with NASA Ames to see if extreme gravitational
forces affect a worm`s ability to regulate cell growth, metabolism and
other genetic functions.

To find out how quickly invasive species adapt on Earth, conference
organizers invited Stanford biologist Harold A. Mooney, the Paul S.
Achilles Professor of Environmental Biology.

Mooney is an authority on how natural ecosystems are transformed by the
introduction of exotic plants and animals.

"Our world, our planet, is now one world," he told the audience,
noting that the oceanic walls separating the continents were breached
long ago by Columbus and subsequent explorers.

Mooney said that improvements in global transportation have caused even
more ecological disruption, pointing out that, between 1961 and 1995, a
new marine species was inadvertently introduced into San Francisco Bay
every week in the ballast water of cargo ships from Asia and other
continents. 

"That`s just a blip in geologic time," Mooney noted, adding that even
Earth-bound ecologists "can`t predict which organisms will become
successful invaders."

Stanford geophysicist Norman H. Sleep presented a paper arguing that
the Earth`s oceans contain just the right amount of water to sustain
oxygen-breathing organisms.

According to Sleep, if the oceans were twice as deep as they are today,
the continents would be submerged, exposing only a small amount of
granite to the atmosphere.

When granite weathers, it turns into clay, which then absorbs excess
carbon from the air as it becomes shale.

Without clay, too much carbon would remain in the atmosphere, stealing
oxygen molecules to form carbon dioxide gas, which is toxic to most
animals.

On the other hand, if the oceans were half as deep, atmospheric oxygen
would be soaked up by iron-rich basaltic rocks that are now submerged
under seawater. "Getting just the right amount of water," Sleep
concluded, "is a hurdle in having complex life forms on a planet."

==========
(2) EROS' AGING CRATERS

From Ron Baalke <BAALKE@kelvin.jpl.nasa.gov>

NEAR image of the day for 2000 April 5
http://near.jhuapl.edu/iod/20000405/index.html

Eros' many craters have a range of ages dating back to  the last time 
the asteroid's surface was "wiped  clean" by geologic processes. This
NEAR  Shoemaker  image   of  the  tip  of  the asteroid, taken March 6,
2000, from a range of 201 kilometers (125 miles), shows craters with
a  variety  of shapes  and  sizes. When  small craters first  form,
they typically have sharp rims   and   round   floors.   As  they  
age, progressively smaller craters are superimposed,  rounding the 
rims  and pitting the  walls   and  floors  until  the  original
underlying crater becomes almost unrecognizable.
----------------------------------------------
Built and managed by The Johns Hopkins University Applied Physics
Laboratory, Laurel, Maryland, NEAR-Shoemaker was the first spacecraft
launched in NASA's Discovery Program of low-cost, small-scale planetary
missions. See the NEAR web site for more details
(http://near.jhuapl.edu) .

==============
(3) AH, FOLLOW-UP OBSERVATIONS INVALIDATE PROTOPLANET CLAIMS

From NASANews@hq.nasa.gov

Donald Savage
Headquarters, Washington, DC                April 6, 2000
(Phone:  202/358-1547)

Nancy Neal
Goddard Space Flight Center, Greenbelt, MD
(Phone:  301/286-0039)

Ray Villard
Space Telescope Science Institute, Baltimore, MD
(Phone:  410/338-4514)

RELEASE:  00-58

SUSPECTED PROTOPLANET MAY REALLY BE A DISTANT STAR

     Follow-up observations of an unusual object initially
suspected to be the first directly detected planet outside our
solar system have shown that the object is too hot to be a planet. 

     Astronomers now believe it is more likely that the strange
object is a background star whose light has been dimmed and
reddened by interstellar dust, giving the illusion that it is in
the vicinity of the double star system in which it was initially
believed to have been a planet.

     NASA's Hubble Space Telescope photographed the mysterious
object, called TMR-1C, in 1997.  The picture shows a bright dot at
the end of a long streamer of reflective dust stretching 135
billion miles (225 billion kilometers) back to the binary star
located 450 light-years away in the constellation Taurus the bull. 
A light year is about 6 trillion miles.

     In 1998, astronomer Susan Terebey of the Extrasolar Research
Corp., Pasadena, CA, reported her observation at a scientific
meeting as a possible young and hot "protoplanet" several times
the mass of Jupiter.  Because of its potential importance and the
compelling nature of the image, NASA also released the picture to
the public with the caution that future observations would be
critical in verifying whether or not this object actually is a
planet.

     Tereby initially proposed that the object had been ejected
from a double star system via a "slingshot" effect (interaction
with one of the stars or another giant planet).  Since then
she has conducted follow-up observations with the 10-meter Keck
telescope in Mauna Kea, HI, to test her hypothesis.

     Now, in results to be published in the May Astronomical
Journal, Tereby reports, "The new data do not lend weight to the
protoplanet interpretation and the results remain consistent with
the explanation that TMR-1C may be a background star.  Although
the Hubble image is striking, there is the alternate possibility
that TMR-1C is an unrelated background star, seen, by chance,
projected close to the young star system.  Finding a clearer
answer is difficult for an object as faint as TMR-1C."

     To better understand the nature of this faint object, Tereby
used the Keck telescope to measure TMR-1C's temperature by
dissecting its light through spectroscopy.  Much like the way a
prism disperses sunlight to make a colorful rainbow, a spectrum
breaks apart the light from the observed object. The relative
amounts of red and blue light help tell the object's temperature.

     Tereby and colleagues then constructed models of dust-
obscured objects to compare with the spectrum of TMR-1C and found
a corresponding temperature of greater than 4400 degrees
Fahrenheit (2700 degrees Kelvin) for TMR-1C. This is hotter than
the predicted temperatures of young giant planets.

     "However the models are not yet reliable at such young ages,
so this test by itself is not conclusive," Tereby cautions. "The
idea remains alive and well that there may be runaway planets and
brown dwarfs (small stars that failed to sustain nuclear fusion)
which formed via ejection from multiple star systems. Theoretical
models by several groups support this idea, and new searches --
including ours -- are finding many new candidates in star-forming
regions. However at this time there is no strong evidence that
TMR-1C itself is a protoplanet."

EDITOR'S NOTE:  The Hubble image of TMR-1C and the initial press
release (from May 28, 1998) are available at:

       http://oposite.stsci.edu/pubinfo/pr/1998/19/

=========
(4) DETECTING SUNSPOTS ON THE FAR SIDE OF THE SUN

From PHYSICS NEWS UPDATE <physnews@aip.org>

SUNSPOTS ON THE FAR SIDE OF THE SUN can be detected through
helioseismic holography, a process in which the sound waves that rumble
through the body of the sun are slightly distorted when they reflect
from the magnetically active regions around sunspots.  In March of
1998, data from the orbiting Solar Heliospheric Observatory (SOHO) were
processed with an algorithm that deduces the locations of those
out-of-sight sunspots. Charles Lindsey and Douglas Braun of the Solar
Physics Research Corp. report that their calculations of presumed
sunspot positions on the far side of the sun correlated well with
actual spots that later swung into view (revolving along with the sun
on its 27-day rotation).  The researchers expect that eventually this
method will be able to give valuable advance warnings of the type of
space storms that arise from the solar flares and coronal mass
ejections associated with the active regions on the sun's surface. 
Predicting "space weather" in the Earth-sun environment is important
since astronauts' lives, the survival of satellites, and the stable
operation of  terrestrial power grids are tied to the particles and
radiation that comes rushing at us from the sun.  (Lindsey and Braun,
Science, 10 March 2000.)

=========
(5) ASTROD ORBIT SIMULATION

D.W. Chiou*) & W.T. Ni: ASTROD orbit simulation and accuracy of
relativistic parameter determination. ADVANCES IN SPACE RESEARCH,
2000, Vol.25, No.6, pp.1259-1262

*) NATL TSING HUA UNIVERSITY,DEPT PHYS,CTR GRAVITAT & COSMOL,HSINCHU
   30043,TAIWAN

In this paper, we present our ASTROD orbit simulation with
uncertainty distributions to investigate the accuracy for
determination of relativistic parameters and other relevant
parameters. ASTROD mission concept is to use drag-free spacecraft in
solar orbits together with a constellation of Earth orbiting
satellites to provide high-precision measurement of relativistic
effects, better determination of the orbits of major asteroids,
improvement in the measurement of (G) over dot, measurement of solar
angular momentum via Lense-Thirring effect and the detection of
low-frequency gravitational waves and salar oscillations in a single
mission. In our orbit simulation, we first establish a deterministic
model and then extend it to a,stochastic model. With this stochastic
model, the accuracy of parameter determination for beta, gamma and
J(2) is obtained and discussed. (C) 2000 COSPAR. Published by
Elsevier Science Ltd.

=========
(6) ANALYTICAL SOLUTION TO THE KOZAI RESONANCE

H. Kinoshita*) & H. Nakai: Analytical solution of the Kozai resonance
and its application. CELESTIAL MECHANICS & DYNAMICAL ASTRONOMY, 1999,
Vol.75, No.2, pp.125-147

*) NATIONAL ASTRONOMICAL OBSERVATORY,2-21-1 OSAWA,MITAKA,TOKYO,JAPAN

When Kozai (1962) studied the secular resonance of asteroids, he
found the so-called Kozai resonance and expressed the analytical
solution with the use of Weierstrass p. Here we discuss the case
where the disturber is outside a disturbed body and give the
analytical solution of the eccentricity, the inclination and the
argument of pericenter with the use of the Jacobi elliptic functions,
which are more familiar than the Weierstrass p. Then we derive the
Fourier expansion of the longitude of node and the mean anomaly. The
analytical expressions obtained here can be used for any value of the
eccentricity and the inclination. Finally we applied these analytical
expressions to several dynamical systems - Nereid, that is a highly
eccentric satellite of Neptune, and newly discovered retrograde
satellites of Uranus. Copyright 2000, Institute for Scientific
Information Inc.

=================
(7) GEOLOGICAL UNITS ON VENUS: EVIDENCE FOR GLOBAL CORRELATIONS

A.T. Basilevsky*) & J.W. Head: Geologic units on Venus: evidence for
their global correlation. PLANETARY AND SPACE SCIENCE, 2000, Vol.48,
No.1, pp.75-111

*) RUSSIAN ACAD SCI,VI VERNADSKY INST GEOCHEM & ANALYT
   CHEM,MOSCOW,RUSSIA

Detailed geologic mapping of approximately 30% of the surface of Venus
has revealed a stratigraphic sequence that appears to be repeated in
widely separated areas on the planet. This sequence shows a transition
from oldest highly deformed terrain units, the tessera, to a series of
widespread volcanic plains units, each with recognizable morphologic
characteristics and interpreted eruption style, and finally to
individual eruptive centers associated with edifices and rift zones.
This sequence of events is accompanied by characteristic and repetitive
patterns of tectonic deformation. In order to test the validity and
broader applicability of this sequence, we compare it with local,
regional, and global mapping published in 17 analyses by other authors.
This comparison shows that the sequence of units, and thus the relative
time sequence of the corresponding geologic events, is generally the
same in virtually all of the widely distributed areas that have been
studied, comprising about one-half the surface of Venus. We then
address several alternative explanations for the observed sequence: (1)
that the similar units and sequences correspond to events that occurred
in different areas at different times (repetitive in different places
but not time correlative); (2) that the sequences occurred generally
synchronously in different places (repetitive and rime correlative);
or (3) that the situation is intermediate between the two cases. In
order to distinguish among these possibilities, we analyze evidence
for the lateral global continuity of units, the chronology of
emplacement on the basis of the density of superposed craters, and
the consistency of stratigraphic relationships based on these data.
We find that this analysis supports the hypothesis that the individual
sequences are repetitive in different parts of the planet, and
generally time correlative between these locations. As a further
test of this stratigraphy, we outline a global model for the geological
evolution of Venus and assess the duration of emplacement of units, the
timing and style of tectonic phases, and the volumes and implied fluxes
of volcanic deposits. We find that the morphologically recognizable
part of the history of Venus comprises only the last 10-20% of its
total history. Emplacement of tessera-forming material and its
deformation into tessera terrain are the major geologic events of the
initial Fortunian time. Several stages of areally extensive volcanism
occurred subsequently burying vast areas of tessera and forming
regional plains during Sigrunian, Lavinian, and Rusalkian times. The
average global rate of volcanism was a few km(3) y(-1), and the
emplacement of plains was accompanied by alternating episodes of
contraction and extension. The last global-scale distributed tectonic
episode, the formation of an extensive network of wrinkle-ridges,:
happened near the end of the Rusalkian Period, and marked the
transition to the present stage of the history of Venus, the Atlian
Period. Atlian times are characterized by a predominance of regional
rifting focused at several broad rises, and localized rift-associated
volcanism in the form of shield volcanic constructions and lobate
volcanic plains-forming units, and is the longest lime duration among
the stratigraphic units considered, although the resulting tectonic and
volcanic features and deposits cover only 10-20% of the surface of
Venus.Comparison of this sequence of events with those revealed by
continued geologic mapping of Venus will permit further testing and
assessment so that a consistent and comprehensive documentation of the
geological record can be presented and used to test models of the
geodynamic evolution of Venus. (C) 1999 Elsevier Science Ltd. All
rights reserved.

=============
(8) AND FINALLY: A TIMELY CLARIFICATION

From Leon Jaroff <NEONLEO@aol.com>
                     
Benny,

please note that my Time story on the asteroid and comet threat, as
turned in by me, described Meteor Crater as being 3/4 of a mile across.
Some scientific illiterate slashed the slash before the magazine went
to press. Well, it happens.

Best regards,

Leon Jaroff

- -
Hi Benny. Here's the last word on the Time asteroid story. Turns out
that the error was only in the web site, NOT in the magazine. Whew!!

Best regards,

Leon Jaroff

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