CCNet 79/2001 - 18 June 2001

"From the enormous increase of recent asteroid discoveries by
LINEAR, LONEOS, Catalina Sky Survey and Kitt Peak, there seems to be an
indication that the number of really new discoveries is slowly
decreasing. What is the reason for this? Are we approaching the end of
asteroid-discovery, assuming that there is a cut-off (gap) in the
distribution of fainter and faintest (main belt) asteroids; or is it
just the consequence of the fact that most instruments/devices are
reaching the magnitude below which the observers have at present not
the possibility to extend their searches towards fainter asteroids? From
this investigation it follows that we are approaching apparently the end
of new discoveries, as the consequence of the fact that the more important
asteroid surveys (in particular, LINEAR) are not searching for new
asteroids beyond magnitude V=19.5."
--Eric W. Elst, Royal Observatory at Uccle, Belgium

"A rocket could be strapped to the asteroid, they say, and the
asteroid maneuvered into an immense orbit more than seven times wider
than the radius of the solar system. The asteroid would then pass
close enough to Earth to tug it gently away from the Sun. (One hitch, the
authors acknowledge, would be a collision, which would "sterilize the
biosphere most effectively, at least to the level of bacteria.")
--Anthony Ramirez, The New York Times, 17 June 2001


    Andrew Yee <>

    Ron Baalke <>


    Andrew Yee <>

    Andrew Yee <>

    The New York Times, 17 June 2001

    The Observer, 10 June 2001

    S. Fred Singer <>


     Andrew Yee <>

     Oliver Morton <>

     John Michael Williams <>


     Discovery News, 18 June 2001



Planetary and Space Science, Vol. 49 (8) (2001) pp. 781-78628-9

Are we approaching the end of asteroid-discovery?
Eric W. Elst <>
Royal Observatory at Uccle, Ringlaan 3, B-1180 Uccle, Belgium
Received 6 September 2000; accepted 30 January 2001

From the enormous increase of recent asteroid discoveries by LINEAR, LONEOS,
Catalina Sky Survey and Kitt Peak, there seems to be an indication that the
number of really new discoveries is slowly decreasing. What is the reason
for this? Are we approaching the end of asteroid-discovery, assuming that
there is a cut-off (gap) in the distribution of fainter and faintest (main
belt) asteroids; or is it just the consequence of the fact that most
instruments/devices are reaching the magnitude below which the observers
have at present not the possibility to extend their searches towards fainter
asteroids? From this investigation it follows that we are approaching
apparently the end of new discoveries, as the consequence of the fact that
the more important asteroid surveys (in particular, LINEAR) are not
searching for new asteroids beyond magnitude V=19.5.

Full text supplied by [ScienceDirect]

© Copyright 2001, Elsevier Science, All rights reserved.


From Andrew Yee <>

News Service
Cornell University

Contact: David Brand
Office: 607-255-3651

FOR RELEASE: June 12, 2001

Instruments aboard CONTOUR spacecraft will provide first surface
'fingerprint' of comet nucleus

ITHACA, N.Y. -- Instruments aboard a spacecraft that will be launched next
year to explore two, and perhaps three or more, comets in the solar system
will for the first time provide a "fingerprint" of the surface of cometary
nuclei, giving the first firm evidence of the composition of the icy, rocky

About 50 of the world's leading comet experts, meeting at the
Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., recently,
were told that the spacecraft's infrared imaging spectroscopy will map the
composition of the nucleus of comet Encke at a resolution of 100 meters to
200 meters (109 to 218 yards), detailed enough to see craters and other
large geologic features and to determine their composition.

Comet Encke will be the first target of NASA's Cornell University-led Comet
Nucleus Tour (CONTOUR), scheduled for launch July 1, 2002. In a report
prepared for the meeting, James Bell, Cornell assistant professor of
astronomy and one of the scientists responsible for the spectrometer on the
close-up imager, noted that the surface resolution of Encke's nucleus
by the CONTOUR spectrometer will be even better than that obtained by the
infrared spectrometer on the Near Earth Asteroid Rendezvous spacecraft
during its recent orbital mission to asteroid 433 Eros. "The CONTOUR
spacecraft will come within about 100 to 160 kilometers (62 to 100 miles) of
the nucleus, although the exact distance is still in doubt because we don't
know the orbital position of the nucleus with extreme precision," said Bell.

The imaging instrument, called the CONTOUR remote image/spectrograph, also
will send back digital-camera images of Encke's nucleus. The camera will
capture the images as the spacecraft speeds through the comet's dusty,
gaseous head, called the coma, at 28 kilometers (about 17 miles) a second in
November 2003. Joseph Veverka, Cornell professor of astronomy and
principal investigator on the $155 million mission, noted at the Cambridge
meeting that "success" will be defined as obtaining digital images of the
nucleus showing automobile-size details, such as rocks, about 4 meters (4
yards) across. Encke, first discovered 225 years ago, is about 8 kilometers
(5 miles) long and has an average radius of about 2.5 kilometers (1.5
miles). It orbits the sun once every 3.2 years, and its most recent
apparition from Earth was last year. It is unique in that it has been
observed from Earth on 56 of its apparitions, more than any other comet,
including Halley.

Encke will not be the only comet on CONTOUR's agenda. In June 2006 the
spacecraft is scheduled to encounter Comet Schwassmann-Wachmann 3 and,
possibly, Comet d'Arrest in 2008. These targets are so-called "Jupiter
family" comets because they are thought to have had their orbital periods
shortened by previous gravitational encounters with the giant planet. The
science team hopes it also might be possible to visit other kinds of comets,
particularly primitive members of the so-called "dynamically young" family
that are in long elliptical orbits and might be making one of their first
close passes by the sun.

Cornell senior research associate and science team member Peter Thomas noted
at the meeting that during the 30-minute flyby of the nucleus, the
spacecraft's instruments "will be able to obtain detailed compositional
measurements of gas and dust in the near-nucleus environment." The comet's
coma is a vast but extremely thin atmosphere, approaching the size of the
sun, consisting of gas and debris thrown off the nucleus as it orbits the
sun. The peak of this shedding of material is reached as the comet
approaches the sun, and all the spacecraft's flybys will occur when the
target comet is near this point in its solar orbit.

The scientific team will be particularly searching the coma for evidence of
curious particles previously detected in interstellar clouds by Jochen
Kissel, a comet researcher at the Max-Planck-Institute for Extraterrestrial
Physics in Garching, Germany. Kissel made his discovery in data sent back by
NASA's Stardust mission, which will reach comet Wild 2 in 2004. The mission
is using the same dust analyzer as will be carried by the CONTOUR. Said
Veverka, "The particles have a completely weird composition and don't seem
to have minerals in them but seem to be made of chains of carbon-hydrogen
and oxygen-nitrogen, like polymers. But there isn't any polymer with that
kind of composition that we are normally familiar with."

There is an indication, said Veverka, that some particles might have
weathered the massive meltdown of material when the sun and planets were
formed from interstellar dust and clouds. "The question now is, have any of
these particles been preserved in comets? We have to get close enough to a
comet to find out." Although Encke has been much studied from ground-based
observatories, little is known about its composition, which is why the comet
experts gathered to exchange information on the object. Most assumptions
about Encke, the researchers agreed, are drawn from data gathered by the
European Space Agency's Giotto spacecraft, which visited comet Halley in
1986. Much of what astronomers know about comets "comes from the one object
we've come close to, comet Halley," noted Casey Lisse, an astronomer at the
University of Maryland. However, the CONTOUR images from Encke will be 25
times higher resolution than those from Halley.

Indeed, the most that the astronomers at the meeting could agree on was that
Encke, some 30 million miles from Earth, is an extremely elongated "icy dirt
ball" with a density, size, shape and rotation that defy precise analysis.
Veverka wryly noted that the conflicting information about the comet is such
that the mission will "not be dependent on any prejudices."

And science team member Anita Cochran, a research scientist at the McDonald
Observatory, the University of Texas, ruefully concluded that "we started
off by saying we didn't know, and we just made up things from there."

The complex journey of CONTOUR is shown in a computer simulation video, made
for NASA by recent Cornell graduate Dan Maas, who previously produced a
video for the 2003 Mars Rover mission. The new video can be seen on the
CONTOUR web site at


From Ron Baalke <>

June 13, 2001


Jeff Medkeff
Rockland Observatory (933)

Bill Owen
Jet Propulsion Laboratory

Extremely Close Pluto Appulse, Possible Occultation Discovered

A very close appulse of Pluto with GSC 5651-1553 will occur on 01 July 2002,
at approximately 23:00 UT.

The event was discovered by Arizona amateur astronomer and Sky & Telescope
Contributing Editor Jeff Medkeff from his home in Sierra Vista. He was using
SkyMap Pro 7.0 software to search for appulses of Pluto past stars in order
to find favorable observing opportunities through the next 14 months.

After initially confirming the event with the Chapront and Francou Planetary
Series (1996) planetary theory, and several other software packages, he
alerted Jet Propulsion Laboratory scientist Bill Owen of the event. The
event geometry is dependent upon three primary variables - the uncertainty
in the position of the star, the uncertainty in the position of Pluto, and
the theory used to describe Pluto's motion. Using the position of this star
from the Tycho-II catalog, Owen's preliminary prediction suggests that the
nominal event will have Pluto passing 1/3 arcsecond north of the star, with
Charon 0.84 arcseconds south of Pluto - so that the star passes between the
two. The uncertainties involved are sufficient that there is a very slim
possibility that Pluto will occult the star.

According to Owen, recent astrometry of Pluto obtained independently by Ron
Stone (USNO) and by Owen will be used by Myles Standish (JPL) to update
Pluto's orbit. If the updated orbit does not rule out an event, additional
astrometry will be pursued to further refine the predictions.

In any case, the event will provide an unusual opportunity for amateur
observers to see Pluto exceptionally close to a field star.



Space Weather News for June 16, 2001

BURSTING COMET: The crumbling comet C/2001 A2 (LINEAR), better known as
"Comet LINEAR," brightened suddenly this week to magnitude 3.3. Its fuzzy
head is easily visible to the unaided eye from dark-sky sites in the
southern hemisphere, and the comet's tail is a beautiful sight through
binoculars, say observers.  Later this month the brightening comet will also
make an appearance in northern skies.

SOLAR ACTIVITY: The sunspot number is up and solar activity is on the rise
as well.  A pair of coronal mass ejections that billowed away from the Sun
on Friday could deliver glancing blows to Earth's magnetic field this
weekend. Forecasters estimate a 15% chance of severe geomagnetic
storms at mid-latitudes by Sunday. Sky watchers should remain alert for
auroras near local midnight.

For more information about viewing comet LINEAR and ongoing solar activity
please visit


From Andrew Yee <>

[ ]

Thursday, 14 June 2001

Celestial backspin inevitable

Venus is strange. It rotates from east to west. Every other planet in the
Solar System turns west to east. It has been widely assumed that this is
because a freak event up-ended Venus on its axis at some point in the past.
Now two astronomers suggest that there are other ways our neighbouring
planet could have gone into backspin.

Alexandre Correla and Jacques Laskar of Astronomie et Systèmes Dynamiques in
Paris, France, calculate that Venus has only four states available to it:
two that spin the normal way, and two retrograde. Under most conditions,
retrograde motion is the most likely final state, they conclude [1].

Laskar has previously shown that, thanks to myriad influences, the tilted
rotation axes of all the inner planets -- Mercury, Venus, Earth and Mars --
can wobble chaotically. This makes their behaviour highly sensitive to tiny
effects and highly unpredictable. Tides sloshing Venus's thick atmosphere
could thus have caused its rotation axis to flip. But only if the initial
tilt was large.

But Venus need not have been in this special initial state to acquire
retrograde rotation. Corella and Laskar have calculated how Venus moves
around its orbit, allowing for tidal effects and for rubbing between the
planet's rocky mantle and its molten core.

They find no unique answer. Because of the chaotic nature of the motion, the
researchers had to run lots of computer simulations for different initial
conditions, and look for the most common outcomes.

The four rotation states that they settle upon are likely to apply to other
planets with dense atmospheres, such as the Earth. But for Venus, the two
prograde states are much less stable than the two retrograde states for a
wide range of initial conditions. So its unusual rotation may be less a
matter of chance, and more an inevitability.

[1] Correla, A. C. M. & Laskar, J. The four final rotation states of Venus.
    Nature 411, 767-770 (2001).

© Macmillan Magazines Ltd 2001 - NATURE NEWS SERVICE


From Andrew Yee <>

News Services
University of Arizona
Tucson, Arizona

Contact Information:
Peter Lanagan, 520-621-1594,
Alfred McEwen, 520-621-4573,
Laszlo Keszthelyi, 520-621-8284,

Jun 13, 2001

UA Scientists Find Evidence for Geologically Recent Shallow Ground Ice at
Mars' Equator

By Lori Stiles

New high-resolution images from the Mars Orbiter Camera (MOC) show evidence
of ground ice on Mars as recently as 10 million years ago.

More striking is that the signs of geologically recent ground ice deposits
are near Mars' equator, where ice was probably no deeper than 5 meters (15
feet) below the surface, University of Arizona scientists say.

"If ground ice was present within 5 meters of the surface only a few million
years ago, it is very likely to persist today within about the upper 10
meters," said UA planetary sciences Professor Alfred S. McEwen. "This is
especially interesting because it is an equatorial region of Mars, more
accessible to exploration."

Peter D. Lanagan, McEwen and Laszlo P. Keszthelyi of the UA Lunar and
Planetary Laboratory, and Thorvaldur Thordarson of the University of Hawaii
have discovered clusters of tens to many hundreds of small "rootless" cones
in MOC images of the Cerberus plains, Marte Valles, and Amazonis Planitia
region near Mars' equator.

The martian cones are similar both in morphology and size to rootless cones
in Iceland, features which form when surface lava interacts explosively with
near-surface groundwater.

"The martian cones sit on pristine lava surfaces, and the cones are
generally close to fluvial (water-carved) channels. The lavas do not appear
to have been modified since they were emplaced, and some of the channels
appear to be similarly pristine," Lanagan said.

Using crater counts and other geologic evidence seen in the detailed new MOC
images, William K. Hartmann of the Planetary Science Institute in Tucson and
others recently determined these lava flows to be as young as 10 million

"We consider recent fluvial recharge to be the most likely origin for the
shallow ground ice," the UA/Hawaii team conclude this week in Geophysical
Research Letters. "If shallow ground ice in these regions was present less
than 10 million years ago, deposits of shallow ground ice probably persist
in the vicinity of the cone fields to the present day."

Rootless cones, or pseudocraters, do not form over volcanic vents.
Thordarson concludes from years of fieldwork that in Iceland, rootless cones
form where molten lava flows over marshy terrain. A crust forms over the
lava flow, while molten lava continues to pump through tubes or pathways
beneath the crust. As lava is shoved through the tubes, it mixes with some
of the underlying water-rich sediment, and in the process of mixing, the
water is heated by lava until it flashes to steam. When the steam pressure
exceeds the pressure of the lava above it, there's a "phreatomagmatic" -- or
groundwater and magma -- explosion. The result of several such sustained
explosions is a cluster of cones associated not with any deep fault or
fissure but with a network of lava tubes over the marshy area.

"We see many hundreds of similar cones in the Mars scape, and they appear to
be associated either with low plains areas or with recent outflow channels,"
Lanagan said. Water would flow to low areas, pond and percolate in low
plains during the floods, recharging ground ice.

"If the terrestrial rootless cone analogy is extended to Mars," he added,
"lava flows erupted over surfaces with ground ice -- probably at a depth of
less than 5 meters -- where they melted the ice to form a water-rich slurry
which mixed with the tube-fed lavas. The process likely would have resulted
in a series of phreatomagmatic explosions, which formed cones on the top of
the chilled lava crust.

"The martian cones are close to outflow channels, so the cones formed in
regions that were probably water- or ice-rich. Also, the martian cones
generally are seen to sit on platy-ridged lavas similar to Icelandic 'rubbly
pahoehoe' lava flows, where lavas delivered through tube networks breaks the
hardened, chilled crust of the flow and move the resulting pieces around
like a pulled-apart jigsaw puzzle. This suggests that the martian cones
formed over lava flows fed by lava tubes, similar to rootless cones in

Researchers debate whether the shallow ground ice that exploded to create
the cones is relic ice leftover from the planet's formation, recondensed
water vapor from the soil-atmosphere water vapor exchange, or recharge from
surface flooding events.

"It is unlikely that relic ground ice has survived for 4 billion years in
equatorial regions of Mars," the UA/Hawaii team concludes.

The argument that equatorial ground ice could be recharged by an exchange of
water vapor between the ground and the atmosphere -- as Arizona State
University scientists have modeled -- is perhaps more plausible, the team

"However, because these cones appear to be near outflow channels, we think
that the water the formed the cones is probably recharge from floods,"
Lanagan said. Scientists studying Viking imagery in the late 1970s and 1980s
noted structures they interpreted to be rootless cones. Most of these were
twice the size of the largest terrestrial cones, however, and it was unclear
if some of these rested on actual volcanic surfaces.

The UA researchers looked at some of these areas again, this time using
high-resolution MOC images, but still could not tell if the cones sit on
volcanic surface because the terrain is either heavily mantled by dust or
significantly eroded, Lanagan said.

"The structures observed by MOC are the first clearly identified martian
cones having dimensions, morphologies, and geologic settings similar to
terrestrial rootless cones," the team wrote in GRL.


Copies of the figures published in the GRL article, "Rootless cones on Mars
indicating the presence of shallow equatorial ground ice in recent times"
are available from the website

Addresses for jpgs and tiffs of the figures are as follows: (284k) (513k) (187k) (1.3M)


[Left] Cluster of cones north of the Cerberus plains on Mars, as seen in an
image from the Mars Orbiter Camera. (PHOTO: NASA/JPL/Malin Space Science)
[Right] Air photo of rootless cone field in Laki lava flow north of Innryi
Eyrar, Iceland.


From The New York Times, 17 June 2001


AS the nation once again reaches for an iced tea to rub against its
forehead, the chat turns inevitably, if listlessly, to global warming, the
artificial raising of the planet's thermostat.

Ratify the Kyoto Protocol? Harms the American economy, says President Bush.
Cut back on greenhouse emissions? Drives up electricity prices, say
economists. Require smaller cars? Minivans carry my children to school, say
the parents. Swelter, swelter, swelter.

Enter three scientists pushing a big, if long-term, idea: cool down the
Earth by slowly moving it - the entire planet, that is - farther away from
the Sun.

In a recent issue of the professional journal Astrophysics and Space
Science, Don Korycansky, Greg Laughlin and Fred Adams playfully propose
finding an asteroid about 60 miles long - about half the length of Long
Island - to be used in a "gravitational sling shot."

A rocket could be strapped to the asteroid, they say, and the asteroid
maneuvered into an immense orbit more than seven times wider than the radius
of the solar system. The asteroid would then pass close enough to Earth to
tug it gently away from the Sun. (One hitch, the authors acknowledge, would
be a collision, which would "sterilize the biosphere most effectively, at
least to the level of bacteria.")

While the solution may seem outsized, the three scientists are actually
eyeing a larger-scale version of global warming. As the Sun burns through
its hydrogen, it gets bigger and brighter, leading to hotter temperatures on
Earth. In a billion years, the Sun will be 10 percent brighter, killing off
many forms of life on Earth.

Moving the planet away from the Sun, in this view, is simply shoving it away
from a red-hot stove.

It would be fitting if the idea occurred to Mr. Korycansky, the paper's
principal author and a planetary scientist at the University of California
at Santa Cruz, on a blistering summer day. But it was on a sunny and mild
September day in 1999 that Mr. Korycansky chatted with Mr. Laughlin, a
scientist at NASA's Ames Research Center, about the daunting problem of the
Sun's lethal luminosity.

Earth-moving was Mr. Laughlin's idea, the asteroid was Mr. Korycansky's,
while Mr. Adams, a University of Michigan physicist, was brought in later to
figure out timing, which, as will be seen, is everything.

As they write in their paper, "the general problem of long-term planetary
engineering is almost alarmingly feasible" using current technologies.

After all, "gravitational slingshots" using Jupiter and Saturn have already
been used to propel the Galileo and Cassini deep-space missions. The
principle is a lot like a planetary square dance in which even the tiniest
dancer can slightly deflect and accelerate a gargantuan partner, and vice
versa, as they swing each other round and round.

An asteroid roughly 60 miles long passing within 10,000 miles of Earth would
tug the planet into an orbit whose radius gets longer by about 30 miles with
each pass, or every 6,000 years. Of course, it would take a long-lived
civilization to witness the feat - the equivalent of the ancient Egyptians
firing a deep-space rocket with the expectation that their descendants would
greet its return in the 21st century.

Nonetheless, Mr. Korycansky and his friends foresee at least one million of
these orbits, slowly balancing out the Sun's increasing ferocity and thus
preserving life on Earth.

BY the millionth pass, however, the Earth would have a 50 percent larger

"Of course, we'd then have to move Mars," Mr. Korycansky said. Jupiter would
be affected, too, and so would Venus, but probably in ways too small to
really matter to Earth. "The larger question is," he said, "if you move a
planet, is it your responsibility to, you know, shepherd the other planets?"

And the Earth, while rescued, would not escape consequences, either. Every
time the asteroid passed, it would exert a tidal force 10 times that of the
moon, leading to likely tsunamis, immense storms and other disruptions. "We
would have to batten down the hatches," Mr. Korycansky said.

Don't even mention the seasons, say skeptical climate researchers. A bigger
orbit means a longer year, affecting the all-important tilt of Earth toward
the Sun.

"At a zero tilt, straight up and down, there would be no seasons," said Dr.
Ronald J. Stouffer, who designs computer climate models at the federal
Geophysical Fluid Dynamics Laboratory. "At a 90-degree tilt, you have two
seasons, one that's all daylight all the time and the other that's all
nighttime all the time."

Of course, the biggest complication of all is simply this: Instead of
missing by a whisker, an ill-timed asteroid larger than Rhode Island could
very well crash into the Earth. It would be the gravest miscalculation
since, perhaps, a similar one many millions of years ago that wiped out
ancient dinosaur astronomers.

Copyright 2001, The New York Times


From The Observer, 10 June 2001,3858,4201561,00.html

Nasa aims to move Earth
Scientists' answer to global warming: nudge the planet farther from Sun

Robin McKie, science editor
Sunday June 10, 2001
The Observer

Scientists have found an unusual way to prevent our planet overheating: move
it to a cooler spot.

All you have to do is hurtle a few comets at Earth, and its orbit will be
altered. Our world will then be sent spinning into a safer, colder part of
the solar system.

This startling idea of improving our interplanetary neighbourhood is the
brainchild of a group of Nasa engineers and American astronomers who say
their plan could add another six billion years to the useful lifetime of our
planet - effectively doubling its working life.

'The technology is not at all far-fetched,' said Dr Greg Laughlin, of the
Nasa Ames Research Center in California. 'It involves the same techniques
that people now suggest could be used to deflect asteroids or comets heading
towards Earth. We don't need raw power to move Earth, we just require
delicacy of planning and manoeuvring.'

The plan put forward by Dr Laughlin, and his colleagues Don Korycansky and
Fred Adams, involves carefully directing a comet or asteroid so that it
sweeps close past our planet and transfers some of its gravitational energy
to Earth.

'Earth's orbital speed would increase as a result and we would move to a
higher orbit away from the Sun,' Laughlin said.

Engineers would then direct their comet so that it passed close to Jupiter
or Saturn, where the reverse process would occur. It would pick up energy
from one of these giant planets. Later its orbit would bring it back to
Earth, and the process would be repeated.

In the short term, the plan provides an ideal solution to global warming,
although the team was actually concerned with a more drastic danger. The sun
is destined to heat up in about a billion years and so 'seriously
compromise' our biosphere - by frying us.

Hence the group's decision to try to save Earth. 'All you have to do is
strap a chemical rocket to an asteroid or comet and fire it at just the
right time,' added Laughlin. 'It is basic rocket science.'

The plan has one or two worrying aspects, however. For a start, space
engineers would have to be very careful about how they directed their
asteroid or comet towards Earth. The slightest miscalculation in orbit could
fire it straight at Earth - with devastating consequences.

It is a point acknowledged by the group. 'The collision of a 100-kilometre
diameter object with the Earth at cosmic velocity would sterilise the
biosphere most effectively, at least to the level of bacteria,' they state
in a paper in Astrophysics and Space Science. 'The danger cannot be

There is also the vexed question of the Moon. As the current issue of
Scientific American points out, if Earth was pushed out of its current
position it is 'most likely the Moon would be stripped away from Earth,' it
states, radically upsetting out planet's climate.

These criticisms are accepted by the scientists. 'Our investigation has
shown just how delicately Earth is poised within the solar system,' Laughlin
admitted. 'Nevertheless, our work has practical implications. Our
calculations show that to get Earth to a safer, distant orbit, it would have
to pass through unstable zones and would need careful nurturing and nudging.
Any alien astronomers observing our solar system would know that something
odd had occurred, and would realise an intelligent lifeform was responsible.

'And the same goes for us. When we look at other solar systems, and detect
planets around other suns - which we are now beginning to do - we may see
that planet-moving has occurred. It will give us our first evidence of the
handiwork of extraterrestrial beings.'

Guardian Unlimited © Guardian Newspapers Limited 2001


From S. Fred Singer <>

Dear Benny

There are a few "problems" with the scheme to move the Earth to a more
distant orbit.

1. A single impulse would simply produce a more eccentric orbit (unless
carefully applied at aphelion). Is that what we really want?

2.  A close passage would also produce huge destructive tides and change the
spin angular velocity of the Earth. I have previously calculated some of
these effects in considering a capture origin of the Moon.

Best wished

S. Fred Singer, President
Science & Environmental Policy Project



Planetary and Space Science, Vol. 49 (8) (2001) pp. 817-830
© 2001 Elsevier Science Ltd. All rights reserved.
PII: S0032-0633(01)00032-0

The end-cretaceous mass extinction in the marine realm: year 2000 assessment
Gerta Keller *
Department of Geosciences, Guyot Hall, Princeton University, Princeton NJ
08544-1003 USA
Received 11 September 2000; accepted 29 November 2000

The current database indicates that the terminal decline and extinction, or
near extinction, of many groups commonly attributed to an asteroid or comet
impact at the Cretaceous-Tertiary (K-T) boundary (e.g., ammonites, bivalves,
planktic foraminifera) began during the last 500k.y. of the Maastrichtian.
By the time of the K-T boundary, extinction-prone tropical and subtropical
marine faunas and floras were almost gone, or had severely reduced species
populations struggling to survive. The K-T boundary kill-effect was largely
restricted to these struggling tropical and subtropical populations that
accounted for 2/3 of the species among planktic foraminifera, but less than
10% of the total foraminiferal population. No significant extinctions
occurred among ecological generalists that dominated across latitudes. No
single kill mechanism can account for this mass extinction pattern. The last
500k.y. of the Maastrichtian were characterized by a series of rapid and
extreme climate changes characterized by 3-4°C warming between 65.4 and
65.2Ma, major volcanic activity between 65.4 and 65.2Ma, a
spherule-producing event between 65.3 and 65.2Ma, and an impact at the K-T
boundary (65.0Ma). All of these events caused major environmental
perturbations and biotic stresses that resulted in severe reductions in
species populations and extinctions that culminated at the K-T boundary. The
mass extinction pattern, and the parallel environmental changes during the
last 500k.y. of the Maastrichtian, suggest that both long-term (climate,
sea-level) and short-term (impact, volcanism) events contributed to the K-T
boundary mass extinction.

*Tel.: 1-609-258-4117; fax: 1-609-258-1671
Full text supplied by [ScienceDirect]

© Copyright 2001, Elsevier Science, All rights reserved.


From Andrew Yee <>

From the Boston Globe, 12 June 2001
[ ]

Tuesday, June 12, 2001

Snowball Earth

Science grapples with a puzzling new theory: the extreme ice age

By David L. Chandler, Boston Globe Staff,

Even the scientists who first thought up the idea didn't think it was
possible: That the entire Earth could have frozen over and been encased in a
solid cover of snow and ice, perhaps for millions of years.

When the idea first showed up in a computerized climate model, it seemed out
of the question. If Earth was frozen solid, how could any life have
survived? And how could an ice-covered planet ever have thawed again?

But a rising tide of evidence over the last decade has turned what at first
seemed like a crazy concept into a mainstream theory. In fact, it may be the
only way to explain a whole series of seeming paradoxes and puzzles about
this planet's geology and climate.

At a recent meeting in Boston of the American Geophysical Union, a long
session on the so-called "snowball Earth" theory was concerned not so much
with whether it happened -- the evidence now indicates it happened at least
twice, and perhaps as many as five times -- but with the details of how, why
and when the planet was suddenly plunged into the deep freeze, and how it
just as suddenly thawed out like a Thanksgiving turkey.

While the "snowball" episodes may have lasted 10 million years or more, the
actual freezing and thawing probably happened in just a matter of decades --
perhaps providing an important clue into just how unstable and vulnerable
the planet's climate system is. And, some scientists now suggest, the cycle
of freezing and thawing may have been crucial in making all higher forms of
life possible, including the humans who are now piecing together this
ancient puzzle.

"Something about the snowball causes life to diversify and change," said
Joseph Kirschvink, a geobiologist at the California Institute of Technology
who first coined the term "snowball Earth" in a 1992 paper in Science.

The concept of snowball Earth first struck Kirschvink during a geological
expedition to Australia in the late 1980s. There, he and a group of other
geologists and biologists specializing in reconstructing the ancient
environment were struck by abundant evidence of extensive glaciers, embedded
in the layers of ancient rock. But there was a big problem: Other evidence
clearly showed that, at the time of these deposits some 700 million years
ago, Australia lay squarely on the equator.

How could sea-level glaciers possibly have existed under the tropical sun?
The implication was clear. If glaciers reached all the way to the sea even
in the tropics, the whole planet must have been frozen at the time.

And, it turned out, the theoretical explanation had already been proposed,
back in the 1960s, from a computer climate model. In a kind of
reverse-greenhouse effect, a sudden depletion of methane in the atmosphere
could cause a dramatic drop in temperatures, leading to an advance of
glaciers similar to the familiar ice ages of more recent times. But there
comes a crucial turning point: If the ice reaches as far south as 30 degrees
latitude -- about the level of northern Florida -- then it triggers an
unstoppable "runaway" freezing cycle.

That's because ice and snow reflect most of the sunlight that falls on them,
radiating away the heat. Darker open water or soil, by contrast, absorbs the
sun's heat. So, as darker surface gives way to white snow and ice, less and
less sunlight can be trapped to warm the planet, and the Earth cools faster
and faster, producing more ice, which cools it even more.

The result: Within a span of a few decades, the Earth could freeze over. Any
remaining simple, single-celled life would be limited to surviving in
deep-ocean thermal vents, ponds melted on the land by volcanic heat, or
patches of ocean where the ice was thin enough for sunlight to filter
through and support photosynthesis.

The big puzzle, at first, was how such a snowball could ever reverse itself
and thaw out again. That was Kirschvink's big breakthrough. He figured out
that even on a frozen-solid Earth, volcanos would continue to erupt,
belching the greenhouse gas carbon dioxide into the air. Over time -- about
10 million years -- at today's rate of volcanism, enough would build up to
create a "super-greenhouse" effect, strong enough to melt the whole planet
-- again, in a span of just a few decades, once the process started.

"I didn't think it was possible" when Kirschvink first proposed the idea,
said James Kasting of Pennsylvania State University, who is now one of the
concept's strongest advocates. "I thought it would have extinguished all
life. Now, I see there are ways out."

And, Kasting said, it is now clear that the theory can explain many
geological features that had been major enigmas for scientists. One of the
most significant ones concerns deep deposits of carbonate rock that appear
in the sedimentary layers immediately following those that show signs of
tropical glaciers.

These "carbonate capstones" can be dozens of feet -- in some places,
hundreds of feet -- thick, and are found all over the globe from the era
immediately following the hypothesized snowball episodes. Geologists had
been at a loss to explain them.

But, in 1998, Paul Hoffman and Daniel Schrag, two geologists at Harvard
University, came up with the explanation: A sudden, dramatic weathering of
exposed rock immediately after the planet thawed out again, flushing
enormous quantities of carbonate into the oceans.

"They're predicted" by the snowball Earth theory, Kasting said of the
carbonate capstones. "They are the smoking gun" that points directly to the
truth of the theory.

And it is largely because of that smoking gun, he said, that the whole
theory has gained acceptance: "When it was first proposed, there was a lot
of resistance. Now, it's become mainstream."

Hoffman himself is more guarded: "The community is really polarized," he
said last week. "There are a lot of people sitting on the fence, because
it's really such a radical idea." But, he said, while Kirschvink's original
theory "was kind of ignored," it is really since he and Schrag published
their paper in 1998 "that the real attention and intense interest has
developed" in the idea.

Now, the focus has shifted to understanding exactly how the process worked,
and how it affected the rise and diversification of life as we know it.

Kirschvink, who presented his latest analysis at the recent geophysics
meeting, said he thinks he now has the answer to what the "something" is
that caused life to burgeon just after the frozen episodes: A huge increase
in oxygen immediately following the snowball's big thaw.

"Snowballs produce massive oxygen spikes," he said, "perhaps stimulating
major evolutionary innovations." And that may include, he suggested, one of
the most crucial innovations of all: The development of multicellular life,
after more than 3 billion years when Earth was populated only by
single-celled organisms.

In Kirschvink's view, the question is not so much why complex animals surged
into existence when they did -- about 550 million years ago, right after the
last snowball episode -- but why that didn't happen much sooner. "There's
nothing in the history of this planet that would have prevented animals from
radiating a billion years ago, or 2 billion," he said in an interview last

"Something was holding them back," he said. "I think it was oxygen."

The reason for the sudden pulse of oxygen involves the action of billions of
tiny single-celled organisms called cyanobacteria, also known as blue-green

It turns out that the big thaw would have produced giant storms and intense
acid rain, producing a surge of intense weathering of the freshly-exposed
rocks and washing vast amounts of carbon, phosphorous, iron and other
essential nutrients into the oceans. "Everything you need for cyanobacteria
to go haywire is there," Kirschvink said -- very similar to the growth media
used to grow colonies of bacteria in the lab. "I think they'd be very

The result, he suggested, would have been "a massive cyanobacteria bloom --
I call it green Earth. If you have a whole planet of growth medium, and
nothing to stop it, the expected result is a massive oxygen spike." 

And there is abundant geological evidence that exactly such a spike of
oxygen did indeed take place, he said. For example, all this oxygen would be
expected to mix chemically with manganese and iron, forming minerals that
would then drop to the sea floor. And indeed, in formations that
arose just after the snowball episode, massive layers of manganese and iron
ores are found in many places.

In fact, he said, the world's largest commercial deposit of manganese,
source of 80 percent of global manganese production, occurs in just such a
formation in South Africa -- called Hotazel, in reference to the
super-greenhouse heating of the planet at that time.

But perhaps the biggest lesson from the whole snowball Earth concept is just
how vulnerable the Earth's climate system is to dramatic, rapid changes and
unanticipated feedback effects.

Snowball Earth "is an extreme example of an instability of the climate
system," Hoffman said. "As a geologist, the remarkable thing about the last
10,000 years is how remarkably stable the climate has been."

© Copyright 2001 Globe Newspaper Company.



From Oliver Morton <>

Michael Paine wrote:

>About one fifth of the ejected rocks eventually return to planet
from which
>they were launched. Davies (1998a) points out the possibility that
>in these rocks might reseed a planet after its biosphere had been
>by huge impacts. This is a possible mechanism for life becoming
>re-established on Earth after the Late Heavy Bombardmant (Bortman
2000- note
>that Bortman does not consider this mechanism in his report).

It may be worth noting that this possibility suggests a pre-adaptation for
transpermia, in that it gives survival value to the ability to hang out in
rocks thrown into space. I think Norm
Sleep and Kevin Zahnle talk about this in "Refugia from asteroid impacts on
early Mars and the early earth" (JGR 103, 28529-28544, 1998); if they don't,
then I guess I must have thought it up after reading their paper.

useful essay -- thanks a lot

          Oliver Morton
            The Apse
     142A Greenwich High Road
         London SE10 8NN

      Tel: 44 20 8293 7171


From John Michael Williams <>

Hello Larry.

A friend sent me a copy of an Email link you sent him.

  by Michael Paine, The Planetary Society Australian Volunteers

The problem with this idea, is that proponents of it have not attempted to
verify it even against elementary calculations that an amateur astronomer
might be able to carry out.

It is virtually impossible for anything to be ejected by an impact from the
surface of Mars or any planet with a similar or greater escape speed.

The short reason is that nothing can be accelerated in solid form by a force
propagating across it faster than 2/3 the speed of sound in it. In fact, as
shown by elementary methods in a paper at, nothing could
have been ejected from Mars intact unless the speed of sound in it was ~7.5
km/s. The speed of sound in a fast rock such as granite is only 6 km/s, and
the speed of sound in a living or dormant cell would be below 2
km/s--probably closer to that in water (1.5 km/s?). Speeds in dry wood range
up to about 4 km/s. The Mars escape speed is about 5 km/s.

It is worrisome that this idea is being promoted as "scholarly": Two of the
persons whose work is often cited in support of it, Melosh and Ahrens,
refuse to comment on the paper above, even in the context of an ongoing
meeting on a related subject. A "scholar" with an imaginative idea should be
willing to entertain that it might be wrong.
                     John Michael Williams


From, 17 June 2001

By Alexander G. Higgins
Associated Press
GENEVA (AP) -- A fist-sized meteorite, one of only 18 rocks on Earth known
to have come from Mars, has been found by Swiss scientists in the Oman
desert -- a prize discovery that could help determine if the planet ever
sustained life.

Scientists at the University of Bern announced the find Friday and said they
are just beginning to examine the meteorite. Most of the other 17 Martian
rocks have been snapped up by collectors, they said, so few are fully
available for study.

"I suspected from the beginning that it was from Mars,'' said Marc Hauser, a
geologist who found the gray, ridged specimen during a collecting excursion
in January. "The color was different and, above all, it wasn't magnetic.''

Initial conclusions could take several months.

Unusually large pockets inside the 223.3 gram (half-pound) rock could
provide evidence about life that is far more conclusive than American
suggestions about possible fossils on an earlier meteorite found in
Antarctica, Hauser told The Associated Press.

The new meteorite was named Sayh al Uhaymir 094 after the region of desert
where the team found it and more than 180 other meteorites. The team, in a
statement, said they were certain it would contribute to rapidly growing
knowledge of the planet.

Interest increased in 1996 after a Martian meteorite found near the South
Pole, known as Allen Hills 84001, showed possible remnants of life. But such
arguments "are hardly taken as solid evidence today," the research team

Most earlier meteorites from Mars were found in the Antarctic before
scientists turned their attention to deserts in recent years.

Hauser said X-rays of the new rock had shown a surprising number of hollow
pockets inside that might contain gases or atmosphere. That could offer
clues about both the meteorite's history and Mars itself.

The pockets have "a much greater potential" than the rest of the rock for
containing evidence of life on Mars, Hauser said.

Most of the 180 meteorites found by the team were magnetic and looked
distinctive, but the Martian rock looked more like rocks from Earth and was
difficult for the team to recognize as a meteorite. The other meteorites
also contained no minerals.

Hauser said the team believes the Martian meteorite is part of another one
found earlier in the same area.

That first rock is in unknown private hands, as are most Martian meteorites
because collectors are willing to pay $1,000 a gram for such treasures. But
the team was able to obtain a small fragment of it for testing, Hauser said,
and its makeup is practically identical.

The team said they and other scientists had determined their meteorite is
from Mars by the nature of its minerals, measurements of its oxygen isotopes
and its overall composition. They conducted analyses on both the entire rock
and tiny fragments of it.

They said the rock had been formed from molten lava, similar to volcanic
rocks on Earth.

Mars is the most Earth-like of all the solar system's planets, and evidence
suggests both planets developed similarly during their first billion years
-- the period when life first appeared on Earth.

The team said recent discoveries about life on Earth in extreme environments
-- such as in very hot ocean springs or within porous rocks deep inside the
planet's surface, support the theory that early Mars could have had
environments suitable for life.

The rare Martian meteorites could be the only physical evidence available to
scientists for at least 10 years, when a U.S. space probe might bring back
500 grams (1.1 pounds) of Martian samples "at very high costs."

Rocks from Mars start their journey toward Earth when a meteorite from
elsewhere slams into the Martian surface, scattering rocks into space at
high speed. They eventually make their way to Earth, sometimes after
millions of years.
Copyright 2001,


From Discovery News, 18 June 2001

By Irene Brown

June 14 - Internet pioneers are laying the groundwork to expand the Web into
space, with testing planned for later this year.
The Interplanetary Internet would link the Web with new hubs on spaceships,
satellites, planets, the moon, robotic probes and other extraterrestrial

"The best way to envision the fundamental architecture of the Interplanetary
Internet is to picture a network of Internets," a research group headed by
Internet pioneer Vinton Cerf wrote in a proposal to the Internet Engineering
Task Force, which sets standards for the Internet.

Cerf, creator of the TCP/IP Internet communications protocol, is working
with representatives from NASA, the Defense Advanced Research Projects
Agency, The Mitre Corp., Global Science and Technology and SPARTA in
developing plans for a next-generation Internet.

The new protocol is expected to be tested on the Space Technology Research
Vehicle, a British-led project to test new space technologies. The satellite
is scheduled to be launched later this year.

And a live test is under consideration for a NASA mission to Mars in 2003.

While technical and security concerns are paramount, the Interplanetary
Internet research team also wants to be sure the new system will support
commercial endeavors, such as communication services, asteroid mining, space
tourism and manufacturing.

"While such developments may still lie decades in the future, the potential
investment and benefits can be appreciated as we contemplate the explosion
of new markets associated with the commercialization of the Internet that
began just 10 years ago. We will therefore architect the Interplanetary
Internet in anticipation of possibly rapid commercialization," Cerf and his
team wrote.

The team envisions an email like approach to interplanetary communications
to account for time delays and hubs that may not always be within range of
each other.

"Sometimes a planet will be between the source and the destination," said
Scott Burleigh of NASA's Jet Propulsion Laboratory, who is a member of the
Interplanetary Internet team.

Ground tests may also be part of a simulated Mars mission taking place in
the Canadian Arctic this summer, said Marc Boucher, with the Mars Society.

Copyright © 2001 Discovery Communications Inc.

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