CCNet 77/2001 - 8 June 2001

"Composite images of Saturn's rings, taken by NASA's Hubble Space
Telescope, have revealed mysterious color variations that hint that
the rings could be made of materials from the outer solar system. [...]
This leads scientists to suspect that, unlike the moons, the rings were
formed from an outer solar system object. This object, they think, careened
too close to Saturn and -- like comet Shoemaker-Levy 9 in 1994  -- was
torn apart by the massive planet's gravity, leaving a trail of
--Kathleen Burton, NASA Ames Research Center, 7 June 2001

"The SDSS observations also showed that the two types of asteroids
are spatially separated with the inner belt of rocky asteroids centered at
about 2.8 AU from the sun and the outer belt of carbonaceous asteroids
centered at about 3.2 AU. This distribution has important
implications for unraveling how the solar system formed and suggests that
planet migrations that seem to be common in other planetary systems have
not occurred in ours."
--Tom Quinn, University of Washington, 5 June 2001

    Andrew Yee <>

    Ron Baalke <>

    Andrew Yee <>


    Andrew Yee <>

    Andrew Yee <>

    Paul Withers <>

    Michael Paine <>

    Leon Neihouse <>

     Michael Paine <>

     BBC News Online, 7 June 2001


From Andrew Yee <>

Kathleen Burton               
NASA Ames Research Center, Moffett Field, CA        June 7, 2001
(Phone:  650/604-1731 or 604-9000)



Composite images of Saturn's rings, taken by NASA's Hubble Space Telescope,
have revealed mysterious color variations that hint that the rings could be
made of materials from the outer solar system. These new findings are
important because scientists have long questioned whether the rings
originated around Saturn, like the planet's retinue of icy moons, or

The Hubble images, captured by a team of scientists between 1996 and 2000,
show Saturn's rings from beneath in a wide-open or "tilted" viewpoint from
Earth, as the planet's Northern Hemisphere swings from autumn toward winter.
When seen edge-on, Saturn's rings, which are only some tens of meters thick,
nearly disappear from view. The composite images, which were released today
by the Hubble Heritage program, can be accessed at:

"The color of the ring material can help tell us what the rings are made of
and will help decipher their origin," said Dr. Jeff Cuzzi, of NASA's Ames
Research Center and a member of the Hubble team. The color variations
indicate that different materials make up the rings. The distribution of the
materials provides information about the processes that shaped the rings, he

"Most people don't know that Saturn's rings aren't white but have a faint
salmon color, which hints that a few percent of complex organic molecules
are mixed in with the water ice the rings are mostly made of," Cuzzi said.
Saturn's seven small icy moons don't have such a reddish color, but many icy
objects in the frozen reaches of the outer solar system do, he explained.
This leads scientists to suspect that, unlike the moons, the rings were
formed from an outer solar system object.  This object, they think, careened
too close to Saturn and -- like comet Shoemaker-Levy 9 in 1994  -- was torn
apart by the massive planet's gravity, leaving a trail of debris.

Over 100 Hubble images were analyzed in eight different colors that cover,
and go beyond, the range of human vision. They include violet, blue, green
and red in the visible range and ultraviolet and infrared in the non-visible

Cuzzi also has shown that there appear to be at least two unknown materials
mixed with the rings' water ice, and that the way these materials are
distributed in the rings is unlike anything seen on the surfaces of nearby
planets or satellites. For example, in some rings
the color gets redder closer to Saturn, and in others, the color trend
reverses in the middle of the ring. In some places, the color gets redder
where the concentration of particles increases, and in other places it gets
redder where the concentration of particles decreases. Scientists hope to
explain these variations in terms of how the composition of the ring
material was initially distributed, and how it has evolved with time.

The Hubble data also show that the ring color changes with viewing angle.
The best explanation, said Dr. Francois Poulet of NASA Ames, who is working
with Cuzzi, is that the ring particles are actually lumpy aggregates of
particles, with many more deep shadows than the relatively smooth surface of
a moon or asteroid. The lit parts of the "lumpy" surface partly illuminate
the shadows with their reddish color, so the rings appear redder as more
shadows are seen.

Cuzzi believes that observations like these, while not currently understood,
eventually will provide insights into the processes by which Saturn's ring
structure was formed and continues to evolve. He noted that the Cassini
spacecraft, which recently passed Jupiter en route to a four-year tour of
the Saturn system starting in July 2004, carries several instruments that
will provide much finer detail and greatly improve the ability to identify
these non-icy constituents in the rings and the structure of the particles.
The Cassini mission also includes an atmospheric entry probe into the
organic smog-shrouded moon Titan, which might have lakes or seas of liquid
ethane on its frigid surface.

Cuzzi's collaborators include Drs. R. French of Wellesley College, L. Dones
of Southwest Research Institute, Mark Showalter of Stanford University, and
Paul Estrada of Cornell University.

The Space Telescope Science Institute (STScI) is concurrently issuing a news
release on the data, "A Change of Seasons On Saturn." It can be accessed,
together with electronic images, animation and additional information, at:

NASA's Hubble Space Telescope is a project of international  cooperation
between NASA and the European Space Agency.


From Ron Baalke <>

Sloan Digital Sky Survey

Media Contacts

Michael Turner                      Steve Koppes
SDSS Scientific Spokesman           University of Chicago
773-702-7974                        773-702-8366

Georgia Whidden                     Satoru Ikeuchi
Institute for Advanced Study        Japan Participation Group
609-734-8239                        81-52-789-2427          

Michael Purdy                       Hans-Walter Rix
The Johns Hopkins University        Max-Planck-Institut für Astronomie
410-516-7906                        49-6221-528-210               

Rene Walterbos                      Barbara Kennedy
Nex Mexico State University         Pennsylvania State University

Steve Schultz                       Vince Stricherz
Princeton University                University of Washington
609-258-5729                        206-543-2580    

Steven Dick                         Bruce Gillespie
U.S. Naval Observatory              Apache Point Observatory
202-762-0379                        505-437-6822  

Amber Jones                         Ray Villard
National Science Foundation         Space Telescope Science Institute
703-292-8070                        410-338-4514            

For release after 9:15 a.m. PDT, June 5, 2001

SDSS 01-01

Early results from the Sloan Digital Sky Survey: From under our nose to the
edge of the universe

Pasadena, Calif. -- Scientists of the Sloan Digital Sky Survey today (June
5) presented results based on early data from the project. The first
glimpses of what will ultimately be the most comprehensive and fully digital
map of the sky included identification of the two most distant objects ever
observed; new light on asteroids; and the first SDSS results on the
large-scale distribution of galaxies.

Sky Survey collaborators also announced the release to the worldwide
astronomy community of the first large piece of the digital sky.



The SDSS collaborators presented the first clear evidence for chemical
segregation in the belt of asteroids between Mars and Jupiter.

By viewing the asteroids in five color bands, explained Dr. Tom Quinn of the
University of Washington, the SDSS survey can reliably separate individual
asteroids into two main classes, rocky silicate asteroids and more primitive
carbonaceous asteroids.

"The SDSS observations also showed that the two types of asteroids are
spatially separated," Quinn said, "with the inner belt of rocky asteroids
centered at about 2.8 AU from the sun and the outer belt of carbonaceous
asteroids centered at about 3.2 AU. This distribution has important
implications for unraveling how the solar system formed and suggests that
planet migrations that seem to be common in other planetary systems have not
occurred in ours."

One astronomical unit, or AU, corresponds to the distance from the sun to
the earth.

The SDSS asteroid sample also turned up another surprise.

"There appear to be fewer asteroids smaller than about 4 km in diameter in
the asteroid belt than we previously thought," said Dr. Zeljko Ivezic of
Princeton University, the leader of the SDSS asteroid team. "Since the
asteroid belt is believed to be the reservoir for Earth-crossing asteroids,
the new SDSS observations suggest that future asteroid collisions with Earth
may be less likely than previously believed."

The SDSS scanning technique allows only five minutes to follow celestial
objects as they move across the field of view, said Dr. Robert Lupton of
Princeton University. During this time asteroids appear to move a distance
just 1/1000th the size of the moon, relative to the distant stars.

"Nevertheless," Lupton said, "we can reliably detect their tiny motions and
even determine their orbital motions around the sun."

The asteroid observations rely on precision position-finding software
developed by SDSS collaborators at the US Naval Observatory.

Images available:



* Diagram of asteroid belt
* Graph of asteroid belt cross section
* Asteroid size distribution


From Andrew Yee <>

Subaru Telescope
National Astronomical Observatory of Japan
Hilo, Hawaii

May 23, 2001

Subaru Discovers Small Objects in Outer Solar System

A Solar System research team from the National Astronomical Observatory of
Japan (NAOJ), the Graduate University for Advanced Studies, and the Science
University of Tokyo have discovered small objects extended within the outer
solar system using Subaru Telescope. Although more than 350 such objects are
now known, these are the first discovered by Japanese astronomers.

Around 1950, Edgeworth and Kuiper independently proposed that there should
be many small objects in the outer solar system that never became planets.
We call them "Edgeworth-Kuiper Belt Objects (EKBOs)." Since we believe that
they are composed of the materials of the early Solar System in their
original state, EKBOs should be very useful objects for teaching us about
how the Solar System formed. EKBOs may also be the source of the
short-period comets, according to computer simulations.

The first EKBO was discovered with the University of Hawaii's 24" telescope
at the summit of Mauna Kea in August 1992. In the nine years since the
discovery of this EKBO (named 1992 QB1), more than 350 EKBOs have now been

On UT February 21 and 24, 2001, the Japanese team of astronomers
[ , 69KB]
discovered nine candidates for new EKBOs using the Subaru prime-focus camera
(Suprime-Cam). Since two of the nine objects have observations on both days
and their initial orbits have been determined, the International
Astronomical Union has classified them as EKBOs and given them provisional
designations "2001 DR106" and "2001 DS106." The distance between the objects
and the earth is approximately 6.3 billion kilometers and their brightness
is approximately 25th magnitude, a value about forty million times fainter
than what can be seen with the unaided human eye (sixth magnitude). The
objects are estimated to be approximately 100 kilometers in diameter,
about 10% the size of the largest asteroid Ceres (910 kilometers). These
observations show that the projected surface density of objects the size of
these two EKBOs is approximately 10 per square degree along the plane of the
ecliptic, consistent with previous results.

Compared to the asteroids which exist between the orbits of Mars and
Jupiter, the motion of EKBOs against the stellar background is very slow
because they are much further from the Sun. Mr. Daisuke Kinoshita (Grad.
Univ. for Advanced Studies) and Mr. Naotaka Yamamoto (Science Univ. of
Tokyo) have developed an auto-detection program for slow moving EKBOs. They
comment, "I tremendously realized the great performance of Subaru and
Suprime-Cam"; "it's impossible to describe the impression when I look at the
results of the program." According to Dr. Jun-ichi Watanabe (NAOJ), the team
leader, "Subaru's wide-field and big mirror offers the highest performance
in the world for this type of work, and I fully expect more discoveries to
be made." This is just the starting point for Subaru's EKBO studies.

The results are reported in Minor Planets Electric Circular MPEC 2001-J33
( issued on May 15, 2001.

[ , 56KB ]
The images of 2001 DR106: the left is at 07:35:36UT on 2001/02/24 and the
right is 08:31:03UT on the same date.



Donald Savage
Headquarters, Washington, DC                           June 6, 2001
(Phone: 202/358-1547)

RELEASE:  01-114


     In the first step of a potential two-step process, NASA has selected
two proposals for detailed mission feasibility studies as candidates for a
Pluto-Kuiper Belt (PKB) mission to explore the only planet in our Solar
System yet to be visited by a spacecraft from Earth.

The President's FY 2002 budget request does not contain development funding
for a Pluto mission.  The Congress requested that NASA not do anything
precipitous which would preclude the ability to develop a Pluto-Kuiper
mission until the Congress could consider it in the context of the FY 2002
budget. If funding is provided in the FY 2002 budget and either proposal is
ultimately selected, the Agency could down-select a proposal for development
to ultimately fly a spacecraft to Pluto and beyond. If a PKB mission is
developed, launch would be in the 2004-2006 time frame and the spacecraft
would arrive at Pluto before 2020. 

"The PKB mission represents a possible opportunity to visit the only planet
not yet explored by spacecraft," said Dr. Colleen Hartman, Pluto Program
Director in NASA's Office of Space Science, Washington, DC. "It's really an
opportunity to, in a sense, look into a deep-freeze of history which could
tell us how our Solar System evolved to what it is today, including the
precursor ingredients of life."
Each team will receive $450,000 to conduct a three-month concept study. At
the end of the three months, NASA will thoroughly evaluate program content
and technical, schedule and cost
feasibilities of both proposals to determine if either is selectable.

The two selected proposals were judged to have the best science value among
the five proposals submitted to NASA in April 2001 in response to the
Pluto-Kuiper Belt Mission Announcement of Opportunity. Each selected
investigation will work with the Office of Space Science at NASA
Headquarters to finalize the design of the spacecraft and its accommodation
of the instrument sets.

The selected investigations are:

Pluto and Outer Solar System Explorer (POSSE). Dr. Larry Esposito, Principal
Investigator, University of Colorado, Boulder, will lead a team including
the following major participants: NASA's Jet Propulsion Laboratory (JPL),
Pasadena, CA; Lockheed Martin Astronautics, Denver; Malin Space Science
Systems, Inc., San Diego; Ball Aerospace Corp., Boulder, CO; and University
of California, Berkeley.

New Horizons: Shedding Light on Frontier Worlds. Dr. S. Alan Stern,
Principal Investigator, Southwest Research Institute, Boulder, CO, will lead
a team including the following major participants: Johns Hopkins University
Applied Physics Laboratory, Laurel, MD; Ball
Aerospace Corp.; Stanford University, Palo Alto, CA; NASA's Goddard Space
Flight Center, Greenbelt, MD; and JPL.

Both proposals are for complete missions, including launch vehicle,
spacecraft and science instrument payload. Both address the major science
objectives defined in the original announcement. Each proposal includes a
remote sensing package that includes imaging
instruments, a radio science investigation, and other experiments to
characterize the global geology and morphology of Pluto and Charon, map
their surface composition, and characterize Pluto's neutral atmosphere and
its escape rate.

Pluto is a different kind of planet. It is not a rocky planet like Earth,
Mars, Mercury or Venus, or a gas giant like Jupiter, Saturn, Uranus or
Neptune. It is a Kuiper Belt Object, a class of objects composed of material
left over after the formation of the other planets, which has never been
exposed to the higher temperatures and solar radiation levels of the inner
solar system.

It is known that Pluto has large quantities of ices of nitrogen, and simple
molecules containing combinations of carbon, hydrogen and oxygen that are
the necessary precursors of life. These ices would be largely lost to space
if Pluto had come close to the Sun. Instead they remain on Pluto as a
representative sample of the primordial material that set the stage for the
evolution of the Solar System as it exists today, including life.

If a PKB mission is developed, it will be a Principal Investigator-led
investigation, bringing together teams from academia, industry, NASA Centers
and other communities, and will be developed following the highly successful
management philosophy of the Discovery  Program.


From Andrew Yee <>

ESA Science News

07 Jun 2001

Mars Express to investigate Phobos

Phobos, the tiny innermost moon of Mars, is to come under unprecedented
scrutiny after Europe's mission to Mars goes into orbit around the Red
Planet late in 2003. Mars Express is due to pass within 3000 km of the
22 km diameter moon a few hundred times during its two-year nominal
mission lifetime.

"There will be many more opportunities for close fly-bys than during NASA's
Viking mission," says Tom Duxbury from NASA's Jet Propulsion Laboratory, a
veteran of previous Phobos observations who is helping to plan the Mars
Express observation campaign.

At a distance of 3000 km, the High Resolution Stereo Camera (HRSC) on board
Mars Express will be capable of taking images with a resolution at least as
good as any taken by Viking. At 1000 km, the Infrared and Visible Mapping
Spectrometer (OMEGA) will also be switched on to map the mineral composition
of the tiny moon's surface; and when the distance is only a few hundred
kilometres, the Planetary Fourier Spectrometer (PFS) and the Sub-surface
Sounding Radar/Altimeter (MARSIS) will record measurements. The Energetic
Neutral Atoms Analyser (ASPERA) will monitor the plasma environment around
the orbit of Phobos during all fly-bys.

"Mars Express will provide the first global map of Phobos. This is important
because we know one side of this moon well, but the other side is less
well-known," says Agustin Chicarro, ESA's Mars Express project scientist.
"We should get a complete view of the satellite in terms of its topography,
sub-surface and composition. This should help us determine once and for all
whether it is a captured asteroid or not," he adds.

Mars Express could generate the most comprehensive suite of observations
ever recorded for Phobos. They will help to resolve some of the outstanding
puzzles about the Martian moon, many of which came to light during previous
observation missions. In addition to Viking, these included the ill-fated
Russian mission, Phobos-2, and NASA's Mars Global Surveyor, which is still
on mission around the Red Planet. Phobos-2 was due to send a lander to the
tiny moon in 1989, but was lost just 100 km above the surface.

Phobos is a world of mysterious origin and destiny. It is light, with a
density less than twice that of water, and orbits just 5980 km above the
Martian surface. One idea is that Phobos and Deimos, Mars's other moon,
are captured asteroids. Data returned by the infrared mapping spectrometer
experiment (ISM) on board the Phobos-2 mission supported this view.

"In general the composition matched that of the inner asteroids. But
we don't know whether Phobos is primordial or whether it has undergone
transformation," says Jean-Pierre Bibring, principal investigator for ISM
and also for OMEGA on Mars Express. "We found some tantalising evidence
for transformation in the form of interesting minerals at the bottom of a
crater, which were absent elsewhere on Phobos, suggesting that the bulk
composition is inhomogeneous. I'm very excited about observing Phobos
again because OMEGA will have much higher resolution and will be able to
determine the surface composition unambiguously and pick out minerals at
the bottom of craters, thus determining the bulk composition."

However, there are other ideas about the origin of these two moons. One,
favoured by Duxbury, is that they are lightly accumulated ejecta from
asteroid impacts on the Martian surface, with Phobos composed of ejecta
orbiting Mars faster than the planet rotates and Deimos, whose orbit is
further out and orbital motion slower, composed of ejecta orbiting more
slowly than the planet rotates.

Another mystery about Phobos concerns the origin of deep grooves on its
surface. Some of these radiate from Stickney, the large impact crater
that distorts the shape of the moon, and are thought to indicate that
the force of the impact nearly shattered the small body. However, others
on the central portion of Phobos run almost parallel and have prompted
another thought.

John Murray, from the Open University in the United Kingdom, and a
co-investigator on the HRSC, thinks that the grooves are strings of
impact craters made by ejecta thrown up by major impacts on Mars. He has
calculated the velocity of such ejecta and the position and direction of
the 'grooves' they might be expected to leave on Phobos. "The direction
of the grooves corresponds to what the hypothesis predicts," he says.
"There are no grooves on the trailing edge of Phobos, which is also what
you'd expect."

However, the leading edge of Phobos has never been imaged in close up
before and the appearance of grooves here will be critical to the theory.
The HRSC on Mars Express should provide the required images for the first
time. "If I'm right, we should see wider chains of grooves crossing at
all angles here," says Murray.

For further information please contact:

ESA Science Programme Communication Service
Tel: +31 71 5653183


* Mars Express home page
* Mars Express instruments
* Phobos and Deimos -- some facts and historical anecdotes


[Image 1: ]
The giant Stickney crater on Phobos is clearly visible on this Viking image.
One of the most striking features on the 27 km diameter, irregularly shaped
Phobos is the presence of grooves over most of its surface. The grooves seem
to radiate in all directions from the giant Stickney crater (left) and
converge on the opposite side of the satellite at a region close to the
Stickney antipode. The grooves are best developed near Stickney, where some
measure 700 m across and 90 m deep. However, most of the grooves have widths
and depths in the 100 - 200 m and 10 - 20 m ranges, respectively.

[Image 2: ]
Deimos, the companion moon of Phobos, was also imaged by the Viking Orbiter.
This computer mosaic of Deimos was made with images acquired from the Viking
Orbiter during one of its close approaches to the moon. The 15 km diameter
Deimos circles Mars every 30 hours. Scientists speculate that Deimos and its
companion moon Phobos were once passing asteroids that were pulled in by the
gravity of Mars.

[Image 3: ]
One of the highest resolution images to date of Phobos obtained with the
Mars Orbiter Camera. This image of Phobos was taken with the Mars Orbiter camera
on the Mars Global Surveyor (MGS) on August 19, 1998, 10 AM PDT. The MGS
spacecraft was approximately 1080 km from Phobos at closest approach. This
image, about 8.2 km wide by 12 km tall, shows the full field-of-view of the
Mars Orbiter Camera (MOC) as spacecraft motion swept across the satellite.
The image as shown here has a scale of 12 m per picture element. Credit:
Malin Space Science Systems/NASA

[Image 4: ]
ESA's Mars Express mission will also obtain valuable measurements on Phobos,
the largest of the Martian moons.


From Andrew Yee <>

Astrochemistry Laboratory
Ames Research Center
Moffett Field, CA

Contact information:

Dr. Louis J. Allamandola
NASA-Ames Research Center

Dr. Max P. Bernstein
Astrophysics Branch, NASA-Ames Research Center

Dr. David Deamer
Dept. of Chemistry and Biochemistry, UC Santa Cruz
831-459-5158, deamer@hydrogen.UCSC.EDU

Dr. Jason P. Dworkin
Astrophysics Branch, NASA-Ames Research Center

Ms. Jamie Elsila
Dept. of Chemistry, Stanford University
650-723-4318, jelsila@Stanford.EDU

Dr. Scott A. Sandford
Astrophysics Branch, NASA-Ames Research Center

Dr. Richard N. Zare
Dept. of Chemistry, Stanford University

FOR RELEASE: 10:00 AM PDT, June 4, 2001


Scientists today described how the interaction of hard radiation and ices
in space leads to the production of complex organic molecules. The report
is being presented to the American Astronomical Society meeting in Pasadena,
CA by Drs. Louis Allamandola, Max Bernstein, Jason Dworkin, and Scott
Sandford of the Astrophysics Branch of NASA's Ames Research Center, in
Moffett Field, CA, Dr. David Deamer of the Biochemistry Department of the
University of California, in Santa Cruz, CA, and Dr. Richard Zare and Ms.
Jamie Elsila of the Department of Chemistry at Stanford University, in
Stanford, CA. The production of organic compounds in space is of special
interest to scientists since these molecules may have played a role in the
origin of life on Earth.

These scientists have been studying the chemistry of organic carbon
compounds that occurs in dense molecular clouds in interstellar space,
the locations where new stars and planetary systems are born. Such clouds
consist of concentrations of dust, ice, and gas that screen out much of
the light produced by outside stars. As a result, the interiors of these
clouds can become very cold, sometimes attaining temperatures as low as
10 Kelvin (-263 C). At these temperatures, many of the molecules and atoms
that are normally present as gases condense to form ice mantles surrounding
the dust particles in the cloud, much as your breath condenses into frost
on a cold window. These ices are primarily made up of simple molecules like
water (H2O), methanol (CH3OH), carbon dioxide (CO2), carbon monoxide (CO),
ammonia (NH3), and methane (CH4).

At such low temperatures, these molecules would not normally be expected to
react with each other, particularly when they are embedded in ice. However,
the ice mantles are exposed to low levels of ionizing radiation in the form
of cosmic rays and ultraviolet photons. This radiation can break apart the
molecules in the ice and produce highly reactive ions and radicals that
can recombine to form larger, more complex molecules.

At NASA-Ames, Allamandola, Sandford, Bernstein, and Dworkin use
cryogenically cooled vacuum chambers and UV lamps in their laboratory to
form and irradiate interstellar ice analogs under conditions that simulate
those found in dense interstellar clouds. "Basically, we freeze mixed
gases onto an extremely cold window and then give the ices the equivalent
of a good suntanning," says Allamandola. "After the sample is warmed up,
we can remove any remaining organic materials from the sample chamber and
study them using a variety of analytical techniques," he continued.

One of these is the technique of two step laser-desorption laser-ionization
mass spectrometry. "That's quite a mouthful," says Stanford graduate
student Elsila, "but essentially this is an analytical technique that
allows us to measure the masses of the various compounds in the organic
residue that results from the ice irradiation." "The surprise," says Zare,
leader of the Stanford group, "is just how complex the population of
organics is. Generally we see a peak at virtually every mass up to and
beyond 500 atomic mass units!" This means that the residue must contain
hundreds of distinctly different molecules, the vast majority of them
being considerably larger than the molecules that made up the original ice.

"We are only just beginning to identify all the compounds that are present,"
notes Dworkin. "One of the more interesting classes of compound we have
identified in the residues are amphiphiles. These molecules have the
interesting property that, if you add them to water, they can spontaneously
form vesicles, that is, walled structures reminiscent of cells." This
raises the possibility similar materials could have fallen on the early
Earth and played a role in the formation of the first cellular structures.
"There is some precedence for this idea," notes Deamer, a biochemist from
UCSC and an expert on membranes. "Primitive meteorites are also known to
contain amphiphiles that, when added to water, make structures that are
very similar to those we make from the simulated interstellar residues,"
he continued.

Other chemical compounds the team has been studying is a class of molecules
called "polycyclic aromatic hydrocarbons," or PAHs for short. These
molecules consist of small sheets of carbon atoms arranged in hexagons with
hydrogen atoms around their edges, much like the shapes you would get if
you cut out pieces of a chicken wire fence. PAHs are common molecules on
the Earth and are a major component of auto exhaust and soot. PAHs are also
very abundant in space, where they are thought to originate primarily in
the outflows of gas given off by stars like our own Sun when they reach the
end of their normal lives. Like the other molecules in space, PAHs should
be frozen into the ice mantles that surround dust grains in interstellar

When the team examined the chemistry that occurred when PAH-containing H2O
ices were irradiated with ultraviolet light, they discovered that the PAHs
were not destroyed, but that many of them did have their edges modified by
the addition of extra oxygen and hydrogen atoms. The addition of oxygen
atoms results in the formation of aromatic alcohols and ketones, i.e., PAHs
where a peripheral H atom is replaced by an -OH group or a doubly bonded
oxygen, respectively. The aromatic ketones are of particular interest.
This class of compounds includes quinones, molecules that currently play
critical metabolic roles in the biochemistry of all living organisms on
Earth. "As with the amphiphiles, this raises the interesting possibility
that the infall of materials made in the interstellar medium may have
played a significant role in getting life started on Earth," notes
Bernstein, who along with Dworkin, makes most of the residues.

"However," Allamandola added, "the production of organics in space can't
play a role in the origin of life on planets if the material is unable to
safely survive transportation from the interstellar medium to the surface
of a newly formed planet. Fortunately, meteorites provide us with evidence
that organic materials can survive this transition." This evidence comes
primarily from the detection of deuterium enrichments in many meteoritic

Deuterium is one of the heavier isotopes of hydrogen, having one extra
neutron. "It turns out that most of the chemical processes that we think
occur in the interstellar medium favor the heavier deuterium over normal
hydrogen," says Sandford. "As a result, the presence of excess deuterium
in meteoritic organics strongly suggests an interstellar connection. One
of our current research activities is to try to understand how deuterium
behaves during our ice chemistry simulations. We are discovering patterns
to the placement of deuterium in the resulting organics and one of our
plans for the future is to compare our results to meteoritic organics to
see if the same patterns appear in them."

Perhaps the most important point of all this, notes Sandford, is that this
type of chemical activity is a universal process that should be happening
in all interstellar dense clouds. "It appears that the universe is, in
some sense, 'hardwired' to produce relatively complex organics," he quips.
"Furthermore, since it is from these clouds that new planetary systems
are made, it is reasonable to expect that essentially all new planets
should have some of this material fall on them. Thus, interstellar
organics may play a wider role in the formation of life on other planets,
not just the Earth."

This work was funded by the National Aeronautics and Space Administration.

More information:

* The Astrochemistry Lab at NASA Ames
* The equipment used to simulate space (center image)
* Related material in the July 1999 issue of Scientific American

Related material which has appeared in the scientific literature:

* Bernstein, M. P., Sandford, S. A., Allamandola, L. J., Gillette, J. S.,
  Clemett, S. J., & Zare, R. N. (1999). UV Irradiation of Polycyclic
  Aromatic Hydrocarbons in Ices: Production of Alcohols, Quinones, and
  Ethers. Science 283, 1135-1138.

* Bernstein, M. P., Dworkin, J. P., Sandford, S. A., & Allamandola, L. J.
  (2001). Ultraviolet Irradiation of Naphthalene in H2O Ice: Implications
  for Meteorites and Biogenesis. Meteoritics and Planetary Science, 36,

* Dworkin, J. P., Deamer, D. W., Sandford, S. A., & Allamandola, L. J.
  (2001). Self-Assembling Amphiphilic Molecules: Synthesis in Simulated
  Interstellar/Precometary Ices. Proc. Nat. Acad. Sci. 98, 815-819.

Images of vesicle research:

[Image 1: (286KB)]
These droplets (~10 microns across) show structures reminiscent of cells
(although they are not alive). They are from a chemically separated
fraction of the bulk residue.

[Image 2: (167KB)]
These droplets (small ones are ~10 microns across) glowing under black
light in the microscope show internal structure and suggest chemical
complexity. They are from a chemically separated fraction of the bulk

[Image 3: (85KB)]
This is a vesicle (~10 microns across) glowing under black light in the
microscope made from the bulk residue. Proof that it is a hollow vesicle,
rather than a simple drop of oil, is the green pyranine dye which we have
trapped inside of it.



From Paul Withers <>

Hi Benny,

Some responses to the discussions on CCnet... Please split them up and post
them as you wish. The common theme seems to be reading the press release
without reading the peer-reviewed paper.

Paul Withers

Re: - 6 (Paine)

The Meteoritics paper gives a range of possible sizes for the impactor that
formed Giordano Bruno as 1 - 3 km depending on the speed of the impactor
(the Holsapple 1993 reference). 850m is close enough to the low end of this
range. In any case, the estimate of how often craters of a
given size are formed is referenced by crater size, not impactor size (the
Neukum and Ivanov 1994 reference). The 15 million year estimate doesn't care
if we are at the small or large end of the 1-3 km size range.

Re: - 8 (Baillie)

There are significant physical differences between hailstones and meteorites
derived from a lunar impact. Either the ejecta from the lunar impact would
burn up completely in the atmosphere, in which case the Scots would have
seen nothing bouncing on the ground to misidentify as hailstones, or some of
it reaches the ground intact, in which case the ground is covered with lots
of meteorites which, unlike hailstones, do not quickly melt away. Maybe the
Scots sheltered from a "hailstorm" then went out, found a load of
meteorites, and had no better way to describe
what happened than as a hailstorm. I think that the chronicler would have
found some way to describe the interesting fact that the ground was covered
in new rocks after the hailstorm if the hailstorm was actually a meteor

Re: - 7 (Lunan)

The issue of how large ejecta escaping from the Moon can be is discussed in
the Meteoritics paper. The "sparks" could not have been large pieces of rock
distinguishable from the surrounding cloud of gas and dust by an eyeball far

The issue of lunar laser ranging and lunar libration is discussed in the
Meteoritics paper. The relevant reference is Yoder (1981).

The inconsistencies between Gervase's text and what we know of large
impacts, such as the phenomenon happening a dozen times or more, is also
discussed in the Meteoritics paper. The relevant reference is Nininger and
Huss (1977).


From Michael Paine <>

Dear Benny

Here is an extract from a web page about tektites that Hermann Burchard
brought to my attention. Does anyone have more information about the
'circular feature' mentioned below?

Michael Paine

From Tektites by David Weir

...The largest known strewn field, encompassing the Austalasian
tektites, has yet to be identified with a particular impact
structure but it is suspected to be located on the Indochina Peninsula.
However, recent gravity and topography data from Seasat and Geosat has
identified an ~100 km circular feature off the coast of Vietnam in the South
China Sea centered at 13.6° N., 110.5° E. that could prove to be the
illusive crater.


From Leon Neihouse <>

Dear Benny,

The Alpha Space Foundation, a nonprofit organization operating in the
asteroid/comet impact arena, plans to introduce the general public to the
hazard through Exhibits set up in shopping malls. Members of this forum are
cordially invited to review (see
and comment (to on this method.

Best regards,

Leon Neihouse


From Michael Paine <>

Dear Benny,

Below are some extracts from abstracts of the conference that Hermann
Burchard alerted me to.

regards Michael Paine

Earth System Processes Conference,
June 24-28, 2001, Edinburgh.

"A major puzzle lies in the role of apparently unrelated
extraterrestrial impacts at or close to the times of these transitions."

"The most intriguing observation is that the "killing efficiency" of
flood basalt eruptions declines rapidly after the Jurassic (if the
Deccan Traps/K-T mass extinction link is disregarded in favour of a more
compelling link with bolide impact)."

"Woodleigh is a recently discovered impact structure with a diameter of
120 km, representing the third largest proven Phanerozoic impact
structure known after Morocweng and Chicxulub... Illite K-Ar ages
indicate a Late Devonian impact age, which coincides with several other
impact events and a major global extinction in the Late Devonian some
365 Ma ago... Woodleigh can be considered as a likely major contributor
to this extinction."

TANNER, Lawrence H.
"The current view is that this event resulted from eruptions of the
flood basalts of the Central Atlantic Magmatic Province (CAMP).
Frequently cited is the sudden increase in atmospheric CO2 from
outgassing during widespread eruptions, resulting in intense global
warming. However, careful measurement of the carbon-isotope composition
of pedogenic calcite from calcareous palaeosols of Late Triassic to
Early Jurassic age fails to document any substantial change in
palaeo-pCO2 across the Triassic-Jurassic boundary. Suggestions of large
increases in Early Jurassic palaeo-pCO2 from CAMP eruptions appear to be
based on overestimates of the CO2 contribution from this magmatism.
Alternative mechanisms for extinction related to volcanism remain to be
explored more fully..."

PÁLFY, József
"Our results suggest that, similarly to other mass extinctions, the
end-Triassic event was also associated with environmental perturbations and changes in the global
carbon cycle...
It appears that the main isotope anomaly near the Tr/J boundary was not
the result of a single event, but rather a culmination of a period of
instability in the Earth systems, perhaps triggered by large-volume
volcanism in the Central Atlantic Magmatic Province."

STOREY, Bryan C.
"Earth history is punctuated by short abrupt periods of massive volcanic
eruptions due to the impact of deep-seated mantle plumes on the Earth's

"Subsurface hydrothermal systems may have also been a refuge for
thermophilic microorganisms during late, giant impacts that appear to have re-shaped
the early biosphere at the end of heavy bombardment."

ZHMUR, Stanislav
"Evidence obtained about litified remnants of carbonaceous meteorites
microorganisms belonging to hydrothermal mats(Zhmur,Gerasimenko,1999)
testifies to the high probability of the existance of mummificated
remnants of microorganisms in carbonaceous meteorites (that was
confirmed by previous investigations) and to the possible presence in
them of live substance which could be considered as panspermia material.
Transportation of live Space substance to the Earth seems real..."

"The mechanisms of silicification under laboratory-controlled conditions
and the implication for silicification in natural environments, the search
for early Earth life and possible evidence of extraterrestrial life are


From the BBC News Online, 7 June 2001

By BBC News Online's Ivan Noble

Scientific research papers normally make dry reading, but this one reads
almost like the start of a whodunnit:

"All Australian land mammals, reptiles and birds weighing more than 100
kilograms perished in the late Quaternary," Richard G Roberts of the
University of Melbourne and his colleagues write in the journal Science.

And the question, of course, is indeed: Who did it? Who or what could
possibly have caused the extinction of so many different creatures in what
was, geologically speaking, a short period of time?

Investigations have been underway for more than a century and two main
suspects have emerged.

Two suspects

The killer may have been a change in the climate, possibly the onset of the
last ice age. Or it may have been that well-known offender with a very long
record, Homo sapiens.

As detective film fans know, the case against the killer often hinges on
establishing the time of death, and this time around is no exception.

But for decades it has been difficult to establish when exactly Australia's
giants died out. There are limits to the accuracy of radiocarbon dating.

Now Richard Roberts and his colleagues have combined two other dating
techniques to come up with more precise timings for a whole range of fossils
from Australia and Papua New Guinea, which in times of lower sea levels were
joined by land.

Key dates

And it looks like hard work for Homo sapiens' defence team:

Optical and uranium-thorium dating techniques both indicate that the
extinctions are most likely to have taken place around 46,000 years ago.

With the last ice age at 19 to 23,000 years ago, the date is much too early
for the climate to have been the culprit.

Instead, the evidence points to human culpability, since the first humans
came to today's Australia around 56,000 years ago.

The scientists are not clear about the modus operandi of the killer,

Because of the margins of error, they cannot be sure whether humans hunted
the giant lizards, birds and mammals to extinction, or whether they simply
caused so much disruption to the ecosystem that the extinctions came as a

Either way, it looks like another case of destruction by humans.

"Our data are consistent with a human role in extinction," the researchers

US study

The Australian research is published at the same time and in the same
journal as a study using computer predictions to try and discover what was
responsible for similar mass extinctions in North America.

John Alroy of the University of California, Santa Barbara, developed a
computer prediction taking into account different possible numbers of humans
in ancient North America, their hunting ability, the degree of competition
between species and the geographic dispersal of different species.

His predictions matched closely to reality, correctly predicting what
actually happened to 32 out of 41 prey species.

And not only was he able to predict which species would die out, but also
when they would die out.

His conclusion was that the major extinctions in North America occured
between 800 and 1,600 years after humans turned up around 13,000 years ago.

The destruction took place on a timescale that was, in geological terms
instantaneous, but nevertheless slow enough in terms of human generations
for those who unleashed it to be unaware of what they were doing.

Another indictment for Homo sapiens, but material at least for a mitigation

Copyright 2001, BBC

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