PLEASE NOTE:
*
CCNet DIGEST, 23 December 1998
WISHING YOU ALL THE BEST FOR THE FESTIVE SEASON & A HAPPY NEW
YEAR
Benny J Peiser
------------------------------------------------------------------
(1) EROS FLYBY BY NEAR TODAY
http://near.jhuapl.edu/
(2) INTEGRATIONS OF THE ORBIT OF 1997 XF11
Andrew Hollis <A.J.Hollis@open.ac.uk>
(3) NEW PUBLICATIONS ON TUNGUSKA & METEORIC PLASMA
Luigi Foschini <L.Foschini@fisbat.bo.cnr.it>
(4) THE JAPANESE LEONID VIDEO STORMLET - REAL AFTER ALL?
Daniel Fischer <dfischer@astro.uni-bonn.de>
(5) DEEP SPACE 1 PLASMA INSTRUMENT ACTIVATED
Ron Baalke <BAALKE@kelvin.jpl.nasa.gov>
(6) NEW COASTAL RESEARCH UNDERWAY
Bob Kobres <bkobres@uga.edu>
======================
(1) EROS FLYBY BY NEAR TODAY
Eros Flyby Scheduled for Dec. 23
http://near.jhuapl.edu/
On Wed., Dec. 23, at 1:43 p.m. EST, NEAR will fly within 2,542
miles
(4,100 kilometers) of the asteroid Eros at approximately .62
miles per
second (1 kilometer per second). The flyby will determine the
size and
shape of the asteroid and whether Eros has any moons. Scientists
are looking at a rendezvous with Eros around May 2000.
=========================
(2) INTEGRATIONS OF THE ORBIT OF 1997 XF11
From Andrew Hollis <A.J.Hollis@open.ac.uk>
I have been carrying out integrations of the orbit of 1997XF11
and it
makes frequent close approaches to Mars and Venus as well as the
Earth-Moon system.
Work is not yet complete but I hope to be able to show the risks
and
stability of the orbit over a 20000 year period in the near
future.
Regards
Dr Andy Hollis
Tel UK 01606 883331
================
(3) NEW PUBLICATIONS ON TUNGUSKA & METEORIC PLASMA
From Luigi Foschini <L.Foschini@fisbat.bo.cnr.it>
Dear Benny,
I would like to inform you about two papers on meteors, which
have been
recently published.
L. Foschini:
A solution for the Tunguska event
ASTRONOMY AND ASTROPHYSICS 342, (1999), L1-L4.
ABSTRACT: This letter presents a new solution for the Tunguska
event of
June 30th, 1908. The solution has been obtained starting
from seismic
data, is in fair agreement with the observational evidence, and
supports
the asteroidal hypothesis for the origin of the Tunguska cosmic
body.
It is based on an improved model of the hypersonic flow around a
small
asteroid in the Earth's atmosphere.
L. Foschini:
On the interaction of radio waves with meteoric plasma
ASTRONOMY AND ASTROPHYSICS 341, (1999), 634-639.
ABSTRACT: In this paper, a meteoric plasma is analyzed from a
physical
viewpoint, with particular emphasis on its interaction with radio
waves. The attention is drawn to some macroscopic
characteristics of a
meteoric plasma and it is shown that the electron--ion collision
frequency is not negligible, as commonly thought.
Thank you very much. Have a happy new year and a merry Christmas.
Cordially,
Luigi Foschini
===============
(4) THE JAPANESE LEONID VIDEO STORMLET - REAL AFTER ALL?
From Daniel Fischer <dfischer@astro.uni-bonn.de>
I found this interesting item in a mailing to reporters from the
AGU:
----------------
Geophysical Research Letters
Highlights of January 1, 1999 issue
(This material is not embargoed.)
Shower seen on tape
The Earth experiences about a dozen major meteor showers each
year when
it encounters debris left behind by comets. About every November
17,
the Earth experiences the Leonid meteor shower that is associated
with
the comet Tempel-Tuttle, which orbits the Sun with a period of
just
over 33 years. Kinoshita et al. ["Preliminary activity of
Leonid meteor
storm observed with a video camera in 1997"] videotaped a
Leonid meteor
burst (100-150 meteors in two seconds) that occurred in 1997 and
analyze six bright meteors from that event. Measurements, made in
Mauna
Kea, Hawaii, indicate that the spread of the meteors in the orbit
is
approximately 100 km along the trajectory and 50 km in the
lateral
direction. These observations indicate the recent disruption of a
larger Leonid meteoroid.
----------------
So the controversial video storm is real after all? Real enough,
it
seems, for a refereed (though risk-taking) science journal! Has
anyone
actually *seen* this video, or is it (or a set of individual
frames)
available on the net or in the literature somewhere?
Daniel
========================
(5) DEEP SPACE 1 PLASMA INSTRUMENT ACTIVATED
From Ron Baalke <BAALKE@kelvin.jpl.nasa.gov>
Southwest Research Institute (SwRI)
San Antonio, Texas
SwRI engineers activate Deep Space One instrument
Plasma experiment for planetary exploration instrument performing
well
San Antonio, December 11, 1998 -- The plasma experiment for
planetary
exploration (PEPE) instrument, one of the most advanced plasma
sensors
ever to fly, was activated December 10 from a distance of more
than 4.5
million miles. The instrument is riding aboard the Deep Space 1
(DS1)
spacecraft, which will fly by asteroid 1992 KD and Comets
Wilson-Harrington and Borrelly. Southwest Research Institute
(SwRI)
designed and built the instrument in cooperation with Los Alamos
National Laboratory.
"So far PEPE is operating perfectly and we're seeing the
things you
expect to see in space -- no surprises yet," says Dr. David
T. Young,
PEPE principal investigator and an Institute scientist in the
SwRI
Instrumentation and Space Research Division. Young and SwRI
Senior
Research Engineer John Hanley turned on PEPE from the control
center at
the Jet Propulsion Laboratory of the California Institute of
Technology. "DS1 is testing 12 new technologies in deep
space,
including PEPE which has several new technologies of its own, to
help
lower the costs and risks of future NASA missions." Other
SwRI
scientists and researchers from elsewhere in the U.S. and Europe
will
help analyze the data collected during the encounters.
DS1 is using an ion propulsion system -- essential for exploring
deep
space because it's more efficient and can propel spacecraft
further out
than typical chemical rockets. PEPE will help determine whether
space
physics measurements can be made from spacecraft using such
propulsion
systems without affecting the scientific data and results. In
addition,
the instrument's high mass resolution will enable it to make
scientifically interesting measurements of asteroid and cometary
environments and to easily distinguish between the two major
species
emitted by the ion propulsion system, xenon and molybdenum. The
instrument's other goals onboard the spacecraft are to validate
the
PEPE design and technologies, which includes multiple plasma
physics
capabilities in a single 6-kilogram package.
"There's a possibility that the propulsion system could
damage PEPE
because the current coming out of the ion thruster is so intense
-- far
more intense than anything you'd normally find in space,"
Young
continues. "I'm beginning to think it's a very small chance,
but we'll
have our finger on PEPE's off switch in case anything goes
wrong."
This is the first ion drive that's ever been used to propel a
spacecraft. Previous missions have avoided using ion propulsion
systems
as the primary system because the technology, and its interaction
with
other instruments, has yet to be proven in space. "We'll
know soon
whether or not we have to take future precautions with
instruments in
this environment," Young says.
PEPE is based on a miniaturized optimized smart sensor, an
ultracompact
sensor developed at SwRI to analyze the plasmas -- ionized gases
--
that are found in the interplanetary medium and the space
environments
of most solar system bodies. PEPE's performance compares roughly
to
that of the Cassini plasma spectrometer (CAPS), also developed at
SwRI,
yet it requires less than 30 percent of the mass and 50 percent
of the
power at a fraction of the cost. The dramatic reduction in mass
and
power was achieved through innovative ion and electron optics,
the use
of electroplated plastics, novel electronics architecture and
packaging, and more efficient high voltage power supplies. CAPS
is
flying aboard the Cassini spacecraft, launched in October 1997,
as it
makes its way to Saturn.
The DS1 mission is the first of NASA's New Millennium Program,
which
focuses on developing and validating promising technologies for
use on
future space missions. Three other deep space and two earth
orbiting
missions are in the development or planning stages. DS1 was
launched
from Cape Canaveral, Florida, on October 24.
For more information about PEPE, contact:
Maria Martinez
Communications Department
Southwest Research Institute
P.O. Drawer 28510
San Antonio, Texas 78228-0510
Phone (210) 522-3305 Fax (210) 522-3547
mmartinez@swri.edu
=====================
(6) NEW COASTAL RESEARCH UNDERWAY
From Bob Kobres <bkobres@uga.edu>
Looks like some interesting coastal research is well underway. I
wonder
if Riggs is finding only evidence of sea level fluctuation or are
some
of his swings due to tsunami events? I haven't contacted him but
plan to
soon.
Bob Kobres
----------
From:
http://www.ecu.edu/research/edge/textonly/SoundEvidence.to.html
SOUND EVIDENCE
Geologist Stan Riggs unravels clues of a volatile coastal
history. His
evidence suggests that sea level has fluctuated dramatically in
recent
history.
GEOLOGY BOOKS EXPLAIN THE FORMATION OF NORTH CAROLINA'S
MODERN-DAY COAST
SIMPLY: It began as the last major ice age ended. At the time,
sea
level was about 400 feet lower than today, and dry land extended
40
miles east of Nags Head. As temperatures warmed, glacial ice caps
melted. Sea level spurted upward and inland for a bit, then
settled
down to a slow, steady increase as the current coastline took
shape
some 5,000 years ago. Except for small adjustments—sea level
rising a
bit more, a little shifting of the Outer Banks—nothing much
has
happened since then.
In a few years, the books may have to be rewritten.
Dr. Stanley R. Riggs, ECU professor of geology, sees indications
that
the Tar Heel coastline has been far more volatile than previously
recognized. Deep underneath the sounds, he is finding evidence of
frequent shifts in sea level and recurring events of the
formation and
disappearance of the Outer Banks. All of this has occurred within
the
last 12,000 years, barely a ticktock in geologic time.
As these findings rewrite the geologic history of North Carolina,
they
also help explain patterns of human settlement along the coast
(see "A
Common Quest" [below]). Perhaps even more important is the
possibility
that these dramatic shifts in sea level have not ended, a
possibility
with serious implications for coastal development. In fact, if
predictions about global warming prove true, the coastline of the
future may be even more volatile than that of the past.
Riggs fully expects to meet resistance to his findings. "If
you want
controversy, just try to modify the sea level curve," he
said last
fall. At least he will not be alone. Spurred on by recent
discoveries
concerning the global climate, scientists around the world are
beginning to challenge long-held assumptions about sea level.
Over the
past decade, cores taken from the deep sea and the Greenland ice
sheet
have shown that the Earth's climate has fluctuated wildly since
the
last ice age. This prompts scientists to ask: If temperatures
have
soared and plunged, would sea level not have done the same?
As temperatures rise, the Earth's ice pack melts, releasing more
water
into the oceans. Conversely, as temperatures drop, ice reforms,
drawing
water out of the oceans. Furthermore, changing the differences in
temperature between the poles and equator affects the speed of
ocean
currents and the degree of storminess, which in turn affect sea
level.
The climatologists' findings struck home with Riggs. "I knew
a lot of
generally accepted concepts about sea level didn't make
sense," he
said. Riggs set out to test his suspicions by examining the
sediment
record from beneath North Carolina's sounds.
Both changing climate and sea level play a role in the way layers
of
sediment form, influencing what the sediment contains and where
and how
it settles. For a record of the period Riggs is examining, North
Carolina's sounds hold special promise. They are large and in a
prime
location to record changes wrought by fluctuations in the
Atlantic
Ocean, but far enough south not to have experienced the rebound
effect
that made land surfaces rise as glaciers retreated. In addition,
because the sounds are enclosed by the Outer Banks, evidence of
changing salinity of the water offers clues to the presence or
absence
of the barrier islands.
Riggs is no newcomer to coastal waters. For 35 years, he has
studied
the origin and evolution of the world's continental margins. His
studies have taken him from coastal plain rivers to the outer
edge of
the continental shelf. For his present study of sea level change,
he
brings a large arsenal of tools to the shallow estuaries.
Riggs and his graduate students spend weeks at a time slowly
crisscrossing the sounds in boats towing a machine that directs
sound
waves into the earth below. Inside the boat, a seismic recorder
displays the waves as they bounce back. Bit by bit and layer by
layer,
the sound waves trace the lay of the land beneath the basin
floor.
Other times, Riggs and company trade in the seismograph for
equipment
that pulls up cores of sediments, sometimes going 100 feet or
more
below the floor of the sound. In the cores, the layers of
sediment take
tangible form, displaying alternating layers of marine, estuarine
and
riverine sediments that reflect rapidly changing conditions. To
put
ages on the changes recorded in the cores, they send samples to
an
analytical lab for radiocarbon dating.
Together, the three tools begin to explain what Riggs had seen
years
before in the Albemarle Sound. The floor of the sound appears to
be
typical of an estuarine basin: broad, shallow and smooth.
Underneath,
one would expect the layers of sediment to be uniform and evenly
distributed. In Riggs's previous explorations, cores from
different
parts of the sound had indeed revealed similar layers of
sediment, but
carbon dating had assigned widely different dates to seemingly
identical layers. "I couldn't make any sense of it,"
Riggs said. "Now,
with seismics, we can see what's going on. [Below the sediment
surface]
the sound is chockabilly full of channels."
The seismic records reveal sets of river channels, some nested
inside
of others. The channels could have been cut only during periods
of low
sea level, and each channel was subsequently backfilled as sea
level
rose again. As a result, the channels are filled with the same
types of
material. Differences occur in the ages obtained from carbon
dating
because the channels were cut and deposited at different times.
Riggs and his graduate students have completed a detailed record
of the
Albemarle Sound and now are methodically applying the same tools
to the
Croatan, Roanoke and Pamlico sounds. New secrets continue to
emerge.
Recorded history, for example, indicates that the Croatan Sound
is a
relatively new body of estuarine water. Until about 200 years
ago,
Roanoke Island was connected to the mainland by marsh, with a
small,
mostly freshwater creek flowing northward through it. About 1817,
Roanoke Inlet closed, forcing the waters of the Roanoke River and
the
Albemarle Sound to find another outlet to the ocean. They
followed the
creek and have been cutting a wider and deeper path through the
old
marsh ever since. The result is the present-day Croatan Sound.
Riggs sent divers to the bottom of the Croatan. Instead of the
smooth
bottom typical of an estuary, they found ridges and crags. Strong
currents have eroded away all the soft mud to reveal ancient,
intact
reefs of oysters and angel-wing clams. Carbon dating puts them at
2,100
years old. This means that 2,100 years ago, the creek was
inundated
with salt water, which requires a major opening in the barrier
islands
north of Roanoke Island.
Riggs sees only one conclusion: "The barrier islands were
blown out."
Taken together, he said, the Croatan evidence and recurring
patterns of
marine sediment elsewhere indicate that the Outer Banks have
formed and
disappeared many times during their history.
Critically important for the theory, the major sea level events
appear
to coincide with fluctuations in global temperature recorded in
the
deep sea and in the Greenland ice core. Although Riggs and others
have
observed such evidence before, they previously chalked it up to
errors
in carbon dating. "We discarded the dates because they
didn't fit the
accepted sea level curve," he said.
At this point, Riggs is not claiming to have definitive proof of
swings
in sea level worldwide, only that the sea level off the coast of
North
Carolina has fluctuated. Still, he has his suspicions. Local or
regional coastal events could explain a sea level change of up to
six
feet, but it would take changes of 20 feet to explain some of the
channels in the Albemarle Sound. "I think sea level changes
of this
magnitude have to be global in scale," he said.
He is encouraged that scientists in other parts of the world are
making
similar discoveries. A French scientist working on the Atlantic
coast
has documented seven major sea level rises and falls of up to 58
feet
in the last 8,000 years. "My experience is, if you're not
alone, you're
probably on the right track," Riggs said. "When
different people are
coming to it, it's real."
From:
http://www.ecu.edu/research/edge/textonly/ACommonQuest.to.html
A COMMON QUEST
Two disciplines unite to trace evidence of sea level, human
habitation.
Geology and archaeology are converging on the North Carolina
coast in
the persons of Dr. Stanley Riggs, ECU professor of geology, and
Dr.
David S. Phelps, professor emeritus of anthropology and director
of the
university's Coastal Archaeology Office. The two have begun a
collaboration they hope will enable them to trace sea level and
human
settlement through the millennia.
The official collaboration grew out of a project off Roanoke
Island,
which is believed to have been the home of the Lost Colony. Riggs
and
Phelps have been searching the waters of the Roanoke Sound to
determine
how much of the island has been lost to coastal erosion and what
was
lost with it. "From the distribution of artifacts [in the
sound], we
hope to reconstruct the coastline at various times," Phelps
said. "In
order to do that, we needed both geology and archaeology.
Geology, to
establish erosion rates and interpret the sediments in which we
find
the artifacts. Archaeology, to date the age of artifacts to
determine
where the shoreline was at a particular period."
They have covered only a small area so far, but their findings
bear out
predictions. Hundreds of yards off the coast at the Elizabethan
Gardens, dredging has turned up artifacts of Indian settlements
dating
back 800 years. As the scientists continue, they will be watching
for
evidence of early English settlement as well.
The most important finding so far relates not to an artifact or a
line
on a map, but to a layer of dark soil. The dark color indicates
that
the soil, called humus, was once exposed to air and rich in plant
life.
For years, geologists have said that the current surface of
Roanoke
Island—a narrow band of humic soil and sand—was
deposited about 12,000
years ago, at the end of the last major ice age. Now it seems
that is
not the case after all.
On their dredging expeditions, Phelps and Riggs discovered
another band
of humic soil, buried below the surface of the sound and running
deep
under Roanoke Island. Carbon dating places the age of the soil at
12,000 years. Everything above it, including many feet of
ocean-born
sand, has been deposited since that time, indicating that the
island as
it exists today is much younger than previously believed.
The discovery tells Phelps that if he wants to put early Indian
settlements in their proper context, he will have to dig deeper.
"This
changes the whole complexion of deposition and erosion and
location of
human settlements through time," he said. "We have to
look at the whole
stratigraphy with an eye to where the placement of things are
within
that stratigraphy."
Phelps and Riggs have begun preliminary work they hope will lead
to a
large research project correlating the placement of prehistoric
Indian
sites along the coast from Currituck through Hatteras Island.
Phelps
will date known sites through their artifacts. Riggs will employ
a tool
called ground-penetrating radar to look underneath those sites
for
evidence of earlier deposits. "The upshot is, not only can
we see the
patterns of coastal settlement and how humans have used the coast
over
the last 12,000 years, but we can also begin to develop the
history of
these dune ridges and when they occurred," he said. "In
that way, we'll
be able to reconstruct the coastline for various periods of
time."
----------------------------------------
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----------------------------------------
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*
THOUGHTS OF THE DAY
SPACE EXPLORATION & SPACE COLONIZATION
From Michael Martin-Smith <martin@miff.demon.co.uk>
Dear Benny-
Firstly, here's wishing you and the CCNet a Happy Christmas and
New Year.
There has been some debate developing in recent times around the
motives - imperialistic or otherwise, of the proponents of Human
expansion into Space - a concept which the NEO impact danger does
nothing to quieten! Some say that we are a liability and should
abstain
from projecting our quarrelsome presence beyond these regions!
One can
see their point.
However, I would only add that Evolution is a game based on the
idea
that its participants play to win; the idea that a species might
so
detest itself as to deliberately abstain from self advancement
runs
counter to the drive that has creatively developed complexity
from
simplicity these past aeons.
For us to confine ourselves to Earth because we think ourselves
unworthy of growth into Space is a kind of racial suicide
and no more
defensible than the more usual personal kind. For our generation
to
foreclose a future possibility with such potential would be a
betrayal
of future generations, and all the billions who could be expected
to
one day - agreed, after many difficulties - have a chance of a
Universal life.
The one unpardonable crime in the Game of Life is to be
less than you
could be! To abdicate from Space is such a choice, and
would be an
ultimate betrayal. I wish to see Mankind become better, greater
and
more creative than we now are. Only a misanthropist could
legitimately
oppose me.
Olaf Stapledon wrote at the end of "First and Last
Men", 2 billion
years in the future, that it was a fine thing to have been Man,
and
added our theme to the Symphony of Life. If we deliberately stunt
our
growth, and curtail our potential by staying here, such words
have no
meaning.
Michael Martin-Smith
===================
SPEAK TO THE FUTURE
From David J. Johnson" <starman@mail.fwi.com>
Dear Benny,
In Andrea Milani's recent article, his final words struck me, and
brought this response to mind. We scientist are the ones,
who are
responsible to speak to the future. As our work, in what ever
field we
study, directly effects or will have a measure of impact on
future
scientist, as their work, will be built upon ours.
My personal research intrests are within theoretical astrophysics
and
cosmology, but I also have a vested intrest in SpaceGuard issues,
as
should all scientists. If we discover an asteroid which will
strike the
Earth 8000 years from now, do we ignore it, or begin work on how
to
form a defense to such an event? In recent years we have all seen
or
been part of the varied debates, yet funding for such projects is
elusive to non-existant, and our warnings ignored.
The subject of NEO research often becomes a raging torrent of
debate,
nearly as hot as Big Bang issues. But in reality, all ideas
should be
considered, even if it sounds like Star Trek, yet many scientists
are
too often worried about appearances, and crediblity, rather than
correctness.
The reality here is that we need a wide ranging program as
suggested by
SpaceGuard, we need eyes on the sky world wide, we need the
ability to
detect NEOs and properly catalog and track them, and we need to
formulate a defense. My friend and colleague in Australia,
Michael
Paine, has stated this case very elegantly over the past year as
to the
need. Yet funding is elusive, almost to the point that one
wonders if
our Governments really care.
Governments, corporations and individuals irrespective of
education,
religon or national origin should as well have a vested interest
in
this effort, if not for ourselves, for the future generations
which
will inhabit this world after we have gone. As parents, we try to
give
our children the best, and insure that they grow up healthy and
strong
and are educated. To me this is the legacy of SpaceGuard, and
science.
We each inherited our own legacy's, we each chose our fields of
study,
and we contribute to them, and we will add our legacy to those
who
came before.
What do each of you wish to leave ?
Regards
Dr. David James Johnson +
Stellar Research Group
Tel:/Fax: 219-723-4425
E-Mail:starman@mail.fwi.com
http://www.angelfire.com/in/stellargroup/index.html