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(meteorobs) Excerpts from "CCNet 104/2001 - 1 October 2001"
Thin issue. But note item #4, where our 'meteorobs' forum's very own
Bob Lunsford expresses a HIGH DEGREE of confidence about this year's
predictions of meteor storms over North and South America! I want to
express my sincere hope that Bob's confidence is justified. ;>
Clear skies,
Lew Gramer
------- Forwarded Message
From: Peiser Benny <B.J.Peiser@livjm.acdot uk>
To: cambridge-conference <cambridge-conference@livjm.acdot uk>
Subject: CCNet 104/2001 - 1 October 2001
Date: Mon, 1 Oct 2001 11:51:39 +0100
CCNet 104/2001 - 1 October 2001
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[...]
(5) NASA PREPARING FOR BIGGEST METEOR STORM IN 35 YEARS
Florida Today, 29 September 2001
(6) BORRELLY, THE UNIVERSE & EVERYTHING
NearEarthdot net, 28 September 2001
[...]
================
(5) NASA PREPARING FOR BIGGEST METEOR STORM IN 35 YEARS
>From Florida Today, 29 September 2001
http://www.floridatoday.com/news/space/stories/2001b/sep/spa092901a.htm
By Kelly Young
FLORIDA TODAY
CAPE CANAVERAL - If satellites could duck and cover, Nov. 18 might be the
time to do it. That's when the worst meteor storm in 35 years is expected to
hit. But from the ground, the storm will appear as beautiful streaks of
light in the night sky, perhaps as many as 2,000 per hour.
Under dark skies on a normal night, it is possible to see four to five
meteors an hour, said Bryan Craven, an officer at the Brevard Astronomical
Society.
This year's Leonid meteor storm could be a treat for skywatchers, but
there's a 1-in-1,000 chance that they could strike a satellite.
The tiny meteors, the size of dust or grains of sand, are left over from the
tail of comet Tempel-Tuttle, which swings through the inner solar system
every 33 years.
When the dust burns up in the atmosphere, it leaves a light streak, or a
shooting star. In the early morning of Nov. 18, North American skywatchers
may see dust left over from when the comet swung by Earth in the 18th
century.
The riskiest aspect of the meteors isn't their size, but their potential for
shorting out a satellite, said Bill Cooke at NASA's Marshall Space Flight
Center.
When a meteor zipping along at 40 miles per second hits an object, it
creates a tiny cloud of ions, or charged particles. That charged cloud could
interfere with a satellite's electronics, Cooke said.
This was the case in 1993 during the Perseid meteor shower when the European
Space Agency's Olympus communications satellite lost control.
But many satellites probably will do nothing different. Turning a camera or
other instruments off may do more harm than good.
"It's always risky doing things with satellites," said Cooke, who analyzes
the threat meteors pose to satellites. "Once it's up there, people like
leaving them up there and doing their thing."
Two of NASA's largest space assets, the Hubble Space Telescope and Chandra
X-ray Observatory, will try to minimize damage by turning their rear ends
into the incoming storm.
NASA never launches a shuttle during a meteor storm. But since the Leonids
only will last a day or two, it probably won't affect the scheduled Nov. 29
launch of space shuttle Endeavour. And the International Space Station
should be safe because of its shielding, Cooke said.
The Leonids, called so because the meteors appear to come out of the
constellation Leo the Lion, produce a meteor shower every year. A meteor
shower typically means one meteor every minute or so. But a meteor storm can
mean thousands of meteors an hour.
"It should be a pretty good show," said Bob Lunsford, visual coordinator for
the American Meteor Society.
Copyright 2001, Florida Today
============
(6) BORRELLY, THE UNIVERSE & EVERYTHING
>From NearEarthdot net, 28 September 2001
http://www.nearearthdot net
from Joshua, NearEarthdot net staff
As long as humans have been alive, breathing, and looking up at the stars,
comets have been enigmas. Historically they have actually been cast in a
negative light, most recently by being associated with the mass suicide of
1997.
There are ancient records of comets, including sophisticated charts
detailing cometary anatomy from China thousands of years ago. But until
fairly recently, the western view of comets submitted to Aristotle's
naturalistic philosophies, with no real, provable explanation of what these
strangers in the sky were. Comets baffled our ancestors for thousands of
years. In fact, the very word 'comet' ("hairy star") implies a shroud, a
comatose kind of state, something mysterious which cannot be penetrated or
fully understood.
Comets are really the only objects in the sky which are visible from Earth
and don't follow a set path like the stars and planets. We can begin to
imagine what it was like for our predecessors to walk out one evening and
suddenly notice something in the sky that just...shouldn't..dot be...there!
Little wonder that these ghostly objects -who appeared for no reason and
vanished just as inexplicably- were feared by so many, for so long.
The mind who provided the first great breakthrough in humankind's
understanding of comets, was, of course, Sir Edmund Halley's. His incredible
achievements are beyond the scope of this article. But suffice it to say
that Halley brought the comets to within our understanding by working them
into the new layout being pioneered by his contemporary -and friend- Isaac
Newton.
Arguably cometary science's second big breakthrough occurred again during an
apparition of Halley's comet, this time in 1986. Comet Halley was joined by
a small fleet of spacecraft, the most daring of which was Giotto, launched
by the European Space Agency. Giotto captured a timeless image of the
nucleus of Halley's Comet. It was, no doubt, a great milestone in our
understanding of comets.
The images were not sharp, and not of high resolution. But they clearly
revealed the dynamic nucleus with its active jets, and perhaps they also
perpetuated the popular image of the comet as a rigid iceberg, floating in
space.
Finally, on Saturday, September 22, the Deep Space One probe, a collection
of some of the most advanced technologies to ever fly, defied all odds and
captured stunning portraits of Comet Borrelly's tiny nucleus. The
engineering which enabled this feat is, again, beyond my scope, but is well
worth investigation.
As DS1 and Borrelly raced past one another, DS1 took a series of about 30
historic images. The most spectacular of these is a gorgeous portrait of
Borrelly's sunlit side. Here we behold the very face of that which so many
great ones have pursued. And it is more complex than most of us expected. We
see areas that are black as chimney soot, lighter areas that indeed resemble
ice, and chaotic interactions of all shades in between. There are ridges and
hills, fault lines and valleys. The jets shoot out like geysers from the
lightest areas on the object, which may show evidence of a sediment of some
sort.
All in all, the comet is like nothing we have ever seen before! A treasure
trove to the organic chemist, virgin territory to the explorer, and maybe
the cosmic seed which led to each of us and all life on Earth.
After the images came in, Charles Morris of NASA's Comet Observation Home
Page called it "really something special". Others called it "remarkable",
and said this effectively doubles our knowledge of comets. Still other have
called it "mind-boggling, and stupendous."
Personally, this is the one of the biggest events of my life. This may be
hard to understand, but when you have been fascinated by these objects all
your life, this is like opening King Tut's Tomb. Or better.
The only thing I can think to compare DS1 to -in terms of raw significance-
happened within a fortnight of the flyby. I refer of course to September 11,
2001.
It would be impossible to write an article about DS1 without associating it
with September 11, 2001. That event also changed this world in an instant..
Jeff Greenfield of CNN said that it will "take us some time to find our legs
in this whole new world."
Deep Space 1 would certainly have received more publicity if not for the
"epoch-making" events of September 11, 2001. One reason I feel it is
important for people to appreciate DS1 is that the reconnaissance we now
have of the structure of potentially hazardous comets may help us
tremendously at a future time, should the unthinkable occur. It may seem
inconceivable, but the potential damage that a hazardous comet or asteroid
promises would dwarf what happened in New York or Washington.
The flyby was also the first world-class achievement on the part of the
United States in the days following the events of September 11, 2001. The
United States is a nation for whom such great discoveries are the norm, but
it was still terrific to have this accomplishment when we did.
Perhaps Deep Space One should have been named "Phoenix".
==========
(7) OLDEST ASIAN TOOLS SHOW EARLY HUMAN TOLERANCE OF VARIABLE CLIMATE
>From National Geographic News, 26 September 2001
http://news.nationalgeographic.com/news/2001/09/0926_asiantools.html
by John Roach
When it's cold outside, modern humans don a sweater to ward off the chill.
But how and when early humans began to develop an ability to cope with
different climates has been a great puzzle in the study of human
evolution.The answer is important because it suggests when early humans were
able to migrate out of tropical Africa and settle all corners of the globe.
Now, researchers have determined that stone tools found in a region of
northern China are 1.36 million years old, which provides direct evidence of
the earliest human occupation of eastern Asia as far as 40 degrees north.
The stone tools were found in China's Nihewan Basin. During the period when
they were used, 1.36 million years ago, much of the area was covered by a
large lake that was ringed with forests of birch and elm trees. Mammals such
as hippopotamuses, hyenas, rhinoceroses, and horses roamed the area.
While the climate was probably humid and warm most of the time, the area is
thought to have experienced bouts of cold and dry weather. To settle in the
region, early humans would have had to adapt to this climate fluctuation.
The stone tools are an indication of that early ability to thrive in a
variable climate. They show that "early humans could live in a wide range of
climate conditions," said one of the researchers, Rixiang Zhu of the
Institute of Geology and Physics at the Chinese Academy of Science in
Beijing. He and his collaborators published a report on their findings in
the September 27 issue of Nature.
Magnetic Dating
The stone tools from the Nihewan Basin were found more than 20 years ago,
but until now their age was unknown. Anthropologists routinely determine the
age of materials through a process known as isotopic dating, a technique
based on knowledge about the rate of decay for certain radioactive elements.
Dating the stone tools from the Nihewan Basin was a challenge because they
lacked suitable material for isotopic analysis. Zhu and his colleagues
overcame the hurdle by correlating the magnetic polarity of the sediments in
which the tools were found with a known timeline of when Earth's magnetic
field shifts its polarity, or attraction toward a specific direction.
"We know that Earth's magnetic field flips polarity from time to time, and
for the last several polarity reversals, the ages are rather precisely
known," said Kenneth Hoffman, a paleomagnetist at California Polytechnic
State University in San Luis Obispo and a co-author of the paper in Nature.
"Sediments record the magnetic polarity of the field more or less as they
are deposited," he explained.
The stone tools were found in a section of sediment that correlates with a
known era of reverse polarity-when the needle in a compass would have
pointed south instead of north-that lasted from 1.77 million years ago to
1.07 million years ago.
Working under the assumption that the sediment was deposited at a constant
rate, the researchers calculated that soils in which the stone tools were
found were deposited 1.36 million years ago. Consequently, the stone tools
must be 1.36 million years old.
"Any uncertainty to the result would come from the assumption of a constant
rate of sedimentation during the reverse polarity period, yet this
uncertainty is likely to be small," said Hoffman.
Evidence of Adaptability
The researchers do not know exactly how the early tools were used. They
consist of several kinds of scrapers and sharp-edged tools, which almost
certainly would have been used to cut meat off the bones of mammals that
inhabited the region.
"That far north, we are dealing with changes in daylight," said Richard
Potts, director of the Human Origins Program at the Smithsonian
Institution's National Museum of Natural History in Washington, D.C., and
co-author of the scientific paper. "There would have been a good growing
season and a season of relative dearth. Reliance on animal food during
certain parts of the year may have been pretty important."
As corroborating evidence that early humans were able to thrive in varied
climatic conditions over a million years ago, the researchers point to
Lantian, an archaeological site on the Yellow River about 560 miles (900
kilometers) southwest of the Nihewan Basin. It was there that the remains of
a 1.1 million year old Homo erectus were excavated in 1963.
Paleoclimatic evidence suggests that Lantian was a relatively cold and windy
place 1.1 million years ago, said Potts.
"These two localities suggest that populations were able to occupy or shift
their range over a considerable area, from Nihewan to the southern margin of
the Loess Plateau, during a time of enhanced global and regional climatic
variability that included intermittent aridification of north China," the
researchers conclude in Nature.
Copyright 2001, National Geographic
===========
(8) AND FINALLY: IF LIFE EXISTS ON MARS, OUR ROBOTIC PROBES MAY HAVE BROUGHT
IT THERE
>From Space Daily, 1 October 2001
http://www.spacedaily.com/news/life-01zg1.html
by Laura Woodmansee
Pasadena - Oct 1, 2001
The results of NASA's 1976 Viking lander missions were largely inconclusive.
But, what if our spacecraft brought tiny forms of Earth life to Mars? Could
it have survived there? If so, what does this mean for the future
exploration of Mars?
And there is Europa, probably the most likely source of extra-terrestrial
life in our solar system. NASA has plans to send an orbiter and then a
lander to search for signs of life in Europa's planet-wide ocean. What is
being done to protect Europan life?
How can we seek out life in the solar system without harming it? Can robotic
probes built on Earth be made clean enough to search for life on other
planets without contaminating it? If we bring samples of alien life back to
Earth, how do we prevent them from contaminating Earth's biosphere?
"Planetary protection" is the prevention of "cross contamination." That is,
preventing life from getting from one planet to another and causing harm.
It's an important factor in space exploration that the public is barely
aware of, but one that NASA spends a lot of time working on.
Dr. Karen Buxbaum, a supervisor of the Jet Propulsion Lab's (JPL) Planetary
Protection Technologies Group says, "There's a certain amount of
responsibility that we have as an agency that's doing exploration to not be
sort of reckless in dumping stuff in other parts of the solar system."
NASA divides planetary protection concerns into two categories; forward and
backward contamination.
Backward contamination is the type of thing that books and movies like H.G.
Wells' "War of the Worlds" and Michael Crichton's "The Andromeda Strain"
have made popular. It is the contamination of Earth life by alien spores,
microbes or organisms.
Science fiction has put the fear of contamination by alien life in our
minds. But, what about the reverse? Could our space probes be "infecting"
other worlds with Earth life?
It turns out that NASA is working to protect life on other worlds from Earth
life, what the space agency calls forward contamination. Buxbaum defines it
this way; "Forward contamination refers to contamination of other solar
system bodies with biological material from the Earth." But, this concern
for alien life remains largely unknown to the American public.
Should we care if we spread Earth life to other planets in our solar system,
or anywhere else? NASA cares and that's why the agency has spent over 30
(1967-2001) years and countless dollars trying to prevent cross
contamination.
Protecting life on other planets is important business for NASA. It is
crucial to the exploration of the solar system. So much so that NASA has
created an entire Planetary Protection branch. Dr. John Rummel, NASA's
Planetary Protection Officer, works to protect life on Earth and life
elsewhere based on NASA's planetary protection policy.
"The policy is actually based on the desire to preserve extraterrestrial
environments for the science opportunities that are there," says Rummel.
In other words, if we bring Earth life with us to another planet, there is
the chance that we may kill or harm indigenous life. Or, we may make it
harder to determine if life ever existed there. We may mistake Earth life
for alien life.
"It's in nobody's best interest to obscure that by contamination with Earth
organisms," says Rummel. "Nor would you want to discover a wonderful new
life form and know that you've killed it ... Essentially we can meet ethical
considerations by the desire to preserve science."
Rummel must approve every NASA space probe before launch. "I often imagine
myself strapped to a booster somewhere," Rummel says in a comic voice,"
'Now, you won't launch this unless you get my signature.'"
The search for life beyond the Earth has lead to the new science of
Astrobiology. Through a combination of many physical and life sciences,
astrobiologists seek out life elsewhere in the solar system and the
universe. It's important to know where life might be in order to understand
where it must be protected. Scientists are only now starting to understand
the so-called "habitable zone," the range of environments where life can
exist.
Rummel ties astrobiology to planetary protection saying, "The idea of
astrobiology ... [is] to study the origin, evolution, and distribution of
life in the universe. And its extremely complementary on one level with
planetary protection, in that by preserving the environments in outer space,
you give yourself the potential to be able to discover more about them."
On Earth, where there is water, there is life. But life doesn't need water
to survive. In the past decade, scientists have discovered "extremophiles",
organisms that live in the limits of the Earth's environment. Scientists
have found life near hydrothermal vents at the bottom of the ocean, deep
inside solid rock, and even at the core of nuclear reactors.
"One of the things that's changed in biology," Rummel says, "Is we've found
life in extreme environments on Earth, that are completely different from
anything you or I would be comfortable living in. Nevertheless, there would
be ample opportunity to have life there. I don't want to live in a boiling
pool in the middle of Yellowstone Park, but there are microbes that just
love it."
Astronomers have found all the necessary ingredients for life (water,
carbon, hydrogen, oxygen and nitrogen) inside clouds of gas and dust
floating in deep space. At last count, our solar system has one star, the
Sun, 9 planets with 68 moons, and thousands of comets and asteroids. It's
quite possible that life arose in at least one of these places.
Detecting life is difficult, and scientists must be careful not to confuse
Earth life with alien life. This would risk ruining future life detection
experiments. Karen Buxbaum says, "Confusing the scientific results is a
threat to the program."
In the near future, NASA plans to use astrobiology to search for life on
Mars again. JPL scientist Dr. Roger Kern is planning for such a mission.
"What we anticipate will happen with the first landers on Mars is there will
be life detection experiments done in-situ, at the site," says Kern. "And
those experiments are probably not going to be looking for life, per se, but
will be looking for molecules associated with life. So we want to remove as
much [Earth life] as possible."
Kern continues, "Where as once NASA was only concerned with sterilizing
spacecraft and making sure that the spacecraft couldn't shed a live
organism, now we have an interest in seeing to it that it doesn't shed a
dead organism as well ... it kind of takes you into a new definition of
clean."
Even with super clean spacecraft, some microbes will always get by. Dr.
Rummel says that the current planetary protection plan includes, "An
inventory of organic constituents that might be delivered to another body.
So that if you happen to go back there and find these things you know that
you brought them."
In preparing a spacecraft for launch, technicians take samples of any
microbes, spores, or cells on the spacecraft's surfaces. They work to reduce
the number of contaminants to as low as possible, cleaning several times if
needed.
Copyright 2001, SpaceDaily
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