PLEASE NOTE:
*
CCNet 60/2003 - 27 August 2003
------------------------------
"Krakatau, Java erupted on 27th August 1883 and was one of
the largest
volcanic eruptions in human history, creating sound waves that
could be
heard 4000 km away and awakening people in Southern Australia.
The
eruption column reached a height of =25 km. Most of the ensuing
deaths
were caused by the many tsunamis that thundered along the
coastline from
late afternoon August 26th, to midday on the 27th August. The 40
m high
tsunamis generated ravaged the shores of the Sunda Straits and
caused
36,000 deaths in 295 coastal fishing villages, whilst casualties
were
recorded as far away as 800 km."
-- http://www.bmg.go.id/krakatau/history.html
(1) 120 YEARS AGO: REMEMBERING THE KRAKATAU DISASTER
(2) INTERNATIONAL SEMINAR/WORKSHOP ON TSUNAMI IN INDONESIA
(3) ASTEROID ALARM: SCIENTISTS DIFFER OVER EXTENT OF SPACEGUARD
FUNDING
(4) STARS IN THEIR EYES: AN INTERVIEW WITH BRIAN MARSDEN
(5) ALIEN INFECTION: WHAT ARE THE RISKS OF SAMPLE RETURN
MISSIONS?
(6) PLANETARY TILT NOT A SPOILER FOR HABITATION
(7) ASTEROID DOUGLASADAMS?
(8) PLANETARY DEFENSE STUDIO @ USC FALL 2003
(9) NATIONAL ASTRONOMY WEEK DEBATE: IS THERE LIFE ON MARS?
(10) AND FINALLY: MARS, NOT ISLAMIC TERRORISTS, TO BLAME FOR
BOMBAY
BLAST ASTROLOGERS CLAIM
==============
(1) 120 YEARS AGO: REMEMBERING THE KRAKATAU DISASTER
http://www.bmg.go.id/krakatau/history.html
Krakatau, Java erupted on 27th August 1883 and was one of the
largest
volcanic eruptions in human history, creating sound waves that
could be
heard 4000 km away and awakening people in Southern Australia.
The
eruption column reached a height of =25 km. Most of the ensuing
deaths
were caused by the many tsunamis that thundered along the
coastline from
late afternoon August 26th, to midday on the 27th August. The 40
m high
tsunamis generated ravaged the shores of the Sunda Straits and
caused
36,000 deaths in 295 coastal fishing villages, whilst casualties
were
recorded as far away as 800 km. Much of Krakatau was very low
altitude
and therefore the huge tsunamis swept headlong further inland
than in
higher areas. Many areas are recorded to have flooded as much as
10 km
inland, and a Man-of-war ship was carried a similar distance and
stranded 10 m above sea level.
The explosion caused the collapse of the Rakata Cone, resulting
in the
northern half slumping into the sea and a caldera 270 m deep
formed
below sea level to replace it. There were 4 large eruptions,
occurring
at 05:30, 06:44, 10:02, 10:52, with the third explosion being the
largest and generating the biggest tsunamis. The tsunamis were
generated
3 minutes after 3 of the explosions, although the tsunami
associated
with the largest explosion preceded it by 15 minutes.
What caused Krakatau tsunamis?
Pyroclastic flow deposits may have generated the smaller
tsunamis, but
it is unlikely that the largest tsunami could have been triggered
in
this way. The largest tsunami may have been generated by the
violent
impact of huge masses of unwelded ignimbrite erupting in the
largest
explosion and being deposited up to 10-15 km away before a whole
minute
had passed.
Another hypothesis involves the largest tsunami being caused by a
submarine explosion, although there is little evidence of the
deposits
that such an event would produce. Run-up heights (the
height of the
wave as it approaches the shore from its peak to its trough)
along the
Sunda Straits are estimated to be 15 m, whilst further away in
the Java
Sea they are estimated at 2 m. Several hundred kilometres
of the
coastlines of Java and Sundra were devastated, and the port of
Anjer was
completely destroyed, whilst even as far away as the Bay of
Biscay,
which is 17,255 km distant, small signals could be detected. The
waves
took just 37 hours to reach the shores of the English Channel,
although
they were greatly diminished by then.
=============
(2) INTERNATIONAL SEMINAR/WORKSHOP ON TSUNAMI IN INDONESIA
Michael Paine <mpaine@tpg.com.au>
Dear Benny
I just found out about this imminent seminar in Indonesia.
It is a
great credit to the Indonesian government for organising a
seminar on
this type of natural disaster - the Krakatau death toll was
around
80,000 with many from tsunami. There are lessons here for other
nations.
Michael Paine
http://www.bmg.go.id/krakatau/
International Seminar/Workshop on Tsunami
"In Memoriam 120 Years Of Krakatau Eruption - Tsunami And
Lesson Learned
From Large Tsunami"
August 26th - 29th 2003, Jakarta and Anyer
To remember the great eruption of Krakatau 120 years ago in
August 27th
1883 and to awakening the people around the tsunami and
earthquake prone
area to the possibility of upcoming tsunami disaster,
Meteorological and
Geophysical Agency (BMG) and Department of Marine Affairs
and Fishery
(DKP) of Indonesia will organize seminar and workshop in
Indonesia. This
occasion is in cooperation with ICG/ITSU, IUGG Tsunami commission
and
several related government institutions in Indonesia.
=============
(3) ASTEROID ALARM: SCIENTISTS DIFFER OVER EXTENT OF SPACEGUARD
FUNDING
The Baltimore Sun, 25 August 2003
http://www.sunspot.net/news/health/bal-te.asteroid25aug25,0,6722743.story?coll=bal-news-nation
Collision: Scientists and others differ over the extent of
resources
that should be devoted to spotting incoming space rocks.
By Dennis O'Brien
Every few years, astronomers who study asteroids are accused of
crying
wolf.
In 1998, one group predicted that an asteroid was headed toward a
collision with Earth in 2028. A day later, another group said the
estimate was based on faulty data and there was no chance of a
disaster.
In April 2002, astronomers announced that they'd found an
asteroid a
half-mile wide that has a 1-in-300 chance of hitting Earth. But
it
turned out that Asteroid 1950 DA, as it's formally known, won't
arrive
until March 16, 2880.
Hollywood has done its part, too. Movies such Deep Impact and
Armageddon
have entertained millions with tales of death-dealing rocks that
are
heading Earth's way.
Experts say alarms like these are the price we pay for better
surveillance of the heavens - and they're likely to continue as
long as
astronomers keep looking skyward.
"These asteroids were passing by before - it's just that we
didn't have
an ability to see them," said Clark Chapman, a planetary
scientist at
the Southwest Research Institute in Arizona.
Curiosity and concern
Asteroids are small celestial bodies that orbit the sun, mostly
between
Mars and Jupiter. Scientists believe they're made of the same
rocks and
metals that formed the planets, and they've long been objects of
curiosity and concern.
NASA, for example, spends $3 million a year to search for
asteroids that
are potentially big enough to wipe out the planet - meaning
bodies at
least a kilometer (about 0.6 mile) in diameter.
About 100 scientists and researchers work on the asteroid search
around
the world, and they expect to have 90 percent of the dangerous
rocks
identified by 2008.
But at least one group of astronomers says that effort isn't
enough.
"We're not alarmists. We're not worried about this happening
tomorrow.
We're just saying more attention should be paid to something that
could
really turn off the lights in a big way," said Thomas D.
Jones, a former
shuttle astronaut and leader of an effort to increase funding for
asteroid searches.
Wiped out the dinosaurs
According to the Southwest Research Institute's Chapman, the
world's
current asteroid fixation dates back to 1980, when Luis W.
Alvarez
hypothesized that a large asteroid had wiped out the dinosaurs by
hitting Mexico's Yucatan Peninsula.
"If one killed off the dinosaurs, I guess it hit home that
someday one
could kill us off," Chapman said.
NASA began to focus on asteroids in 1990, when a series of highly
publicized close calls piqued public interest and prompted
Congress to
appropriate funds to search for them. Spaceguard, a worldwide
effort
established in 1991, has so far found 650 asteroids at least a
kilometer
wide.
In a recent letter to Congress, Jones joined 10 astronomers,
historians
and other experts who argued that Spaceguard's efforts aren't
enough.
They want the United States to increase spending almost sevenfold
to
build better telescopes and look for smaller asteroids. The
smaller
rocks, they note, hit more often - about once every thousand
years.
Their impact would have the force of a nuclear blast that could
destroy
major cities and perhaps entire countries.
"One of the big questions facing us as a species is, how
much stuff is
out there that poses a danger to us, and how much of a danger is
it?"
said Lucy Ann McFadden, a University of Maryland astronomer who
signed
the letter. "We really don't know."
Jones, McFadden and others say the United States should hire more
observers and build larger telescopes dedicated to the search for
200-meter asteroids, often too small to spot now but big enough
to cause
a major regional catastrophe on impact.
Near Earth Objects
Most asteroids are in a doughnut-shaped belt between Mars and
Jupiter.
They revolve in the same direction as Earth and take three to six
years
to complete an orbit. But others reside outside the belt, and any
that
approach within 30 million miles are classified as Near Earth
Objects,
or NEOs.
Comets can also be NEOs, but they generally travel much farther
away
than asteroids and are less likely to strike Earth.
Based on records of asteroid hits and the number of asteroids
actually
found by astronomers - about 100 a year - experts estimate that
there
are roughly 1,100 NEOs. But that's just a guess.
"We really don't know how many there are," said Brian
Marsden, who
operates the Smithsonian's Minor Planet Center in Cambridge,
Mass.,
where newly discovered asteroids are listed.
Hits and close calls
History is filled with asteroid hits and close calls. Many
scientists
credit asteroids with wiping out the dinosaurs 65 million years
ago,
forming the Chesapeake Bay 35 million years ago and creating a
mile-wide
crater in Arizona a mere 50,000 years ago. Researchers say
asteroids
also might have first brought water to the planet, allowing
dinosaurs
and other life forms to thrive.
In 1908, an asteroid 330 feet wide exploded over Siberia,
creating the
equivalent of a 10-megaton nuclear blast that felled trees over
40
square miles.
In January 2002, a 300-yard-wide asteroid that could have
destroyed an
area the size of New England missed Earth by 500,000 miles -
about twice
the distance to the moon.
Scientists agree that a strike by a kilometer-wide asteroid would
cause
global catastrophe, clouding skies, dropping temperatures and
killing
off most plants and animals. Even smaller asteroids that break up
in the
atmosphere can cause tremendous destruction. The 1908 Siberian
asteroid
generated enough blast force to kill thousands if it had struck
an
inhabited region.
"If you happen to be in the area where a 10-megaton blast
occurs, it's
still going to cause serious damage, whether it leaves an impact
crater
or not," Jones said.
But not all astronomers are convinced that a search for smaller
asteroids is necessary. "Identifying smaller asteroids may
seem like
they're worth doing, but the question is, are they worth doing in
place
of other programs?" Chapman said.
Then what do you do?
A key question: Is there anything we do about an Earth-bound
asteroid
once we know about it? Movies notwithstanding, technology to
throw an
asteroid off-course would take about two decades to develop, said
David
Morrison, who oversees NASA's asteroid efforts at the Ames
Research
Center at Moffett Field, Calif. The method would depend on the
asteroid's composition, size and speed, but recent studies have
focused
on changing its orbit with rockets or solar deflectors planted on
the
surface.
Still, the chances that a kilometer-wide "doomsday
asteroid" will hit us
are minuscule - by NASA's estimate, once or twice every million
years.
But NASA says there are an additional million smaller asteroids
at least
50 meters across out there.
"We are likely to be hit somewhere on Earth by one of those,
with an
energy equivalent to a large nuclear bomb, sometime in the next
couple
of centuries," Morrison warns on a NASA Web site.
After the 1998 scare, the International Astronomical Union
established
protocols calling for peer review of asteroid discoveries that
would
check all calculations within 72 hours. But Morrison noted that
there's
nothing to prevent rushing to publication on the Internet:
"It's a very open process, but we're going to post the
information [on
Web sites] anyway and let the chips fall where they may. I'm sure
there
will be other controversies."
Copyright, The Baltimore Sun
==============
(4) STARS IN THEIR EYES: AN INTERVIEW WITH BRIAN MARSDEN
New Scientist, 24 August 2003
http://www.newscientist.com/opinion/opinterview.jsp?id=ns24091
Every day, astronomers make thousands of observations of
asteroids and
other celestial objects in the hope of finding one that no one
else has
seen. The task of sorting through them falls to Brian Marsden and
a
couple of colleagues at the Minor Planet Center in Cambridge,
Massachusetts. Eugenie Samuel Reich talks to him about his
affection for
the amateur skywatchers whose work is crucial to astronomy
You have daily contact with a lot of amateur astronomers and have
got to
know many of them. What sort of people are they?
They tend to be people with considerable persistence. Most
amateur
astronomers are somewhat possessed by what they are doing. By
definition
an amateur is someone who's retired, or who's got another job,
who puts
in a day at the office and then gets home and sits at the
telescope.
There are relatively few female amateur astronomers. There are
many
professionals, but the only amateurs I can think of are a woman
in Italy
who regularly makes observations of asteroids and one in Japan,
who does
some work on supernovae - exploding stars - with her husband.
Many observations today are made by large professional surveys
that
search for near-Earth asteroids by making tens of thousands of
observations each night. What can amateurs contribute?
Most of the work that amateurs do involves following up on
observations
that the large surveys have done. When we get reports of an
object that
could be a comet or a near-Earth object, we post a rough
prediction of
its orbit on a web page. Then people let us know where they see
the
object, which helps us refine its orbit to the point where we can
number
it. We have between 120 and 150 observatories doing this
follow-up work
at any given time, and probably 90 per cent of them are amateurs.
An amateur astronomer is often seen as someone gazing up through
their
telescope from their backyard. Does that still hold?
Nowadays people have very automated set-ups. They have telescopes
taking
film or digital images - with charge-coupled devices or CCDs - of
the
sky and often they study these from the comfort of their homes.
It is a
far cry from the rugged astronomer in his backyard. We get
relatively
few visual reports nowadays. They are so hard to do.
The CCD is particularly suited to spotting supernovae as you can
compare
the new image with the archive. In the UK two amateurs, Mark
Armstrong
and Ted Boles, are doing a great job on supernovae using CCDs.
Armstrong
operates his telescope by remote control on the roof of his house
in
Kent.
Other amateurs find supernovae without realising. They make their
images
available online and then professionals scrutinise them using
more
advanced software. Nowadays you don't even need a telescope to do
astronomy, because you can look at professional images or the
images of
other amateurs. I myself started out as an amateur, but I was
never an
observer. I made orbital calculations.
However, the first amateur to start discovering supernovae - Bob
Evans,
a clergyman in Australia who has been doing it since 1981 and has
found
more than any other amateur - did it entirely visually. He used
no
photographs or CCD images.
How would you go about making a visual discovery?
You need to look at hundreds of galaxies per night to have a
chance of
seeing one. Evans would simply look from one galaxy to another
and he
had all the galaxies memorised, so he would know if he saw a
change. He
would know if the galaxy didn't look right, if perhaps there was
a new
star or a supernova in it. And rather than write it down at the
time, he
would just remember where he had seen it, so he could look at
more
galaxies each night. Then he'd write it down the next day.
The British amateur astronomer George Alcock worked like that
too. After
finding four comets he decided comets, with their characteristic
fuzzy
appearance, had become easy for him, so he tried novae - stars
that
brighten suddenly and temporarily - and he found five of them
too. He
had to learn all the stars so he'd know if there was something
new
there. When you think about it, that's a tremendous thing.
Are amateur observations really as good as professional?
Most amateurs produce very high-quality data. They make mistakes,
but so
do professionals. For example, we've actually had quite a few
reports of
Neptune as a nova from professional astronomers, in one case from
the
director of an observatory. I usually reply with a one-word
message,
"Neptune". One thing that happens twice a year to some
amateurs is that
they get their observations systematically wrong, and then we
realise
they neglected to make the change from daylight saving time. The
professionals don't make that mistake.
Most discoveries are made by professional surveys, yet the
amateurs play
a crucial role. How do they get credit?
This is one of the problems we have. The surveys notch up lots of
minor
planets, but their work is dependent on what we do here at the
Minor
Planet Center to link their observations to those of others, and
on the
amateurs who make those other observations. So does the survey's
observation really count as a discovery? It does, when it reports
it
first. However, surveys often don't realise what they have seen
and so
don't report the object as new. So we give extra credit to people
who
are among the first to report an object and who know what they
have
seen.
For example, in 1983 Alcock reported his fifth comet. I had heard
that
people working with the Infrared Astronomical Satellite had seen
some
kind of fuzzy object a week before. When I heard about Alcock's
comet I
contacted them and told them to send me their data by the next
day at
noon or I would call it Comet Alcock. They sent in their data,
and in
the meantime another independent observation came in from Japan.
So we
called it Comet IRAS-Araki-Alcock. IRAS saw it first, but they
hadn't
even looked at their plates properly. I really think that if
you're
making a discovery, you should appreciate that you have a
discovery.
Alcock was like that: he really knew when he had something
special.
It's too bad we can't give the amateurs more credit. I'm a firm
believer
in giving credit. Amateurs are going out of their way to do this
work.
How many amateurs are usually involved in the discovery of a new
object?
I'll give you an example. A large asteroid, 3 or 4 kilometres
across,
was spotted on 22 May this year by the LINEAR telescopes in
Socorro, New
Mexico, which are run by the Massachusetts Institute of
Technology's
Lincoln Laboratory in Lexington. A professional Czech observer
got onto
it half a day later, and we refined the orbit further. Later we
got
reports from amateur astronomers in Mallorca in the Canary
Islands, from
an amateur in Lafayette, Indiana, and from the Tenagra II
telescope in
Arizona which I happen to know is owned by amateur Mike Schwartz.
We
then knew exactly where it was and so 24 hours after the first
sighting
we sent out our announcement. The interesting thing was that the
final
observation was made by Paulo Holvorcem, an amateur astronomer
who is a
professional mathematician and wasn't even at a telescope. He was
looking at Schwartz's images on the internet. The telescope was
in
Arizona, but he was in Brazil.
This is such a bright object that I'm quite surprised no one had
seen it
before. We might well get a report of a prior sighting. Some
amateurs do
archive work. Reiner Stoss, who is in Germany but uses the
Mallorca
observatory, likes to look at old photographic plates to see if
he can
find a previous sighting of a reported new discovery. If he does
that
for this asteroid, and the orbit matches up, the eventual credit
for the
discovery may not go to LINEAR.
Where are most of your amateurs based?
It's very odd, but our most active amateurs are in the UK. It's
surprising because they have inferior skies. Then there are
people in
the southern hemisphere and they really have an advantage because
the
professional surveys don't look there.
You are responsible for evaluating all astronomical observations.
Sounds
like a huge job...
It is. We get a few hundred reports every day, some containing
just one
observation, others several thousand. The LINEAR telescope can
report
over 60,000 observations in one night. Yet we have only three
people
here to process them all. The number of observations has vastly
increased. The first asteroid was logged in 1801, and we reached
10,000
in early 1999. But since then, we've logged another 55,000. The
large
increase is mainly the result of the huge sky surveys for
detecting
near-Earth asteroids.
Many of your colleagues at the centre have been with you for
quite some
time. Do you need a long perspective to do the job well?
Dan Green, who runs the Central Bureau for Astronomical
Telegrams, which
is responsible for reporting on astronomical objects that are not
asteroids, has been here since 1980. My associate Gareth Williams
has
been here 13 years. Yes, you need to understand what has happened
in the
past. So many professional astronomers don't seem to have an
appreciation for anything that happened more than five years ago.
A lot
of the amateurs are in it for a long time. They might do it for a
few
years and then have a family and then go back to it. I certainly
think I
have good successors in Dan and Gareth.
Didn't Gareth marry your daughter?
Yes he did. He came here in 1990, the year my daughter joined the
US
navy, so in the beginning they only met a few times. But she came
back
here two years ago and was living in our basement and they were
both
around and were married last October. We fell behind in orbital
calculations that month.
Copyright 2003, New Scientist
=============
(5) ALIEN INFECTION: WHAT ARE THE RISKS OF SAMPLE RETURN
MISSIONS?
Astrobiology Magazine, 26 August 2003
http://www.astrobio.net/news/article570.html
By Leslie Mullen
When diseases like SARS, Mad Cow Disease and Monkeypox cross the
species
barrier and infect humans, they dominate news headlines. Just
imagine,
then, the reaction if potentially infectious pathogens were found
in
rock samples from Mars.
As we look toward exploring other worlds, and perhaps even
bringing
samples back to Earth for testing, astrobiologists have to
wonder: could
alien pathogens cross the "planet" barrier and wreak
havoc on our world?
Even though there is no proof of bacterial or viral pathogens
anywhere
except Earth, there is already a worried advocacy group called
the
International Committee Against Martian Sample Return, and
science
fiction novels like "The Andromeda Strain" depict
nightmare alien
infection scenarios. The possibility of cross-planetary
contamination
has concerned NASA since the early days of the Apollo program,
so, as a
precaution, the astronauts were quarantined for three weeks after
they
left the moon.
Chris Chyba, who holds the Carl Sagan Chair for the Study of Life
in the
Universe at the SETI Institute, says there are two types of
potential
alien pathogens: toxic and infectious. Toxic pathogens act as a
poison
on other organisms. Infectious pathogens are viruses or bacteria
that
are passed between organisms, causing sickness.
Some viruses and microbes rely on specific biological systems in
order
to replicate and infect their host, so not all pathogens affect
all
organisms the same way. Chicken farmers, for instance, can remain
untouched by a disease that decimates their flocks. It could be
that a
martian microbe would enter the human body, but is rendered
harmless
because it is incompatible with human physiology.
"After living in the dirt of Mars, a pathogen could see our
bodies as a
comparable host; they could treat us 'like dirt,'" says John
Rummel,
NASA's Planetary Protection Officer. "But, to quote Donald
Rumsfeld,
we're dealing with the unknown unknowns. It could be that even if
the
microbes lived inside us, they wouldn't do anything, it would
just be
this lump living inside you."
The conditions on Mars are much different than those in the human
body,
so an inert pathogen seems the most likely scenario -- especially
since
any life on Mars would have evolved without humans being present.
Co-evolution is why some pathogens only affect certain organisms.
Infectious pathogens evolve based on the reactions of their
hosts. As
the host develops defenses against a predatory pathogen, the
pathogen
has to devise new means of sustaining itself within the host (or
risk
its own extinction).
Some toxins also developed through co-evolution. As predatory
organisms
seek food, their prey develop ever more sophisticated means to
escape
being eaten. Many organisms developed specially targeted toxins
as part
of this evolutionary arms battle.
Rummel says that humans have evolved a complex defense system to
prevent
us from getting sick from a whole host of disease and pathogens.
But
non-specific microbes - where human physiology did not influence
their
evolution - may evade our defense mechanisms.
The best way to understand the spread of potential alien
pathogens is to
examine the spread of such non-specific pathogens on Earth.
One example of a non-specific toxic pathogen is cyanobacteria
that
produce hepatotoxins (toxins affecting the liver) and
neurotoxins.
According to Chyba, cyanobacteria living in lakes on the alpine
pastures
of Switzerland have been implicated in a hundred cattle
poisonings over
the past 25 years. Chyba says the cyanobacteria most likely did
not
develop their toxins in order to escape predation from cows (or
to kill
the cows in order to eat them!).
"Rather, the susceptibility of cattle to these toxins seems
simply to be
an unfortunate coincidence of a toxin working across a large
evolutionary distance," Chyba writes.
An example of an infectious pathogen working across large
evolutionary
distances is the bacterium Serratia marcescens. It is found in a
variety
of animal species, and also can be found free-living in water and
soil.
Its transmission from human sewage has resulted in the decimation
of
Caribbean elkhorn coral.
"The distance between humans and corals emphasizes the
possibility that
certain organisms may prove pathogenic across a wide evolutionary
divide," Chyba writes.
Of course, the evolutionary divide between humans and coral would
not be
as wide a gulf as between any martian organisms and human beings.
Yet
one theory for the origin of life on Earth is that it was
transferred
here from Mars by meteorites. This variant of the
"Panspermia" theory
suggests that life on Earth and any life on Mars might be closely
related.
If Mars and Earth share the basis for life, this life would
presumably
have evolved well beyond the original form. Such a large
evolutionary
divide could provide protection from infection. But it could also
mean
that if infection does occur, it might be related closely enough
to some
Earth life to blaze through that population unchecked.
Human infection is not the only concern of planetary protection.
Life on
Earth forms an interconnected, highly dependent web, so a
pathogen
affecting any life on Earth could have serious repercussions for
the
health and environment of our planet.
Protecting the Earth is, of course, an international concern. The
Committee on Space Research (COSPAR) of the International Council
on
Science, through consultation with the United Nations, makes
recommendations to space-faring nations on planetary protection
policy.
The United Nations Outer Space Treaty of 1967 requires that the
introduction of extraterrestrial materials must not adversely
alter the
Earth's environment.
The treaty also says that we must not contaminate other planets
as we
explore outer space. Astrobiologists especially are concerned
about
inadvertently transmitting microbes from Earth. Bacteria can
endure the
cold, dry vacuum of space, so a long journey of months and even
years
may not be sufficient to ensure spacecraft sterilization. Our
search for
life elsewhere will be frustrated if we come across microbes on
another
planet, only to later find that we were the ones who brought them
there.
The previous Mars landers, from Projects Viking and Pathfinder,
were
constructed and handled in clean environments to prevent Earth
microbes
from hitching a ride to the Red Planet. The Mars Exploration
Rovers
"Spirit" and "Opportunity" that currently are
headed for Mars followed
similar "clean handling" guidelines.
The MER missions will not bring samples of Mars back to Earth,
but
future mission proposals do include bringing samples back for
testing.
For instance, one recent Mars scout proposal suggests collecting
atmospheric dust. The spacecraft would fly through the
atmosphere,
collect the dust, and then sterilize the dust as it flies back to
Earth.
This strategy follows the guidelines set by a 1997 US National
Research
Council report, which said sample returns must be either
contained or
sterilized.
"Sterilization might present a problem for some samples, but
it is well
suited to atmospheric dust since you have a dry medium,"
says Rummel.
"Sterilization involves heating, and that wouldn't alter the
dry dust
much."
Fearing that containment or sterilization will not be adequate
for
protecting the Earth from potential pathogens in martian samples,
some
have suggested that the International Space Station (ISS) should
be used
to study samples. But Rummel doesn't agree.
"A lot of time and resources are needed to keep the station
where it is,
but what goes up must eventually come down," says Rummel.
"ISS has an
orbital life of decades, not hundred of thousands of years.
Knowing
that, we need to ask if it is a good place to conduct biological
research."
"Containment is also a problem, since there's not much space
to work
with," Rummel adds. "What do you do if a person on
board is exposed? The
Earth, on the other hand, has ample space to deal with accidents,
or to
build a new lab next door, if necessary."
The only samples that have been returned to Earth so far have
come from
the moon. Astronauts on the Apollo missions returned 379
kilograms (835
pounds) of rock and soil from the Moon, and three Russian
spacecraft
(Luna 16, 20 and 24) also returned moon samples. The samples were
kept
in sealed containers until they arrived at their respective
laboratories
for study.
Some might argue that the precautions of containment or
sterilization
are not necessary, since samples from other celestial bodies have
been
falling on Earth since its origin. Comets and asteroids are
believed to
have impacted the Earth frequently in its earliest years, seeding
the
young planet with water and organic chemicals.
In addition, many meteorites have been identified as originating
from
Mars. A storm of controversy erupted when, in 1996, NASA
researchers
claimed to have found fossilized life forms in the martian
meteorite ALH
84001. Although this claim is still hotly debated, some see it as
evidence that martian microbes already have arrived on our
planet.
"There may indeed be a natural exchange of microbes between
Earth and
Mars," says Rummel. "But we're being cautious, and we
will apply the
appropriate controls. We can't make the risk zero, but we can
make it
very small. That's the reason why space exploration is so
important --
it allows us to start to address the sorts of questions we are
asking."
What's Next
According to Rummel, there are no set plans to bring a Mars
sample back
to Earth. However, some proposals discuss having both the
European Space
Agency and NASA launch martian sample return missions by 2011,
with
samples returning to Earth by 2016.
Sample return missions currently in progress include spacecraft
designed
to sample a comet, an asteroid, and the solar wind. Although life
is not
likely to be found in these places, the precursor chemicals that
make
life possible may be present.
NASA's Stardust mission, launched in 1999, will reach comet Wild
2 in
January 2004. Stardust will return to Earth with both cometary
and
interstellar dust particle samples in January 2006.
NASA's Genesis mission was designed to collect solar wind
samples. The
spacecraft was launched in August of 2001 and is now collecting
particles coming off the sun. The samples will be returned to
Earth in
September 2004.
Japan's MUSES-C spacecraft, launched May 2003, is headed for
asteroid
1998 SF36. After its arrival in June 2005, the spacecraft will
gather up
to one gram of material from a variety of sites on the asteroid.
The
samples are expected to arrive back on Earth by June 2007.
===============
(6) PLANETARY TILT NOT A SPOILER FOR HABITATION
Andrew Yee <ayee@nova.astro.utoronto.ca>
Penn State Erie
Contact:
A'ndrea Elyse Messer, (814) 865-9481, aem1@psu.edu
August 25, 2003
Planetary Tilt Not A Spoiler For Habitation
Erie, Pa. -- In B science fiction movies, a terrible force often
pushes
the Earth off its axis and spells disaster for all life on Earth.
In
reality, life would still be possible on Earth and any Earth-like
planets if the axis tilt were greater than it is now, according
to Penn
State researchers.
"We do not currently have observations of extrasolar
planets, but I
imagine that in the near future, we will uncover some of these
small
planets," says Dr. Darren M. Williams, assistant professor
of physics
and astronomy, Penn State Erie, the Behrend College. "The
issue before
us is what will they be like? Will they have moons? What will
their
climates be like? Will they be teaming with life or will life be
rare?
"I suspect, based on simulations and our own solar system,
that many
Earth-like planets will have spin axes that are tipped more
severely
than Earth's axis."
Williams, working with David Pollard, research associate in
geoscience
at Penn State, used general circulation climate models to
simulate a
variety of tilts, carbon dioxide levels and planets. They
reported on
their findings in the International Journal of Astrobiology.
The researchers first looked at present-day Earth with tilts of
23, 54,
70 and 85 degrees. Earth's tilt today is about 23 degrees. The
simulation that mimicked today's Earth and tilt closely matched
today's
climate, including regional precipitation patterns, snow and ice
cover
and drought.
"Tilts greater than the present produce global annual-mean
temperatures
higher than Earth's present mean temperature of about 57 degrees
Fahrenheit," says Williams. "Above 54 degrees of tilt,
the trend is for
the global annual-mean temperature to decrease as tilt
increases."
The Penn State scientist explains that this decrease occurs
because more
land exists north of the equator in present-day Earth.
Annual-mean
temperatures, however, are not the best way to determine if a
planet
might be habitable, as seasonal temperature variations could be
extreme.
The researchers also looked at these tilted Earths with ten times
the
carbon dioxide in the atmosphere. Carbon dioxide as a greenhouse
gas
increases the temperatures on a planet. These models produced
Earths
with 11 to 18 degrees Fahrenheit higher annual-mean temperatures.
Because all planets will not have Earth's geography, the
researchers
took a page from Earth's history and modeled a
750-million-year-old
Earth representing the Sturtian glaciation and a
540-million-year-old
Earth, the closest approximation available for the Varanger
glaciation.
"During the Sturtian, land masses were mainly equatorial and
clumped
mostly within 30 degrees of the equator," says the Penn
State Erie
researcher. "In the Varanger model, everything is close to
the south
pole."
While current day Earth is about 30 percent land to 70 percent
water,
these ancient geographies are about 22 percent land and 78
percent
water.
"The highest temperatures and seasonal variations happen
with the
largest land areas at the mid to high latitudes," says
Williams.
The researchers also ran some of the model Earths with zero tilt.
"Present Earth is one of the most uninhabitable planets that
we have
simulated," says Williams. "Approximately 8.7 percent
of the Earth's
surface is colder than 14 degrees Fahrenheit on average, and this
percentage peaks at 13.2 percent in February owing to the large
landmasses at high latitude covered by snow."
The only planets colder than today's Earth are those planets
simulated
with no tilt.
The Varanger simulation, with most land in the southern
hemisphere, is
the most extreme with 15.6 percent of the surface below 14
degrees
Fahrenheit in July and 9.3 percent of the surface above 122
degrees
Fahrenheit in January. On average, nearly 28 percent of this
planet's
land mass is uninhabitable by Earth standards.
"This simulation suggests that planets with either large
polar
supercontinents or small inventories of water will be the most
problematic for life at high obliquity," says Williams.
None of the planets with increased tilt had permanent ice sheets
near
the equator. This, however, does not guarantee that a world is
suitable
for life, the researchers note. The extremes of temperature on
most of
the simulated earths would make it difficult for all but the
simplest
Earth life forms to survive. Extremes caused because the tilt
puts large
portions of the planet in 24-hour darkness or 24-hour sunlight
for long
periods would also inhibit photosynthetic organisms.
The researchers suggest that even with high tilt, life can exist
on the
planets they modeled.
"Provided the life does not occupy continental surfaces
plagued
seasonally by the highest temperature, these planets could
support more
advanced life," the researchers say. "While such worlds
exhibit climates
that are very different from Earth's, many will still be suitable
for
both simple and advanced forms of water-dependent life."
So there is no reason to eliminate Earth-like planets with more
tilt
than Earth from future searches for life beyond the solar system.
"We have one planet and we have a lot of species on this
planet, but it
is only one data point," says Williams. "Maybe one day
we will figure
out everything about life on our own planet, but no where near
what is
possible elsewhere."
The National Science Foundation supported this work.
The International Journal of Astrobiology, founded in 2002, is
published
by Cambridge University Press. The editors are Dr. Simonj Mitton
(Cambridge), smitton@cambridge.org
and Dr. Lynn Rothschild (NASA-Ames),
Irothschild@mail.arc.nasa.gov
.
**aem**
EDITORS: Dr. Williams may be reached at 814-898-6008 or at
dmw145@psu.edu by
email. Dr. Pollard may be reached at 814-865-2022 or at
pollard@essc.psu.edu by
email.
============= LETTERS =============
(7) ASTEROID DOUGLASADAMS?
Alan Boyle <alan.boyle@msnbc.com>
Dear Benny:
In response to a Cosmic Log column last week, a reader (later
identifying himself as Sean Ferris) suggested that a minor planet
should
be named after Douglas Adams of "Hitchhiker's Guide"
fame, and so far
the response to the idea has been favorable. I thought a fitting
asteroid would be 2001 DA42, a designation that contains the year
of
Adams' untimely death, his initials and 42, the answer to the
Ultimate
Question of Life, the Universe and Everything. I wondered if it
would be
appropriate to put this question (about the asteroid, not the
UQLU&E) to
the CCNet community.
Here's the item in http://www.msnbc.com/news/750150.asp
that contains
the suggestion:
NAME AN ASTEROID: How does Asteroid Jesus strike you? Or Asteroid
Coyote
Thunder? Or Trusco Camu-Camu? These are just some of the
suggestions
sent in by Cosmic Log readers responding to Thursday's item about
the
system for naming minor planets.
Some nominated their own names or the names of relatives, which
would be
a no-no under the International Astronomical Union's guidelines.
To my
mind, the top prospect is Douglasadams, a name that would honor
the late
author of "Hitchhiker's Guide to the Galaxy." And I
think I've found the
perfect asteroid.
Admittedly, it wouldn't be the first minor-planet tribute to
Adams'
work. Oh, sure, there's an asteroid named Adams, but that
actually
honors 19th-century astronomer J.C. Adams. The best tribute to
Douglas
Adams so far came just before his death in 2001, when the Minor
Planet
Center announced that an asteroid was being named after Arthur
Dent, the
lead character in "The Hitchhiker's Guide."
A Cosmic Log reader writing under the nom de plume Anarchy Ape
thinks
it's time to honor Adams in his own right: "He was an
adamant supporter
of the space program and should be honored," says Ape.
In addition to his seriousness about space exploration, Adams
also
brought a touch of mind-twisting whimsy to his writings: I
particularly
like the idea that the answer to the ultimate question is
well-known -
42 - and that it's the "question to the ultimate
answer" that's the
killer.
Thus, if I were in charge of naming minor planets, I would go
with a
rock in the main asteroid belt currently known as 2001 DA42,
discovered
by the LINEAR program. Its numerical designation incorporates the
year
of Adams' death, his initials and the number 42 to boot.
The name isn't up to me, of course: Rather, that's something that
the
folks at LINEAR and the IAU will have to decide. But if there's
not
already a Douglasadams in the works, I think 2001 DA42 would be
the
perfect candidate.
--- Best, Alan Boyle, MSNBC
=============
(8) PLANETARY DEFENSE STUDIO @ USC FALL 2003
Andrew Ball <a.j.ball@open.ac.uk>
Benny,
Input for CCNET?
Best wishes,
Andrew.
-------------
Subject: Planetary Defense Studio @ USC Fall 2003
From: "thangavelu-girardey" <thangavelu-girardey@cox.net>
Date: Sun, 10 Aug 2003 23:28:17 -0700
Greetings ISUers !
Guess what we have in store for this fall at the University of
Southern
California in sunny (not baking yet!) southern Cal ? System
Architectures for Planetary Defense. Read on.......
Cataclysmic events, triggered by mechanisms both internal to
planet
Earth and extraterrestrial, continue to shape life on Earth. This
course
will look at extraterrestrial processes involved such as cometary
and
asteroidal impacts and their effects and examine potential
resonant
mechanisms and create innovative space system concepts for
mitigation of
such a threat. Class will study :
Recent research and evidence of cratering on Earth.
-Effects of Impact
-Alternative space and ground segment architectures for threat
mitigation will include :
-Survey and Detection
-Threat Assessment
-Avoidance, Mitigation and Neutralization
-Damage Control and Recovery
-Post-Event, Long Term Adaptation Strategies
Participants will propose their alternative system architecture
concepts
ideas to a panel of experts at midterm and they will work on a
team
project that will then be presented to a panel of experts for
final
review and feedback.
Please call Marietta in the AME Dept @ 213 740 5353 for more
details. Of
course, I would be happy to answer any questions re. course as
well.
Madhu Thangavelu
310 378 6259
===============
(9) NATIONAL ASTRONOMY WEEK DEBATE: IS THERE LIFE ON MARS?
Theresa Cooper <theresa@theresac.demon.co.uk>
Benny,
please could you advertise the following debate arranged as part
of
Cardiff Astronomical Society's celebration of National Astronomy
Week.
Details attached, its free and all are welcome.
NATIONAL ASTRONOMY WEEK AUGUST 23 - 30 2003
Joint Patrons:
Professor Sir Martin Rees (Astronomer Royal)
Professor Sir Arnold Wolfendale
Professor John Brown (Astronomer Royal for Scotland)
National Astronomy Week aims to raise the profile of astronomy
and space
science within the UK. It gives the opportunity for every
astronomical
and scientific organisation, amateur or professional to combine
in
providing events and observing sessions. The focus of the week is
the
planet Mars to coincide with its closest approach to the Earth
for 6 000
years and to capitalise on the expected media coverage this will
receive.
Saturday August 30th 2.30 pm. National Museum and
Gallery Cardiff
This will be a free event and open to the public.
A debate entitled:
Is There Life on Mars? The Case For and Against.
This will be presented by Professor Mike Edmunds, Head of the
Department
of Physics and Astronomy, Cardiff University and Vice President
of
Cardiff Astronomical Society and
Dr Jonathan Davies, Department of Physics and Astronomy, Cardiff
University
This will last approximately 1 hour and the audience will be
invited to
vote on the evidence presented.
Any further information (maps etc.) is at
http://cardiff-astronomical-society.org
Many thanks
Theresa Cooper
==============
(10) AND FINALLY: MARS, NOT ISLAMIC TERRORISTS, TO BLAME FOR
BOMBAY
BLAST ASTROLOGERS CLAIM
AFP, 26 August 2003
http://story.news.yahoo.com/news?tmpl=story&u=/afp/20030826/od_afp/india_attacks_offbeat_030826125131
NEW DELHI (AFP) - While Indian authorities blamed Islamic
militants*
[*media euphemism for terrorists] for car bombings in Bombay that
killed
52 people, astrologers are convinced the culprit was Mars, which
is
dangerously close (sic) to Earth.
Astrologers believe the current positions of the moon, Mars,
Saturn and
Rahu -- an imaginary malefic planet in the horoscope -- bode ill
for the
near future, with the Indian government due to make wrong
decisions and
the public responding violently.
Astrologer R.L. Kanthan told The Times of India that the spell of
misfortune will not ease until September 20 with the movement of
Mars,
the planet that "portends violence, wars, bloodshed and
combat".
Satish Sharma, another astrologer, saw Thursday as a day of arson
and
rioting, as the Earth, Mars and the sun would be all in one line.
He said another example of the impending chaos was the political
turmoil
in India's most populous state Uttar Pradesh, whose leader,
Mayawati,
quit Tuesday.
Sharma noted that the symbol of Mayawati's party was the elephant
--
associated with Rahu.
"Rahu is traditionally associated with fire and sudden
explosions,"
added fellow astrologer Mahendra Mishra.
He was more pessimistic than his colleagues, saying the current
danger
would not be over until Mars enters Pisces on December 6 --
coincidentally the anniversary of the 1992 razing of a mosque in
Ayodhya
by Hindu fanatics which set off India's deadliest riots since
independence.
At least 52 people were killed and 150 injured Monday in bombings
outside the landmark Gateway of India monument and in a busy
market near
a Hindu temple.
Officials have blamed the attacks on local Islamic militants
working
with Lashkar-e-Taiba, an extremist group founded in Pakistan but
banned
there last year.
Copyright 2003, AFP
-----------
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