CCNet 39/2002 - 22 March 2002

"Modest doubt is called the beacon of the wise"
--William Shakespeare, Troilus and Cressida

"An unusually warm period a millennium ago may have been part of a
natural planetary cycle, researchers say in a study of tree rings
that scrutinizes the link between human activity and climate change.
The study, appearing Friday in the journal Science, analyzed ancient tree
rings from 14 sites on three continents in the northern hemisphere and
concluded that temperatures in an era known as the Medieval Warm Period
some 800 to 1,000 years ago closely matched the warming trend of the
20th century."
--Paul Recer, Associated Press, 21 March 2002

"Simply put, objects the size of the Tunguska impactor pass within
the distance that 2002 EM7 did about 25 times every year."
--Jim Scotti, Spacewatch, University of Arizona

    Associated Press, 21 March 2002

    Fox News, 21 March 2002

    Sky & Telescope, 20 March 2002

    Ron Baalke <>

    Andrew Yee <>

    Richard Taylor <>

    Hermann Burchard <>

(8) ASTEROID 2002 EM7
    Andy Nimmo <>

    Andy Smith <>

(10) RE: SETTLING THE GALAXY (CCNet 38/2002)
     Stephen Ashworth <>

     John Michael <>
     2002 EM7 FALL-OUT:

     Sky & Telescope, 21 March 2002


     Billingsgazette, 21 March 2002

     Stuttgarter Zeitung, 21 March 2002



>From Associated Press, 21 March 2002

By PAUL RECER, AP Science Writer

WASHINGTON - An unusually warm period a millennium ago may have been part of
a natural planetary cycle, researchers say in a study of tree rings that
scrutinizes the link between human activity and climate change.

The study, appearing Friday in the journal Science, analyzed ancient tree
rings from 14 sites on three continents in the northern hemisphere and
concluded that temperatures in an era known as the Medieval Warm Period some
800 to 1,000 years ago closely matched the warming trend of the 20th

In recent years, many climate scientists have said an unprecedented warming
spell that began last century and continues is caused by the Greenhouse
effect. The Greenhouse effect is blamed on an increase in the atmosphere of
gases, principally carbon dioxide, from the burning of fossil fuels, which
trap heat just as do glass panes in a greenhouse.

The tree-ring study gives another perspective on Earth's natural cycles,
said Edward Cook of the Lamont-Doherty Earth Observatory in Palisades, N.Y.
Cook is co-author of the study with Jan Esper and Fritz Schweingruber of the
Swiss Federal Research Institute.

Cook said the study shows the Earth to be "capable of rapid changes and long
periods of above average warmth on its own without greenhouse warming.

"We don't use this as a refutation of greenhouse warming," said Cook. "But
it does show that there are processes within the Earth's natural climate
system that produce large changes that might be viewed as comparable to what
we have seen in the 20th century."

Cook said the study found that, based on the growth of rings in the trunks
of trees that lived hundreds of years ago, the temperatures during the
Medieval Warm Period were about equal to the warming trend that started in
the 20th century.

"Greenhouse gases were not a factor back in the Medieval Warm Period," said

The Intergovernmental Panel on Climate Change, an international group, has
predicted that the current warming trend will continue deep into the 21st
century, with average temperatures rising by 2.5 and 10 degrees. Based on
this prediction, there have been international proposals for systematic
reductions in the burning of fossil fuels. The proposal has been resisted by
the United States, particularly the Bush administration.

Cook said data used in the climate change panel's calculation is based on a
model that compared the preindustral age climate with the climate of the
20th century. The model did not include a Medieval Warm Period. Including
data from that era could change the calculations, Cook said.

"The Medieval Warm Period is in some sense comparable up to 1990 in the 20th
century," said Cook. "But that does not say that the 20th century hasn't
been perturbed by greenhouse gases. The real challenge is to factor out the
natural variability from" manmade causes of global warming (news - web

Cook said the panel's temperature warming prediction could be correct. Based
on the new tree-ring data, however, he said the warming could be in the
lower part of the temperature range forecast by the group.

Keith Briffa and Timothy Osborn, climate scientists at the University of
East Anglia in Britain, said the study by Cook and his colleagues "provides
evidence for greater climate swings in the last 1,000 years than has yet
been generally accepted."

In a commentary in Science, Briffa and Osborn said a need exists for more
such independent studies to refine predictions for global warming in this

Copyright © 2002 The Associated Press.
for deatils see:
Blowing hot and cold

Low Frequency Signals in long Tree-Ring Chronologies for Reconstructing Past
Temperature Variability


>From Fox News, 21 March 2002,2933,48456,00.html
By Rand Simberg

We had another (cosmologically speaking) close call the other day: A piece
of cosmic debris passed within half a million kilometers of the planet, a
little farther than the distance to the moon.

It was previously uncatalogued and approached us from the direction of the
sun -- our blind side.

If it had hit, it would have been at least as devastating as the Tunguska
explosion in Siberia early last century, in which trees were leveled for
miles around. Such a strike in a populated area could kill thousands, or

Current estimates of the probability of such an event are one in 10 million.
I've previously discussed the desirability of at least doing a good sky
survey to get a handle on the problem, but I'd like to talk again about a
different aspect of it.

Suppose that after multiplying the probability times the potential damage
and getting some kind of expected value of avoidance we do decide that this
is a problem to which we should devote societal resources. Who should take
care of the problem?

Many would reflexively say NASA, just because (unfortunately) NASA remains
synonymous with space in many people's minds (though I'm working daily and
weekly to change that perception). But NASA is an agency set up for
research, development and science -- not deflecting wayward space rocks.

Well, it's a threat, so maybe we should put the Pentagon in charge. This
actually makes sense, until you think about the problem a little more. If we
were being attacked by ET or Marvin the Martian or his Martian buddies, then
sure, let's send the Space Patrol up there to kick some scrawny Martian

But this is a natural phenomenon, not a smite from heaven at the behest of
some malign intelligence (at least as far as we know). It's more like a
forest fire, or a tsunami, or an earthquake or a ... flood.

A flood - yeah, that's the ticket.

It's basically just a problem of managing the whims of nature, and to the
limited degree that we are capable of doing that we have an agency in charge
of such things. They build dams and levees and take preventive measures
against future disastrous natural events. They're called the Army Corps of

In addition to the fact that it seems like a natural (so to speak) role for
them, the other thing that I like about the idea of using the ACE is that
they could take fresh approaches - they wouldn't be bound by the
institutional inertia of NASA and the Air Force Space Command in how they'd
tackle the problem.

They'd have to take new approaches, because it would require different
capabilities than any other space activity to date - moving minor planets.
And the technology that allows us to divert asteroids to prevent them from
pulverizing the neighborhood is the same technology that will allow us to
utilize many of the abundant resources available in the solar system.

Finally, it would set up some competition in government space activities,
which is sorely needed, and best of all, it might give them something else
to do so they won't have time to build any more of those dam ... err ...
darn dams.

I should also note that science Weblogger Jay Manifold has a nice report
direct from the Lunar and Planetary Science Conference with the latest
thoughts of planetary researchers on the subject....

Copyright © 2002 Fox News Network, LLC 2002.


>From Sky & Telescope, 20 March 2002

By Edwin L. Aguirre

March 20, 2002 | In the seven weeks since the discovery of Comet
Ikeya-Zhang, two more comets have been discovered visually by amateur
astronomers. While neither is expected to rival Ikeya-Zhang's brightness
this spring, these new finds show that the era of backyard comet hunting is
far from over.

The first of the new comets was bagged on March 11th. Douglas Snyder swept
up the faint object in Aquila while scanning the predawn skies with a
20-inch f/5 Dobsonian telescope at his backyard observatory in Palominas,
Arizona. Seven hours later, as dawn approached Japan, Shigeki Murakami in
Matsunoyama, Niigata Prefecture, picked up the interloper with his 18-inch
f/4.5 reflector. Designated Comet Snyder-Murakami, C/2002 E2, the object is
currently visible in medium-size telescopes as a 10th-magnitude glow moving
north-northeast in the morning sky, from Aquila to Sagitta and then to

"This is such a rare and rewarding event," says Snyder, "and I'm still so
overwhelmed at my luck in finding it."

Orbital calculations by Brian G. Marsden (Central Bureau for Astronomical
Telegrams) show that C/2002 E2 reached the point in its orbit closest to the
Sun (perihelion) last February 21st, at a distance of 220 million
kilometers. Although it is moving farther away from the Sun, the comet
should remain around 10th magnitude until early April, after which it will
slowly begin to fade. Amateur CCD imagers should be able to keep track of it
throughout spring and beyond.

The last time a comet was discovered visually in the United States was on
April 22, 1998, when Patrick L. Stonehouse of Wolverine, Michigan,
discovered C/1998 H1 with a 17½-inch reflector.

Just one week after the Snyder-Murakami find, in the early morning twilight
of March 18th, Japanese observer Syogo Utsunomiya discovered another comet.
Experts have yet to calculate the orbit of the new object (dubbed C/2002
F1), but for the past couple of days, the fuzzy ball has shone at 11th
magnitude in Pegasus.

Copyright 2002 Sky Publishing Corp.


>From Ron Baalke <>

The Comet Hunter
The Associated Press
March 21, 2002

MORI, Japan - The homemade telescope in Kaoru Ikeya's front yard isn't much
to marvel at. It's painted flat black, has half a pair of binoculars for its
makeshift finder, and looks its age of 25 years.

"I don't have a lot of money to put into my equipment," Ikeya said. "But it
does the job."

Last month, Ikeya discovered his sixth comet, a cosmic wanderer making its
first return to this part of the solar system in about 340 years. But in an
age when most comets are found by professionals using multimillion dollar
equipment, the days of discovery for amateur star buffs such as Ikeya may be

It's been more than 34 years since his last comet discovery, however.

Full story here:


>From Andrew Yee <>

ESA Science News

20 Mar 2002

Rosetta Runs Hot and Cold

Like a hardy mariner preparing for a marathon journey from the tropical
shores of Brazil to the icy waters of Cape Horn, the mettle of ESA's Rosetta
spacecraft has been tested to the limit in recent weeks.

After being alternately baked and frozen in a large thermal vacuum chamber
at the European Space Technology and Research Centre (ESTEC) in Noordwijk,
The Netherlands, Europe's comet chaser has come through with flying colours.

Imprisoned in the giant, airless chamber, the Rosetta orbiter, its Lander
and their complement of 20 scientific instruments were exposed to the
conditions of extreme heat and cold that they will experience during their
10-year, 5 billion kilometre mission to Comet Wirtanen.

In order to simulate the warmth of the inner Solar System, the exterior of
the spacecraft was heated to a sizzling 150 C. During subsequent tests, the
temperature was allowed to plummet to minus 180 C. Sensors indicated that
the spacecraft's insulation and heat control systems enabled Rosetta to
survive these thermal tortures in fine shape, with internal temperatures
restricted to between 50 C and minus 20 C.

"These tests show that Rosetta can survive the tremendous temperature
contrasts it will endure as it flies from the vicinity of the Sun to the
orbit of Jupiter," said John Ellwood, Rosetta Project Manager. "This gives
us great confidence that the spacecraft will be able to survive its long
exposure to the harsh environment of space."

Rosetta's punishing pre-launch programme is not over. Later this week it
will be prepared for the next set of environmental tests. Once the high-gain
antenna and huge solar arrays are mounted in early April, the spacecraft
will be moved into an acoustic and then vibration chambers where it will be
mercilessly shaken in order to check whether it can survive the stresses of
a rocket launch.

These intensive trials will play a vital role in ensuring the success of
Rosetta's unique mission to unravel the mysteries of Comet Wirtanen.

During its 10-year, 5 billion kilometre mission of exploration, Rosetta will
travel from the benign environment of near-Earth space to the dark, frigid
regions beyond the asteroid belt. During three circuits of the Solar System,
the amount of light and heat radiation reaching Rosetta will vary by as much
as 25 times.


* Rosetta home page
* Rosetta arrives at ESTEC (movie)
* Rosetta spacecraft design

Rosetta in the ESTEC thermal vaccum chamber.

[Image 1: ]
[Image 2: ]
[Image 3: ]
[Image 4: ]
[Image 5: ]



>From Richard Taylor <>

Probability Research Group and

Dear Benny

In his recent message to CCNet James Marusek  makes the point that to date
much of the discussion regarding the asteroid impact threat has been focused
on detection and impact prevention/deflection. He suggests that there is
another aspect that he thinks has been almost completely overlooked and
which requires a paradigm shift in both our thinking and actions. He says
that this third element is how to survive a meteor impact, and draws
attention to his website where he
sets out a general survival plan for a large comet or meteor impact.

While I do not agree that the matter of post-impact environmental and
ecological restoration have been completely overlooked it is broadly true
that little in the way of in depth scientific studies have been done for
more than a small part of the wide range of possible types of disaster
impacts, and their secondary consequences, can produce. James Marusek  has
put a great deal of thought and work into his site and what it contains
could stimulate interest in researching a range of local and semi-global to
fully global restoration strategies.

He suggests that: "Mankind has the intellect, resourcefulness and adaptability to succeed where
the dinosaurs could not.  A large meteor impact is only the end of the world
if we let it be. So why should the Australian government reactivate their asteroid detection
program?  Because even though we may not be able "to stop them" today, we
are able to survive the impact"

However, together with some of my colleagues who have looked at some of the
restoration survival options, I consider that James seriously underestimates
the lethality of an event of the size he considers and similarly
overestimates environmental and human resilience and speed of recovery. An
impact of the scale he cites would almost certainly be the end of  >50% of
Earth's >50 kg species and there is very little, most would say no, chance
that humans and civilization could pull through. Nevertheless, he has drawn
attention most effectively to an important and neglected aspect of impact
mitigation. More of us should think through the possible post-impact
scenarios and their possible restoration outcomes. Those interested in this
area should certainly take a look at James Marusek's site. At some point of
the scale of impact events some of his suggestions certainly would begin to
have relevance.


Richard Taylor


>From Hermann Burchard <>

Dear Benny,

while several contributors on CCNet seemed to imply that asteroid 2002 EM7
could not have been detected in advance (appearing from the direction of the
Sun initially), you provided welcome clarification when you remarked (as
quoted by MSNBC, CCNet, 3/20/02) "within the next 20-some
years we will have satellite-based search programs that will be able to
detect objects that come out of the blue."

Indeed, even with present-day equipment, NEOs approaching from close to the
Sun, such as daytime meteor showers, can be detected, and have been in the
past [e.g., Duncan Steel, "Rogue Asteroids..", page 118], so I find these
statements that it can't be done puzzling and misleading.

Best NEO regards,

(8) ASTEROID 2002 EM7
>From Andy Nimmo <>

Dear Dr Peiser,

The lesson of Asteroid 2002 EM7 must be that it is time the Governments of
Europe and the US gave ESA & NASA some extra funding to place robot
observers in the Earth/Sun L4 and L5 points. That way the blind spot would
cease to be blind, as from these positions anything coming from our Sun
directly towards Earth would be clearly visible.

This has been pointed out several times in the past, but nothing has been
done about it. It is not something that would be all that difficult to do,
nor all that expensive when one considers the potential losses of not doing
it, so we ought not waste any more time. A joint ESA-NASA project along
those lines should be set up without further delay.

Best wishes, Andy Nimmo (SDC Secretary).


>From Andy Smith <>

Hello Benny and CCNet,

We are having a very productive few days of NEO technical interchange at
this conference, which is being sponsored, in cooperation with the American
Society of Civil Engineers. There are now three engineering and
engineering/public societies carrying NEO sessions, on a regular basis
(AIAA, National Space Society and the ASCE) and we continue to promote this
as an effective way to inform the technical communities and the

As you know, we are approaching the asteroid/comet threat as an
international emergency situation and we are pressing to get larger
telescopes involved in the critical NEO hunt and to get space system design
organizations to participate in an effort to reduce the global emergency
(NEO defense)response time, as much as possible (we call this Project Quick
Draw). Finally, we are studying ways to enhance civil emergency preparedness
(special emphasis on emergency food production, under low-light and
temperature conditions).

The Hunt...Good News

LINEAR is leading the charge (about 70% of the 2002 NEO discoveries) and we
are heading toward another record year (700 or more). NEAT is also making a
major contribution (in the 10% range) and the entire world effort is
impressive. We especially welcome CATALINA back.

Japan may soon be making a significant input. Last year, we suggested that a
good near-term goal would be 1,000 new NEO per year....and with luck, we
will not be far from that.  Three-cheers for the Humans.

Unfortunately, we cannot find most of the NEO population-of-concern, without the help of larger
telescopes/CCD. We hope the 8 meter Dark-Matter Telescope gets a green light
(funding) and we are trying to find other ways to get a few more large systems into the mix
(perhaps as upgrades to existing sites). There are some new materials and
designs possible, which could help and we should be able to provide some
numbers and design options, soon.

We are also making progress in our search for low-light/temperature crops
and we are looking at genetic engineering options and doing some agricultural work in caves.

In closing, we want to thank all of the countries and individuals who are
helping in this impressive global volunteer activity. Now is the time to
study the NEO dangers, complete the critical NEO inventory and develop
defensive options and emergency preparedness possibilities.  Let's pray that
we will have the time we need, to prepare.


Andy Smith

(10) RE: SETTLING THE GALAXY (CCNet 38/2002)

>From Stephen Ashworth <>

Dear Dr Peiser,

Ellen Barry's Boston Globe article on interstellar spaceflight (CCNet
38/2002 - 20 March 2002, item 12) betrays the common unspoken assumption
that an interstellar spacecraft could be launched by a basically terrestrial
civilisation.  On the contrary, the power and reliability requirements of
such a project would be as far beyond the capabilities of a single planet as
a trip to the Moon would have been for the Vikings.

If an interstellar spacecraft is one day built, it will therefore
necessarily be done by an interplanetary civilisation having unrestricted
access to, say, solar energy, asteroidal construction materials and helium-3
from the gas giant planets.

The existence of such a civilisation presupposes a large population already
living permanently off the Earth in artificial habitats. It therefore
presupposes that the problems of "life confined within a space capsule"
would have been long solved by societies domiciled on the Moon and Mars, on
bases on the asteroids and the moons of the outer planets and in free-flying

Incidentally, Ms Barry reports that NASA engineers are conceptualizing
rocket technology that would shorten the journey-time to the Alpha Centauri
system to "several centuries".  This should be compared with the fact that
in 1978 the British Interplanetary Society published a detailed technical
conceptualisation of a rocket, named Daedalus, designed to make the crossing
to Barnard's star on a fly-by mission within 50 years of launch, a
capability which translates to a 70-year trip to Alpha Centauri, allowing
for deceleration at the destination.  (The propulsion system chosen was
powered by the nuclear fusion of deuterium with helium-3 mined from the
atmosphere of Jupiter, giving an exhaust velocity of 10,000 km/s.)

Of course we cannot say what the maximum human lifespan might be when such
voyages first become possible, but it seems unlikely that it would be as
short as it is today.

Yours sincerely,

Stephen Ashworth
Oxford, UK
20 March 2002

>From John Michael <>
Dear Benny,

Whilst researching the origins of the Red Dragon symbol on the flag of Wales
I decided to look again at the English translation of the Welsh name for the
Red Dragon.

In the ancient Welsh language it is known as 'Draig Goch' - (Red Dragon),
from 'draig' - (dragon) and 'goch' - (red). But in "Y Geiriadur Cymraeg
Prifysgol Cymru", the "University of Wales Welsh Dictionary", (Cardiff,
University of Wales Press, 1967, p. 1082) there are given translations for
the various uses of the Welsh word 'draig'.

Amongst them are common uses of the word, which today is generally taken
just to mean a 'dragon', but in times past it has also been used to refer

'Mellt Distaw' - (sheet lightning)

and also

'Mellt Didaranau' - (lightning unaccompanied by thunder).

According to this authoritative dictionary the most interesting common usage
of the word 'draig' in earlier times was to refer to:

'Maen Mellt' - the word used to describe a 'meteorite'.

And this makes perfect sense, as the Welsh word 'maen' translates as
'stone', while the Welsh word 'mellt' translates as 'lightning' - so
literally a 'lightning-stone'.

John Michael

2002 EM7 FALL-OUT:


>From Sky & Telescope, 21 March 2002

By Stuart J. Goldman

March 21, 2002 | Billed as the "blind-spot" asteroid, a building-size space
rock passed the Earth unnoticed two weeks ago. An automated sky survey
detected minor planet 2002 EM7 on March 12th. Subsequent orbital
calculations determined that the asteroid had come closest to the Earth four
days earlier at a distance of about 464,000 kilometers (288,000 miles),
slightly more than the distance from the Earth to the Moon. Prior to the
flyby, 2002 EM7 was too close to the Sun, hence the "blind-spot" moniker.

When the close call was made public, it raised considerable concern.
Researchers estimated the object to be about 50 to 70 meters across, thought
to be a little smaller than the object that exploded over the Tunguska River
region of Siberia in 1908 and flattened thousands of square kilometers of
forest. A Tunguska explosion over a populated area would undoubtedly cause
incredible damage.

Despite the media attention in the wake of 2002 EM7's passage, such "close"
flybys are not uncommon. According to Jim Scotti (University of Arizona),
"Simply put, objects the size of the Tunguska impactor pass within the
distance that 2002 EM7 did about 25 times every year." Rocks the size of
2002 EM7 come by nearly 100 times a year. This particular instance grabbed
headlines because the minor planet was actually observed. Scotti explains
that astronomers cannot fully tally asteroids about 50 m in diameter using
today's survey techniques, regardless of whether the objects are moving from
the direction of the Sun or not. Alas, this is of little solace to people
worried about space-borne threats.

Copyright 2002 Sky Publishing Corp.


>From, 20 March 2002

Earth's close call with an asteroid catches astronomers by surprise.

by Vanessa Thomas

On Friday, March 8, an asteroid slipped past Earth completely unnoticed -
missed even by astronomers on the watch for nearby asteroids. At the time,
the interplanetary interloper was coming at us from the direction of the sun
and was masked by the glare. Not until March 12 - four days after the
near-miss - did astronomers from the Lincoln Near Earth Asteroid Research
(LINEAR) program first spot the intruding asteroid and realize our planet's
close call.

At its closest, the near-Earth asteroid now known as 2002 EM7 flew a mere
289,000 miles (465,100 kilometers) from our planet. That's just 1.2 times
farther from us than our moon.

Without knowing more about 200 EM7, specifically how much light it reflects,
astronomers have a hard time estimating the newfound object's size. Assuming
it has an albedo typical for near-Earth asteroids, scientists at the Jet
Propulsion Laboratory guess that the recent visitor is about 50 meters (164
feet) wide.

Although 2002 EM7 "is not terribly big" says Brian Marsden of the Minor
Planet Center in Massachusetts, "only one larger object is known to have
come closer." That was 720-foot-wide (220-meter-wide) asteroid 1996 JA1,
which passed just 281,000 miles (453,000 km) from our planet on May 19,

>From a few dozen observations of 2002 EM7 obtained since its discovery last
week, astronomers calculate that 2002 EM7 won't come so close to Earth again
anytime this century. However, a more intimidating encounter looms on the
not-too-distant horizon. On August 7, 2027, a kilometer-sized asteroid
called 1999 AN10 will zoom about 242,000 miles (389,000 km) overhead. Soon
after its discovery, astronomers worried that 1999 AN10 might hit Earth in
2039 or 2044, but a pre-discovery image of the asteroid from 1955 helped
improve its orbit and put those fears to rest.

While larger objects like 1999 AN10 pose a greater threat to life as we know
it, it's the objects like 2002 EM7 that should have astronomers worried,
Marsden believes. "The smaller ones are more dangerous," he says, because
they're fainter and not likely to be found until they are very close to
Earth. There's also a lesser chance of small asteroids showing up in older,
archived images, which otherwise could help us predict whether a collision
is in our future.

Marsden thinks we can improve our odds by devoting more time to asteroid
searches, not only for large objects but smaller ones as well. The more we
search, he says, the better chance we have "to find something before it
finds us."

Copyright © 1996-2002 Kalmbach Publishing Co. 


>From  Billingsgazette, 21 March 2002

MELBOURNE, Fla. (AP) - An asteroid large enough to demolish a city the size
of Orlando passed within 288,000 miles of Earth without being noticed by
astronomers until four days later.

The asteroid, about 165 feet across, came from the direction of the sun,
making it difficult for astronomers to spot. It passed by Earth on March 8,
but wasn't seen until March 12 as it hurtled away.

Gareth Williams of the International Astronomical Union's Minor Planet
Center in Cambridge, Mass., helped spot the asteroid after it passed by. It
was a close call in space terms. The moon is only 250,000 miles away.

"The key is to detect these objects before they come out of the (sun's
direction)," Williams said.

That way, astronomers can quickly determine an asteroid's orbit and predict
whether it will hit the Earth.

A similar-sized object flattened a 20-mile-wide patch of Siberian forest in

Copyright 2002 Associated Press.


>From Stuttgarter Zeitung, 21 March 2002
Kosmisches Geschoss hätte größere Stadt zerstören können
Washington - Vollkommen unbemerkt ist ein Asteroid an der Erde vorbei gerast
und erst Tage später von Astronomen entdeckt worden. Nach US-Medienberichten
passierte der 50 bis 100 Meter große Brocken mit der Bezeichnung 2002EM7 die
Erde bereits am 8. März in etwa 480 000 Kilometern Entfernung, das
entspricht der 1,2fachen Distanz von Erde und Mond. Da er aber aus Richtung
der Sonne kam, blieb er im gleißenden Licht unbemerkt. Erst am 12. März
wurde das kosmische Geschoss von einem Asteroiden-Teleskop des Massachusetts
Institute of Technology registriert, und die Wissenschaftler konnten seine
Flugbahn und damit auch den Weg berechnen, den es genommen hatte.

Der Asteroid sei groß genug gewesen, eine größere Stadt auf der Erde zu
zerstören, erläuterte der Astronom Gareth Williams aus Boston. Dennoch sei
2002EM7 zu klein, um als potenziell gefährlicher Asteroid klassifiziert zu
werden, berichtete das britische Wissenschaftsmagazin "New Scientist" im
Internet. Dem Astronomen Brian Marsden vom Harvard-Smithsonian Center für
Astrophysik zufolge sei es eine der zehn dichtesten Begegnungen mit einem
Kleinstplaneten gewesen, nur einer dieser Brocken sei größer gewesen.
2002EM7 mit einer Umlaufzeit von 323 Tagen werde in den kommenden 100 Jahren
mehrmals der Erde nahe kommen. Die Gefahr eines Einschlags bewege sich
Marsden zufolge jedoch lediglich zwischen eins zu sechs Millionen und eins
zu einer Milliarde.

Copyright 2002, Stuttgarter Zeitung

(16) ASTEROID RISK SPOTTED TOO LATE,5744,3991827%255E401,00.html

Ninguém deu pelo asteróide

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