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(meteorobs) Excerpts from "CCNet 11/2001 - 24 January 2001"
------- Forwarded Message
From: Peiser Benny <B.J.Peiser@livjm.acdot uk>
To: cambridge-conference <cambridge-conference@livjm.acdot uk>
Subject: CCNet, 24 January 2001
Date: Wed, 24 Jan 2001 13:23:51 -0000
CCNet 11/2001 - 24 January 2001
------------------------------
(1) JAPANESE TEAM FINDS 3,544 METEORITES
Ron Baalke <baalke@jpl.nasadot gov>
[...]
(3) NEAR SHOEMAKER CLOSING IN ON EROS
Astronomy.com News, 23 January 2001
[...]
(7) METEOR: GEWALTIGE EXPLOSION UBER DEUTSCHLAND [MASSIVE EXPLOSION OVER
GERMANY]
Der Spiegel, 23 January 2001
[...]
==================================================================
(1) JAPANESE TEAM FINDS 3,544 METEORITES
>From Ron Baalke <baalke@jpl.nasadot gov>
>From Space.com, 23 January 2001
http://www.space.com/scienceastronomy/antarctic_meteors_010123_wg.html
TOKYO (AP) -- Japanese scientists have found 3,554 meteorites in Antarctica
during a three-week search -- a collection that could yield clues about the
rest of our solar system, a government official said Tuesday.
The finds were made around the Yamato mountain range about 185 miles (300
kilometers) from Japan's base on the rim of Antarctica, said Shigeru Kure of
Japan's science ministry.
A meteorite is a meteor that survives the destructive effects of a flight
through the atmosphere and falls to the ground whole or in pieces.
Six members of the Japanese observation team took part in the latest search
conducted between Nov. 19 and Jan. 10, Kure said.
"Such a large number of meteorites discovered may include some rare ones
that could help in finding the origin of the solar system, or the
possibility of any traces of life on other planets,'' Kure said.
In 1998, a total of 4,180 fallen meteors were discovered by the Japanese
team in Antarctica -- the largest number found in a single search, Kure
said.
To date, Japanese observation teams have found about 13,000 meteorites in
Antarctica, about half of all found there.
Copyright 2001, Space.com
==================================================================
(3) NEAR SHOEMAKER CLOSING IN ON EROS
>From Astronomy.com News, 23 January 2001
http://www2.astronomy.com/Content/Dynamic/Articles/000/000/000/282pybyl.asp
The asteroid-orbiting spacecraft is making a couple of final approaches to
Eros before the mission's end next month.
by Vanessa Thomas
This week, the NEAR Shoemaker spacecraft will make two approaches of the
21-mile-long (34-kilometer-long) asteroid Eros. With only three weeks left
in the mission, planetary scientists are taking advantage of every last
data-collecting opportunity.
Throughout January, NEAR Shoemaker has been circling 22 miles (35
kilometers) above Eros. This distance is perfect for the spacecraft's
X-ray/Gamma-Ray Spectrometer (XGRS), which allows scientists to study the
elemental composition above and below the asteroid's surface. Earlier in the
mission, x-ray emissions revealed chemical resemblances between Eros's upper
layers and chondritic meteorites, believed to be the most primitive fossils
of the early solar system. The gamma-ray instrument will examine emissions
produced by cosmic rays and natural radioactivity, disclosing secrets buried
even deeper below the asteroid's gray exterior.
"The gamma-ray spectrometer allows us to see about four inches below the
surface," said XGRS team leader Jack Trombka. "This is helping us determine
if the chemistry we've seen so far is characteristic of the whole asteroid
or just the thin, top layer."
The x-ray observations are also benefiting from the current peak of the
sun's 11-year solar cycle. The x-ray spectrometer can get its best data when
large solar flares emit more x rays that, in turn, produce brighter
reflections off the surface of Eros. But these flares can be dangerous as
well. Exceptionally large solar flares and coronal mass ejections can thrust
high-energy particles at the spacecraft, overloading the XGRS.
"Too much current will fry the detectors - like burning out the filament in
a light bulb," Trombka explained. "Fortunately, the spacecraft senses this
and shuts the instrument down when things get too hot. The on-board computer
can automatically turn XGRS back on when the current returns to safe levels,
or await word from operators on Earth to activate it. The system has worked
like a dream so far and we've had some excellent results."
On Wednesday, January 24, NEAR Shoemaker will drop to an orbit that will
bring it within 3 or 4 miles (5 or 6 kilometers) of the potato-shaped
asteroid's ends. Four days later, the spacecraft will make its closest
approach yet, flying just 1 to 2 miles (2 to 3 kilometers) above Eros. "The
maneuvers are kind of risky, but we want to end the mission getting a lot of
bonus science - with images better than we've ever taken," said NEAR
Shoemaker's mission director, Robert Farquhar.
The observations will end just two days short of Near Shoemaker's one-year
anniversary around Eros. On February 12, the craft will make a controlled
descent to the asteroid's surface, capturing high-resolution images along
the way. Before it touches down onto Eros's "saddle" region, NEAR Shoemaker
could expose details as small as four inches (10 centimeters) across.
Copyright ) 1996-2001 Kalmbach Publishing Co.
==================================================================
(7) METEOR: GEWALTIGE EXPLOSION UBER DEUTSCHLAND [MASSIVE EXPLOSION OVER
GERMANY]
>From Der Spiegel, 23 January 2001
http://www.spiegeldot de/wissenschaft/0,1518,113556,00.html
Von Alexander Stirn
Das Ende war exorbitant: Im November 1999 ist ein Meteor in rund 15
Kilometern Hvhe |ber Norddeutschland explodiert. Seismologen haben jetzt die
Spuren der Detonation untersucht
FULL STORY at http://www.spiegeldot de/wissenschaft/0,1518,113556,00.html
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