[meteorite-list] Response To Asteroid Threat Depends On Its Geology

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 09:55:46 2004
Message-ID: <200201141656.IAA07422_at_zagami.jpl.nasa.gov>

http://www.floridatoday.com/!NEWSROOM/localstoryA8757A.htm

Response to asteroid threat depends on its geology
By Kelly Young
FLORIDA TODAY
January 13, 2002

CAPE CANAVERAL -- Asteroids are like the snowflakes of outer space -- no two
are identical.

"Asteroids can run the gamut anywhere from an ex-cometary fluff ball to a
slab of solid iron," said Donald Yeomans, manager of NASA's Near Earth
Objects program. That makes finding a cure-all for destroying an
Earth-approaching asteroid difficult.

"You need to know the enemy and . . . you'd need to know what it was made
of," said Yeomans. "There is some rationale for studying them up close with
spacecraft."

More than 100,000 asteroids have been catalogued and named. But "there are
many, many more than that -- millions and millions," said Robert Jedicke, an
asteroid hunter at the University of Arizona.

All of the solar system's asteroids began their life between Mars and
Jupiter. There, a planet tried to form but couldn't because of the
overpowering presence of Jupiter, the largest planet in the solar system,
astronomers believe.

"Jupiter kept stirring them up," Yeomans said.

The larger asteroids in the main belt are like miniature planets with an
iron core, a silicate mantle and a surface battered by collisions. These
objects smash into one another, creating fragments that sometimes veer
toward the inner solar system.

Scientists think the asteroid that flew by Earth last Monday was probably
made of silicate like other Near Earth Objects.

Some asteroids are spent comets that have lost all of their ice. The remains
are fragile enough to crumble in someone's hands.

Other asteroids are just conglomerates of rock rubble held together by their
own gravity.

The asteroid Ceres, the first one discovered, spans about 600 miles across,
about the distance from New York City to Dayton, Ohio.

Vesta, the solar system's third largest asteroid, can be seen with the naked
eye. NASA will send the Dawn spacecraft to Ceres and Vesta later this
decade.
Received on Mon 14 Jan 2002 11:56:24 AM PST