[meteorite-list] 15th Anniversary of the Peekskill Meteorite Fall

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue, 9 Oct 2007 09:42:15 -0700 (PDT)
Message-ID: <200710091642.JAA08676_at_zagami.jpl.nasa.gov>

On October 9, 1992, thousands of people along the Eastern
coast of the United States witnessed a bright fireball and heard sonic
booms as the fireball passed through the Earth's atmosphere.
A 27.3 pound (12.4 kg) meteorite fell in Peekskill, New York, and
struck a 1980 Chevy Malibu sitting in its driveway. The
meteorite penetrated all the way through the trunk of the car.
Analysis of the fireball's flight path led to the determination
of the object's orbit around the Sun prior to its impact on Earth,
which not surprisingly showed it has originated from the main
asteroid belt. Closer examination of the video also showed the
bright fireball had broken up into about 60 pieces, but the
fragment that hit the car was the only one ever recovered.
The owner of the car, Michelle Knapp, sold the car and the
meteorite to meteorite dealers. I obtained a piece of the
Peekskill meteorite just a few weeks after it had fallen, and
my piece has red paint from the car on the fusion crust.

Ron Baalke

-----------------------------------------------------------


For JPL internal use only.

http://www.americanheritage.com/articles/web/20071009-peekskill-meteorite-astronomy-chevy-malib

The Thing From Space That Destroyed the Car
By John Steele Gordon
AmericanHeritage.com
October 9, 2007

Luckily for astronomers, it was a Friday night in the autumn. That meant
that hundreds of thousands of people were at high school football games,
many with camcorders at the ready to preserve any gridiron heroics. What
they preserved as well, from at least 16 different locations from
Kentucky to New York, was the path of a fireball across the sky as it
streaked northeastward at better than ten miles a second. (See videos
they shot here
<http://aquarid.physics.uwo.ca/~pbrown/Videos/peekskill.htm>.) As
earth's atmosphere tightened its grip, the yard-wide meteor, which
weighed several tons and shone brighter than the full moon, broke up
into at least 70 pieces. The only piece ever found weighed about 28
pounds. It announced its arrival on planet Earth by crashing through the
back of a car parked in Peekskill, New York, on the night of October 9,
1992, 15 years ago today.

The owner of the car, a red 1980 Chevy Malibu, was 17-year-old Michelle
Knapp. She went outside with a friend to investigate the noise, and when
they saw the damage to the car, they looked beneath it and discovered
the meteorite, nestled in a small crater it had made in the driveway. It
was still warm from its passage through the atmosphere. Knapp called the
police, who inspected the car and filed a report of criminal mischief.
(Given the extensive damage to the car (see photos here
<http://www.nyrockman.com/pages/peekskill-germany.htm>), the criminal
class in Peekskill must have been very well-armed indeed for mischief to
have been a plausible explanation.) The persistent smell of gasoline
from the ruptured fuel tank brought the fire department as well. Thanks
to the many videos available, astronomers were able to calculate the
angle at which the meteoroid had hit the earth's atmosphere: 3.4
degrees. Had it been much shallower, it would have skimmed through the
atmosphere and escaped back into space. (When in space, such an object
is a meteoroid. When it enters the atmosphere and is incandescent, it
becomes a meteor. If it explodes or disintegrates in the atmosphere, it
is termed a fireball or bolide. After the pieces land, they are called
meteorites.)

Astronomers were even able to determine the path that the meteoroid had
taken around the sun. For millions of years it had traveled as close as
80 million miles from the sun, inside the earth's orbit, and had reached
out as far as nearly 200 million miles, well beyond Mars. It had taken
1.8 earth years to complete an orbit.

In the early days of the solar system, four billion and more years ago,
the earth was frequently bombarded with meteorites, many of them huge.
The moon was almost certainly formed by a collision between the
proto-Earth and a Mars-size object at that time. Even today, in the
sedate middle age of the solar system, earth's considerable
gravitational field sweeps up a lot of space junk as the planet orbits
the sun. Every day the earth adds many tons to its mass this way. Most
of it is in the form of dust, which simply slows up in the atmosphere
without incandescing.

But so-called "shooting stars," which are about the size of grains of
sand, can be seen on any clear night by the dozens from any spot on
earth, if you have the patience to wait for them. During meteor showers,
such as the Perseids in August and the Leonids in November, when the
earth passes through the debris left in the orbits of comets, they can
often be seen at a rate of more than one a minute, all seeming to come
from the same point in the sky, called the radiant. Very rarely, a
meteor storm is encountered, and shooting stars can be seen by the
thousands, such as on the night of November 12 to 13, 1833, when at
least a quarter of a million shooting stars were seen over North America.

Much rarer, fortunately, are the larger hunks of space debris that are
too big to be vaporized in the upper atmosphere. These meteor falls are
still surprisingly common, however. One landed in a field in Yorkshire,
England, in 1795 and narrowly missed a worker. It settled the
long-standing argument about whether stones really do fall from the sky.

In this country, a woman napping on her couch in her home in Sylacauga,
Alabama, was struck by a meteorite on November 30, 1954, when it crashed
through her roof, bounced off a radio, and hit her on the leg (see
AmericanHeritage.com article here
<http://www.americanheritage.com/places/articles/web/20051130-meteorite-alabama-smithsonian-space-race-cold-war.shtml>).
Houses in Wethersfield, Connecticut, were struck by meteorites only 11
years apart, in 1971 and 1982.

Larger meteors pose graver, but exponentially rarer, dangers. The meteor
that produced the Barringer Crater in northern Arizona about 50,000
years ago was roughly 50 yards wide and released about 2.5 megatons of
energy to produce a crater nearly a mile wide and 570 feet deep. Such a
meteor strikes the earth every thousand years or so.

The "Tunguska event," in 1908, was probably a comet that did not strike
the earth but rather exploded in the atmosphere over unpopulated
Siberia, with a force equal to that of a hydrogen bomb. It flattened an
estimated 80 million trees. Had its path through space been very
slightly different, it might have exploded over densely populated
Europe, with catastrophic consequences.

A one-kilometer-wide meteor would cause globally devastating effects,
but they hit only every half million years or so. A six-mile-wide meteor
would end civilization and quite possibly annihilate the human race. One
roughly that size is believed to have killed off the dinosaurs 65
million years ago. There are now programs seeking to locate major
asteroids and comets with earth-crossing orbits and develop ways of
deflecting them, should they prove to be on a collision course.

The meteorite that slammed into Michelle Knapp's car had no such
literally earthshaking consequences. Indeed, it proved a boon to
Michelle Knapp. She told reporters that she had bought the 12-year-old
car from her grandmother for only $100, and therefore the loss was
small. But meteorites have a ready market, especially ones that achieve
individual fame, often selling for thousands of dollars. (In fact, a
fragment of the Peekskill meteorite, along with some video footage and
pieces of the Malibu's smashed taillight, will be sold at auction later
this month, with an estimated price of $2,000 to $3,000.) Knapp also
sold the old clunker of a car, which later toured the world, for enough
to buy a brand-new one.

So modest-size meteorites are invited to hit my car if they'd like to.
As long as I'm not in it at the time, of course.
Received on Tue 09 Oct 2007 12:42:15 PM PDT