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(meteorobs) Fireball-Like Object Observed Over Wyoming




----- Original Message -----
From: Peter Brown <pbrown@julian.uwodot ca>
To: <epmajden@home.com>
Cc: Multiple recipients of list <miac-l@uquebecdot ca>
Sent: Friday, August 24, 2001 10:04 AM
Subject: Re: [MIAC-L] Fw: [meteorite-list] Fireball-Like Object Observed
Over Wyoming


> This is the fireball which occurred in Southern Colorado
> at 10:44 PM on August 17 (last friday night). We detected it from multiple
> infrasound stations. Below is the Denver museum news release on the
> event.
>
> Cheers,
> Peter
> ----------------------------
>
> Information Release
> August 21, 2001
>
> From: Jack A. Murphy, Curator of Geology
> Department of Earth and Space Sciences
> Denver Museum of Nature and Science
> Phone 303-370-6445
> jmurphy@dmns.org
>
> EXTREMELY BIGHT METEOR WIDELY SEEN OVER SOUTH CENTRAL COLORADO BEFORE
MINDNIGHT
> ON AUGUST 17, 2001
>
> FALL AREA DETERMINED TO BE OVER RUGGED MOUNTAINS IN SOUTHERN SAN JUAN
MOUNTAINS,
> CONEJOS COUNTY, COLORADO.
>
> A very bright, white meteor lit up the skies over a large portion of
central and
> eastern Colorado August 17, 2001, at 10:44 PM/MST. Many people called
television
> stations or law enforcement agencies thinking a plane had crashed and
started a
> forest fire.
>
> Calls to the meteorite research team at the Denver Museum of Nature &
Science
> overloaded phone lines and e-mails.  More than 400 calls were taken over
the
> past 3 days from locations in all corners of Colorado including Grand
Junction,
> Alamosa, Ft Collins, and Colorado Springs, thus giving us information
about the
> point in the sky where the fall terminated.  The Museum's main motivation
is to
> answer media requests, be an educational resource, and hopefully to
eventually
> locate meteorites on the ground.
>
> The museum is in contact with Forest Service officials in the area to
emphasis
> that meteorites, if found, are the property of the land owner.  Meteorites
found
> on private property belong to the land owner and if found on government
property
> the Smithsonian Institution is the custodian of those specimens.
>
> For the Colorado fireball Friday night, most people were particularly
impressed
> with two aspects; the steep downward angle of descent, and the dazzling
> brilliance accompanied by sparks. Museum investigators are amazed that
loud
> sonic booms or explosive sounds were not readily heard by observers.  It
appears
> that this phenomenon is related to the steep descent.
>
> The meteor was seen as far away as New Mexico, Wyoming, Idaho, Nebraska
and
> Kansas. It mainly was spotted by late night travelers facing southwestern
> Colorado. As far as is known no one captured the event on video but people
with
> security videos or banks with ATM cameras should check back if they have
tapes
> from last Friday night.
>
> The Museum now has sufficient information to preliminarily locate the
general
> area of the fireball over south central Colorado, most likely in the
southern
> Rio Grande National Forest area in Conejos County, a rugged, forested
region in
> the southeastern part of the San Juan Mountains.
>
> Because the meteor was so bright, people automatically thought it was
closer to
> them than it actually was. Those who saw the meteor from Denver and along
the
> Front Range looked to the southwest; it appeared to go directly down into
the
> mountains on the other side of the Dakota Hogback near Morrison, while
people in
> Colorado Springs saw it plummet behind the Pikes Peak region.
>
> Many people in the Evergreen area thought it had landed on the east side
of the
> mountains. People in Grand Junction and Durango, on the other hand, were
looking
> to the east or southeast when they saw the bright event. Travelers going
along
> I-70 near Dillon Reservoir saw it to the south of them, some thought they
were
> flares or fireworks.
>
> In addition to the witness accounts, the Museum now has data from a
> sophisticated sound detection system at Los Alamos, New Mexico that has
located
> the atmospheric position of the fireball over the eastern San Juan
Mountains.
> This acoustic network at Los Alamos detects sound waves originating from
the
> atmosphere.  They have successfully recorded other similar fireballs this
year,
> most notably the July 2001 event over the East Coast.
>
> The data from Los Alamos National Laboratories, from Dr. Peter Brown(1) "
.is
> around 50 Tonnes TNT equivalent yield which for a nominal 18 km/sec entry
> velocity suggests an entry mass of order a metric tonne. " This velocity
is the
> same as 11.25 miles per second.
>
> Depending on initial mass and velocity, most meteors arrive into the
earth's
> orbit at a velocity as high as 26 miles per second, then their speeds drop
off
> during entry between 10 miles per second and 26 miles per second (Norton,
1998,
> p. 46). They begin giving off light in the upper atmosphere and flare very
> bright as friction increases during decent. Dr. Brown estimates the peak
> magnitude for the Friday, August 17th event to be around -17 to -18 on the
> astronomical magnitude scale.  As a comparison, the full moon is
approximately
> -13 magnitude brightness so the fireball works out to be about 40 times
> brighter(2).
>
> The process the research team uses to locate the position of fireballs is
more
> efficient now with the Internet.  Many people in Colorado are interested
and
> knowledgeable about fireballs and meteorites as evidenced by the high
quality of
> data received at the Museum. We attribute this to experience in the last
few
> years investigating other similar meteors.  In addition, a program of
networked
> camera's is in the works that will view and record the day and night sky
in an
> effort to more easily triangulate a meteor's trajectory.  This All Sky
Camera
> Network is a collaboration between the Museum and a team of Colorado
teachers
> which will then be used statewide by students(3).
>
> The museum research team, consisting largely of volunteers, will still
have to
> do exacting fieldwork to locate meteorites if they fell, unless someone
> coincidentally finds a meteorite or locates a fresh hole thorough the roof
of a
> building. Specific compass bearings and measurements of the altitude of
the
> breakup point above the horizon from different locations are essential to
map a
> meteorite fall. The Museum team has investigated other Colorado fireballs
and
> informed communities of the chances of locating meteorites. Classes are
> presented at schools and in communities to explain about meteorites and
their
> scientific value-that they are free samples from space that provide
evidence of
> the age and composition of the Solar System.
>
> At this time there is no evidence of meteorites on the ground in south
central
> Colorado or in the Conejos area and no ground search is being conducted.
> However, Museum field research staff will likely travel to the Monte Vista
area
> and interview witnesses.
>
> Definitions:
>
> Meteor: the bright light in the lower reaches of the atmosphere created
from
> friction on a falling solid mass, usually reserved for natural objects
such as
> rocks from space that are thought to originate in the Asteroid Belt
between
> Jupiter and Mars.
>
> Meteoroid: the name for a natural piece of rock from space, probably a
piece of
> asteroid, that is attracted by Earth's gravity and descends through the
> atmosphere at a high rate of speed.
>
> Meteorite: the solid stony or iron material that survives flight through
the
> atmosphere and lands on the ground. Meteorites should be collected as soon
as
> possible for chemical tests that can ascertain its composition and age.
>
> Sources:
> (1). Dr. Peter Brown, Los Alamos National Laboratory Technical Area
> Group EES-8, Earth and Environmental Sciences Division
> Mail Stop J577
> Los Alamos, New Mexico
> Phone 505-665-7134
>
> (2). Larry Sessions, North American Skies
> www.webcom.com/safezone/nas
> email: starman@usadot net
>
> (3) For more information on the All Sky Camera Network contact:
> Gianna Sullivan
> Community Liaison
> Denver Museum of Nature & Science
> 303-370-6097
> gsullivan@dmns.org
>
>
>
> Rocks from Space, by Richard Norton (1998); Published by Mountain Press,
> Misoussla , Montana, 447 pages.
>
>
> end
>
>
> Ed Majden wrote:
>
> > ----- Original Message -----
> > From: Ron Baalke <baalke@zagami.jpl.nasadot gov>
> > To: Meteorite Mailing List <meteorite-list@meteoritecentral.com>
> > Sent: Friday, August 24, 2001 9:38 AM
> > Subject: [meteorite-list] Fireball-Like Object Observed Over Wyoming
> >
> > >
> > >
> > > http://www.trib.com/HOMENEWS/WYO/23StrangeLight.html
> > >
> > > Strange light reported near Rock River
> > > August 23, 2001
> > >
> > > ROCK RIVER, Wyo. (AP) - A Cheyenne man and an astronomy group reported
> > > seeing a very bright light in the night sky.
> > >
> > > Peter Davenport, director of the National UFO Reporting Center in
Seattle,
> > > Wash., said he is seeking others who saw the light around 10:30 p.m.
> > Friday.
> > >
> > > Paul Ayers, 38, and Ayers' son, 19, said a fireball-like object rose
> > > straight from the ground in the Rock River area. The light was so
bright
> > it
> > > washed out the headlights of their vehicle, according to Davenport.
> > >
> > > Davenport declined to provide other details because he wants other
> > witnesses
> > > to provide independent reports.
> > >
> > > Ayers said he and his son were on a fishing trip.
> > >
> > > "It illuminated the whole neighborhood," he said. "It was just a weird
> > > occurrence that needed to be reported."
> > >
> > > University of Wyoming astronomer Allyn Smith said at least 60 people
at a
> > > Wyoming Under the Stars gathering saw the light from the UW
observatory at
> > > Jelm Mountain.
> > >
> > > Smith said he saw a flash on the dome wall of the observatory about 25
> > miles
> > > southeast of Laramie.
> > >
> > > "The people who were outside described a large meteor, or bolide, a
bright
> > > meteor," he said.
> > >
> > > Such meteors usually explode high in the air, he said, and theorized
that
> > an
> > > icy meteor, a stony or iron meteor, or a piece of space junk caused
the
> > > light.
> > >
> > > "I would estimate it was almost as bright as the full moon," he said.
> > >
> > > _______________________________________________
> > > Meteorite-list mailing list
> > > Meteorite-list@meteoritecentral.com
> > > http://www.pairlistdot net/mailman/listinfo/meteorite-list
>
> --
> *********************************************************************
> Dr. Peter Brown
> Los Alamos National Laboratory
> Technical Area - 51, Bld 80
> Group EES-8, Earth and Environmental Sciences Division
> Mail Stop J577
> Los Alamos, New Mexico
> 87545
> USA
>
> ph:505-665-7134
>
> email:pbrown@vega.lanldot gov
>
> fax:505-667-9122
>
> ph:505-820-2480 (H)
> *********************************************************************
>
>

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