Hello members,
This was published in the newsletter of the University of Colorado, Denver center.
And Cotopaxi is the newest Colorado meteorite. A small, weathered iron. It fits just right in my hand!! :-)
___________________________________________
Colorado skies rain fireballs
By: Sean Ball
10/22/02
--------------------------
Local astronomers are wishing upon a shooting star for several meteorites that illuminated the Colorado skies in October. Among approximately 1,200 witness reports, some claimed the fireballs changed color or produced sonic booms as they exploded within one day of each other, beginning at 7:22 p.m. on Sunday, Oct. 6, and continuing though 7:18 p.m., Monday, Oct. 7.
"The Sunday, Oct. 6 fireball exploded 10 to 20 miles high, hitting the dense part of our atmosphere like a brick wall," said Chris Peterson, a research coordinator for the Denver Museum of Natural and Science (DMNS) and director of the Cloudbait Observatory in Guffey, Colo. "It may have broken up, sending debris westbound from northeastern Colorado toward the Utah border."
Witness reports are being collected in the hopes of tracking the original orbit of the meteorite, which could be confirmed by its debris if it is ever found.
"Seeing a fireball is a once in a lifetime experience," Peterson said. "If you should be so fortunate enough to see one and can keep your wits about you, your observation could be scientifically valuable."
One witness, Heather Lawler of Englewood, who was driving westbound on 1-70 that Sunday night, thought the meteorite was a plane. "I saw it coming down the direction of the airport. It was beautiful — changing colors — and kind of arched southward," she said.
According to Peterson, such color information can be useful to experts: "Data that is of value … includes what colors the fireball changed, its trajectory, whether there was a smoke trail present, and if the meteorite stayed in one piece."
The earth is entering the middle of its annual meteorite season as it passes through ancient comet orbits at this part of its rotation around the sun. Three such peaks occur: The Persid shower in mid-August averages about 200 flashes per hour; the Orinid, beginning Oct. 21, with 75 per hour; and the Leonid, beginning Nov. 18, with 45 per hour.
In light of Colorado's recent fireball activity, Peterson is hopeful that this Orinid spike will be higher than in previous years.
"Most meteorites that make the designation of shooting stars are common, as several an hour — each not much bigger than a pea — are burned up completely with no trace (left on) the ground," Peterson said.
By contrast, Colorado's fireball record occurred at 10:44 p.m., Aug. 17, 2001, and was roughly equivalent to a one-ton filing cabinet entering the atmosphere at 34,000 mph before exploding 10 miles above the ground with the equivalent power of 50 tons of TNT. According to records, it burned 100 times brighter than a full moon.
"Basically, it's a matter of size, composition and speed," Peterson said. "Meteorites are made of the stuff that makes a planet: dense stony masses that attract iron to their core. Since 95 percent of the mass is burned off in entry, we are always hoping for more specimens to study and understand."
According to Alberto Sadun, a physics professor at UCD, "A meteorite is like a glance back into time to the earliest days of the solar system. We are interested in composition, size (and) frequency of the shower so we can learn and map dead comets."
In August with the help of DMNS funding and volunteers, Peterson assembled an exhibit outlining Colorado's fireball record, and in doing so a very special find was made when a Colorado Springs couple came forward with an iron meteorite discovery that turned out to be the first of its kind reported in Colorado in more than 30 years.
"It turns out this specimen's chemical composition could make it (unique)," said Jack Murphy, curator of geology at the DMNS, of the meteorite's unusually high nickel content. "In the longstanding tradition of naming a find after its nearest post office, this specimen is already being referred to as the Cotopaxi Meteorite."
"Pardon the pun," said Richard Walker, a Colorado Springs federal investigator and co-discoverer of the meteorite, "but the odds of finding one of these things is literally astronomical."
Walker and his then-fiancée, Sharon, were prospecting for gold on Oct. 8, 2000, with the help of a metal detector. With a little beginner's luck, they turned out the discovery of a lifetime in less than 45 minutes when they uncovered, tangled in the root of a fir tree and buried under eight inches of dirt, a specimen the likes of which has never been found in Colorado.
"It was heavy, that's why we wanted to get it analyzed," Sharon Walker said.
Offers for the debris have exceeding $6,000, and the couple is considering donating it to the museum. The specimen was found on private property, and they announced plans to split profits, if any, with the landowner.
--------------------------
Story Source: UCD Advocate
