Scientists at the Smithsonian Astrophysical Laboratory in Cambridge, as well as at the Goddard Space Flight Center in Maryland and the Smithsonian Institute in Washington, are currently studying our latest extraterrestrial visitor- a 21- pound meteorite found last Friday near Lost City, Oklahoma.
Although meteors- or "shooting stars" -are common, meteorites are more rare. A meteorite is the part of a shooting star that reaches the earth.
Most meteors are reduced to dust by atmospheric friction, so any substantial surviving fragment is valuable.
The Lost City meteorite is particularly valuable because scientists will be able to determine exactly where in space it came from.
The Observatory traced the descent with its Prairie View network of unmanned cameras stationed in the Midwest By tracing its path back into space, scientists will have a unique record of its history before it fell to earth.
This meteorite is the first stone found by the Prairie View network since it began operating in 1962.
But scientists have amassed a large number of photographic records of shooting stars. So they will be able to use the Lost City find as a standard for interpreting their previous data.
Visible Throughout Midwest
The meteorite's fall was visible throughout large sections of the Midwest on January 3.
Using data from the Prairie View cameras, Richard McCrosky, a lecturer in Astronomy and the scientist in charge of the meteor project, predicted that the meteorite would land in a one-mile-square area near Lost City.
Gunther Schwartz, field manager of the camera network, found it lying on a dirt road six days later.
Rapid recovery was essential, because much of the information scientists hope to gain from the meteorite is based on low-level radioactivity.
The particular isotopes the researchers are interested in have half-lives of only 5 to 14 days. so after about two weeks the fragments would have been useless to many scientists.
These scientists intend to use a method similar to carbon dating to examine the effects of solar radiation in deep space.
The Lost City meteorite is very ordinary as meteorites go, just an oblong chunk of stone and metal with a black crust.
Because it is so ordinary, it is useful as a standard for calibrating photographs of meteors and other meteorites that were never found.
Geologists are now comparing samples of the Lost City rock with other meteorite fragments and with the lunar rocks.
Scientists are very pleased with their find. "It's as if we'd gotten back a spacecraft from a deep space probe," said James Cornell of the Smithsonian Observatory. He added, "This is a very valuable rock."