Meteorites fall to Earth all the time. One estimate says that between 36 and 166 meteorites larger than 10 grams (0.02 pounds) make their way down here every year. Most of the time, these incidents are non-events, but sometimes they can turn violent, like when a space rock ripped through the roof of a Costa Rican home last month.
Now, upon further investigation, the two-pound rock that destroyed a family's dining room has an even odder quality: It's a carbonaceous chondrite, a rare meteorite filled with organic compounds and water, say the researchers at Arizona State University who recently got their hands on it.
“Many carbonaceous chondrites are mud balls that are between 80 and 95% clay,” says Laurence Garvie, a research professor in the School of Earth and Space Exploration and a curator for ASU's Center for Meteorite Studies, in a press statement. “Clays are important because water is an integral part of their structure.”
When word spread throughout the scientific community that the dining room destroyer might be a carbonaceous chondrite, a ticking clock began. April marks the end of Costa Rica's dry season and the beginning of its rainy season, and any outside water could ruin the rare sample.
“These had to be collected quickly and before they got rained on,” Garvie says. “Because they are mostly clay, as soon as these types of meteorites get wet, they fall apart.”
With a bit of luck, the dry season held out for five days as meteorite collectors were able to retrieve the rock. The entire meteorite had been around the size of a washing machine; the fragment that crashed into the house was merely a part of a much larger object. So far, 55 pounds of meteorites have been collected from the Costa Rican site, which add up to about the size of a beach ball.
After paying the family that had the misfortune of running into a meteorite, two new races were on.
“I was in the lab by 5 a.m. the next morning after picking up the samples to get them ready for the initial analyses,” Garvie says. “Classification of new meteorites can be like a race with other institutions, and I needed ASU to be first so that we’ll have the recognition of being the collection that holds and curates the type specimen material.”
Beyond other institutions, Garvie also had to struggle with nature. Meteorites quickly adapt well to their new home-a little too well for scientists.
“If you left this carbonaceous chondrite in the air, it would lose some of its extraterrestrial affinities,” Garvie explains. “These meteorites have to be curated in a way that they can be used for current and future research, and we have that ability here at ASU.”
By sheer luck, it's been 50 years since known carbonaceous chondrites have fallen to Earth, when they hit western Australia in 1969. The Murchison meteorite, as it's come to be known, is among the most studied meteorites in the world.
Components of DNA and RNA found on Earth were found in the Murchison meteorite, which crashed into a cattle ranch at the time. It's responsible for the discovery of a new family of extraterrestrial amino acids, among other things.
"Carbonaceous chondrites are relatively rare among meteorites but are some of the most sought-after by researchers because they contain the best-preserved clues to the origin of the solar system,” says Meenakshi Wadhwa, Director of ASU's Center for Meteorite Studies. “This new meteorite represents one of the most scientifically significant additions to our wonderful collection in recent years.”
If you happen to be in Arizona, samples from the Costa Rican meteorite are on public display public at the ASU Tempe campus.
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