ALEX CHADWICK, host:
In Kansas, a group of scientists have used truly groundbreaking technology to find a 154-pound meteorite.
Joining us now is Carolyn Sumners. She's director of astronomy at the Houston Museum of Natural Science. She led the team that uncovered this meteorite. Carolyn Sumners, what can you tell us about this?
Dr. CAROLYN SUMNERS (Director of Astronomy, Houston Museum of Natural Science): It's a rock no one has ever seen before. And we have preserved not only the meteorite, but the area around it. And we're going to let it tell all of its story. We want to know when it hit. We want to know where it came from, and we're even going to animate the event that brought it to Earth.
CHADWICK: Well, where is this in Kansas? What's it around? What's the area like, and how deep in the ground was this meteorite?
Dr. SUMNERS: We're in Greensburg, Kansas - that's in the western part of Kansas. We have rocks buried four feet below the soil, or maybe even further. We have to find them with metal detectors. And then, because we wanted the pristine environment of this meteorite, we used ground-penetrating radar in this application for the first time, in this area, to see the rock completely before we dug the area out around it.
CHADWICK: And you want to dig up the soil that's around the meteorite in order to figure out just what conditions were like when it hit?
Dr. SUMNERS: Correct. There's a lot of mythology about a meteorite falling in the central part of the United States. This meteorite is called the Brenham meteorite. It's produced a lot of rocks on the ground. And we want to know exactly when it fell. There have been stories that it fell 20,000 years ago, which is too early.
Now we think from the stratigraphy of the soil around the meteorite that it had to be less than 10,000 years, which makes it an anthropological event, as well as a physical and astronomy one.
CHADWICK: It's a - as I see from an Associated Press story - a pallasite meteorite. What does that mean?
Dr. SUMNERS: Oh, this is wonderful. Less than one percent of all meteorites are pallasites. And they are iron meteorites with olivine crystals embedded in them. This meteorite was once part of the core-mantle boundary of a large asteroid. The asteroid had to have broken up billions of years ago. The meteorite, then, was a piece from the asteroid from a very special part where the iron core of the asteroid melts the silicon mantle, and the olivine crystals indicate that very narrow part of the asteroid.
And this meteorite came from that very special part. And then we think maybe 10,000 years ago, maybe less, it actually exploded in the upper atmosphere -maybe 12 miles up. We're not sure about that yet, but we're working on it. And we're trying to get the trajectory of the impact to actually recreate this event all the way back to the asteroid in the asteroid belt.
CHADWICK: Tell me this. I know that this kind of ground-penetrating radar that you're testing out and using there might be used someday to help explore Mars, but could you use it for an Earth application? Could you find landmines, say, in areas where you wanted to clear them away?
Dr. SUMNERS: The trick that we have discovered here is water. Essam Heggy, who is our scientist on board - he's from the Lunar and Planetary Institute in Houston - and he is preparing experiments to take ground-penetrating radar over the surface of Mars to find water.
Well, water abounds on the Earth. So the limitation of ground-penetrating radar in what we have to really work with is not to use it where it's so wet that all you get are the signals that reflected water. The meteor-wrongs that we uncovered in the last two or three days - and some of them we can see directly - the things that have water associated with them become much stranger signals and signatures in the ground-penetrating radar.
CHADWICK: Meteorites, meteor-wrongs. Carolyn Sumners, the director of astronomy at the Houston Museum of Natural Science, joining is from Greenberg, Kansas. Carolyn, thank you and congratulations.
Dr. SUMNERS: Thank you. Come to the museum and see the rock.
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CHADWICK: NPR's DAY TO DAY continues.