Meteorites: Hunting missiles from outer space
(CBS News) When a meteor fell out of the blue and exploded with enormous power over Russia this past week, people all over the world took notice, and began looking anxiously UP into the sky ourselves. There is a lot going on up there, much of it untrackable. But true experts in the field are often looking DOWN, hunting for those cosmic bits and pieces underfoot that have fallen and KEEP falling all the time. Rita Braver reports our Cover Story:
The meteor that shot through the sky over Central Russia on Friday, exploding into a shower of fireballs, created sound waves that were felt for miles. More than twelve hundred people were injured, shattered glass was everywhere, and thousands of buildings were damaged.
Though meteors do fall frequently, such devastating events are rare. But remember, many scientists believe it was an asteroid smashing into the Earth some 65 million years ago that caused wildfires that changed the environment so much, dinosaurs could no longer survive.
And for generations, humans have been trying to understand the hows and whys of these missiles from outer space.
The Smithsonian's Museum of Natural History has amassed a major collection of them, overseen by Linda Wellzenbach, and its exhibit of meteorites is the largest in the world, including some which look like sculpture.
"Iron meteorites are really interesting in many ways, because they are fragments of an asteroid that has been completed disrupted. So we're getting pieces of something that at one time was a full planet," she said.
In fact, most of the meteorites that land on Earth come from the asteroid belt, an area between Mars and Jupiter, where space debris collects.
And here's a little space terminology:
Asteroids are minor planet-like objects that usually orbit the sun. Meteoroids are much smaller bodies. When either enters the Earth's atmosphere, they are known as meteors. And when they hit the Earth, they are called meteorites.
The Smithsonian has about 50,000 meteorites in its collection. "Why are you still trying to get more?" asked Braver.
"Because every single one is a puzzle piece that adds to the information that we understand about the history of our solar system and the history of the development of the Earth," Wellzenbach said.
In fact, meteorites are so sought after that a little-known federal government program -- the Antarctic Search for Meteorite program, or ANSMET -- sends scientists (including Wellzenbach) on annual expeditions.
Ralph Harvey, associate professor of planetary science at Cleveland's Case Western Reserve University, has been leading the 37-year-old program since 1991.
He says it's not that there are more meteorites in Antarctica than the rest of the world, but that they are better preserved in the frigid landscape.
"There are meteorites we've collected in Antarctica, where they're so young we can't measure that age," Harvey said. "There are others we found that fell several million years ago. And there's everything in-between. The average seems to be about 25-30,000 years."
To the scientists' delight, they've even found samples from the Moon and Mars.
"This is an Easter egg hunt unlike any Easter egg hunt anywhere," he said. "When somebody sees one, they stop, and their first job is to do a little dance, and then we all converge on the site."
The yearly catch is shipped to NASA's Johnson Space Center where, in the nondescript building #31, you have to suit up to protect the meteorites from contamination.
The precious cargo is unpacked and cataloged under the watchful eye of curator Kevin Righter.
"They're frozen from the time they're collected and returned, all along the legs of the journey to get to Houston," he said.
Each sample is carefully examined and given a name based on where it was found.
Righter showed Braver an example of a Martian meteorite: "This sample is Elephant Moraine 79001. It's a basaltic rock from Mars."
In fact, it was studying a Martian meteorite found in Antarctica that led scientists to the discovery that there was once water on mars. And though these ugly duckings may all look similar to the naked eye, each meteorite has different chemical and mineral contents.
Under a polarizing microscope, they are as beautiful as stained glass windows.
But it's what they may someday tell us that really matters:
"I would say that the study of meteorites is akin to where biology was in the pre-Darwin area," said Harvey. "We're bringing back all sorts of funky, new creatures, and we're trying to fit them into a framework and understand how one relates to another."
Since the Antarctic program began in 1976, it's cost about $25 million. The Curiosity rover mission now analyzing samples on the surface of Mars cost about $2.5 billion -- and won't even bring back any material to Earth.
"This is a way to get a piece of Mars that costs us a millionth of what that project might cost," said Harvey. "Poor person's space mission."
The Antarctic missions have brought back more than 20,000 meteorites, and the program has loaned thousands of samples to researchers all over the world who are trying to make discoveries about the evolution of planets and stars.
Still, at the Smithsonian, Antarctic meteorite curator Cari Corrigan and her colleague Linda Wellzenbach are well aware that some members of Congress want to shut down the project.
"That's very disheartening to me, because I think that's not looking at the big picture," said Corrigan. "This silly little rock that it looks like you could just pick up in your back yard can tell us four billion years of history of the solar system."
As you might expect, there's major interest at the Smithsonian in what happened in Russia. And keep in mind, Friday's Russian meteor is estimated at about 50 feet in diameter, versus more than six miles across for the one believed to have wiped out the dinosaurs. So could something even worse ever be headed out way?
"There're a lot of large objects out there," said Wellzenbach. "And at any time, they can be put into the inner solar system and intersect Earth's orbit. So the answer is, it could happen."
But the unsettling reality is, there's nothing researchers could do anything about.
So they are far more focused on solving the puzzle of how the solar system formed.
"it's a daunting task, sure," laughed Corrigan.
"It is," said Wellzenbach. "But I think that the excitement of finding the next thing and the new questions that are generated from that next thing, is what keeps us going. The picture does become slightly clearer each and every time we find something new."
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