The dangers we face from meteorites — or not | ASU News

The dangers we face from meteorites — or not
ASU Center for Meteorite Studies curator sets record straight on space-rock odds, their characteristics — and the incident in India
Before we begin reporting on his talk, let’s get something out of the way that Laurence Garvie, research professor and curator for Arizona State University's Center for Meteorite Studies at the School of Earth and Space Exploration, has been hearing about for two weeks.
Whatever killed the Indian bus driver about two weeks ago was not a meteorite.
“We still don’t have a direct hit,” Garvie said at a reception before his lecture on “Asteroids, Meteorites, and Dangers to Life on Earth.”
Meteorites don’t create explosions, he explained. And the likelihood of someone being killed by a rock falling from space is still astronomically low.
In 1954, a woman in Sylacauga, Ala., was hit by a particle from a meteorite that fell through the roof of her house. “Even then, it didn’t hit her directly,” Garvie said. “It hit the fridge and bounced off her arm.”
“It all comes down to probability, doesn’t it?” he said. “From above, we’re about a foot wide. And there are 7 billion people on Earth ... we could do the numbers!”
A meteorite like the one that wiped out the dinosaurs (such as the ones on his tie) is likely to occur only once every 100 million years, said ASU research professor Laurence Garvie. This and photo below by Ben Moffat/ASU Now
Garvie presented several numbers during his lecture, all of them fascinating.
Some 78,000 tons of extraterrestrial material hits the Earth every year, most of it dust. Most meteorites come from the asteroid belt between Mars and Jupiter. The asteroid belt is not like what you see in the movies; it’s not that crowded. Meteorites also come from the moon or Mars. “We’ve sent rovers there, but we haven’t brought anything back,” Garvie said. “Nature has done that for us.”
“As these objects come into the atmosphere, they produce a massive spectacle,” he said.
Meteorites are not hot and glowing when they hit the ground. In space, heated by the sun, they might only reach 200 degrees. Even when they fall through the stratosphere, they only have about four seconds to get hot. Garvie compared them to Baked Alaska; the inside is still cool.
Meteorites fall everywhere, but they’re tiny.
“The vast majority of meteorites are about a centimeter or so,” he said.
“Fortunately for us the very large events are rare,” Garvie said. A fall like the one captured on many dashboard cameras three years ago in Chelyabinsk, Russia, happens about once a generation.
A Tunguska-level eventThe Tunguska event was a large explosion that occurred near the Stony Tunguska River, in Yeniseysk Governorate, nowKrasnoyarsk Krai, Russian Empire, on the morning of 30 June 1908 (N.S.).[1][2] The explosion over the sparsely populated Eastern Siberian Taiga flattened 2,000 km2 (770 sq mi) of forest and caused no known casualties. The cause of the explosion is generally thought to have been a meteor. It is classified as an impact event, even though no impact crater has been found; the meteor is thought to have burst in mid-air at an altitude of 5 to 10 kilometres (3 to 6 miles) rather than hit the surface of the Earth. — Wikipedia as happened in Russia in 1915 occurs about once every 100 years. Chicxulub, which slammed into the Yucatan Peninsula, wiped out the dinosaurs and trashed the entire planet, is likely to occur only once every 100 million years.
A 100-foot-diameter asteroid is orbiting Earth in a wobble and will next pass by in March. Scientists estimate it has a one in 250 million chance of hitting Earth. If it does, it will create a crater only a few hundred meters wide.
“What I hope you go away with is that you’re safe, basically,” Garvie said. “Will there be another large impact? Yes. When will it happen? Hopefully not soon.”
The School of Earth and Space Exploration’s New Discoveries Lecture Series brings exciting scientific work to the general public in a series of informative evening lectures, each given by a member of the faculty once a month throughout the spring. The School of Earth and Space Exploration is an academic unit of the College of Liberal Arts and Sciences.
Scott Seckel
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Clutching hopes, dreams and minerals, about 50 people waited to approach Captain Fireball. Did they own interesting and valuable meteorites? Or just another rock?With the speed and finality befitting his nickname, Captain Fireball — aka research professor Laurence Garvie, collections manager of the Center for Meteorite Studies at Arizona State University — crushed dreams like a metal lump shat...
Between a rock and a hard place
It's the one day a year public can bring rocks to meteorite center to be ID'd.
Rocks traveled from across the U.S. — but not the galaxy — for ASU's space day.
November 9, 2015
People from across US enjoy ASU's meteorite-ID event, even if not all get the verdict they want
Clutching hopes, dreams and minerals, about 50 people waited to approach Captain Fireball. Did they own interesting and valuable meteorites? Or just another rock?
With the speed and finality befitting his nickname, Captain Fireball — aka research professor Laurence GarvieLaurence Garvie is a research professor in the School of Earth and Space Exploration, which is part of ASU's College of Liberal Arts and Sciences., collections manager of the Center for Meteorite Studies at Arizona State University — crushed dreams like a metal lump shattering a window.
There wasn’t time to waste. Saturday was Earth & Space Exploration Day at ASU. The open house, hosted by ASU's School of Earth and Space Exploration, features science-related activities for families, and it is the one day a year the public is invited to bring in what might be a meteorite for identification. The rest of the year, the center’s doors are closed firmly, as is stated — multiple times — on nearly every single page of the center’s website. The university’s meteorite identification program was closed five years ago because they were overwhelmed with requests.
“Nope,” Garvie said to one hopeful visitor. “It’s a pebble that has a shape to it.”
“No,” he said to another. “It’s not fusion crust. It just has some weathering on it.”
“The physical attributes of the sample are completely wrong,” he said to a gentleman who insisted he has something from space. (“I get one of those every time,” Garvie said.)
“You’re 100 percent sure it’s not a meteorite?” the gentleman insisted. He had a stack of data printouts. Tests have been done, he told Garvie, expensive tests.
“It’s not like any meteorite I’ve ever seen,” Garvie said. Captain Fireball sends the crestfallen but still insistent man downstairs to Dr. Rock, a geologist who was identifying rock specimens.
Ron DePlazes did not have a meteorite either, but he was not disappointed. The Phoenix man owns a company that paints road cuts for state highway departments across the West so they’re not glaring white. You can see his work along the Beeline Highway on the way up to Payson.
“I paint rocks,” he said. He doesn’t collect them. “No, I don’t. I pick up Indian stuff. I like meteorites, though.”
DePlazes was walking across the yard of his business at Central Avenue and the Salt River with his son Wednesday morning when he spotted his sample.
It is heavy, and magnetic — DePlazes affixed two small magnets to the rock — but it’s not a meteorite. It is similar to the Argentinian Chajari meteorite, according to Garvie, who sliced a sample from it and analyzed it in his lab.
“They don’t know it’s not a meteorite, but they don’t know what it is,” DePlazes said. “He’s a lot more sophisticated than I am.”
Before coming in to the event, DePlazes carefully went over the meteorite ID page on the center’s website and answered the five questions on the page.
“I didn’t think I had a meteorite,” he said. But he wanted to come in and check anyway. “He doesn’t know what it is, and that’s amazing considering how much they know here at Arizona State,” he said.
Rex Myerscough and his son, Rex Jr., drove two days from Clearwater, Florida, to ASU's Earth & Space Exploration Day with a 76-pound rock that has quite the origin story. But was it declared a meteorite Saturday in Tempe? Alas, no.
Deanna Dent/ASU Now
(From left) Jesse, Dylan, Robin, Bennett and Shelby DeWitt pose with their sample of bronze found while Jesse was rabbit hunting in northern Arizona. It was pronounced a "meteor-wrong" Saturday.
Deanna Dent/ASU Now
Jeff Christensen drove in from Mesquite, Nevada, with a handgun case full of rocks. Christensen found his rocks while he was working at the local airport.
Deanna Dent/ASU Now
“What are you going to do in Mesquite?” Christensen said. “There’s 1,800 people. I just kick rocks when it’s slow.” He didn’t have a meteorite either.
Deanna Dent/ASU Now
Ron DePlazes was walking across the yard of his business at Central Avenue and the Salt River in Phoenix with his son Wednesday morning when he spotted his sample. It is heavy, and magnetic but — not a meteorite.
Deanna Dent/ASU Now
Brother Richard and Chris Pool show off a cool-looking rock that turned out to be another meteor-wrong Saturday.
Angela Zapata and Maylo Corella and their children, Myles and Alisse Corella, pose with their meteor-wrong sample Saturday. The family had purchased it from a neighbor and hoped it might be a meteor, though no one could positively identify what the sample was composed of.
Photo by Deanna Dent/ASU Now
Lane and Bernadyne Agan of Show Low hold their meteor-wrong. Lane said he saw it fall and wondered whether he picked up the wrong rock.
Photo by Deanna Dent/ASU Now
Hilarie O’Dell and her three children brought in a sample found by her husband camping by St. Johns. It turned out to be industrial slag. “It’s the most common ‘meteor-wrong,’ ” Garvie said.
Deanna Dent/ASU Now
John Patrick of Payson (left) and Steve Thomas of Phoenix show their samples, which turned out to be meteor-wrongs Saturday.
Deanna Dent/ASU Now
Laurence Garvie, collections manager of the Center for Meteorite Studies and a research professor in ASU's School of Earth and Space Exploration, did not identify a single meteorite Saturday. Some years are like that.
Deanna Dent/ASU Now
Jeff Christensen drove in from Mesquite, Nevada, with a handgun case full of rocks. It was either drive south to Arizona State University or north to Brigham Young University to get them identified. Christensen found his rocks while he was working at the local airport.
“What are you going to do in Mesquite?” he said. “There’s 1,800 people. I just kick rocks when it’s slow.”
He didn’t have a meteorite either.
“He’s saying they don’t get those bubbles in there,” Christensen said. “That’s weird.”
Weird doesn’t even begin to describe the Myerscough saga. Rex Myerscough and his son, Rex Jr., drove two days from Clearwater, Florida, with a 76-pound rock that, could it communicate with a meteorite, would have a better story to tell than simply falling from space. It’s a story spanning a quarter-century of drama. Pay attention. It gets complicated.
The Myerscough saga began in 1972, when Rex Sr. bought three lots and built a house on one. In the process of prepping a second lot for construction, he found an unusual rock. He took it to the school where his wife taught and left it in a classroom as a curiosity.
After some years, his wife retired. Some time after that, the school principal called. A geologist had dropped by the school and said the rock was a meteorite. The principal didn’t want something that valuable in the school, so Myerscough picked it up and brought it home.
Myerscough repairs and maintains pressure washers for a living. NASA called him because they had a broken pressure washer. He told NASA he would fix it for free if they would identify his rock. It was a deal.
Then the deal fell through. The scientist who was slated to inspect the rock was transferred to a facility in Tennessee. It was disappointing, not least because of the effort it took to take a sample from the rock.
Lori, Kal (center) and Steve Baker chat with ASU research professor Laurence Garvie while examining a meteorite display at Earth & Space Exploration Day on Saturday in Tempe. Photo by Deanna Dent/ASU Now
“You had to take an 8-pound sledge and beat it and beat it just to get a little matchstick off it,” Myerscough said.
Then the rock was stolen from Rex Jr.
“I was robbed at gunpoint,” he said.
A suspect was taken into custody. The pair of detectives assigned to the case looked familiar to Mrs. Myerscough, and she looked familiar to them. It turned out she’d taught both of them in elementary school.
“The detectives said they had a white room,” Myerscough said. “They said, ‘We’ll take him in the white room and we’ll find out where it is.’”
The suspect confessed in the white room. The rock was buried under the monkey bars on a Catholic school playground.
“They sent a SWAT team out there and recovered it,” Myerscough said. “I go out there and there’s all these SWAT guys standing around looking at it.”
They thought it was a million-dollar meteorite.
Finally, in this multi-decade quest to identify the mystery rock, Myerscough found out about the meteorite identification event at Earth & Space Exploration Day. He and his son packed the rock in a sawn-off orange Home Depot bucket, placed it on a dolly, and took off for Arizona.
“I couldn’t send this thing off to Tennessee or wherever,” he said. “UPS wouldn’t take it. The airlines wouldn’t take it. It weighs 76 pounds.”
It took two days and more than 2,100 miles to drive from Clearwater to Phoenix.
“After all that, it’s not a meteorite,” Rex Jr. said.
The Myerscoughs, having solved the mystery, are taking the rock home, where they will keep it. Was the trip worth it?
“Oh, I’ve never been to this part of the country before,” Myerscough said.
Laurence Garvie (right) explains to Ron DePlazes that by sanding the edge of the sample he can give a definitive answer whether his sample is a meteorite (it was not) Saturday in Tempe. Photo by Deanna Dent/ASU Now
Meanwhile, back at the identification table the carnage continued.
Hilarie O’Dell and her three children: “My husband found that camping by St. Johns. It’s not a meteorite?”
It turned out to be industrial slag. “It’s the most common ‘meteor-wrong,’ ” Garvie said. He gamely looked at it anyway — after all, this was a woman who had waited in line with three children — and pointed out all the reasons it wasn’t a meteorite.
Lane Agan from Show Low: “I saw it fall. Did I pick up the wrong rock?”
“It’s totally unlike a meteorite.”
A young man with a tiny box lined with white cotton holding two specks.