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UC Berkeley junior hot on the trail of Sutter’s Mill meteorites

When a fireball exploded over California's Gold Country on April 22, Cal geology major Jason Utas wrapped up his final exam and headed to Sutter's Mill with a dozen of his friends to look for fragments. Four of them, including Utas, found small pieces of a rare carbonaceous chondrite, a type of meteorite that may have carried the building blocks of life to Earth billions of years ago.

Jason Utas, a junior majoring in geology and psychology at the University of California, Berkeley, developed a passion for meteorites after his father gave him one at age eight. Since then, he and his father, Peter, have found nearly 300 and purchased many more.

Jason Utas.

Junior Jason Utas of Los Angeles with the meteorite (black pebble) lying in the middle of the trail where he discovered it on April 27.

So, it’s no surprise that when a shooting star the size of a minivan exploded over the Sierra Nevada foothills on April 22, rattling homes and setting off car alarms, his first reaction was, “I’m going.”

After finishing a final exam in psychology, Utas, 21, gathered a dozen of his friends, many of them UC Berkeley geology majors, and headed for California’s Gold Country: ground zero for debris from the bolide. His mother, Barbara, paid for motel rooms for a week. Five days after the meteorite burned through the atmosphere above Nevada and California, the group fanned out west of Lotus, Calif., magnet-tipped canes in hand and eyes to the ground in search of any coal-black, metallic objects. They tripped over snakes, battled mosquitoes and negotiated with occasionally unwelcoming landowners.

In the first two days, Utas and two other students, plus Utas’s mother, found pieces totaling 15.5 grams of what has come to be called the Sutter’s Mill meteorite. That’s a respectable chunk of the 400 grams total – about a pound – found so far, and a good haul in light of the NASA scientists, meteorite dealers and rockhounds swarming the area.

“It was dumb luck and a lot of time,” he said.

At a going price for the Sutter’s Mill meteorite of $1,500 to $2,000 per gram, the small group had also struck it rich.

Not that Jason Utas is in it for the money. Since 2010, when he was a freshman, he has carted out his extensive meterorite collection, weighing hundreds of pounds, for a show-and-tell at UC Berkeley’s annual Cal Day open house. With contagious enthusiasm, he explains to kids and adults alike the origins of the meteorites, ranging from heavy iron and nickel bolides to stony chondrites, in his collection. One of the most impressive is a 326-pound iron meteorite from Texas – the largest discovered in the United States in the last 36 years. Buying and selling meteorites helps him pay for his education.

“It’s fun, and meteorites are amazing,” he said. “These rocks are solid evidence of what was going on in the solar system 4.5 billion years ago.”

Meteorites are pieces of comets or asteroids – rubble from the formation of the solar system – that orbit the sun and collide with Earth, zipping through the atmosphere at tens of thousands of miles per hour. In their descent, they heat up and often break into pieces. They show up in the nighttime sky as shooting stars or, if they are large enough, as fireballs visible even during the day, as was the case with the Sutter’s Mill meteorite. As it falls, a meteorite’s leading surface melts to form a glassy sheath that sometimes looks just like the nose cone of an Apollo spacecraft command module.

“These things are coming through the atmosphere? They have a nose cone?” he asked rhetorically. “That, to an eight-year-old, was cool.”


Utas and his mother found several pieces of the Sutter's Mill meteorite, including two (top) that were once a single rock that split upon landing. To date, some 400 grams of material have been found from what was originally a meteor weighing several tons.(Robert Sanders photo)

The Sutter’s Mill meteorites – so-called because the first specimens were found near Marshall Gold Discovery State Historic Park, home to Sutter’s Mill, where James Marshall first discovered gold in 1848 – are a kind of black gold. They come from a rare carbonaceous chondrite, which contains small spherical chondrules cemented together by fine-grained minerals and carbon that gives the chondrite its dark appearance.

“Carbonaceous chondrites are much more rare than the ordinary chondrites, which make up about 80 percent of all meteorite falls,” said Kees Welten of the cosmochemistry group at UC Berkeley’s Space Sciences Laboratory. “These meteorites often contain water and amino acids, and are probably the rocks that, at some point in Earth’s history, brought water and amino acids to this planet, and may have started life.”

Welten said Utas worked with him two summers ago as a lab assistant and impressed him with his enthusiasm for collecting meteorites. Welten, too, got caught up in the recent meteorite fever, joining a NASA team that scoured the area around Lotus and Sutter’s Mill. Welten struck out, but his group at the lab received a small, 50milligram piece of the meteorite for isotope analysis.

The lab, run by researcher Kunihiko Nishizumi, devotes about half its efforts to dating meteorites to determine how long they have been traveling in orbit around the sun. To do this, they look at isotopes produced only when cosmic rays – high-speed protons zooming through space – slam into meteorites. By measuring the isotope ratios, they can tell how long ago a small – that is, a VW Bug-sized or smaller – meteorite split off from a larger asteroid and exposed its outer layers to cosmic rays.

“Carbonaceous chondrites have short exposures to cosmic rays, which means they broke off from bigger asteroids not that long ago,” Welten said. “Ultimately, we’d like to know which asteroids which meteorites came from. It’s good to know what’s out there and how fast they can make it to Earth, in order to identify the most dangerous ones.”

Utas would be happy to donate part of his finds for research to benefit science. One meteorite in his collection was recently referenced in a scientific paper by a UCLA researcher. For now, though, he plans to keep the specimens or loan them out for educational purposes.

He doesn’t yet know whether or not he will end up focusing on the study of meteorites after he graduates in 2013, but this summer, at least, he’s devoted to finding more of the Sutter’s Mill meteorite. After turning in a final paper on May 9, he left again for the Sierra Nevada foothills and doesn’t plan to return anytime soon.

UC Berkeley meteorite hunters.

Nine of the UC Berkeley students and former students who met in the Sierra Nevada foothills to search for pieces of the Sutter's Mill meteorite. Back row, left to right: Geology graduate student Ian Rose, undergraduates Ryan Turner, Sevag Mehterian, Rebecca Trinh and Amelia Weiss, Berkeley graduate Michelle Myers and Jason Utas. In front are graduate student Amanda Thomas and undergraduate Ara Alexanian.

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