In April of this year, the scientists recovered a rare meteorite which contains clues to the early history of the solar system.
Using Doppler radar, the same technology used by weather forecasters, the scientists detected a shower of meteors raining down over the communities of Coloma and Lotus, just after the asteroid broke up in the atmosphere.
That allowed scientists to, for the first time, quickly find, recover and study a primitive meteorite that had little exposure to the elements.
It’s the most pristine look at the surface of ancient asteroids scientists have been able to study so far. Because of the rapid recovery of materials, scientists were able to detect compounds that quickly disappear once a meteorite hits Earth.
Reporting in Science, the researchers say their rare find was classified as a Carbonaceous-Mighei or CM-type carbonaceous chondrite meteorite, which is known to contain water and complex organic compounds, such as amino acids, molecules that help form life.
But, according to NASA’s Danny Glavin, he and the other scientists weren’t able to detect many of the amino acids in their find because it appeared the samples had been heated in space before arriving on Earth.
“The small three meter-sized asteroid that impacted over California’s Sierra Nevada came in at twice the speed of typical meteorite falls,” said lead author Peter Jenniskens, of the SETI Institute and NASA’s Ames Research Center, both located in California. “Clocked at 64,000 miles per hour, it was the biggest impact over land since the impact of the four meter-sized asteroid 2008 TC3, four years ago over Sudan.”
The scientists also say that, for the first time, they were able to identify the region of space where these types of meteorites come from.
After studying photographs and video of the asteroid, Jenniskens figured that it came in on an unusually low-angled orbit, more like a comet‘s orbit, passing closer to the sun than what has been learned from past recorded meteorite falls.
Scientists found the asteroid, as it was in orbit, was influenced by the gravity of both the Sun and Jupiter at times.
“It circled the sun three times during a single orbit of Jupiter, in resonance with that planet,” Jenniskens said.
The asteroid that spawned the meteorite was estimated to be around 45359 kg. Of that, less than 1kg was actually recovered on the ground in the form of 77 tiny meteorites. The biggest of those meteorites was 205 grams.
While the scientists didn’t find much actual gold in the Sutter’s Mill meteorite, about 150 parts per billion, it was still “scientific gold,” according to co-author and cosmochemist Qing-zhu Yin of the University of California at Davis.
“With 78 other elements measured, Sutter’s Mill provides one of the most complete records of elemental compositions documented for such primitive meteorites,” he said.