Scientists Reveal Findings on Sutter's Mill Meteorite
A meteorite that exploded over California's Sierra foothills this past spring was among the fastest, rarest meteorites known to have hit the Earth. After collecting and studying fallen pieces of the meteorite, an international team of scientists is ready to announce their research, reporting on everything from the meteorite's age, to it's travelled course and original size.
The researchers found that the meteorite that fell over Northern California on April 22 was the rarest type known to have hit the Earth — a carbonaceous chondrite. It is composed of cosmic dust and presolar materials that helped form the planets of the solar system.
The scientists learned that the meteorite formed about 4.5 billion years ago and was knocked off its parent body, which may have been an asteroid or a Jupiter-family comet, roughly 50,000 years ago. That began its journey to earth where it hit Sutter's Mill, the site that sparked the California Gold Rush.
As it flew toward Earth, it traveled an eccentric course through the solar system, flying from an orbit close to Jupiter toward the sun, passing by Mercury and Venus, and then flying out to hit Earth.
The fiery, minivan-sized boulder entered the atmosphere at about 64,000 miles per hour. The study said it was the fastest, "most energetic" reported meteorite that has fallen since 2008, when an asteroid fell over Sudan.
"If this were a much bigger object, it could have been a disaster," said co-author and UC Davis geology professor Qing-zhu Yin. "This is a happy story in this case."
Before entering Earth's atmosphere, the meteorite is estimated to have weighed roughly 100,000 pounds. Most of that mass burned away when the meteorite exploded. Scientists and private collectors have recovered about 2 of those pounds.
Meteorites like Sutter's Mill are thought to have delivered oceans of water to the Earth early in its history. Using neutron-computed tomography, UC Davis researchers helped identify where hydrogen, and therefore water-rich fragments, resides in the meteorite without breaking it open.
Yin says, "This first report based on the initial findings provides a platform to propel us into more detailed research. Scientists are still finding new and exciting things in Murchison — a similar type of meteorite to Sutter's Mill — which fell in Victoria, Australia, in 1969. We will learn a lot more with Sutter’s Mill."
The findings are being published today in the journal Science.
Read more at University of California Newsroom.
Meteorite image via Shutterstock.