UC Davis professor to speak about meteorite that broke over the Sierra in April

The minivan-sized meteorite that broke up over the Sierra on Sunday, April 22, 2012 was not just any old space rock. It was one of the rarest types of meteorites to fall to Earth — a carbonaceous chondrite, the earliest solid material to form in our Solar System more than four and a half billion years ago, before the planets, including the Earth, formed.

This meteorite could turn out to be one of the most important observed fall since the late 1960s, says UC Davis geology professor Qing-Zhu Yin. These primitive meteorites provide a glimpse into the first few millions of years of the Solar System's history. Professor Yin will speak at the Tahoe Center for Environmental Sciences on Nov. 1 beginning at 6 p.m.

This meteorite fall came at the opportune time as both NASA and JAXA (NASA’s counter part in Japan) prepare two space craft sample return missions (OSIRIS REx and Hayabusa-2) from the two carbonaceous chondrite parent asteroids, which may hold clues to the origin of the Solar System and organic molecules as building blocks for life.

Professor Qing-Zhu Yin of the UC Davis Department of Geology uses extinct radioactivity and general isotopic anomalies in the early solar system recorded in primitive meteorites as a tool to study the time scales and site of nucleosynthesis, the time of formation of the solar system and planetary differentiation. Professor Qing-Zhu Yin’s research focuses primarily on reconstructing the history of chemical and physical processes involved in the formation of the Sun and the planets.

To address these problems, he studies the isotopic compositions of those elements, which were produced during nucleosynthetic processes in stellar outflows, sprinkled into interstellar medium, and subsequently mixed into the solar nebula ~4567 million years (Ma) ago, and locked into a diverse set of planetary materials including the Earth. Some of these newly generated nuclides decay radioactively with relatively short half-lives (t1/2 =0.1-10 Ma). These short-lived radionuclides can therefore be used to obtain high-resolution chronologic constraints on early solar system processes.

In this general public talk, Dr. Yin will review what scientists could learn and have already learned about the origin of our solar system from the Sutter’s Mill meteorite and similar meteorite fall like the one in Sutter’s Mill; why scientists need a lot more materials; how to identify the general features of CM carbonaceous chondrites in the field, with examples from Sutter’s Mill; how to handle the sample for safe storage, how we might be able to find more samples before the rainy season starts, followed by a brief question-and-answer session.

— Writer Heather Segale is an environmental specialist at the Tahoe Center for Environmental Science. She can be reached at (775) 881-7562 or hmsegale@ucdavis.edu