While approximately 18,000 to 84,000 meteorites larger than 10 grams hit the Earth each year, one recent rock carried contents far less common than the average stoney or metallic mass from space. Eight months ago, a meteorite crashed to Earth that contained primitive space rocks that are not only older than the Sun, but older than our entire solar system. These ancient rocks, first of their kind to be discovered in such pristine condition, may provide scientists further insight into our solar system’s origins.
First spotted as a fast-moving fireball in the skies over California and Nevada, the U.S. Air Force and doppler weather radar installations tracked the meteorite during its descent on April 22, 2012. The three and a half meter wide meteorite struck ground in Sutter’s Mill, the famed location of the California Gold Rush’s beginning in 1848. The careful tracking of the meteorite’s descent allowed scientists to quickly collect pieces of it and prevent rain from damaging the fragments and changing their composition.
And that quick collection makes all the difference with rare rocks like these. Called “carbonaceous chondrites,” they are like sponges and are 30 percent empty. Carbonaceous chondrites draw water into themselves and cause chemical reactions that change their own composition–providing a perfect location for ancient chemicals to react, combine, and transform.
The importance of collecting these rocks before contact with water was evident in comparing two samples: a fragment that was exposed to water showed immense change in the composition of sulfur-bearing minerals. One researcher working with the Sutter’s Mill fragments, Dr. Peter Jennisken, told ABC that they found calcium sulfide in the rocks, a chemical compound that is so water-sensitive that it disappears if a person breathes on it.
The pristine quality of these ancient grains was verified by researchers from the SETI Institute and NASA’s Ames Research Center. More than an unusual find, the samples from the Sutter’s Mill meteorite are utterly unique: this was the first meteorite collected of its kind that did not come in contact with water on Earth. And with such reactive properties, it is remarkable that these samples were discovered as pure as they were.
Scientists believe these rocks represent the materials from which the solar system was formed and may offers insights on the creation of the Sun and planets, 4.5 billion years ago. These rocks are not only miniature time capsules for the matter of our planets and Sun. Carbonaceous chondrites also contain organic carbon molecules, which might be the early building blocks for life on Earth.