Two more pieces of the fireball that exploded over the Bay Area in mid-October have been found, bringing the total of meteorite fragments found to four -- all in Novato.
"This rock has been floating around space relatively unchanged for a little over four and a half billion years, and it just happened to land in our backyard a few weeks ago," said Jason Utas, a University of California at Berkeley geology student who made the third find. "It's pretty darn cool."
Utas and Robert Verish, an Escondido-based meteorite hunter, each found a meteorite, both measuring about 2 inches, on Oct. 27. The first find was by Lisa Webber on Oct. 20, at her home on St. Francis Avenue in Novato's Pleasant Valley neighborhood. Two days later, meteorite hunter Brien Cook found another space rock two miles away.
"The second one (Cook's find) was found two miles southeast of the Webbers' house," Verish said. "Then pretty much north by two miles of that find is the other two." Like the first two, the space rocks are termed ordinary chondrite, the most common type of meteorite found.
The first and second finds have been confirmed as chondrites by Alan Rubin, a researcher at UCLA's Institute of Geophysics and Planetary Physics who is an expert on such identification. The third and fourth space rocks are chips off the old meteor, so to speak.
Meteors hurtle toward the Earth at 36,000 mph, and when they hit the Earth's atmosphere they slow down. Just as when brake shoes come into contact with a tire, there's friction, and the heat from the friction chars the outside of the rock. This causes what's known as a fusion crust -- the clear mark of a space rock.
The minute Utas saw his meteorite up close, he knew he had a strike.
"I found it in the middle of the road," said Utas, 22, who has hunted meteorites since the age of 8. "I've walked around 100 miles in the last two weeks" looking for a fragment from the Oct. 17 meteor shower.
"I saw it while driving. I couldn't tell if it was a meteorite. It was one of those moments when you don't know if it's worth stopping."
But stop he did. "I knew it was one (meteorite) as soon as I saw it. I called my dad right away, then my mom and then my girlfriend," Utas said. Utas and his father, who is also a meteorite hound, have a website devoted to their collection, Falls and Finds: http://www.fallsandfinds.com/.
"The more pieces we can recover, the better picture we will have of what this asteroid was all about," said Peter Jenniskens, the NASA-affiliated meteor hunter at the SETI Institute in Mountain View, who is coordinating the hunt. "Each rock comes from a different spot on the asteroid, and together they make up the pieces of the puzzle."
A diagram of where the meteorites are believed to have fallen can be found on Jenniskens' blog at http://cams.seti.org/. There is also a site tracking Novato meteorite finds at http://asima.seti.org/n/. Those who think they may have found a meteorite should send email to Petrus.M.Jenniskens@nasa.gov.
Verish encouraged amateur meteorite hunters to look in their backyards, especially those in Sonoma County, Yountville and St. Helena.
"Some insurance adjuster may be writing up a report of broken glass without realizing it's not vandalism -- unless you want to call it cosmic vandalism," Verish said.