About 6 a.m. Saturday, some residents of Tuolumne and Calaveras counties reported a thundering boom right after the space shuttle Columbia passed overhead.

Some heard one roar; others heard two. Some people said it shook their homes and rattled the windows.

Representatives at NASA headquarters in Washington, D.C., yesterday said the orbiter was too high to make a sound on Earth.

However, Doug Kohl, a Confidence man who worked as a site test conductor for John F. Kennedy Space Center in Cape Canaveral, Fla., said the noises could have been sonic booms caused by shuttle tiles falling from Columbia.

The space orbiter fell apart as it re-entered Earth's atmosphere Saturday, killing all seven astronauts on board just minutes before its scheduled landing in Florida.

A sonic boom is a thunderlike noise made when an aircraft or other passing object breaks the sound barrier or decelerates from above to below the sound barrier, Kohl said.

NASA reports show Columbia's landing path cruised between Lake Tahoe and Yosemite National Park, and Kohl said his analysis of latitude and longitude coordinates show the shuttle sped right over Sonora.

Therefore, if pieces of tile dropped over Sonora from the shuttle at that time traveling many times the speed of sound they fell close enough that residents in Tuolumne and Calaveras counties could hear the sonic boom, Kohl said. NASA has theorized that the orbiter's breakup began over the West Coast and has dispatched investigative teams to look at objects people have found since Saturday morning.

In Tuolumne, Lou and Sue Quilla were watching Columbia cross the sky when they heard two booms. They heard the first sound about three minutes after seeing the shuttle's trail streak by.

"It was a rumble-type noise," Sue said. "It was further away than the normal sonic boom that I've heard in the past, but I didn't think anything was wrong."