More than two dozen people in Nevada and California reported seeing a fireball cross the sky early Thursday morning.
The reports, listed by the American Meteor Society, were that the fireball lit up the night sky at about 5 a.m. In all the society's website received 30 reports.
Fleischmann Planetarium Associate Director Dan Ruby said he didn't see the fireball, but that he'd heard people saw a blue flash above Lake Tahoe.
"We got some calls," he said. "My best guess is that it was the break-up of a bolide, a form of meteor."
Meteors strike the Earth's atmosphere regularly but sightings are relatively rare.
"Most are not very big and they're going very fast, so they break up in the atmosphere," he said. "If they're big enough to make a noise like the one in April they can be picked up by microphones that listen for nuclear tests."
Ruby said the majority of fireballs happen where people can't see them.
"The earth gains 100 tons every day from meteorites hitting it," he said. "There are about 2,000 fireballs a day, just not where people see them. That people saw it in the daytime is rare. That they heard the sonic boom is really rare."
On April 23 a fireball crossed over Western Nevada in broad daylight, accompanied by a sonic boom. The meteor broke up over the Sierra foothills in California.
Before the April fireball, the last time a meteor was visible over Nevada was November 2009, when a fireball that could be seen by people between Reno and Salt Lake City, flew overhead.
Fleischmann Planetarium: http://planetarium.unr.nevada.edu/
The American Meteor Society: www.amsmeteors.org