Astronomers say a loud explosion heard across a large swath of Nevada and California on Sunday morning was likely caused by a meteor, just after the peak of an annual meteor shower.
The sound of the explosion around 8am prompted a flood of calls to law enforcement agencies on both sides of the Sierra Nevada in the two states.
Observers in the Reno-Sparks area of Nevada reported seeing a fireball at about 8 a.m. local time, accompanied or followed by a thunderous clap that experts said could have been a sonic boom from the meteor or the sound of it breaking up high over the Earth.
"It made the shades in my room shake hard enough to slam into the window a couple times," said Nicole Carlsen of the Reno area. "I kept looking for earthquake information, but (there was) nothing. I even checked the front of my house to make sure no one ran into the garage. I wish I had seen the meteor."
Some people in the two states reported seeing a fireball streak across the sky at the same time.
Being daylight, most of the reports are of a white object with blue and green being most mentioned secondary colors. The average brightness reported by witnesses was between that of the sun and the light produced by a full moon. While this is most likely a random event, there is a possibility this fireball was a member of the Lyrid meteor shower.
Dan Ruby of the Fleischmann Planetarium at the University of Nevada, Reno, says the reports indicate the meteor broke up above Earth somewhere over the Sierra southwest of Reno. When debris enters the atmosphere it creates explosions similar to the sonic boom of a fast-moving aeroplane, according to meteorologists.
There were no reports of earthquakes at the time.