Astronomers: Meteor Caused Calif., Nevada Explosion It rattled windows from Sacramento to Reno yesterday morning By Mark Russell, Newser Staff Posted Apr 23, 2012 5:47 AM CDT 5 comments Comments Astronomers say a loud explosion heard around much of California and Nevada was most likely a meteor. (Shutterstock) (Newser) – No need to panic: That loud explosion heard early yesterday morning around large parts of California and Nevada? It was likely just a ... meteor, say astronomers. The mysterious explosion rattled windows and shook houses from Sacramento to Reno, causing residents throughout the region to phone police. Some people also reported seeing a fireball right around 8am. One astronomer tells the AP that the meteor likely broke up somewhere over the Sierra southwest of Reno.