LOS ANGELES -- Many people took to social media Tuesday evening to say they'd seen a bright light streaking across the sky, reports CBS Los Angeles.
The mystery light was reported by dozens of people on social media, including some in Las Vegas, Death Valley, Santa Barbara, Ventura, Indio, Corona, and Irvine.
Many described it as a fireball with debris falling from it as it moved, the station says.
CBS Las Vegas affiliate KLAS-TV said it had "received numerous reports of some sort of a fireball that shot across the Vegas Valley sky." It posted video.
Lt. Col. Martin O'Donnell, of the U.S. Strategic Command told CBS News the light was Russian space debris -- an SL-4 rocket body booster -- that re-entered the atmosphere at about 7 p.m. MST. The debris may have been from the rocket that launched a Soyuz supply vehicle to the International Space Station on Monday.
"Every day, hundreds and hundreds of tons of material slam into the Earth's atmosphere," UC San Diego physics professor Brian Keating told CBS News. "But we're quite fortunate that most of these objects that are produced on Earth are tracked, and we can control, to some extent, what their characteristics are going to be when they come back to Earth."
Among the tweets CBS Los Angeles cited when the source of the light was still very much up in the air: