The American Meteor Society (AMS) says it received more than 200 reports about a bright green fireball over San Antonio, Texas on Saturday night. The fireball lit up the sky at about at about 8:45 p.m. local time, burning "five times brighter than a full moon," according to the AMS website.
Bill Cooke of NASA's Meteoroid Environment Office said at a press conference on Sunday, "This was definitely what we call a fireball, which by definition is a meteor brighter than the planet Venus."
"This event was so bright that it was picked up on a NASA meteor camera in the mountains of New Mexico over 500 miles away, which makes it extremely unusual," he said. "This was a very bright event."
Based on NASA data, Cooke estimated that the meteor was at least four feet wide and weighed about 4,000 pounds. He explained that when a piece of a comet or asteroid hurtling through space hits the Earth's atmosphere, pressure causes it to break apart violently in an explosion.
It is not yet known whether any meteorite fragments hit the ground.
NASA is not sure where the Texas fireball originated. One source could be the North Taurid meteor shower, which is going on right now. It could also have been a piece of rock from the main asteroid belt between Mars and Jupiter, according to Cooke.
"We're going to have to wait until we get more data to discriminate between the two of them," Cooke said
Thousands of fireballs streak across the Earth's atmosphere each day, according to the American Meteor Society. Though they are relatively common, they are rarely noticed because they usually occur over the ocean or uninhabited areas, or are obscured by daylight or cloud cover.
"A city dweller in the U.S. might expect to see events this bright once or twice per year," Cooke said.
"This one was around 8:40, so there were a lot of people outside and those events get a lot of notice," he said. "There would have been far fewer reports if it happens around 3 a.m."
The event was caught on several cameras and generated a large amount of social media traffic.