The sky is falling, but it's meteors, not satellite debris, that lit up the sky in Kentucky, Texas and Italy.
After numerous people in Kentucky reported seeing blue-green light streaks and hearing thunder-like noises late Friday, the Federal Aviation Administration told pilots to be on the lookout for "a potential hazard ... due to re-entry of satellite debris into the Earth's atmosphere."
That explanation seemed to fit with what had happened a few days before, when two communications satellites collided 490 miles above northern Siberia.
But the FAA notice was quickly withdrawn after the military advised that no satellite debris was falling, FAA spokeswoman Kathleen Bergen said Monday.
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"It was the result of some sort of natural phenomenon," Bergen said.
It turns out, astronomers say, that the satellite debris was too high to be falling back to Earth this quickly — and probably too small to make much light and noise.
That means that what people saw were meteors, the bits of space dust or rock that hit the Earth's atmosphere and nearly always burn before hitting the surface.
Three fireball meteors were seen over Italy just hours before the lights began streaking across Kentucky, the Web site SpaceWeather.com reported.
The Kentucky light and sound show was seen over a large area of the state, with some people saying it shook houses and briefly turned night into day.
Then, on Sunday, runners in a marathon in Austin, Texas, saw a fireball so bright that it was visible in daylight.
Bill Cooke of NASA's Meteoroid Environment Office looked at a video of that fireball and told SpaceWeather.com that "it's a natural meteor, definitely."
University of Kentucky astronomy professor Tom Troland, who is doing work at a Spanish observatory, said the reports of what people saw fit the meteor explanation.
"As you know, meteors are seen all the time. Occasionally they are very bright and lead to a sonic boom-type noise," he said.
A spokeswoman with the North American Aerospace Defense Command and U.S. Northern Command, which tracks man-made objects entering the Earth's atmosphere over North America from Colorado Springs, Colo., said she was not aware of Friday's reports from Kentucky. But Master Sgt. Claudette Hutchinson said they sounded similar to what was coming out of Texas on Sunday.
She said that NORAD saw nothing on its radar on Friday night or over the weekend and there was "definitely nothing" from last week's satellites hurtling through the sky.
"If something was re-entering the Earth's atmosphere, we'd track it," she said.