The US space agency says reports of a flash in the sky along much of the US East Coast appeared to be a “single meteor event”.
Social media sites have been buzzing with reports of the flash that streaked across the sky.
It was spotted as far south as Florida and as far north as New England, reports said.
Bill Cooke of Nasa’s Meteoroid Environment Office said it “looks to be a fireball that moved roughly toward the southeast, going on visual reports.”
“Judging from the brightness, we’re dealing with something as bright as the full moon,” Mr Cooke said.
“We basically have [had’a boulder enter the atmosphere over the northeast.”
He says the meteor was widely seen, with more than 350 reports on the website of the American Meteor Society alone.
Robert Lunsford of the society told USA Today “it basically looked like a super bright shooting star”.
Derrick Pitts, chief astronomer at Philadelphia’s Franklin Institute, agrees that the sightings had all the hallmarks of a “fireball”.
Mr Pitts said this one got more attention because it happened on a Friday evening.
He said it also helped that Twitter has provided a way for people to share information on sightings.
But Mr Pitts said experts “can’t be 100% certain of what it was, unless it actually fell to the ground and we could actually track the trajectory”.
However, he said the descriptions by so many people are “absolutely consistent” with those of a meteor.