It was not the first time in recent memory that people have wondered about seemingly mysterious activities overhead.

In December 2018, the sky over New York City erupted in a blue light. People theorized about a U.F.O. flyby or an alien invasion, though the cause turned out to be a transformer explosion at a Con Edison substation. In 2015, a 500-pound meteor streaked through the sky above western Pennsylvania triggering a sonic boom, The Pittsburgh Post-Gazette reported. More recently, in October, a boom shook homes in New Hampshire, giving rise to theories that an earthquake or an aircraft was to blame. (Satellite imagery, however, suggested a meteor exploded in the atmosphere above the state.)

In Pittsburgh on Saturday, Ms. Lake said that nobody reported seeing anything “below the cloud deck,” which was about 2,000 feet above the ground. Ms. Lake thinks the meteor could have been “a couple of thousand feet” above the ground, but not below the cloud cover.

For now, a meteor explosion is the best theory about what happened over Pittsburgh on Saturday, Ms. Lake said, though it will remain just that — a theory — “unless someone finds some rocks in their backyard,” she said.

Ms. Turnshek, the Carnegie Mellon lecturer, said that what she and others in Pittsburgh experienced on New Year’s Day was “rare and notable,” a “once-in-a-lifetime event.”

Despite the rarity, there is no shortage of movies depicting the dangers of a meteor, asteroid or comet crashing to Earth (including “The Day the Sky Exploded,” “Meteor,” “Armageddon” and the recent “Don’t Look Up”).

Astronomers are on the lookout for such things, Ms. Turnshek said. “If we had found a large body incoming,” the best solution would probably be to “send a rocket to sit next to it, and the gravitational pull of the rocket will pull it off course.”