(CNN) - A bright, strange-looking light streaked across Northern California on Wednesday night, its appearance coinciding with a scrapped rocket launch and leaving the Twitterverse asking, "So, what's that in the sky?"
The answer: Probably a meteor.
The phenomenon was spotted over the Lake Tahoe area, the Sacramento Valley and the Bay Area around 5:45 p.m. local time.
It has not been 100% identified, however "evidence is growing the object seen was a meteor," according to the National Weather Service Bay Area, reiterating that stance on Thursday after the American Meteor Society called the flash a fireball.
"A meteor can create a very high level cloud called a noctilucent cloud," the weather service said.
Noctilucent clouds were previously observed over Monterey, California in 2011, the National Weather Service said via Twitter. They were formed by the launch of the NPOESS Preparatory Project spacecraft from Vandenberg Air Force Base near Santa Barbara.
Dr. Edwin C. Krupp, the longtime director of the Griffith Observatory in Los Angeles, said the fireball was seen in the western sky, traveling east to west over the Pacific Ocean.
He said the object was probably an interplanetary rock moving so fast that it superheated and compressed the night air, creating a streak of light. The meteor that created the fireball, known as a bolide, was probably small enough to fit in a human hand, he judged.
There was speculation that the cloud-like formations seen Wednesday were related to a planned rocket launch at Vandenberg.
However, United Launch Alliance, a launch service provider for national security missions, announced that the launch had been scrubbed due to "indications of booster complications."
It was the fourth time United Launch Alliance scrubbed the much-anticipated launch of a Delta IV-Heavy rocket from Vandenberg to carry the NROL-71 satellite into orbit for the National Reconnaissance Office.
The launch has been rescheduled for December 30, at the earliest.
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