San Diego boom
© Fox5
A day after a "mystery boom" shook San Diego County, the strange sensation remains talk of the town — but so far there's still no clear explanation for the phenomenon.

From the South Bay through the city of San Diego and in to North County, residents reported a loud "boom" accompanied by the rattling of windows around 8:15 p.m. Tuesday.

Monitors didn't record any sort of significant earthquake in the region at that time, leaving a single educated guess, geologist Pat Abbott, a professor at San Diego State, told FOX 5.

"If the sound didn't emanate from underground there's only one more place to look and that's up above," Abbott told FOX 5, referring to a sonic boom. "Some aircraft ... something traveling at a rate faster than sound, oriented in the right direction."

While officials at Camp Pendleton have warned that artillery exercises may be heard in parts of San Diego this week, the sensation appeared to emanate from farther south, based on reports from residents. A military spokesperson added that aircraft they had over San Diego at the time are not capable of supersonic flight.

Short of a military-related explanation that's not being made public, Abbott posited another possible theory.

"We do know that incoming meteorites, something the size of a basketball or larger, can hit the atmosphere at the right angle that it effectively sends a shockwave a sonic boom to the earth," he told FOX 5.

In the end, all the speculation is enjoyable for people like the professor, who enjoyed watching the theories fly online. "Sometimes it's more fun not knowing the answer than knowing it," Abbott said.