Witnesses across Alabama reported a mysterious “boom” that rocked their counties on Tuesday evening. NASA said the origin of the blast “remains unclear” as social media went awash with conspiracy theories and even devoted a song to the unexplained event.

The sound blast could have been generated by a “bolide, large supersonic aircraft or a ground explosion” but wasn’t caused by a Leonid meteor, NASA said, as cited by meteorologist James Spann from the American Meteorological Society (AMS). The unknown event was reported by the National Weather Service in Birmingham, as well as St. Clair and Blount Counties.

Re: loud boom heard: we do not see anything indicating large fire/smoke on radar or satellite; nothing on USGS indicating an earthquake. We don't have an answer, and can only hypothesize with you. 1) sonic boom from aircraft; 2) meteorite w/ current Leonid shower? — NWS Birmingham (@NWSBirmingham) November 14, 2017

Reports of a loud sound coming in from various parts of the county. We will post information as soon as it becomes available. — St. Clair County EMA (@stclairema) November 14, 2017

Alabama residents flocked to Twitter, with many saying the event even shook their homes. The boom was detected on a seismograph in Cleburne County, according to meteorologists from the local TV stations.

@spann I heard and felt an incredibly loud boom from inside my home in Moody around 1:40-1:45pm today. Shook the entire house. Any news? Thanks! #boom — Jeff Harbison (@JeffSellsHouses) November 14, 2017

The incredible boom many of us heard this afternoon was actually detected on a seismograph in Cleburne County. Thanks to Steve Jones at Earth Alabama for the data. pic.twitter.com/qdqFJZqtft — James-Paul Dice (@jpdice_Fox6) November 14, 2017

The “mysterious boom” seems to have become a topic of the day as a local singer-songwriter Trey Cochran even wrote a song titled ‘The Bama Boom.’

In the meantime, supporters of conspiracy theories who still believe “the truth is out there” suggested that what they heard was “UFOs” or secret drills at the Redstone Arsenal military facility in Huntsville.

Way too many lights on for 1:49 pm......I think it's paranormal activity. Hahaha! — DMc Geography 🇹🇼 (@GeographyDMc) November 15, 2017