Antenna
© KSBWKSBW's Salinas station looks a little bit like a UFO tracking center.

Salinas, California - Somebody get Fox Mulder. A mysterious loud boom was heard and felt Monday morning from as far south as Soledad all the way north to Seaside Monday morning.

The big boom happened at 10:51 a.m. and rattled residents in Soledad, Chualar, Pebble Beach, Carmel, Monterey, Salinas, Marina, and Seaside.

Military and law enforcement officials told KSBW they are not sure what caused the explosive-like sound.

Several residents said they ran outside, looked up, and spotted an extremely fast-moving military jet making a U-turn over the Carmel Valley.

"Almost broke my windows, ran outside and saw a curved jet stream over Carmel Valley," resident Melinda Mayland said.

With no confirmed cause of the boom, rumors about UFO's, and requests to alert X-Files TV character FBI Special Agent Fox Mulder, quickly spread through the local rumor mill.

It is not unusual for U.S. Navy planes on training missions to fly out of Naval Air Station Lemoore near Visalia, Calif. and streak over south Monterey County. Their powerful engines can cause a sonic boom when they break the sound barrier.

Jet Stream
© KSBWThis jet stream was spotted above Carmel Valley when Monday's boom was heard.

NAS Lemoore spokeswoman Melinda Larson said three F/A-18 jets were flying Monday morning, but the pilots never accelerated faster than the speed of sound while above Monterey County.

It is possible that the jets broke the sound barrier while they were over the ocean, where it's legal for them to leave sound waves in the dust.

Sonic booms happen when an object zips through the air faster than the speed of sound -- about 768 miles per hour -- and creates shock waves. It's similar to how a boat sailing through the ocean creates waves in front and behind it.

People on the ground hear an explosive sound when the shock waves cross their location.

As of 1 p.m., air traffic controllers at Monterey Regional Airport and Salinas Municipal Airport said they were not aware of any aircraft that could have caused the boom.

Local law enforcement officials said there were no explosions reported that could make a sound heard by half the Central Coast.