UPDATE APRIL 19: The weird noise in Southern Highlands Tuesday morning is getting an enthusiastic response from our viewers.
Several people have emailed and commented with thoughts on what the loud, continuous, low-pitch humming might be.
Anna Katerlin says she heard the sound for 12 minutes straight after midnight while she watched TV, and the source of it stumped her.
"I was scared but I don't know," Katerlin said. "Never heard anything similar like that."
She ruled out trains rolling through the desert because she's heard that before.
A man emailed us saying it sounded like a semi-truck, or several of them, driving on the grooves that line the Interstate 15 freeway. He believes a noise like that could hover and echo through the nearby mountains for several minutes.
13 Action News put the question to Facebook and the responses ranged from the wild to the weird to the plausible.
Someone said it was a pump station for the water department, and another said it was aliens coming down to take his ex-girlfriend back to her home planet.
A man who said he was a boiler operator wrote it sounded like a safety valve releasing pressure.
LAS VEGAS (KTNV) -- Something strange happened in Southern Highlands early Tuesday morning.
A loud, continuous, low-pitched humming noise drew neighbors outside, but no one seems to know what it was.
"Humming I would say," said Anna Katerlin, who heard the noise. "Like a metal, iron humming."
Katerlin says the mysterious pitch started at 12:15 a.m. and lasted 12 straight minutes.
She and her husband didn't see anything moving in the sky.
They asked 13 Action News to try to figure out what the sound was.
We thought it may have come from the U.S. Army Reserve Center close by. Our email to them wasn't returned.
Katerlin's husband says in the video they sent us it sounded like a train.
That seems possible because tracks run in the desert on the other side of the mountains next to Katerlin's neighborhood, but Katerlin is convinced it wasn't a train because in her two years of living there, she's never heard anything like the noise.
Neither the Bureau of Land Management nor the owner of a nearby quarry got back to us about whether a train was running at the time Katerlin heard something.
Katerlin's neighbors aren't as hungry for the truth as she is.
"It's a weird noise but even if I woke up by it, I wouldn't think about it too much," Marleny Calhoun said.
13 Action News asked Katerlin if she's considered an explanation more supernatural.
She said she doesn't believe in UFOs, but she does believe in "higher powers."
Let us know what you think about the noise on our social media accounts.