A “mysterious spiral” that was briefly visible in the sky over Alaska left local photographers wondering what they had just seen. However, an expert said the truth behind it is pretty simple.

Around 2:00 a.m. on Saturday, Todd Salat was out to take photos of the northern lights near Delta Junction when he spotted “maybe the most bizarre thing I’ve ever seen in my life,” according to theAnchorage Daily News.

Elizabeth Withnall, who was hundreds of miles away in the Kotzebue, said she’s used to seeing “very unusual” things in the sky — but was completely clueless about the sight, per theAnchorage Daily News.

“I just thought, ‘this is some weird thing in the sky, and I don’t know what it is, but it’s pretty cool,’ " the midwife recalled thinking.

RELATED VIDEO: NASA Announces First Woman and Black Man for Moon Mission in 2024

Of course, in the end, the mysterious spiral wasn’t actually a mystery.

Don Hampton, a research associate professor at the University of Alaska Fairbanks Geophysical Institute, told theAssociated Pressthe galaxy-like vision was just a result of aSpaceX rocketreleasing excess fuel.

Never miss a story — sign up forPEOPLE’s free daily newsletterto stay up-to-date on the best of what PEOPLE has to offer, from celebrity news to compelling human interest stories.

“When they do that at high altitudes, that fuel turns into ice,” he told the news agency. “And if it happens to be in the sunlight, when you’re in the darkness on the ground, you can see it as a sort of big cloud, and sometimes it’s swirly.”

And although the photos may have “created a bit of an Internet storm” and looked “really cool,” it was “just water vapor reflecting sunlight.”

For some, knowing the truth is a bit of a let down.

“I did enjoy that mystery, and the unknown, because after I found out what it was, I noticed that the wonder of it all kind of faded a little bit,” Salat told theAnchorage Daily News. “It was kind of a shame to think of it as exhaust.”

Joking about SpaceX’s role in what happened, Withnall wrote on social media, “Seriously Elon? You gotta ruin my aura?I was hoping a spaceship would land and aliens would hop out.”

source: people.com