The explanation is simple, and somewhat… disappointing.

Early Saturday morning, Todd Salat pointed his camera toward the skies above Delta Junction, hoping to capture the stunning aurora borealis. But this time, he encountered a strange sight.

In the northern sky, a cluster of lights grew brighter and closer toward Salat, gradually forming a strange spiral shape. “ It kept getting bigger and bigger, and I had no idea what it was ,” photographer Todd Salat recalled.

On aurora “hunting” groups, many people also captured strange spirals and posted questions. Most of the answers were related to SpaceX, or more specifically, a spacecraft launched by Elon Musk’s aerospace agency.

The answer was confirmed the next morning, when researcher Don Hampton sent out an email explaining the situation. Few expected Hampton’s explanation to cause … disappointment.

The fact was confirmed in an email sent out on Saturday, the same day the spiral was discovered. Don Hampton, a researcher at the University of Alaska’s Geophysical Institute, confirmed that the spiral “ appears to be exhaust from a rocket engine belonging to SpaceX’s Transporter-7 mission, which [the space agency] launched a Falcon 9 rocket from the California area about three hours before [Todd Salat took the photo] .”

“ The water vapor from the cryogenic engine is absorbed by the light from above, which then shines and creates the spiral shape of a galaxy, ” Hampton added .

Mr. Salat said the answer was not very satisfying, not creating the same overwhelming feeling as when he witnessed the strange phenomenon with his own eyes.

“ The spiral is absolutely perfect. It’s beautiful. I have to say, it’s a shame that it’s spaceship waste ,” Todd Salat said, expressing his disappointment. “ I was so interested in the mystery, in the unknown, because when I found out what it was, I found that interest faded a little bit .”