A Russian cosmonaut aboard the International Space Station (ISS) has shared footage of what he describes as “space guests,” or UFOs, that made an unexpected appearance in a time-lapse video he captured of the southern lights.

On Wednesday, Ivan Vagner posted a one-minute video on Twitter showing the “peak” of the Aurora Australis as it moved between the Antarctic and Australia.

“In the video, you will see something else, not only the aurora,” he teased in the post.

In a follow-up tweet, Vagner directs his audience to look closely at the nine to 12 second-mark in the video to spot the unidentified flying objects.

“5 objects appear flying alongside with the same distance. What do you think those are? Meteors, satellites or…?” he wrote.

Those five bright objects appear in a straight line just above the curve of the Earth in the night sky for what seems like only a brief instant in the time-lapse video; however, they were actually visible for 52 seconds, Vagner explained.

“The frames were captured 1 per sec and later assembled in a video with 25 frames per sec rate. Meaning, the real observation time is 52 sec,” he wrote.

It’s unclear when exactly the footage was captured and if Vagner saw the UFOs when they appeared or later on the video.

While there has been no public comment from NASA about Vagner’s video, Russia’s space agency, Roscosmos, retweeted the post with the accompanying caption: “An interesting and at the same time mysterious video made by the cosmonaut of Roscosmos Ivan Wagner from the International Space Station.”

In another tweet, Vagner said he sent the video to Roscosmos management, Central Research Institute of Machine Building (TsNIIMash), and the Space Research Institute of the Russian Academy of Sciences for further analysis.

A spokesperson for Roscosmos was quoted by the Russian news agency TASS as saying that experts were studying the video to determine what the objects in it might be.

“It is too early to make conclusions until our Roscosmos researchers and scientists at the Space Research Institute of the Russian Academy of Sciences tell us what they think,” Vladimir Ustimenko said. “It was decided to hand over those materials to experts, who will tell us what that was in their opinion.”

Vagner has been working aboard the ISS with fellow Russian Anatoli Ivanishin and American commander Chris Cassidy since April.

According to a recent NASA blog post, Vagner was “exploring ways to improve Earth photography techniques” on Wednesday before he posted the time-lapse video. A subsequent blog post from the space agency did not make any mention of the footage and the apparent UFOs.

This content was originally published here.