A camera on top of Hawaii’s tallest mountain has captured what looks like a spiral swirling through the night sky.
Researchers believe the strange phenomenon is linked to a military GPS satellite that launched from a SpaceX rocket in Florida.
The images were captured on 18 January by a camera at the summit of Mauna Kea, outside the National Astronomical Observatory of Japan’s Subaru telescope.
A time-lapse video shows a white orb spreading out and forming a spiral as it moves across the sky. It then fades and disappears.
Ichi Tanaka, a researcher at the observatory, said he was doing other work that night and did not see it immediately. Then a stargazer watching the camera’s livestream on YouTube sent him a screenshot of the spiral using an online messaging platform.
“When I opened Slack, that is what I saw and it was a jaw-dropping event for me,” Tanaka said. He saw a similar spiral last April, also after a SpaceX launch, but that was larger and more faint.
SpaceX launched a military satellite on the morning of 18 January from Florida’s Cape Canaveral Space Force Station. The location of the spiral matched where the second stage of the SpaceX rocket was expected to be after its launch.
SpaceX did not respond to an email seeking comment.
Tanaka said the observatory installed the camera to monitor the surroundings outside the Subaru telescope and to share images of Mauna Kea’s clear skies. Someone watching the sky in less clear conditions, for example from Tokyo, might not have seen the spiral, he said.
The livestream is operated jointly with the Japanese newspaper Asahi Shimbun, and frequently gets hundreds of viewers. Some people tune in to watch meteors.
The summit of Mauna Kea has some of best viewing conditions on Earth for astronomy, making it a favoured spot for the world’s most advanced observatories. The summit is also considered sacred by many native Hawaiians, who view it as a place where the gods dwell.