The Hubble Space Telescope captured a newly revealed image of the mysterious, ghostly shadows on Saturn’s rings — the latest sighting of the so-called “spokes” that continue to baffle scientists.

The composite photo, released Thursday by NASA, was taken by Hubble on Oct. 22 as Saturn was about 1.37 billion kilometers away, according to the space agency. The space observatory has been orbiting Earth just a few hundred miles above the surface for more than three decades.

Astronomers have long known about the perplexing spokes on Saturn’s rings, which look like apparitions skating along the rings and can be spotted