New Hubble Telescope Image Shows Mysterious Spokes On Saturn's Rings

The Hubble Space Telescope has captured a recent image revealing the enigmatic and ethereal shadows on Saturn's rings, marking the latest observation of the puzzling phenomena known as "spokes," which continues to perplex scientists.

Released by NASA on Thursday, the composite photo was taken by the Hubble on October 22 when Saturn was approximately 850 million miles (1.37 billion kilometres) away, as reported by the space agency. Orbiting Earth at just a few hundred miles above the surface for over three decades, the space observatory has provided valuable insights.

Scientists have been aware of the mysterious spokes on Saturn's rings for a long time. These peculiar features resemble spectres gliding along the rings and can be observed in different locations depending on Saturn's position in its orbital cycle.

Through ongoing observations, it has been noted that the quantity and characteristics of the spokes on Saturn's rings fluctuate in correspondence with the planet's seasonal cycle. Comparable to Earth, Saturn possesses an axis with a tilt that induces seasonal transformations. However, each season on Saturn extends for approximately seven years, as disclosed by NASA.

Hubble is poised to closely study this perplexing phenomenon during its peak activity, as researchers endeavor to unveil its secrets.

"We are heading towards Saturn equinox, when we'd expect maximum spoke activity, with higher frequency and darker spokes appearing over the next few years," said Amy Simon, the lead scientist of Hubble's Outer Planet Atmospheres Legacy, or OPAL, program, in a statement. Simon is based at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

Saturn's autumnal equinox is expected to occur on May 6, 2025, CNN reported. 

Saturn's spokes are transient features that rotate along with the rings. Their ghostly appearance only persists for two or three rotations around Saturn. During active periods, freshly formed spokes continuously add to the pattern, NASA said. 

In 1981, NASA's Voyager 2 first photographed the ring spokes. NASA's Cassini orbiter also saw the spokes during its 13-year-long mission that ended in 2017.

Hubble continues observing Saturn annually as the spokes come and go. This cycle has been captured by Hubble's Outer Planets Atmospheres Legacy (OPAL) program that began nearly a decade ago to annually monitor weather changes on all four gas-giant outer planets.