This photo of Saturn was taken by NASA’s Hubble Space Telescope on October 22, 2023, when the ringed planet was about 85,000 miles from Earth. Hubble’s razor-sharp vision reveals a phenomenon called ring spokes.
Saturn’s spokes are temporary features that rotate with the rings. Their ghostly appearance only lasts for two or three revolutions around Saturn. During the active period, newly formed spokes continually add to the pattern.
In 1981, NASA’s Voyager 2 took the first photo of a ring spoke. NASA’s Cassini spacecraft also discovered Spoke during her 13-year mission, which ended in 2017.
Hubble continues to observe Saturn every year as its spokes come and go. This cycle is captured by Hubble’s Outer Planet Atmospheric Legacy (OPAL) program, which began nearly a decade ago to annually monitor weather changes on all four gas giants.
Hubble’s clear images show that the frequency of the spokes’ appearance is seasonal, and they appeared in the OPAL data for the first time in 2021, but only on the morning (left) side of the ring. Long-term monitoring has shown that both the number and contrast of spokes change with Saturn’s seasons. Saturn’s axis is tilted like Earth’s, and its seasons last about seven years.
“We’re heading toward the Saturn equinox, when the spoke activity is expected to be at its peak, and we’ll see a number of “We will see higher frequencies and darker spokes throughout the year.” .
This year, these ephemeral structures will appear on both sides of the Earth simultaneously, rotating around the giant world. Although it appears small compared to Saturn, its length and width can extend to more than Earth’s diameter.
“The leading theory is that the spokes are connected to Saturn’s strong magnetic field, and that some interaction between the sun and the magnetic field is bringing them about,” Simon said. As Saturn approaches its vernal equinox, Saturn and its rings tilt less away from the Sun. In this configuration, the solar wind could hit Saturn’s massive magnetic field even harder, promoting spoke formation.
Planetary scientists believe that the electrostatic forces generated by this interaction cause the dust and ice to float above the ring, forming the spokes, but even after decades, no theory can fully predict the spokes. . Continued Hubble observations may ultimately help solve the mystery.