Explanation: Don’t be frightened by Saturn’s mysterious ghostly spokes! Today’s space image features a nearly two-hour time-lapse of Saturn and its rings, shown moving forward and backward. Because a day on Saturn lasts only about 10 hours, this observation captures a significant portion of the planet’s rotation. Look closely and you may notice a haunting shadow appear and disappear as Saturn’s B Ring rotates. Decades of observations from Voyager 2, Cassini, and the Hubble Space Telescope reveal that Saturn’s ring spokes change with the planet’s seasons. Like Earth, Saturn’s spin axis is tilted relative to the plane of its orbit around the Sun. During Saturn’s equinox, the rings are tilted less directly toward the Sun, allowing sunlight and the solar wind to reach the planet and its rings more evenly. Although scientists are still investigating their exact origin, Saturn’s spokes may be created by shadows and reflections from electrically charged dust and ice particles levitating above the rings. These particles could be influenced by electromagnetic interactions between the solar wind and Saturn’s magnetic field.
Find a dark-sky location and look up this August to enjoy the Perseid meteor shower without interference from moonlight!
Tomorrow’s picture: the COSMOS
Source: science.nasa.gov