Cassini image shows Saturn heading toward solstice
A visible-light image of Saturn and one side of its rings taken by NASA’s Cassini spacecraft on February 3, 2017, shows the planet’s shrinking shadow on the rings as it approaches its May 2017 solstice.
Looking to the sunlit side of the rings from a position approximately 10 degrees above the ring plane, the image was captured by Cassini’s wide-angle camera.
It was taken from a distance of about 760,000 miles (1.2 kilometers) from the giant planet, with an image scale of 46 miles (73 kilometers) per pixel.
Saturn’s changing seasons as it progresses in its nearly 30-year solar orbit can be seen in images taken by the probe since it began orbiting the planet in July 2004.
Shadows of the planet on the rings grew longer from Cassini’s 2004 arrival through its equinox in August 2009, when they subsequently began to shrink.
An image taken by Cassini in 2015 shows shorter shadows than those taken in 2009.
In the recent photo, the shadows are even shorter, stretching only to the innermost A ring. Images captured in earlier years show longer shadows extending to the middle and even outer A ring.
Seasons on Saturn, like those on Earth, are caused by the planet’s axial tilt, which, at 26.7 degrees, is slightly greater than that of Earth, which is 23.4 degrees.
Laurel Kornfeld is an amateur astronomer and freelance writer from Highland Park, NJ, who enjoys writing about astronomy and planetary science. She studied journalism at Douglass College, Rutgers University, and earned a Graduate Certificate of Science from Swinburne University’s Astronomy Online program. Her writings have been published online in The Atlantic, Astronomy magazine’s guest blog section, the UK Space Conference, the 2009 IAU General Assembly newspaper, The Space Reporter, and newsletters of various astronomy clubs. She is a member of the Cranford, NJ-based Amateur Astronomers, Inc. Especially interested in the outer solar system, Laurel gave a brief presentation at the 2008 Great Planet Debate held at the Johns Hopkins University Applied Physics Lab in Laurel, MD.