Yearly snapshot of Saturn helps astronomers monitor the ringed world
UC Berkeley helps lead an annual campaign by NASA to photograph our solar system's giant, gaseous planets
September 12, 2019
The Hubble Space Telescope’s annual snapshot of Saturn reveals a turbulent, dynamic atmosphere with small storms popping into view as others disappear, all framed by the planet’s bright, icy rings.
Analyzed by Mike Wong of UC Berkeley and Amy Simon of NASA’s Goddard Space Flight Center, the Hubble portrait is part of a yearly campaign to record the giant planets in the solar system — Jupiter, Saturn, Uranus and Neptune — to track shifting weather patterns and discover new phenomena. NASA released its annual portrait of Jupiter last month.
Though storms in Saturn’s atmosphere have come and gone in the last year, much remains the same. A fascinating six-sided pattern called the “hexagon,” which is caused by a high-speed jet stream, still distinguishes the north pole. It is so large that four Earths could fit inside its boundaries, and has no counterpart at the planet’s South Pole.
The amber colors of Saturn come from summer smog-like hazes produced in photochemical reactions driven by solar ultraviolet radiation. Below the haze lie clouds of ammonia ice crystals, as well as deeper, unseen lower-level clouds of ammonium hydrosulfide and water. Saturn’s banded structure is caused by alternating winds that result in clouds at different altitudes at each latitude.
The rings are composed mostly of pieces of ice, with sizes ranging from tiny grains to giant boulders. And they are constantly moving around the planet in an intricate cosmic dance.
Four of Saturn’s moons are captured in this photo taken by NASA’s Hubble Space Telescope on June 20. (Photo courtesy of NASA, ESA, Amy Simon/GSFC, Mike Wong/UC Berkeley and OPAL Team)
The new image was taken by Hubble’s Wide Field Camera 3 on June 20, 2019 as the planet made its closest approach to Earth — about 845 million miles away. This is the second yearly portrait taken as part of the Outer Planets Atmospheres Legacy (OPAL) project, which is helping scientists understand the atmospheric dynamics and evolution of our solar system’s gas giants.