Hubble’s Annual Snapshots Help Astronomers Monitor the Ringed World
Saturn is so beautiful that astronomers cannot resist using the Hubble Space Telescope to take yearly snapshots of the ringed world when it is at its closest distance to Earth.
These images, however, are more than just beauty shots. They reveal a planet with a turbulent, dynamic atmosphere. This year’s Hubble offering, for example, shows that a large storm visible in the 2018 Hubble image in the north polar region has vanished. Smaller storms pop into view like popcorn kernels popping in a microwave oven before disappearing just as quickly. Even the planet’s banded structure reveals subtle changes in color.
This new Hubble Space Telescope view of Saturn, taken in late June of 2019, reveals the giant planet’s iconic rings. Saturn’s amber colors 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. The planet’s banded structure is caused by winds and clouds at different altitudes. Hubble’s Wide Field Camera 3 observed Saturn on June 20, 2019, as the planet made its closest approach to Earth, at about 845 million miles away. Credit: NASA’s Goddard Space Flight Center
But the latest image shows plenty that hasn’t changed. The mysterious six-sided pattern, called the “hexagon,” still exists on the north pole. Caused by a high-speed jet stream, the hexagon was first discovered in 1981 by NASA’s Voyager 1 spacecraft.
Saturn’s signature rings are still as stunning as ever. The image reveals that the ring system is tilted toward Earth, giving viewers a magnificent look at the bright, icy structure. Hubble resolves numerous ringlets and the fainter inner rings.
This image reveals an unprecedented clarity only seen previously in snapshots taken by NASA spacecraft visiting the distant planet. Astronomers will continue their yearly monitoring of the planet to track shifting weather patterns and identify other changes. The second in the yearly series, this image is part of the Outer Planets Atmospheres Legacy (OPAL) project. OPAL is helping scientists understand the atmospheric dynamics and evolution of our solar system’s gas giant planets.
This Hubble time-lapse movie shows the orbits of some of Saturn’s icy moons as they circle the planet over an 18-hour period. The video is composed of 33 Hubble snapshots of the planet, taken June 19 to 20, 2019, by the Wide Field Camera 3. The closer the moon is to Saturn, the faster it orbits, according to the laws of gravity. Credit: NASA, ESA, A. Simon (Goddard Space Flight Center), M.H. Wong (University of California, Berkeley), the OPAL Team and J. DePasquale (STScI)