Say Cheese, Outer Planets! Hubble Captures New Images of Jupiter, Saturn, Uranus and Neptune

Part of its yearly grand tour of the outer solar system, NASA’s Hubble Space Telescope captured new technicolor images of the giant planets: Jupiter, Saturn, Uranus, and Neptune. The collection of Hubble images released this month by NASA are part of the Outer Planets Atmospheres Legacy program (OPAL), which creates yearly maps of each planet, a statement explains.

By studying these fresh cosmic yearbook photos, astronomers gain insight into each planet's unique weather patterns. Understanding these planets' ever-changing atmospheres could in turn help researchers learn more about how similar systems on our planet work, reports Dennis Overbye for the New York Times.

Like Earth, other planets orbiting the sun experience atmospheric shifts and seasonal variations. Planetary scientists interested in understanding how often and when certain weather patterns occur compare past and present images to understand how the planets change over time, reports Georgina Torbet for Digital Trends.

However, unlike terrestrial planets like Earth and Mars, gas giants consist of freezing concoctions of hydrogen, helium, ammonia, methane, and deep water—all wrapped around a hot core, per a statement. Weather patterns on these planets are vastly different and still not fully understood.

Orbiting 340 miles high above Earth, the Hubble telescope has been eyeing the outer planets since the 1990s, where it has seen Jupiter flush red with stormy weather, imaged seasonal weather on Saturn and Uranus, and observed a dark spot occasionally appear and disappear on Neptune.

This year, Jupiter and Saturn were captured in intense, crisp detail. Jupiter’s newest portrait taken on September 4, 2021, revealed that recent storms called barges formed above its equator, reports Jamie Carter for Forbes.

The planet’s Great Red Spot is home to storms that have raged on for 150 years at 400 miles per hour. New images show that activity at its center is slowing down while its outer edges are speeding up, the New York Times reports.

Saturn, imaged on September 12, is approaching autumn in its northern hemisphere. Previous Hubble images of Saturn from 2018, 2019 and 2020 showed that the planet undergoes seasonal transitions like Earth does. A change in season on Saturn is indicated by the color of its bands. For example, the faint blue color in the planet’s southern hemisphere represents the remainder of winter.

In the recent photo, Saturn’s hexagonal storm on its north pole is visible. The hexagonal storm was first discovered in 1981 by the Voyager 2 spacecraft. 

Uranus was imaged on October 25 during springtime in its northern hemisphere. Because Uranus is tilted on its side, its polar region is directly pointed towards the sun, so the region is bathed in ultraviolet light. Researchers suspect this glow is further brightened by concentration of atmospheric methane gas, smog and wind patterns at the pole, the New York Times reports.

Finally, Neptune’s portrait taken on September 7 sported a dark spot against a nearly solid deep blue backdrop. While blue, Neptune’s sapphire color is a result of methane gas, not water. The dark spot—which is more expansive than the Atlantic Ocean—is a storm whirling around the atmosphere, per Forbes.

Storms like these appear in the planet’s mid-latitudes and eventually spin towards its equator, where it usually disintegrates. But, in 2018, a storm heading towards the equator changed course and went back towards the north pole—to the astonishment of researchers observing the phenomenon. 

Elizabeth Gamillo | | READ MORE

Elizabeth Gamillo is a daily correspondent for Smithsonian and a science journalist based in Milwaukee, Wisconsin. She has written for Science magazine as their 2018 AAAS Diverse Voices in Science Journalism Intern.