An amazing new image of Jupiter captured by the Hubble Space Telescope could shed light on the gas giant's mysterious atmospheric dynamics.
One of the most prominent mysteries involves Jupiter's famous Great Red Spot, which has been shrinking since at least the 1800s.
The centuries-old enigma is very complex, said officials with the Space Telescope Science Institute (STScI) in Baltimore, which runs Hubble's science mission: "Attempting to understand the forces driving Jupiter's atmosphere is like trying to predict the pattern cream will make when it is poured into a hot cup of coffee."
But scientists have tried. The Earth-orbiting Hubble turns its eyes to all the outer solar system planets at least once a year to check on their weather. And luckily, Jupiter has an interplanetary visitor — NASA's Juno spacecraft — scanning the planet's clouds to gather more information.
Just over a year ago, Hubble observations showed that the spot is getting taller and turning orange as it shrinks in diameter. Historical work suggests that the Great Red Spot was once large enough to cover the width of three Earths, but as of April 2017, the storm was just a little wider than one Earth, raging at a diameter of 10,159 miles (16,350 kilometers), according to NASA.
One new key to the shrinking-spot puzzle could be the color intensity of the clouds that Hubble spotted in its fresh image, which was obtained on June 27. This newest view revealed a "more intense color palette" than seen in other years, STScI officials said, adding that changes in the colors show variations in processes happening in the atmosphere.
"The bands are created by differences in the thickness and height of the ammonia ice clouds," STScI officials said in a statement. "The colorful bands, which flow in opposite directions at various latitudes, result from different atmospheric pressures. Lighter bands rise higher and have thicker clouds than the darker bands."
The Great Red Spot itself churns along counterclockwise between two cloud bands, with each band moving in opposite directions above and below the hurricane. Bands cover much of the planet, but they tend to stay in place, even while changing color, due to jet streams constantly screaming through Jupiter's atmosphere at up to 400 mph (644 km/h).
Researchers also noted a worm-shaped feature below the Great Red Spot, which is a cyclone or vortex that has winds spinning the opposite direction of those inside the spot. "Researchers have observed cyclones with a wide variety of different appearances across the planet. The two white, oval-shaped features are anticyclones, like small versions of the Great Red Spot," STScI officials said.
Two more probes are scheduled to visit the Jupiter system in the next decade, and both will focus on the gas giant's icy moons. In 2023, NASA plans to launch the Europa Clipper spacecraft, which will study the potentially habitable, ocean-bearing moon Europa during dozens of flybys. The agency wants to launch a life-hunting Europa lander shortly afterward, although both missions may be in some budgetary trouble.
The European Space Agency's Jupiter Icy Moons Explorer (JUICE), meanwhile, is scheduled to launch in 2022 to examine the satellites Ganymede, Callisto and Europa.
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