Astronomers have combined the powers of telescopes on Earth and in space to produce a unique set of images of Jupiter that deliver astounding views and new insights about the giant planet’s intense storms, according to a statement from NASA.
Jupiter is more than twice as massive as all the other planets in our solar system combined, however its bulk is anything but solid. The planet’s surface is a roiling mix of gases and liquids, whipped into swirls and stripes by hurricane-force winds and forming massive storms. A single storm, known as the Great Red Spot, is twice as wide as Earth and has been raging for more than 300 years.
Astronomers looking to better understand the gas giant’s intense atmospheric conditions used the Hubble Space Telescope orbiting Earth, the ground-based Gemini Observatory in Hawaii and the Juno spacecraft orbiting Jupiter to image the planet’s surface in unprecedented detail.
Combining these three sources allowed scientists to map Jupiter’s powerful lightning and revealed that dark patches seen within the Great Red Spot are gaps in its cloud cover and not different types of cloud, the researchers report in the Astrophysical Journal Supplement Series.
The Juno spacecraft entered Jupiter’s orbit in 2016, and every 53 days it passes just 3,100 miles from the planet’s cloud tops. At this close range, Juno’s instruments can detect radio waves emitted by lightning bolts, allowing it to see through the storm clouds.
Whenever Juno is skimming Jupiter’s turbulent surface to detect lightning, Hubble and Gemini capture high-resolution images of the planet to help astronomers put Juno’s observations in context.
"Juno's microwave radiometer probes deep into the planet's atmosphere by detecting high-frequency radio waves that can penetrate through the thick cloud layers. The data from Hubble and Gemini can tell us how thick the clouds are and how deep we are seeing into the clouds," says Amy Simon, planetary scientist at NASA’s Goddard Space Flight Center, in a statement.
Hubble’s images cover the visible light spectrum while Gemini’s use thermal infrared to see how heat is distributed across Jupiter’s surface. The research team used these observations to map lightning strikes and the Jovian cloud conditions that are associated with lightning.
"Scientists track lightning because it is a marker of convection, the turbulent mixing process that transports Jupiter's internal heat up to the visible cloud tops," says Michael Wong, planetary scientist at the University of California, Berkeley, in a release. "Ongoing studies of lightning sources will help us understand how convection on Jupiter is different from or similar to convection in the Earth's atmosphere."
The researchers found lightning storms clustered around areas where deep, moisture-laden clouds coincided with 40-mile-high columns of moist, upwelling air—similar to thunderheads on Earth—and gaps in cloud cover—perhaps caused by downwelling.
Showing that Jovian lightning is associated with moisture will help researchers improve estimates of how much water is in Jupiter’s atmosphere, which may allow them to understand how the gas giant—and the rest of the solar system—formed.
The thermal infrared images captured by the Gemini North telescope on Hawaii’s Maunakea offer some of the highest resolution of any ever obtained from the ground. The thermal infrared images display heat as fiery orange glowing through the cracks in Jupiter’s thick cloud cover.
"It's kind of like a jack-o-lantern," Wong says in a statement. "You see bright infrared light coming from cloud-free areas, but where there are clouds, it's really dark in the infrared."
The high-resolution images of these cloud-free areas also allowed Wong and his colleagues to properly interpret prior observations of the Great Red Spot. Past images in the visible light spectrum from telescopes such as Hubble showed shadowy areas in the counter-clockwise spinning storm. The new observations revealed these dark patches are actually gaps in the cloud cover and not just differences in color.
The 300-mile resolution thermal images were made possible by a technique called "lucky imaging," that selects the sharpest images from a large number of very short exposure shots. The sharpest images come when the distortions normally introduced by Earth’s atmosphere momentarily stabilize.
"These images rival the view from space," Wong says in a statement.
The ability to regularly obtain such high-resolution images is allowing scientists to begin to look for patterns on Jupiter’s stormy surface. “This is our equivalent of a weather satellite,” says Simon in a statement. “We can finally start looking at weather cycles.”