When the James Webb Space Telescope (JWST) blasted off from French Guiana Dec. 25, 2021, astronomers anticipated it would deliver breathtaking images of distant galaxies and star-forming regions, as well as analyze the chemical makeups of exoplanet atmospheres. And NASA’s flagship space telescope has not disappointed.
JWST has already captured images of galaxies so far from Earth that cosmic expansion has shifted their light well into the infrared part of the spectrum, which the telescope is built to detect. And the observatory’s Near-Infrared Spectrograph (NIRSpec) has even discovered carbon dioxide in the atmosphere of exoplanet WASP-39 b — the first definitive detection of this gas in a world beyond our solar system.
But JWST has set its sights closer to home, too. On July 27, astronomers targeted Jupiter with the telescope’s powerful infrared eye. The resulting images reveal a planet both familiar and exotic. “We’ve never seen Jupiter like this. It’s all quite incredible,” said principal investigator Imke de Pater of the University of California, Berkeley, in a statement. “We hadn’t really expected it to be this good.”
JWST’s Near-Infrared Camera (NIRCam) captured two images of our solar system’s largest planet. In the striking close-up (right), taken through three different filters, Jupiter displays numerous cloud bands, as well as storms and auroral emissions. The Equatorial Zone spans the planet’s girth and looks bright white because its high-altitude hazes reflect lots of sunlight. For the same reason, the massive Great Red Spot in Jupiter’s southern hemisphere shows up as a bright oval. Smaller storms across the planet appear whitish or reddish white.
The cyan hues, meanwhile, reveal clouds buried deeper in the jovian atmosphere, showing light reflected from the planet’s main cloud level at a pressure of about 1 bar (roughly the atmospheric pressure at Earth’s surface). The image also showcases the transition between the banded structures seen at equatorial and mid-latitude regions — a favorite among earthbound observers — plus more complex vortices at higher latitudes.
Jupiter’s massive auroral ovals appear as reddish glows near the giant’s north and south poles. These emissions come from ionized hydrogen atoms that extend up to 625 miles (1,000 kilometers) above the cloud tops. The greenish areas around the poles come from hazes in the gas giant’s atmosphere located about 60 to 120 miles (100 to 200 km) high. If you look carefully, you can trace this haze layer along the limb down to equatorial latitudes.
The spectacular wide-field view of Jupiter (top) combines images through two infrared filters. The jovian clouds and aurorae still stand out, but many more details appear in this composite photo. The power of JWST is exemplified by its ability to capture Jupiter’s faint and dusty rings in the same image as the planet itself, which shines 1 million times brighter than the rings. Also present are two faint inner moons: Amalthea (155 miles [250 km] in diameter) and Adrastea (12 miles [20 km] across). Adrastea is a dim dot at the edge of the rings to the left of the planet while Amalthea lies about twice as far from Jupiter’s limb.
