When NASA finally launches the James Webb Space Telescope, planetary scientists will use it to observe the largest planet in our solar system, Jupiter. The giant observatory is expected to lay the groundwork for far-reaching scientific discovery.

Imke de Pater of the University of California, Berkeley, and Thierry Fouchet of the Observatoire de Paris and an international team of researchers have collaborated to design a complex program that will perform some of the first scientific observations in the solar system using the Webb telescope. The team will conduct studies about Jupiter, its rings, and two of its moons: Io and Ganymede.

"It will be a really challenging experiment," said de Pater. "Jupiter is so bright, and Webb's instruments are so sensitive, that observing both the bright planet and its fainter rings and moons will be an excellent test of how to get the most out of Webb's innovative technology."

Jupiter's Rings

The gas giants of the solar system -- Jupiter, Saturn, Uranus, and Neptune -- all have rings, with Saturn's being the most prominent. Jupiter's rings, however, are so faint. And due to the brightness of the planet, they appear almost invisible, making it a challenge for scientists to study it.

The research team hopes to find new discoveries in the rings of Jupiter. De Pater is most interested in finding "ephemeral moonlets" and potential ripples in the ring from comet impacts, like those observed and traced back to the impact of Comet Shoemaker-Levy 9 in 1994.

Jupiter's Satellites

De Pater and his team are particularly interested in just two of Jupiter's moons -- Io and Ganymede. There's so little we know about these Galilean satellites, but we do know that Io is the most volcanically active world in the solar system. Its surface is littered with hundreds of massive volcanoes. The ones on Earth would look like mounds. Scientists intend to use Webb to discover the effects of Io's volcanoes on its atmosphere.

As for Ganymede, there's evidence that its thick ice surface may have a liquid saltwater ocean underneath. This is Webb will investigate by way of spectroscopic observations of salts and other compounds.

The James Webb Space Telescope will launch on Oct. 31, 2021. It will help solve mysteries in our solar system, as well as observe distant worlds around other stars. The observatory s an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.