NASA’s James Webb Space Telescope will unlock secrets of the atmospheres of Uranus and Neptune.
The cold and remote giant planets Uranus and Neptune are nicknamed the «ice giants» because their interiors are compositionally different from Jupiter and Saturn, which are richer in hydrogen and helium, and are known as the «gas giants.» The ice giants are also much smaller than their gaseous cousins, being intermediate in size between terrestrial planets and the gas giants. They represent the least-explored category of planet in our solar system. Scientists using Webb plan to study the circulation patterns, chemistry and weather of Uranus and Neptune in a way only Webb can.
«The key thing that Webb can do that is very, very difficult to accomplish from any other facility is map their atmospheric temperature and chemical structure,» explained the studies’ leader, Leigh Fletcher, an associate professor of planetary science at the University of Leicester in the United Kingdom. «We think that the weather and climate of the ice giants are going to have a fundamentally different character compared to the gas giants. That’s partly because they’re so far away from the Sun, they’re smaller in size and rotate slower on their axes, but also because the blend of gases and the amount of atmospheric mixing is very different compared with Jupiter and Saturn.»
All the gases in the upper atmospheres of Uranus and Neptune have unique chemical fingerprints that Webb can detect. Crucially, Webb can distinguish one chemical from another. If these chemicals are being produced by sunlight interacting with the atmosphere, or if they’re being redistributed from place to place by large-scale circulation patterns, Webb will be able to see that.
These studies will be conducted through a Guaranteed Time Observations (GTO) program of the solar system led by Heidi Hammel, a planetary scientist and Webb Interdisciplinary Scientist. She is also Vice President for Science at the Association of Universities for Research in Astronomy (AURA) in Washington, D.C. Hammel’s program will demonstrate the capabilities of Webb for observing solar system objects and exercise some of Webb’s specific techniques for objects that are bright and/or are moving in the sky.
Uranus: The Tilted Planet
Unlike the other planets in our solar system, Uranus — along with its rings and moons — is tipped on its side, rotating at roughly a 90-degree angle from the plane of its orbit. This makes the planet appear to roll like a ball around the Sun. That weird orientation — which may be the result of a gargantuan collision with another massive protoplanet early in the formation of the solar system — gives rise to extreme seasons on Uranus.
Story Source: Materials provided by NASA/Goddard Space Flight Center. Note: Content may be edited for style and length.