|
|
Webb Telescope Reveals Detailed Rings Around Uranus
24 April 2023
EIRNS—New images recently released by the James Webb Space Telescope have revealed intricate rings around the icy giant planet Uranus. The NASA website noted: "The Webb data demonstrates the observatory’s unprecedented sensitivity for the faintest dusty rings, which have only ever been imaged by two other facilities: the Voyager 2 spacecraft as it flew past the planet in 1986, and the Keck Observatory with advanced adaptive optics…. “Uranus has 13 known rings and 11 of them are visible in this Webb image [see link below]. Some of these rings are so bright with Webb that when they are close together, they appear to merge into a larger ring. Nine are classed as the main rings of the planet, and two are the fainter dusty rings (such as the diffuse zeta ring closest to the planet) that weren’t discovered until the 1986 flyby by Voyager 2. Scientists expect that future Webb images of Uranus will reveal the two faint outer rings that were discovered with Hubble during the 2007 ring-plane crossing.” As any elementary school child can know, the seasons on any planet are determined by its tilt on its axis of rotation, not just its distance from the Sun. This is why the Earth’s Northern Hemisphere experiences the summer when it is farthest from the Sun. Uranus is very unusual in this regard, because, while Earth has a tilt of approximately 23° , Uranus’ spin is nearly 90° from the plane of its orbit. This means that it experiences extreme seasons, as it takes 84 years to complete an orbit, each of the four seasons lasts about 21 years. The Webb images also revealed more about Uranus’ atmosphere, as NASA explains: “On the right side of the planet there’s an area of brightening at the pole facing the Sun, known as a polar cap. This polar cap is unique to Uranus—it seems to appear when the pole enters direct sunlight in the summer and vanish in the fall; these Webb data will help scientists understand the currently mysterious mechanism. Webb revealed a surprising aspect of the polar cap: a subtle enhanced brightening at the center of the cap. The sensitivity and longer wavelengths of Webb’s NIRCam may be why we can see this enhanced Uranus polar feature when it has not been seen as clearly with other powerful telescopes like the Hubble Space Telescope and Keck Observatory.” Given that the atmosphere of Uranus (primarily hydrogen, helium and a small amount of methane) has virtually no nitrogen or carbon dioxide, it makes for an ideal “natural” home for those on Earth who object so strenuously to those two nasty gasses. (https://www.nasa.gov/feature/goddard/2023/nasa-s-webb-scores-another-ringed-world -with-new-image-of-uranus; https://www.windows2universe.org/uranus/uranus_magnetic_poles.html ;
|
