We’ve just been given a breathtaking new viewpoint on what could be the strangest ball in the Solar System.
The James Webb Space Telescope has trained its golden, infrared gaze on Uranus, the intriguing seventh planet from the Sun, and the image it has returned shows the turquoise planet in sparkling brilliance. Moons, rings, and everything.
Every planet and dwarf planet in the Solar System has its own unique quirks and eccentricities, but Uranus is genuinely unique. The chilly, gelid environment appears commonplace at first glance, yet the closer you look, the stranger – and more beautiful – it becomes.
You have to look beyond the colors we can see with our own eyes, in which Uranus looks to be a pretty featureless ball of pale blue. Scientists have been able to measure the physical features of Uranus’ weak, ice rings using thermal imaging, which includes radio and infrared wavelengths.
JWST is the most powerful space telescope ever launched, yet it only observes the Universe in infrared and near-infrared wavelengths. That makes it ideal for capturing the extended glow of light shed billions of years ago.
Fortunately, that infrared sensitivity can be used for more than only peering deep into space to see the birth of the Universe; it can also be used to look closer to home to help understand the mysteries of our own Solar System. Because infrared wavelengths can disclose a lot about Uranus’s workings, JWST has been scheduled to take a closer look.
Despite having only 12 minutes, the space telescope was able to resolve previously unseen details.
Uranus’ peculiar spin, tipped over on its side in regard to its orbital plane, is something you’ll notice right away. This means that its polar seasons differ greatly from those of the other planets. During its 84-year orbit, Uranus’ poles will get the full brilliance of the Sun during the summer, but total darkness during the winter.
When Voyager 2 sailed past Uranus in 1986, it was summer on the south pole; presently, it is late spring on the north pole, with summer due to hit in 2028, and summer due to hit in 2028.
This means that the JWST was able to picture a phenomenon unique to Uranus: polar brightening as the planet advances into full summer Sun illumination. What generates this dazzling polar cap is unknown, but scientists hoped that the JWST’s extraordinary resolution will reveal some new insights.
They were not mistaken. The findings show a slight but distinct zone of heightened illumination towards the polar cap’s core.
We don’t know why, but scientists will be able to use this information when they investigate the phenomenon further.
Clouds, which are associated with storm activity in the ice giant’s mainly hydrogen and helium atmosphere, are also visible in the photograph.
Uranus features barely over a dozen lowly circlets, compared to Saturn’s spectacular collection of rings. The JWST captured images of 11 of the planet’s 13 known rings, including the two weak, dusty inner rings that were found by Voyager 2 in 1986.
Scientists expect that future JWST scans will be able to catch the two weak outer rings beyond the main group.
Finally, the telescope captured many of Uranus’ 27 known moons, but not all of them. Some are too little to see. However, the orbits of these moons are significantly different. The six moons visible in the image above all share Uranus’ equatorial plane, as do the smaller, inner moons. Uranus, on the other hand, has a collection of irregular, far more distant moons with inclined, elliptical orbits, comparable to Jupiter’s irregular moons.
The specifics of these moons may be significant in understanding how Uranus came to be the way it is, a difficult topic that defies simple answers.
Additional JWST observations of Uranus are either underway or planned for the future. Let us hope they can assist scientists in making a persuasive case for deploying a dedicated probe to this fascinating world.
