Nearly 40 years ago, Uranus received one brief visit by Voyager 2 probe – but most questions remained unanswered at that time.
Planetary scientists are prioritizing a mission to Uranus as one of their top priorities, according to a decadal survey conducted by the National Academy of Sciences. Such an expedition would bring diverse scientific insights ranging from astrophysics and magnetospheres studies.
Uranus is an ice giant
Voyager 2 visited Uranus in 1986 and found an unexpectedly complex, multilayered cloud structure comprising water, ammonia, and methane at lower levels and methane above them. Similar to Jupiter and Saturn in terms of composition but featuring exotic ices instead of hydrogen-helium elements.
Though the outer atmosphere consists of gases, scientists believe that an inner methane layer appears liquid. They suspect a subterranean slush of partially frozen water, ammonia, and methane exists within its depths as an extremely dense form of supercompressed ice.
Titania and Oberon, two outermost moons of Uranus, are composed of ice. Ariel features dark surface with canyons. Miranda (named after Prospero’s daughter Miranda from Shakespeare’s “The Tempest”) has an intriguing landscape composed of three long rectangular areas called coronae walled off by cliffs that may indicate past violence on Uranus. Uranus also hosts 27 known moons including Cordelia and Ophelia that prevent its last ring from expanding further outward.
It has 27 moons
Uranus, the ice giant planet, boasts 27 moons that can be seen with medium to large telescopes; six major ones, Ariel, Puck Miranda Umbriel and Oberon can be spotted through these lenses. Their orbits lock onto Uranus so one side faces towards it while the other points away.
Uranus features 13 inner moons and 13 faint rings, two of them, Cordelia and Ophelia, being called “ring shepherds.” Their purpose is to keep together the particles that comprise its thin blue outer epsilon ring.
The other moons scattered through the ring system range in size and brightness from Ariel, the small, dark moon, to Titania, a large, bright one. Most are named for characters from Shakespeare or Alexander Pope; nine were named after their namesakes among Apollo 1 astronauts Roger Chaffee, Gus Grissom and Ed White who perished when their spacecraft was destroyed in launch pad fire; five others have negative orbital periods suggesting they are captured asteroids – Caliban, Stephano Sycorax and Prospero have negative orbital periods that suggest they might also belong here.
It has a ring system
Scientists are exploring how Uranus’ ring system operates. Although the ice giant boasts 13 rings and multiple moons, its distance makes measuring them impossible. Furthermore, studying its magnetosphere requires traveling two billion miles round trip from Earth.
Voyager 2 captured some images of Jupiter and its rings during its flight across space, providing us with our only up-close views. It revealed 10 narrow rings and three diffuse ones; their names reflect Greek letters used to describe their characteristics: Alpha, Beta, Eta, Gamma Delta Lambda Epsilon
Scientists using the James Webb Space Telescope’s Near-Infrared Camera, or NIRCam, have made an interesting discovery: Uranus’ polar cap appears brighter than expected – suggesting there could be another ring orbiting closer to Uranus without providing its expected dust source.
It has a magnetic field
Uranus provides scientists with an unprecedented opportunity to study its unique atmosphere, which was formed due to an ancient collision between two giant worlds. This event altered Uranus’ rotation and caused water-rich comets to bombard it, creating effects that ripple through chemistry, clouds and circulation patterns; shaping the orbits of its moons; potentially even having an influence over how our Solar System developed itself.
An ambitious mission to Uranus could also aid planetary scientists in exploring whether ice giants like Uranus and Neptune have oceans similar to Earth – something of which planetary scientists are keenly interested. Such knowledge would prove instrumental in convincing Congress of the need to fund such an exploratory mission to this fascinating planet.
Scientists are developing a mission concept, comprising an orbiter and atmospheric probe. Their goal is to use proven technologies from previous missions on this one and launch in early 2030 for optimal time and energy usage.