Uranus is famed for how it spins sideways. Naturally, the ice giant’s tilted rotation has a part to play in how auroral activity manifests on the planet.
If you think auroras on Earth are a strange and mesmerizing sight, that’s nothing like what occurs on the perplexing world of Uranus.
Our solar system’s ice giant is famed for how it spins sideways. Naturally, Uranus’ tilted rotation has a part to play in how auroral activity manifests on the planet.
Now, an international team of researchers who mapped the vertical structure of Uranus’s upper atmosphere have discovered new insights into how auroras form on the planet. The team’s findings, published Feb. 19 in Geophysical Research Letters, offers “the most detailed portrait yet of where the planet’s auroras form” and “how they are influenced by its unusually tilted magnetic field.”
“This is the first time we’ve been able to see Uranus’s upper atmosphere in three dimensions,” study leader Paola Tiranti, a researcher at Northumbria University in the United Kingdom, said in a statement.
Here’s what to know about the researchers’ findings, and what it suggests for aurora activity on Uranus.
How big is Uranus? What to know about 3rd largest planet
The seventh planet from the sun, Uranus is also the third largest in our solar system behind Jupiter and Saturn. It’s four times wider than Earth.
Much of our understanding of Uranus comes from Voyager 2’s flyby, which to date remains the only time a spacecraft has visited the planet, NASA says. Voyager 2 stopped by Uranus on Jan. 24, 1986, coming within 50,600 miles of Uranus’ cloudtops and returning detailed photos and other data on the world, its moons, magnetic field and dark rings.
The observations are what have allowed scientists to categorize Uranus as a very cold and windy planet surrounded by more than two-dozen small moons. Uranus also has a strange magnetic field that causes the planet to rotate on its side.
NASA’s Webb telescope gets a look at auroras on Uranus
While NASA’s James Webb Space Telescope hasn’t exactly gotten close to Uranus, its distant observations are leading to new insights about the planet.
Using Webb’s Near-Infrared Spectrograph (NIRSpec) instrument, a team of researchers observed Uranus during nearly one day, or rotation, of the planet – equivalent to about 17 hours. The data they gathered then helped the scientists map Uranus’ upper atmosphere in unprecedented detail, revealing more about the planet’s auroras.
“Uranus’s magnetosphere is one of the strangest in the solar system,” Tiranti said in his statement. “It’s tilted and offset from the planet’s rotation axis, which means its auroras sweep across the surface in complex ways.”
By studying the temperature and density of Uranus’ upper atmosphere – known as the ionosphere – about 3,000 miles above the cloudtops, the researchers drew new insights into how the magnetic field influences its auroras.
Auroras on Uranus nothing like displays on Earth
Scientists have been aware of auroras on Uranus since the Hubble Space Telescope first detected them in 2012.
But Uranus’ lopsided rotations means the auroras that form are not in line with its northern and southern poles, as is the case on other planets like Earth, Jupiter and Saturn.
In the recent study, the researchers said they were able to spot two bright auroral bands near Uranus’ magnetic poles, along with “a distinct depletion in emission and ion density” in the region between the bands. That suggests “transitions in magnetic field lines” could be influencing the planet’s aurora displays, according to the researchers.
What is the James Webb Space Telescope?
The James Webb Space Telescope launched on Christmas Day 2021 aboard an Ariane 5 rocket from the European Space Agency’s Ariane Space Spaceport in French Guiana.
Webb, which then began its cosmic operations in July 2022, was designed to operate for up to 10 years. But as fortune would have it, the mission team determined the observatory should have enough propellant to allow it to operate in orbit for more than 20 years.
Billed by NASA as “the largest, most powerful and most complex telescope ever launched into space,” the James Webb Space Telescope far surpasses the abilities of its predecessor, the Hubble Space Telescope. The observatory is named for NASA’s second-ever administrator.
Orbiting the sun rather than Earth, Webb is outfitted with a gold-coated mirror more than 21 feet in diameter and powerful infrared instruments to observe the cosmos like no instrument before.
In the case of its Uranus observations, researchers who conducted the study contend that the data could help scientists understand more about how energy behaves in ice giants’ upper layers.
“By revealing Uranus’s vertical structure in such detail, Webb is helping us understand the energy balance of the ice giants,” Tiranti said in his statement. “This is a crucial step towards characterising giant planets beyond our solar system.”
Eric Lagatta is the Space Connect reporter for the USA TODAY Network. Reach him at [email protected]
