The icy planet is the seventh-closest to the Sun and thought to be the coldest planet in the solar system, thanks to its frigid atmosphere and strong winds.
Uranus is four times as wide as Earth and was being buffeted by a strong solar storm at the time Voyager was studying it.
A celestial “hurricane” of charged particles from the Sun was crashing into Uranus, which squashed the magnetic field, scientists have found, stripping away much of its plasma, making it appear desolate. Scientists believed this meant the five moons of Uranus would be dead, with no activity.
However, this is not the status quo for Uranus, as it is only hit by such a solar barrage 4% of the time, Nasa scientists now think.
“Almost everything we know about Uranus is based on Voyager 2′s two-day flyby. This new study shows that a lot of the planet’s bizarre behaviour can be explained by the scale of the space weather event that occurred during that visit,” said Dr William Dunn, from UCL, the study author.
“We now know even less than we thought about what a typical day in the Uranian system might look like and are even more in need of a second spacecraft to visit to truly understand this mysterious, icy world.”
The revelation that Uranus may not be as barren as previously thought means astronomers now think it is possible that there could be a water ocean on one of the Uranus moons.
Voyager did not detect any signs of oceans, but the discovery of it being subjected to a storm means it is possible the signals were simply undetectable at the time.
Dunn added: “A big piece of evidence against there being oceans on Uranus’s moons was the lack of detection of any water-related particles around the planet – Voyager 2 didn’t find water ions. But now we can explain that: the solar storm basically would have blown all that material away.”
Dr Jamie Jasinski of Nasa’s Jet Propulsion Laboratory, the lead author, said: “If Voyager 2 had arrived just a few days earlier, it would have observed a completely different magnetosphere at Uranus. The spacecraft saw Uranus in conditions that only occur about 4% of the time.”
Nasa is currently working on a flagship mission to go to study Uranus in more detail, with it deemed a priority for future projects.
Other studies have found that exoplanets – planets outside our solar system – are most likely to be similar in size and composition to Uranus, which makes understanding the ice giant a priority for learning more about the possibility of life elsewhere in the universe.
The study is published in the journal Nature Astronomy.
