• When Voyager 2 flew previous Uranus in 1986, it discovered that the planet’s magnetosphere wasn’t what scientists anticipated.
• The magnetosphere confirmed intense electron radiation belts however no supply of energized particles to feed these lively belts.
• Now scientists discovered that the photo voltaic wind was the wrongdoer, with a uncommon occasion that briefly modified the magnetosphere whereas Voyager 2 was making its observations.

NASA printed this unique story on November 11, 2024. Edits by EarthSky.

Mysteries at Uranus

When NASA’s Voyager 2 spacecraft flew by Uranus in 1986, it supplied scientists’ first — and, to date, solely — shut glimpse of this unusual, sideways-rotating outer planet. Alongside the invention of recent moons and rings, baffling new mysteries confronted scientists. The energized particles across the planet defied their understanding of how magnetic fields work to lure particle radiation. And so Uranus earned a fame as an outlier in our photo voltaic system.

Now, new analysis analyzing the information collected throughout that flyby 38 years in the past has discovered the supply of that exact thriller is a cosmic coincidence: It seems that within the days simply earlier than Voyager 2’s flyby, the planet had been affected by an uncommon form of house climate. This house climate occasion squashed the planet’s magnetic area, dramatically compressing Uranus’ magnetosphere.

Jamie Jasinski of NASA’s Jet Propulsion Laboratory in Southern California is the lead writer of the brand new work printed in Nature Astronomy on November 11, 2024. Jasinski stated:

If Voyager 2 had arrived just some days earlier, it might have noticed a totally completely different magnetosphere at Uranus. The spacecraft noticed Uranus in situations that solely happen about 4% of the time.

What’s a magnetosphere?

Magnetospheres function protecting bubbles round planets (together with Earth) with magnetic cores and magnetic fields. They protect worlds from jets of ionized fuel — or plasma — that stream out from the solar within the photo voltaic wind. Studying extra about how magnetospheres work is vital for understanding our personal planet. And it’s additionally vital to know worlds in seldom-visited corners of our photo voltaic system and past.

That’s why scientists had been keen to check Uranus’ magnetosphere. And what they noticed within the Voyager 2 knowledge in 1986 flummoxed them. Contained in the planet’s magnetosphere had been electron radiation belts with an depth second solely to Jupiter’s notoriously brutal radiation belts. However there was apparently no supply of energized particles to feed these lively belts. Actually, the remainder of Uranus’ magnetosphere was nearly devoid of plasma.

The lacking plasma additionally puzzled scientists as a result of they knew that the 5 main Uranian moons within the magnetic bubble ought to have produced water ions, as icy moons round different outer planets do. They concluded that the moons have to be inert with no ongoing exercise.

Fixing the thriller at Uranus

So why didn’t we observe plasma? And what was taking place to beef up the radiation belts? The brand new knowledge evaluation factors to the photo voltaic wind. When plasma from the solar pounded and compressed the magnetosphere, it doubtless drove plasma out of the system. The photo voltaic wind occasion additionally would have briefly intensified the dynamics of the magnetosphere, which might have fed the belts by injecting electrons into them.

The findings may very well be excellent news for these 5 main moons of Uranus: A few of them may be geologically lively in spite of everything. With an evidence for the briefly lacking plasma, researchers say it’s believable that the moons really could have been spewing ions into the encompassing bubble all alongside.

Planetary scientists are specializing in bolstering their data concerning the mysterious Uranus system, which the Nationwide Academies’ 2023 Planetary Science and Astrobiology Decadal Survey prioritized as a goal for a future NASA mission.

New research of Uranus

JPL’s Linda Spilker was among the many Voyager 2 mission scientists glued to the photographs and different knowledge that flowed in in the course of the Uranus flyby in 1986. She remembers the anticipation and pleasure of the occasion, which modified how scientists thought concerning the Uranian system.

Spilker, who has returned to the long-lasting mission to guide its science group as challenge scientist, stated:

The flyby was filled with surprises, and we had been trying to find an evidence of its uncommon conduct. The magnetosphere Voyager 2 measured was solely a snapshot in time. This new work explains among the obvious contradictions, and it’ll change our view of Uranus as soon as once more.

Voyager 2, now in interstellar house, is sort of 13 billion miles (21 billion km) from Earth.

Backside line: A brand new evaluation of information reveals that when the Voyager 2 spacecraft flew previous Uranus in 1986, it noticed a skewed view of the planet’s magnetosphere as a result of a big photo voltaic wind occasion had simply buffeted Uranus.

Supply: The anomalous state of Uranus’s magnetosphere in the course of the Voyager 2 flyby

Through NASA/JPL-Caltech

Learn extra: Proof for ocean on Uranus moon Miranda is a shock