Something supercharged Uranus with radiation during Voyager flyby 40 years ago. Scientists now know what.

Two side by side images of the planet Uranus. The one on the left is a pale blue sphere while the one on the right has concentric circles of orange, yellow and green and dark blue to show the various layers of its atmosphere. Both are against a black background.

Scientists may have solved a long-standing mystery surrounding Uranus' extraordinarily strong radiation belt.

A new analysis of Voyager 2 data suggests that a temporary space weather event may have made the planet's electron radiation belt more intense than usual as Voyager 2 was passing by. The findings could help to explain why the radiation belt was so much stronger than scientists had predicted it would be.