Life on Earth benefits from having a stable magnetosphere that protects our planet from the solar wind. If we had to rely on Uranus’s magnetic field, however, we would have been in trouble because a new analysis of data from Voyager 2’s flyby of Uranus suggests that the planet’s magnetosphere may flicker like a light bulb that is about to fail.
Uranus rotates very nearly on its side as compared to Earth’s rotation, with a spin axis that is tilted by 98 degrees, and the magnetosphere is tilted by another 60 degrees. As Uranus rotates, the magnetic lines are tumbled, which causes the magnetosphere to open and close regularly as the magnetic lines disconnect and reconnect.
Simulating the magnetic activity on Uranus was something of a challenge because, as Carol Paty, an associate professor at Georgia Tech’s School of Earth & Atmospheric Sciences, put it, “Uranus is a geometric mess.”
Also, participants in the study were working with data that is more than 30 years old. Voyager 2 flew past the planet in 1986. Hubble can observe details such as auroras on Uranus, but it is difficult to discern how those auroras are affected by Uranus’ magnetic field.
NASA is currently considering options to study the planets of the outer solar system, especially Uranus and Neptune. These options include possible flybys, orbiters and a spacecraft that can periodically dive into the atmosphere of an ice giant like Uranus. Studying these planets could help scientists refine their understanding of how planets similar to the ones in the outer solar system form and why Uranus has such an unusual orientation and magnetic field.
Uranus might be a “geometric mess” and it might be the butt of all the jokes, but the long gap in studying this planet up close may soon be over. The messy, flickering magnetosphere is of special interest because it will help scientists understand the importance of magnetic fields in protecting planets from the effects of the highly charged solar wind.