#planetaryrotation

Source: NASA

New Insights from Space – Uranus Spins Slower Than Believed

In a significant breakthrough for planetary science, researchers using over a decade of data from the Hubble Space Telescope have recalculated the length of a day on Uranus Rotation Period, revealing it is longer than previously thought. According to the updated findings, the ice giant completes one full rotation in 17 hours, 14 minutes, and 52 seconds, which is 28 seconds longer than the long-standing estimate based on data from NASA’s Voyager 2 mission in 1986.

Voyager 2, the only spacecraft to have visited Uranus, initially estimated the planet’s rotation at 17 hours, 14 minutes, and 24 seconds. This measurement relied on detecting radio signals from Uranus’ auroras and readings of its magnetic field. For nearly four decades, this figure served as the foundation for building planetary maps and calculating the planet’s geographic coordinates. However, the new study suggests that the original calculation carried enough uncertainty to gradually throw off the planet’s coordinate system by up to 180 degrees in longitude, leading to a complete loss in the accurate orientation of its magnetic axis.

Hubble Observations Unlock Magnetic Clues

To correct these inaccuracies, a team led by Laurent Lamy from the Paris Observatory analyzed the motion of Uranus’ auroras using Hubble data gathered between 2011 and 2022. These auroras, caused by interactions between the planet’s magnetic field and solar wind, offered consistent markers for tracking rotational movement. By following the periodic patterns of these glowing emissions, researchers were able to precisely determine the planet’s true spin rate and magnetic pole locations.

Lamy emphasized the importance of long-term data in the findings, noting, “The continuous observations from Hubble were crucial. Without this wealth of data, it would have been impossible to detect the periodic signal with the level of accuracy we achieved.”

The updated rotation rate now provides a far more dependable reference system for Uranus Rotation Period that scientists believe will hold for decades. The recalibration not only restores a stable planetary coordinate system but also enhances the understanding of the planet’s magnetic field orientation—an essential element for mapping and future exploratory missions.

A New Technique with Far-Reaching Potential

Beyond improving knowledge about Uranus, this technique marks a broader advancement in planetary science. Researchers now have a proven method to calculate the rotation rates of other celestial bodies that possess auroras and magnetic fields. This includes not only other planets in our solar system but also exoplanets light-years away.