After over a decade of observations, scientists now know exactly how long a day lasts on Uranus. This breakthrough comes from an 11-year-long study using NASA’s Hubble Space Telescope.
How is a Day Actually on Uranus?
According to the new findings, a full day on Uranus lasts 17 hours, 14 minutes, and 52 seconds. This is 28 seconds longer than what NASA‘s Voyager 2 spacecraft estimated in 1986.
The research was published on April 7 in the journal Nature Astronomy.
Voyager 2’s Earlier Estimate
Voyager 2 was the first spacecraft to closely observe Uranus. In 1986, it measured the planet’s rotation using radio signals from its auroras and data from its magnetic field. Based on that, scientists then estimated a day on Uranus to be about 17 hours, 14 minutes, and 24 seconds.
However, that estimate came with a 36-second uncertainty. Over the years, this slight error made it harder for scientists to pinpoint the planet’s exact magnetic orientation.
What Did the New Study Do Differently?
To get a more precise measurement, researchers analyzed six sets of Hubble data from 2011 to 2022. They tracked the movement of auroras near Uranus’ magnetic poles. From these auroras, scientists identified the accurate location of the magnetic poles.
Using that information, they calculated the planet’s updated rotation period. The new measurement has an uncertainty of less than 0.04 seconds.
Why is This Important?
Laurent Lamy, the lead author of the study and an astronomer at the Paris Observatory, emphasized the importance of Hubble’s long-term data. “Without this wealth of data, it would have been impossible to detect the periodic signal with the level of accuracy we achieved,” he said.
Even though the new result is only 28 seconds longer than the old one, its high accuracy is a game-changer. Tim Bedding, an astronomer from the University of Sydney, told New Scientist that the difference isn’t in the number but in its precision. “It’s now accurate enough to be more useful,” he explained.
What’s Next for Uranus Exploration?
This improved measurement will help future space missions. A proposed Uranus Orbiter and Probe mission could use this new data to better plan its journey and entry into the planet’s atmosphere.
Scientists also say this updated rotational data can now support studies for decades, providing a stable system to track Uranus’ magnetic field and auroral activity.
A Look Back and Ahead
Thanks to Hubble’s long-term tracking and advances in aurora mapping, we can now understand Uranus better than ever before. This new discovery will not only help with future explorations but also allows scientists to re-analyze 40 years’ worth of Uranus observations with improved accuracy.
As the space community looks toward more missions targeting the outer planets, this type of precise data is crucial for unlocking more secrets about our solar system.
