A day on Uranus has been found to be 28 seconds longer than previously thought, thanks to more accurate measurements by the Hubble Space Telescope.
A day on Uranus has been found to be 28 seconds longer than previously thought, thanks to more accurate measurements by the Hubble Space Telescope. This difference may seem minor, but it could have significant implications for planning future missions to explore the gas giant.
Uranus is an icy giant planet located in the outer reaches of the solar system.
It has a thick atmosphere composed mostly of hydrogen, helium, and methane, which gives it a distinct blue color.
The planet's rotation is highly tilted at 98 degrees, resulting in extreme seasons on Uranus.
With a diameter of approximately 51,118 kilometers, Uranus is one of the largest planets in our solar system.
Its moons include Titania, Oberon, Umbriel, Ariel, and Miranda.
Measuring the rotation period of planets like Uranus is much harder than for smaller bodies in our solar system. The planet’s extreme wind storms make direct measurements impossible, requiring scientists to rely on indirect methods such as observing the magnetic field and radio emissions from aurora at its poles.

Researchers at the Paris Observatory in France, led by Laurent Lamy, have made a new measurement of Uranus‘s rotation period using images of the planet’s ultraviolet aurora taken between 2011 and 2022 by the ‘Hubble Space Telescope‘ . Their method is 1000 times more accurate than previous measurements, reducing the margin of error to a fraction of a second.
The new measurement should remain valid for decades, making it possible to accurately determine positions on Uranus and calculate mission-critical objectives such as where a probe might orbit and enter the planet’s atmosphere. ‘While the difference in rotation period may seem minor,’ said Tim Bedding at the University of Sydney, ‘the increased accuracy is crucial for planning future missions.’
While the new measurement may not change the length of a day on Uranus significantly, it represents an important step forward in our understanding of this complex planet. As we continue to explore the solar system and beyond, accurate measurements like these will be essential for ensuring the success of future space missions.
- newscientist.com | How long is a day on Uranus? Slightly longer than we thought, it seems