Astronomers have just revealed that a day on Uranus is longer than was previously thought, at 17 hours, 14 minutes and 52 seconds. This is 28 seconds longer than the previous estimate, which was made by NASA's Voyager 2 probe during its flyby of the ice giant planet back in 1986. The new figure—which is 1,000 times more accurate—was calculated based on a decade's worth of observations of Uranus's aurorae made by NASA/ESA's Hubble Space Telescope. The long-term data on the planet's auroral emissions enabled the researchers to track the positions of the planet's magnetic poles and, by extension, its...