NASA corrects major error: Uranus does emit more heat than it receives from the Sun

For nearly four decades, a single data point from NASA’s Voyager 2 flyby has defined our understanding of Uranus as a cold, inactive world with no internal heat. That 1986 observation made the ice giant a major outlier compared to Jupiter, Saturn, and Neptune, which all radiate more heat than they receive from the Sun. Now, a new NASA-supported study corrects this long-standing assumption.

A team of scientists has used advanced computer modeling to re-examine decades of data, concluding that Uranus does in fact generate its own heat. The research, published in the Monthly Notices of the Royal Astronomical Society, found that the planet releases about 15% more energy than it receives from the Sun.

The previous conclusion hinged entirely on that one measurement from Voyager 2. “Everything hinges on that one data point,” said Amy Simon, a planetary scientist at NASA’s Goddard Space Flight Center. “That is part of the problem.”

The new research, led by Patrick Irwin of the University of Oxford, developed a computer model that integrated everything known about the planet's atmosphere from years of telescope observations. This model accounted for Uranus's clouds, hazes, and seasons, leading to a different conclusion. “We realized that it is actually more reflective than people had estimated,” Irwin said. This meant less of the Sun’s energy was being absorbed, and the planet’s own internal heat was a bigger factor in its energy budget than previously thought.