A new analysis of decades’ worth of observations has revealed that Uranus does indeed emit more heat than it receives from the rays of the Sun.
This conclusion, arrived at by two independent teams of scientists, finally resolves a puzzle that first emerged when Voyager 2 cruised past the stinky planet all the way back in 1986. Those observations suggested that Uranus was not emitting any excess heat – a finding that put it at odds with all the other giant planets in the Solar System.
A team led by planetary scientist Xinyue Wang, formerly of the University of Houston, now at the University of Michigan, Ann Arbor, has now found that Uranus is emitting around 12.5 percent more heat than it receives from the Sun.
This is consistent with findings about Uranus made by a team led by planetary physicist Patrick Irwin of the University of Oxford in the UK, made available earlier this year on arXiv.
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“This means it’s still slowly losing leftover heat from its early history, a key piece of the puzzle that helps us understand its origins and how it has changed over time,” Wang says.
“From a scientific perspective, this study helps us better understand Uranus and other giant planets. For future space exploration, I think it strengthens the case for a mission to Uranus.”
Previous research has already shown that Voyager 2’s flyby occurred at a time when elevated solar activity was making Uranus behave in anomalous ways. It is, therefore, perhaps not surprising to find that other readings made by the probe may have misrepresented the planet’s usual state of existence.
However, the findings of Wang’s team still suggest that something weird is going on with the planet. Jupiter emits 113 percent, Saturn 139 percent, and Neptune 162 percent more heat than they receive from the Sun. Since Neptune is farther from the Sun than Uranus, the distance can’t be an explanation for Uranus’s lower internal temperature.
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This suggests that there’s still something weird happening inside the giant – whether it’s a different internal structure, or something about its evolutionary history. This difference, the researchers say, underscores the need to probe our Solar System’s overlooked outer planets.
“A future flagship mission to Uranus would provide critical observations to address more unresolved questions of this enigmatic ice giant,” they write in their paper.
The research has been published in Geophysical Research Letters.
