Neptune sits thirty times farther from the Sun than Earth yet radiates about 2.5 times more energy than it receives — the hidden heat beneath the coldest reaches of the planetary system remains uncertain, even as it helps distinguish Neptune from its strangely quiet twin, Uranus

Voyager found Neptune emits 2.61 times the solar energy it absorbs, exposing an internal heat flow still far stronger than the revised estimate for Uranus. The post Neptune sits thirty times farther from the Sun than Earth yet radiates about 2.5 times more energy than it receives — the hidden heat beneath the coldest reaches of the planetary system remains uncertain, even as it helps distinguish…