Uranus is pale blue in colour while Neptune is a deeper shade of blue, and an atmospheric model can explain the difference
Uranus and Neptune are different shades of blue, and we may finally know why.
In visible-light images, Uranus appears a pale blue, while Neptune is a deeper, cobalt hue. Using data from the Hubble Space Telescope and ground-based observatories, as well as information gleaned from the Voyager 2 spacecraft, Patrick Irwin at the University of Oxford and his colleagues have developed detailed models of the atmospheres of both worlds that might explain the colour difference.
The thick, enshrouding skies of these planets are …