In Brief

7 September 2016

Here’s what colourful clouds on alien gas giants would look like

Red orb with central yellow band
Like a burning coal


IMAGINE a world where the skies glow traffic-cone orange and indigo. That’s the view from hot Jupiters, faraway gas giants that lie much closer to their stars than Mercury sits to our sun.

We have seen evidence of clouds in their atmospheres, but the details are still, well, cloudy. So Vivien Parmentier at the University of Arizona, Tucson, and colleagues modelled the planets’ temperature variations, based on factors like distance from a star and wind circulation. Different temperatures lead to different clouds because of the way various elements condense (Astrophysical Journal,

Looking down from a spaceship, a cloudless sky would appear deep blue because of the presence of sodium, which absorbs red light. Hotter regions would glow like burning coal and reddish-orange manganese sulphide clouds would cloak cooler areas.

This article appeared in print under the headline “Vibrant clouds paint exoplanet skies”