Asked by: Damion Ries, Reno, USA
Venus has an optical phenomenon called a ‘glory’ which – like a rainbow – forms when sunlight falls on cloud droplets. However, glories are caused by the interference of light waves within droplets, whereas rainbows are caused by the reflection, refraction and dispersion of light.
Unlike the broad arc of a rainbow, a glory is typically seen as a series of coloured concentric rings. In 2011, a Venusian glory was observed by ESA’s Venus Express probe, probably caused by sunlight interacting with the sulphuric acid/ferric chloride droplets in the planet’s atmosphere.