The Glory Of Venus
When travelling above the clouds, airplane passengers sometimes witness a glory: a light phenomenon similar to a ring-shaped rainbow. Droplets in the clouds back-scattering the sunlight are responsible for this appearance. A team of scientists led by the Max Planck Institute for Solar System Research (MPS) in Göttingen have now fully imaged a glory on Venus – and thus for the first time on a planet other than Earth. The data was obtained by ESA’s space probe Venus Express. The data imply that the sulfuric acid in Venus’ cloud tops could additionally contain pure sulfur or iron chloride – and may help solve one of the oldest mysteries of Venus research.
The veil of clouds surrounding Venus is as beautiful as it is hostile to life. Sulfuric acid constitutes their main component. Together with the planet’s dense atmosphere composed mainly of carbon dioxide, this cloud cover causes Venus’ extreme greenhouse effect. Temperatures of more than 400 degrees Celsius are common on the planet’s surface. The exact composition of the creamy-yellow clouds is still unclear. Almost 90 years ago, ground-based observations had shown that these clouds “swallow” ultraviolet light of certain wavelengths. Sulfuric acid alone cannot be responsible for this effect.