The atmosphere of Venus continues to recover from an intense shower of sulfuric “acid rain,” according to January 24 images from the Hubble Space Telescope (HST) that have given scientists a first-time look at the planet in the ultraviolet spectrum. The images, taken when Venus was about 113.6 million km from Earth, reveal that the amount of sulfur dioxide in the atmosphere has declined by a factor of 10 since 1978 when the Pioneer Venus Orbiter flew.
“If Venus is a twin of the Earth, it's an evil twin,” says Larry W. Esposito, a planetary astronomer at the University of Colorado at Boulder. While the Earth is surrounded by water-vapor clouds, Venus is enshrouded by clouds of sulfuric acid. In addition, the temperature on Venus is about 427°C.