What's the weather for Mars and Venus? The Hubble telescope has given astronomers a peak. The telescope is serving as an interplanetary weather satellite for studying the climate on Earth's neighboring worlds, Mars and Venus.
To the surprise of researchers, Hubble is showing that the Martian climate has changed considerably since the unmanned Viking spacecraft visited the Red Planet in the mid-1970s. The Hubble pictures indicate that the planet is cooler, clearer, and drier than a couple of decades ago. In striking contrast, Hubble's observations of Venus show that the atmosphere continues to recover from an intense bout of sulfuric "acid rain," triggered by the suspected eruption of a volcano in the late 1970s.