New Scientist: Venus is extremely hot, lacks liquid water, and has a toxic atmosphere. Yet a new simulation suggests that as recently as 1 billion to 2 billion years ago, the planet might have been habitable. David Grinspoon of the Planetary Science Institute in Tucson, Arizona, and his colleagues used a variation of a simulation of Earth's climate to create several possible models of the evolution of Venus's climate. The results suggest that an early Venus would have been quite similar to Earth at around the same time that life first evolved on our planet. However, a period of extreme volcanism 715 million years ago turned Venus into the searing planet it is today.
