26 August 2004, 07:00 AM ET
In an interview, David Grinspoon explains how Venus evolved from a wet planet similar to Earth to the scorching hot, dried-out furnace of today. Then he discusses the possibility that Venus was once an inhabited world.
02 August 2004, 07:14 AM ET
Sunlight drops when Mercury or Venus cross the face of the Sun and when sunspots cross the surface. Yet when there are few sunspots, sunlight also decreases.