Join Steve to celebrate Earth Day.

The Goldilocks zone, or habitable zone, is the region around a star where liquid water may exist on a planet’s surface. In our solar system Venus, Earth and Mars fit this definition. However, only Earth presently has surface water. Venus and Mars show evidence of surface water in the distant past but Venus is now a hellscape and Mars a cold, dry desert. What happened and what does this bode for our planet?