This is a flowchart summary of the histories of the terrestrial planet atmospheres (Venus, Earth, and Mars). It shows the histories side-by-side so it is easier to compare the planet histories.
The chart for Venus up to the dashed arrow describes the runaway greenhouse process that happened several hundred million to a few billion years ago. The bottom diamond describes the current condition. The chart for Mars up to the dashed arrow describes the runaway refrigerator process that happened a LONG time ago. The bottom rectangle describes the current condition. The chart for the Earth describes the carbon dioxide cycle as it currently operates. The Earth exists balanced between the two extremes of Venus and Mars.
last updated: June 4, 2010