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Projects: Observing EarthCarl Sagan—on Venus and Marsby Charlene M. Anderson
In any comprehensive history of the idea of climate change, references to Mars and Venus will keep popping up—and with them, the name Carl Sagan. Carl made his first major contribution to planetary science in 1960, when he published work that identified the greenhouse effect as the culprit in heating Venus’ surface to more than 900 degrees Fahrenheit (500 degrees Celsius). By 1973, he had devoted considerable attention to Mars and published a paper titled “Climate Change on Mars” in Science magazine. Perhaps more important than his scientific papers were Carl’s contributions to helping people everywhere appreciate how different our Earth is from its close siblings—and how distinctive are the physical systems that make it an abode for life. Planet-girding oceans, ever-churning plate tectonics, the water cycle, and the carbon cycle will keep our world from ever reaching the barren states of Mars and Venus. Carl cofounded The Planetary Society in 1980 with Bruce Murray and Lou Friedman, and we keep his example in mind as we expand our organization’s mission to include the planet Earth. —Charlene M. Anderson, Associate Director of The Planetary Society |
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