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Carl Sagan and the Exploration of Mars and VenusInspired by childhood readings of books by Edgar Rice Burroughs, Carl Sagan's first interest in planetary science focused on Mars and Venus. Typical of much of his career he was skeptical of early views about these planets. Early in this century it was thought that the Martian wave of darkening, a seasonal albedo change on the planet, was biological in origin. He suggested instead that it was due to massive dust storms, as was later shown to be the case. He was the first to recognize that Mars has huge topography gradients across its surface. During the spacecraft era, as ancient river valleys were found on the planet, he directed studies of Mars' ancient climate. He suggested that changes in the planets orbit were involved in climate shifts on Mars, just as they are on Earth. Carl had an early interest in Venus. Contradictory observations led to a controversy about the surface temperature, and Carl was one of the first to recognize that Venus has a massive greenhouse effect at work warming its surface. His work on radiative transfer led to an algorithm that was extensively used by modelers of the Earth's climate and whose derivatives still dominate the calculation of radiative transfer in planetary atmospheres today. Carl inspired a vast number of young scientists through his enthusiasm for new ideas and discoveries, his skeptical approach, and his boundless energy. I had the privilege to work in Carl's laboratory during the peak of the era of Mars' initial exploration. It was an exciting time, and place. Carl made it a wonderful experience.
Document ID
20020051148
Document Type
Conference Paper
Authors
Toon, Owen B. (NASA Ames Research Center Moffett Field, CA United States)
Condon, Estelle P.
Date Acquired
August 20, 2013
Publication Date
January 1, 1997
Subject Category
Lunar and Planetary Science and Exploration
Meeting Information
Spring Meeting of the American Geophysical Union(Baltimore, MD)
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.