Carl Sagan

Carl Edward Sagan (November 9, 1934 – December 20, 1996) was an American astronomer and science popularizer. He pioneered exobiology and promoted the Search for ExtraTerrestrial Intelligence (SETI). He is world-famous for his popular science books and the television series ', which he co-wrote and presented. In his works, he frequently advocated the scientific method.

Scientific achievements

Sagan was among the first to hypothesize that Titan{{ref|science}} and Jupiter's moon Europa may possess oceans (a subsurface ocean, in the case of Europa) or lakes, thus making the hypothesized water ocean on Europa potentially habitable for life. Europa's subsurface ocean was later indirectly confirmed by the spacecraft Galileo.

Related Topics:
Titan - Europa - Life - Galileo

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He furthered insights regarding the atmosphere of Venus, seasonal changes on Mars, and Saturn's moon Titan. Sagan established that the atmosphere of Venus is extremely hot and dense. He also perceived global warming as a growing, man-made danger and likened it to the natural development of Venus into a hot life-hostile planet through greenhouse gases. He suggested that the seasonal changes on Mars were due to windblown dust, not to vegetation changes, as others had proposed.

Related Topics:
Venus - Mars - Titan - Global warming - Greenhouse gas

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