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When Did the asteroids Become Minor Planets? - http://aa.usno.navy.mil/faq/docs/minorplanets.php
Discusses the discovery of the first asteroids, their designation as planets, and their reclassification. |
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The Planet Mars: A History of Observation and Discovery - http://www.uapress.arizona.edu/onlinebks/mars/contents.htm
On-line version of the book by William Sheehan. |
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Orbits and Gravitation - http://www-groups.dcs.st-and.ac.uk/~history/HistTopics/Orbits.html
The development of the mathematics of planetary motion. |
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Is Mars Habitable? - http://www.wku.edu/~smithch/wallace/S730.htm
A. R. Wallace's 1907 critique of Lowell's Book "Mars and Its Canals" |
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Neptune and Pluto - http://www-groups.dcs.st-and.ac.uk/~history/HistTopics/Neptune_and_Pluto.html
Mathematical discovery of planets |