inferior planet, planet whose orbit lies inside that of the earth. There are two inferior planets, Mercury and Venus. They always seem to be close to the sun in the sky; the greatest elongation of Mercury is 28°, and that of Venus, 47°. For this reason, neither can be seen for more than two or three hours after sunset or before sunrise.
"inferior planet." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (September 20, 2018). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/inferior-planet
"inferior planet." The Columbia Encyclopedia, 6th ed.. . Retrieved September 20, 2018 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/inferior-planet