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"From our vantage point,
Mercury and Venus, called
inferior planets because their
orbits lie between the earth and the sun, appear to
oscillate back and forth relative to the sun over a
short angular distance, as if attached to it by an
invisible extendable cord. For the ancients they were
the guardians of the sun, sometimes leading and other
times following the great luminary. By constrast, the superior planets, Mars, Jupiter, and Saturn, possessing orbits outside that of the earth, advance all the way around the sky and occasionally can be seen opposite the sun." "Ancient people were fascinated with the periodic backward loops turned by Mars every two years."
(Skywatchers) |
