Empirical Earth · How We Know — History & the Cosmos
The claim
“Motion is relative, so geocentrism is just as valid as heliocentrism.”
What is measured
Aberration (1729) proved the Earth moves; parallax (1838) proved it orbits. A Sun-centered, Newtonian solar system predicts both to the arcsecond; a stationary Earth predicts neither without inventing a daily-spinning, faster-than-light cosmos. The observation that ended pure geocentrism is the phases of Venus.
What would show this is wrong
a measured stellar parallax or aberration consistent with a stationary Earth, or phases of Venus matching the Ptolemaic (crescent-only) prediction.
Sources
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