Empirical Earth · Rotation & How We Measure It

Travel east and you weigh less — the Eötvös effect

The claim

“If the Earth were spinning, wouldn’t there be some measurable mechanical sign of it?”

What is measured

Gravimeters read lighter heading east and heavier heading west. It is a small but routinely measured effect of Earth’s rotation, predicted by Eötvös, confirmed by ship trials in 1908, and corrected for in gravity surveys today. Your weight depends on your heading only because the Earth spins.

What would show this is wrong

showing gravimeter readings are identical for eastward and westward travel at the same speed and latitude, with no heading-dependent difference, contrary to the measured Eötvös correction.

Sources

  1. The Eötvös effect. Apparent gravity decreases for eastward motion and increases for westward motion because of Earth’s rotation (the vertical component of the Coriolis force); geodesists app link
  2. Discovery & 1908 confirmation. Eötvös found the east–west gravity discrepancy in Oskar Hecker’s 1901–1905 shipboard data and confirmed it with two ships crossing the Black Sea in opposite di link
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