Return to IndexEquinox vs. Equilux (1)
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The equinoxes are the two days each year - the vernal equinox around the 20th of March and the autumnal equinox around the 22nd of September - when the Earth's axis of rotation is perpendicular to the Earth-Sun line and so neither tilts towards the Sun nor away from it. The geometry of this situation, and indeed the name "equinox", would lead one to assume that the length of daylight and night-time on these days was equal but this is not actually the case. This article explains why not, calculates a value for the difference between them, and explores the possibilty of there being days when equality is in fact achieved. Click on the title to read the article. |