A year connects timekeeping to a repeating astronomical cycle. Earth completes an orbit around the Sun in roughly 365¼ days, but the exact duration depends on the reference point. The tropical year follows the seasonal cycle; the sidereal year follows Earth’s position relative to distant stars. They differ slightly. The Gregorian calendar is designed to track the seasonal year using whole days. Its mix of ordinary and leap years is an approximation, rather than a claim that nature runs in exact calendar units.
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What is a year?
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Original explanatory text informed by the sources below. Last source check: September 17, 2026. These sources are not endorsements of Losslessly.
U.S. Naval Observatory · Seasons and orbitTokens are units of text counted by a tokenizer. They are not a measure of meaning or difficulty.
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A short before-and-after practice on calendars. No time limit.