Mystery #1Tier 1earth & space / time
Why is a day exactly one day long, and where does that length come from?
Every morning the Sun climbs up one side of the world, and every evening it slips down the other. Then, like clockwork, the whole thing happens all over again. Something is keeping perfect time, over and over, without a single battery. What is actually setting the length of a day?
Your guess
What do you think decides how long one day lasts?
There's no single magic word to type, have a go in your own words, then reveal the answer to see how close you got.
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