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Earth rotated faster in the past
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Today I learned that on early Earth a day was only ~4-6 hours long.

.. csv-table::
   :header: "era", "years ago", "hours per day", "days per year"

   "present", "0", "24", "~365"
   "middle devonian", "~370M", "~22", "~400"
   "early earth", "~4.5B", "~4-6", "~1460"