The Washington Post
Health & Science

Why, in the Jurassic era, an Earth day may have been only 23 hours long.
By Ivan Amato, Published: September 23

... “We naively think there always has been 24 hours per day,” says Thomas O’Brian, chief of the Time and Frequency Division of the National Institute of Standards and Technology (NIST). “But that is not the case.” ...

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