Days Were Shorter 70 Million Years Ago
Earth turned faster at the end of the time of the dinosaurs than it does today, rotating 372 times a year, compared to the current 365, according to a new study of fossil mollusk shells from the late Cretaceous. This means a day lasted 23 and a half hours, according to a study in by American Geophysical Union’s journal ‘Paleoceanography and Paleoclimatology’. The length of a year has been constant over earth’s history, because earth’s orbit around the sun does not change. But the number of days within a year has been shortening over time because days have been growing longer. The length of a day has been growing steadily longer as friction from ocean tides, caused by the moon’s gravity, slows earth’s rotation. Of course, in the history of the moon, 70 million years is a blink in time.