Earth’s day was half hour shorter 70 million years ago

Using data from an ancient fossil shell, scientists have determined that 70 million years ago the Earth’s day was about 30 minutes shorter, and that a year comprised 372 days.

This result is not a surprise, as scientists have known for a long time that the day has been growing longer as the Moon’s gravity, producing tides, wears away at the Earth’s rotation. This data however is the most precise yet, and will allow scientists to better constrain not only the Earth’s changing rotation over time but the Moon’s orbit. As it slows the Earth’s rotation its own orbit around the Earth gets longer, pushing it farther away.