Space / DAY 07 OF 40
Earth used to clock out early.
An ancient day may have lasted less than 19 hours.
Here's the strange part.
Earth did not always take 24 hours to complete the daily programme. Researchers used ancient sediments and orbital modelling to estimate a day of about 18 hours and 41 minutes, 1.4 billion years ago. Rocks can preserve clues to repeating climate patterns, making them a very slow kind of clock. The number is a reconstruction, not a stopwatch reading from ancient Earth. (Science / AAAS)
This is an estimate reconstructed from ancient rocks and orbital models. The rate of change is not constant across Earth's history.
REALITY CHECK · TRUE OR FALSE?
Who forgot to wind ancient Earth?
The ancient day length is a reconstruction, not a direct clock measurement.
Go straight to the receipts.
Curious about the methods, dates or details? Open the original source and keep the caveat in view.
ORIGINAL SOURCEScience / AAASOpen publication ↗NEXT IN THE 40-DAY TRAIL / DAY 08This jellyfish has a reset button. ↗