Were days shorter 2 billion years ago than they are now?
Yes. The Moon was formed by the Giant Impact around 4 billion years ago. As is the normal physical process, the Earth and Moon will continue to undergo the process of becoming binary orbs. One day, a few billion years from now, the Earth will show the same side to the Moon just as the Moon does towards Earth today. The process we see as this occurs is the Moon continuing to move away from Earth by 1.5 inches per year and also the Earth continuing to slow in its rotation speed (days and nights becoming longer). Two billion years ago, the days on Earth were shorter than today. In fact, evidence shows that one half billion years ago, days were twenty-two hours long.
