When Earth Had 6-Hour Days — The Moon Changed Everything

Added: 2026-05-28

[00:00:00]There was a time when a full day on Earth lasted less than 6 hours.

[00:00:04]And the reason is the moon.

[00:00:06]Billions of years ago, the moon was much closer to Earth.

[00:00:10]Because of that, our planet rotated far faster than it does today.

[00:00:14]A single day may have lasted only around 5 to 6 hours.

[00:00:18]Imagine experiencing four sunrises within what we now call one day.

[00:00:23]But the moon's gravity has been slowly slowing Earth down through tidal forces.

[00:00:28]At the same time, the moon itself is gradually drifting [music] away from us.

[00:00:33]Today, it moves farther from Earth by about 3.8 cm every year.

[00:00:39]Scientists measured this using lasers reflected off mirrors left on the lunar surface by the astronauts of Apollo 11 moon landing.

[00:00:47]So, the moon is not just hanging [music] in the sky.

[00:00:50]It is actively changing the rotation speed of our planet, even right now.