Day length variation on planet earth

[Eternity]

Hi

Is it possible that a day on planet earth was once 25 hours and will be 22 hours (in 6 billion years for example)? Or vice versa (25 hours in 1.5 billion years)? Are there any realistic causes that could change day length drastically?

Thanks for answering!

[rstevenson]

The day length was less in the past, perhaps as little as 6 hours when the Earth was formed. The day was about 22 hours long about 620 mya. Tidal acceleration is causing this gradual change in the day length. More info here.

Rob

[bystander]

The rotation of the Earth is slowing and the days are getting longer, though we won't notice the difference within our lifetimes.

http://en.wikipedia.org/wiki/Tidal_acceleration

lol, Rob beat me to it.

[neufer]

Hi

Is it possible that a day on planet earth was once 25 hours and will be 22 hours (in 6 billion years for example)?
Or vice versa (25 hours in 1.5 billion years)? Are there any realistic causes that could change day length drastically?

http://asterisk.apod.com/viewtopic.php? ... 78#p141878

<<The 2011 Tōhoku earthquake shifted the Earth's axis by 25 cm. This deviation led to a number of small planetary changes, including the length of a day and the tilt of the Earth. The speed of the Earth's rotation increased, shortening the day by 1.8 microseconds due to the redistribution of Earth's mass. The axial shift was caused by the redistribution of mass on the Earth's surface, which changed the planet's moment of inertia. Because of conservation of angular momentum, such changes of inertia result in small changes to the Earth's rate of rotation. These are expected changes for an earthquake of this magnitude.>>