My limited understanding: zero degrees may be most likely but there's a lot of random variation as things get whacked by lots of large objects in their formation. Tidal forces don't get rid of the tilt, they cause precession. --Joshua Zucker On Sat, Apr 10, 2010 at 9:27 PM, Henry Baker <hbaker1@pipeline.com> wrote:

The earth's axis is inclined ("axial tilt") at approx 23.5 degrees to its orbit around the Sun.

How did it get that way?  If most of the stuff in the solar system originally had the same axis of angular momentum, then wouldn't the earth most likely end up with a zero degree axial tilt?

What is the current best explanation for the tilt?  Did the earth get hit by another body from an odd angle -- e.g., when the Moon was formed?

Wouldn't tidal forces eventually get rid of the tilt?

Thanks in advance for any pointers.

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