why does the angle of inclination of the earths axis with its orbital plane 66 1/2 degrees
The axis of the earth makes an angle of 66.5 degree with its orbital plane. The some of the possible reasons as to why the earth is tilted at this angle are :
a. It might have tilted due to the collision with some asteroid millions of years ago.
b. Due to the gravitational effect between the earth and moon.