Why does the earth spin at an angle?
Probably from a collision with a large object.
No one really knows but it is surmised that the birth of the earth's moon came from the collision the earth had in its early days with another large object.
In its earliest days the earth endured a literal bombardment of object of all sizes. We believe that is how earth got its water. But one object was particularly large, plunged into the earth and pushed it to the side.