Gyroscopic effect on planetary motion!! Hi PFians This is my first ever post in astrophysics since I've got very interested in it from last 2 days... I was wondering when earth rotates about it's axis and at the same time changes it's direction due to revolution about sun....won't it have to handle gyroscopic effects. When a spinning object like a bicycle wheel is forced to change direction(while steering), it undergoes rotation about an axis perpendicular to the changed direction and hence the whole bicycle rotates (to counter this we lean the bicycle at an angle). Similarly, when the spinning earth will change its direction due to movement about sun, it will undergo rotation about an axis exactly perpendicular to rotational axis. Correct me if I am wrong!!