The two major motions of Earth as it travels through space are:

1. Rotation: This is the spinning of Earth on its axis. It takes approximately 24 hours for Earth to complete one full rotation, which is why we have day and night.

2. Revolution: This is the movement of Earth around the Sun in an elliptical orbit. It takes approximately 365.25 days for Earth to complete one full revolution, which is why we have a year.