Her tilt of axis
With orbital period
Gifts us the seasons.
.
CLP 12/11/2018
n.b Earth’s axial tilt wobbles but the mean is currently c. 23.5 degrees. The orbital period around the Sun is our Earth year. It is described as a sidereal orbit because the Earth’s circuit of the Sun is on an orbital plane that is relatively settled during the brevity of human lifespans.