Every year, there are two special days where every place on Earth receives the same amount of sunlight — 12 hours — split evenly between night and day: the equinoxes!
Like all known objects that revolve around another due to gravity, the Earth rotates along its journey around the Sun. But on those two days of the equinox (from the Latin, meaning “equal nights”), the Earth’s axis-of-rotation makes a 90° angle to the imaginary line connecting the Earth to the Sun.
As a result, every place on Earth* spends exactly half the day basking in the sunlight and half the day out of view of the Sun, enjoying the night…..
Read more: scienceblogs.com