The Vernal Equinox
Ah, spring! This season brings increasing daylight, warming temperatures, and the rebirth of flora and fauna.
The word equinox is derived from the Latin words meaning “equal night.” The spring and fall equinoxes are the only dates with equal daylight and dark as the Sun crosses the celestial equator. At the equinoxes, the tilt of Earth relative to the Sun is zero, which means that Earth’s axis neither points toward nor away from the Sun. (However, the tilt of Earth relative to its plane of orbit, called the ecliptic plane, is always about 23.5 degrees.)