An equinox is an astronomical event that occurs when the plane of Earth’s equator passes through the center of the Sun's apparent path across the sky. During this time, the amount of daylight and nighttime hours are nearly equal across the globe. Two primary equinoxes occur annually: the vernal equinox, signaling the beginning of spring in the northern hemisphere, and the autumnal equinox, marking the transition to autumn. These events are characterized by the Earth's tilt relative to the Sun achieving a balance, resulting in the planet receiving approximately equal solar insolation on both hemispheres, marking a significant point in the annual cycle of seasons.