SOLAR SYSTEM

Detailed explanation-1: -On 21st March and September 23rd, direct rays of the sun fall on the equator. At this position, neither of the poles is tilted towards the sun; so, the whole earth experiences equal days and equal nights. This is called an equinox.

Detailed explanation-2: -On Earth, there are two equinoxes every year: one around March 21 and another around September 22. Sometimes, the equinoxes are nicknamed the “vernal equinox” (spring equinox) and the “autumnal equinox” (fall equinox), although these have different dates in the Northern and Southern Hemispheres.

Detailed explanation-3: -Equinox in Latin means equal night, giving the impression that the night and day on the equinox are exactly 12 hours long.

Detailed explanation-4: -For all practical purposes, the length of day and night for any location on the equator is constant throughout the year at about 12 hours.