equinox
Day and night are of equal length during the equinoxes, which occur in spring and autumn. The phenomenon is called an equinox, which means "equal night" in Latin.
Because the Earth's axis is perpendicular to the Earth's orbit on that day.
Any place on earth that lie on the equator will have equal day and night time.
solstice ?
The length of day and night is equal at the Vernal and Autumnal equinox.
A period of time when the day time hours are equal to the number of night time hours is called an equinox. This occurs twice a year, in spring and autumn, when the Earth's axis is tilted neither toward nor away from the sun.
The length of day and night on Earth are not always equal. The amount of daylight and darkness varies depending on the time of year and the latitude of a location. This difference is more pronounced the closer you are to the poles and during the equinoxes.
Rotation
the Equinox.
An Equinox.
Day and night are of equal length at the equator, which is an imaginary line that circles the Earth halfway between the North and South Poles. This phenomenon occurs during the equinoxes, which happen around March 20-21 and September 22-23 each year.