While March 20 marks the springequinox in the Northern Hemisphere, the Southern Hemisphere will celebrate the autumnal equinox, which marks the beginning of autumn.
Tuesday marked the astronomical first day of spring for those in the Northern Hemisphere.
In 2018 it will be on September 22 at 8:54 p.m. But when the Earth passes through an equinox, both poles receive equal sunlight, because the planet is tilted neither towards or away from the sun. Day and night are "approximately" equal in length and the earth isn't leaning to one side or the other as we orbit the sun. The name "equinox" is actually derived from the Latin words meaning equal and night, according to the National Weather Service.
The latestGoogle Doodle, by Sophie Diao, celebrates the springequinox 2018 with an animation showing this year's seasonal Doodle series protagonist, Quinn, "strumming a pleasant tune to coax a mysterious creature out of hiding".
Chester, who is also an astronomer, says spring has been observed by civilizations since time immemorial. The SpringEquinox marks a 24-hour period on Earth when day and night are nearly exactly equal lengths of 12 hours because the earth's axis is perpendicular to the sun's rays.