Autumnal equinox. Designed by Marimekko.
Google Doodle today March 20, 2012 in Peru come with a theme Equinoccio otoñal. Diseñado por Marimekko. Or Autumnal equinox. Designed by Marimekko, same with google doodle in previous article.
Google logo is present is very beautiful, appeared with a picture of leaves with bright colors.
Equinox is called at the time of year when the Sun is located in the plane of Earth Ecuador, where it reaches its zenith. The parallel decline of the sun and the sky then Ecuador match. The word equinox comes from Latin aequinoctĭum and means "equal night".
It happens twice a year: 20 or 21 March to 22 or September 23 of each year, three times when the two poles of the Earth are at equal distance from the Sun, sunlight falling equally in both hemispheres .
Equinox is also each of the dates when the days have a duration equal to that of night everywhere on Earth. At the equinox happens the contrary annual change of seasons in each hemisphere of the Earth.
more detail read in wikipedia.