Spring 2020: Google marks end of winter with colourful doodle

Spring begins with the vernal equinox, the day when the Sun passes directly over the Earth’s equator. This makes days and nights exactly 12 hours, or equal in length. The vernal equinox extends till the summer solstice, when the days become longer than nights. In winter, the nights are longer.

There are two equinoxes every year, in March and September. The March equinox marks the moment the sun crosses the celestial equator — the imaginary line in the sky above the Earth’s equator — from south to north and vice versa in September.

On the day of the equinox, the sun rises directly in the east and sets directly in the west. At other times in the year, it appears off-centre, if you’re facing those directions.

The March equinox is often used by astronomers to measure a tropical year — the mean time it takes for the Earth to complete a single orbit around the sun.