The Vernal Equinox

The Equinox is when the Earth's axis is neither away nor facing the sun. This occurs only twice a year. There is a Spring(Vernal) Equinox(March) and Autumn(September).
It originates from the Latin 'Aequus' meaning equal. It is at both Equinox's that Day and Night are equal. Almost!
It is also believed that Night in both the Northern Hemisphere and Southern Hemisphere are the same.

The Equinox's and the Past:-
The Vernal  Equinox played an important role in the past. In Celtic and Pagan times the Vernal Equinox was the beginning of spring. The people believed that Earth was asleep during the Winter and awoke at the Vernal Equinox. So our ancestors may have been aware of the Environment and Astronomy far before we have been!
For Christians, the timing of Easter depends in the Vernal Equinox. Easter occurs  on the first Sunday after the first full moon after the Vernal Equinox.

Our ancestors who built Newgrange in Co. Meath positioned its entranceway for the Equinoxes so sunlight would light up the passage ways.

The Vernal Equinox at Newgrange