What is the spring equinox?
The four seasons are equally split between four astronomical phenomena known as equinoxes and solstices – two each.
These are caused by the planet’s axis being tilted by 23.44 degrees in relation to its path around the Sun.
On the days of the equinox, the Earth’s hemispheres receive the same amount of sunlight and night and day are said to be equal.
EarthSky astronomer Deborah Byrd said: “In fact, the word equinox comes from the Latin aequus (equal) and nox (night).
“For our ancestors, whose timekeeping was less precise than ours, day and night likely did seem equal. But we today know it’s not exactly so.”
At the equinox, the Earth’s terminator – the line that divides day and night – runs in a straight line from north to south.
source: express.co.uk