Equinox

Subject : Geography

Section: Climatology

Concept :

Equinox today (March 21) marks the end of winter in northern and summer in southern hemisphere.

About Equinoxes (Vernal & Autumnal)

The word equinox is derived from two Latin words – aequus (equal) and nox (night).
There are only two times of the year when the Earth’s axis is tilted neither toward nor away from the sun, which results in a nearly equal amount of daylight and darkness at all latitudes. These events are referred to as Equinoxes.
The equinoxes happen in March (about March 21) and September (about September 23) on these days the Sun is exactly above the Equator
The equator and places near the equator experience nearly 12 hours of the day and 12 hours of the night.
Reasons:
- The phenomenon occurs due to the Earth’s axial tilt, or the angle by which the planet is tilted relative to the Sun.
- The imaginary axis of our planet is not straight up and down but is tilted by 23.5 degrees.
- This is why different regions of the Earth experience different measures of sunlight.
Implications:
- The days become a little longer at the higher latitudes (those at a distance from the equator) because it takes the sun longer to rise and set.
- The solstices, together with the equinoxes, are connected with seasons, harvests and livelihood.
- Therefore, many cultures celebrate various combinations of the solstices, the equinoxes, and the midpoints between them, leading to various holidays arising around these events.

Solstices (Summer & Winter)

The two solstices happen in June (20 or 21) and December (21 or 22). These are the days when the Sun’s path in the sky is the farthest north or south from the Equator.
In the Northern Hemisphere, the June solstice marks the start of summer, this is when the North Pole is tilted closest to the Sun, and the Sun’s rays are directly overhead at the Tropic of Cancer.
The summer solstice occurs when the sun is directly over the Tropic of Cancer which is located at 23.5° latitude North and for every place north of the Tropic of Cancer, the sun is at its highest point in the sky and this is the longest day of the year.
The winter solstice marks the shortest day and longest night of the year, it occurs when the sun is directly over the Tropic of Capricorn, which is located at 23.5° south of the equator.