Equinox

Equinox is the situation when the duration of day and night is equal all over the Earth. During an equinox, the Sun is positioned directly over the equator. There are mainly two types of equinoxes:

1. Spring Equinox

2. Autumn Equinox

The Spring Equinox occurs on March 20 or 21, as on this day, the Sun is exactly over the equator, making the day and night equal across the Earth. Similarly, the Autumn Equinox happens on September 22 or 23, when the Sun is again positioned directly above the equator, resulting in equal lengths of day and night all over the Earth.

Reason for an Equinox:

The literal meaning of the word "equinox" is "to be equal." An equinox occurs when the Earth's tilt is neither towards nor away from the Sun. Instead, the Earth is tilted in such a way that the Sun's rays fall directly and vertically on the equator.

Our Earth always orbits the Sun with a 23.5º tilt on its axis. Throughout the year, there is one point where the Earth is tilted completely towards the Sun, and another point where it is tilted away from the Sun. Similarly, there are two times during the year when the Earth is not tilted towards or away from the Sun but is in the middle. This position is called an equinox.

This happens twice a year, which is why the length of day and night is nearly equal on these occasions. According to the English calendar, at the beginning of the year, around January, the Sun moves towards the Southern Hemisphere, and then gradually shifts towards the Northern Hemisphere. By the end of the year, around December, the Sun returns to the Southern Hemisphere. During this movement, the Sun passes directly over the equator twice a year, causing the equinox.

Importance of the Equinox on Earth:

Equinoxes mark important seasonal changes throughout the year. It is because of the equinox that the Earth experiences seasonal shifts. The Earth's slightly flattened shape and the angle at which the Sun's rays hit the Earth are the two main reasons why different places on Earth experience different climates. The Earth's climate changes geographically throughout the year, which is why we see seasonal changes across the Earth during the entire year.