Autumn Equinox in the Northern Hemisphere on 22 Sept: Significance, everything else you need to know

The length of the days and nights are not equal most of the days. While the winters see longer nights, we experience longer days in summers. However, there are exactly two days a year when the duration of the day time and the night time becomes equal. The two equinoxes take place when the Sun is exactly above the equator. The fall equinox or the autumnal equinox, for the Northern Hemisphere, falls on 22 September this year. This day marks the beginning of autumn and cooler temperatures. On the other hand, spring starts in the Southern Hemisphere. [caption id=“attachment_8840401” align=“alignnone” width=“1280”] There are exactly two days a year when the duration of the day time and the nighttime becomes equal.[/caption] While the solstices also usher in seasons, these are the days when the Sun’s path in the sky is the farthest north or south from the equator. According to Science Alert, the fall equinox will begin at 7 pm IST today. This phenomenon, along with the other solstices and equinox, 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. The equator and places near the equator experience nearly 12 hours of the day and 12 hours of night the whole year through. On the day of the equinox, the Earth is not tilted towards or away from the Sun and therefore, the entire planet gets equal division of day and night. However, as a CNN report points out, the days and the nights are not exactly equal. This is due to the refraction of sunlight. Even before the Sun has risen, the star might appear above the horizon for some people due to the bending property of light. Similarly, people might think the Sun is yet to set long before it has. The report added that this change is dependent on the location you are watching the Sun from. So if you are near the equator, the day will be a bit smaller than the areas near the poles. On this fall equinox, the day will be about 12 hours and 6 and half minutes long at the equator. At a latitude of 60 degrees, the day is going to be about 12 hours and 16 minutes long.