On September 22, people in Pakistan and much of the world will witness a rare celestial event where day and night are almost equal in length. Known as the September Equinox, this event happens when the sun moves from the Northern Hemisphere to the Southern Hemisphere, passing directly over the equator. In Pakistan, this will occur at 5:43 PM local time.
During the equinox, the duration of daylight and nighttime is nearly the same—around 12 hours each—across most regions of the world. This happens because the sun’s rays strike the equator directly, making it an important moment in the Earth’s annual journey around the sun. The equator, an imaginary line that divides the Earth into the Northern and Southern Hemispheres, plays a key role in this astronomical phenomenon, which takes place twice a year: once in March and again in September.
What makes this event even more special is that the sun rises exactly in the east and sets precisely in the west. For those in the Northern Hemisphere, including Pakistan, the September Equinox marks the start of autumn, leading to shorter days and longer nights as the colder months set in. Meanwhile, in the Southern Hemisphere, the equinox signals the beginning of spring, with longer days and warmer weather.
This natural balance of light and dark is a result of the Earth’s tilt on its axis as it orbits the sun. At different times of the year, the Earth either tilts toward or away from the sun, causing the varying lengths of days and nights. In addition to the equinoxes, other important solar events include the Summer Solstice in June, which brings the longest day of the year, and the Winter Solstice in December, marking the shortest day.
Historically, equinoxes and solstices were used to track the seasons, helping ancient civilizations with agriculture and cultural practices. Today, the September Equinox continues to be a significant astronomical event, reminding us of the Earth’s fascinating relationship with the sun.
