The fall equinox marks the official start of autumn in the Northern Hemisphere. It is a time when the Earth’s axis is tilted neither toward nor away from the sun, resulting in nearly equal amounts of daylight and darkness at all latitudes. The tilt of the Earth’s axis is what gives us seasons, as different areas of the planet receive direct sunlight at different times. During the equinox, the sun shines directly at the equator, giving equal love to both the Northern and Southern Hemispheres. Other planets tilted on their axes also experience equinoxes, but the time scales can vary significantly.
The autumnal equinox in the Northern Hemisphere falls on September 22nd this year, marking the transition from summer to fall. During the equinox, the sun rises as close to east and sets as close to west as possible, making it a foolproof compass. This time of year also features the fastest sunrise and sunset of the year, with the sun appearing and disappearing in just a few seconds due to the steep angle at which it rises and sets. Equinoxes are different from solstices, which are associated with Earth’s tilt but result in extremes in daylight and nighttime hours.
Satellites in orbit around Earth provide a unique perspective of the equinox, showing how the positioning of the sun’s light changes with the shifting of the seasons. While the fall equinox may not be as visually spectacular as events like eclipses or meteors, it is a significant moment that marks the transition between seasons. Celebrating the fall equinox can be as simple as acknowledging the changing of the astronomical season and embracing the arrival of autumn. You can take part in autumn foliage sightseeing adventures, don your favorite sweater, go for a scenic drive, and enjoy a pumpkin spice latte to welcome fall in style.
Equinoxes occur on other planets as well, with each planet’s tilt and orbital path affecting the timing and duration of these events. While Earth experiences equinoxes every year, other planets like Saturn and Neptune have much longer seasons, lasting over seven years and even decades. Despite the variations in other planetary equinoxes, we can appreciate the relatively short and predictable seasons on our own planet. The changing seasons are a natural cycle shaped by the tilt of the Earth’s axis and its orbit around the sun, showcasing the beauty and complexity of our solar system.
