What is the difference between an equinox and a solstice?
As the Earth glides along its path around the Sun, due to its tilt, our glowing orb rises and falls in the sky and its position marks the different seasons.
Before the advent of the electric light, all of mankind could look up at the heavens during the night and see the universe and the countless glowing lights in all of their splendor. The ever-changing night sky had a rhythm to its modifications that repeated year after year. The earliest astronomers memorized those patterns and created stories to help pass their knowledge down through the generations.
Its importance was fundamental for organizing and preparing for what would happen at any given time during the year. Especially for gathering food, like knowing when animals would be migrating and when certain plants would be ripe for harvesting or seeds could be sown.
Likewise, during the day they could also track the Sun’s path through the sky given that our star, from the vantage of most inhabitants of Earth, changes its position relative to the horizon throughout the year. When it reached certain points, equinoxes and solstices, humans could demarcate the beginning and end of the seasons.
You may also be interested in: What is the official first day of fall 2024? What is the exact time?
What is the difference between an equinox and a solstice?
The Earth takes 365 days, 6 hours, 9 minutes to revolve around the Sun which makes keeping a physical calendar accurate difficult over long periods of time. However, the seasons will always occur during any given year at the same time regardless of the calendar date synchronized with the tilt of the Earth in relation to the Sun as our planet makes its trek around our star.
Our planet’s inclination of 23.45 degrees from the plane of its orbit around the Sun means that as it travels around our star, the glowing orb will move higher or lower in the sky throughout the year. The changing position in the sky affects how long the days and nights are, with the effect being more pronounce the higher the latitude on Earth.
Above the Artic and Antarctic Circles, for example, there are eternal days and nights that last for about six months at the poles. It also means that the seasons in the Northern and Southern Hemisphere are opposite each other.
The length of the days in turn plays a major role in the climatic conditions on our planet. As the Sun gets higher in the sky the days become warmer and vice versa as it gets lower in the sky temperatures drop.
When the Sun reaches its highest and lowest point in the sky, we call that a solstice. For the Northern Hemisphere the Summer Solstice, the longest day of the year, occurs around 20-22 June when the Sun is directly over the Tropic of Cancer. The Winter Solstice, the shortest day of the year in the Northern Hemisphere, happens around 20-22 December when the Sun is directly over the Tropic of Capricorn.
Equinoxes occur twice each year around March 20–21 and September 22–23, spring and autumn, respectively in the Northern Hemisphere. This is when the Sun crosses the Celestial Equator, and both day and night last roughly the same amount of time.