SALT LAKE CITY (ABC4) – Tuesday is the summer solstice, also known as the longest day of the year in the northern hemisphere.

Why is summer solstice the longest day of the year? Well, the answer is simple:

According to Encyclopedia Britannica, summer solstice is the longest day of the year because it is the day when the sun travels its longest path in the sky, allowing for the longest period of daylight to occur during one day each year.

The day is prefaced by the spring equinox which arrived Sunday, March 20 this year, marking the start of the spring season.

“Equinox” is defined as the time at which the sun crosses the celestial equator, when day and night are of approximately equal length. The word comes from the Latin terms “aequus” (equal) and “nox” (night).

Therefore, spring equinox, or “March equinox,” occurs in the northern hemisphere when the sun crosses the equator, heading north. The event marks the first day of spring for the northern half of the world.

The shift means that the Northern Hemisphere is more tilted toward the sun, which results in increased daylight hours and warmer temperatures.

Thus, the spring season has earlier dawns and later sunsets.

The amount of daylight per day continues to increase during the spring until the summer solstice (when the sun travels its longest path in the sky).

The summer solstice also marks the beginning of summer, which lasts until the autumnal equinox (September 22 or 23 in the Northern Hemisphere, or March 20 or 21 in the Southern Hemisphere), when the sun once again crosses the celestial equator.

Historically, there are many references to the solstice, including Stonehenge, which was built between 5,000 and 3,500 years ago on a windswept plain in southwest England by a sun-worshipping Neolithic culture. Experts still debate its purpose, but it is aligned so that on the summer solstice, the sun rises behind the Heel Stone and rays of sunlight are channeled into the center of the circle.