Summer Solstice falls at the precise moment when the Sun's power is at its zenith. It is the time of year when the noon sun appears to be farthest north from the celestial equator. "Solstice" is Latin for "sun stands still" (sol "sun" and sistere "to stand"). Summer Solstice is so named because to the naked eye the sun appears stationary in its northern and southern progression. The sun is directly over the tropic of Cancer at the summer solstice, at which time the sun is 23°27' north. The sun travels 23.5 degrees to reach its maximum distance from the celestial equator during both the summer and winter solstice. It is the longest day and shortest night of the year. From the moment of Summer Solstice, the Sun immediately begins to wane. The journey into the harvest season has begun.
Midsummer has been one of the important solar events throughout the evolution of humankind. It was an indicator that the year was about to begin waning, thus winter would be again returning. Although not all the ancients were as precise in the calculations from an astronomical point, you can be sure that they were keenly aware of the sun's progression, and did most assuredly know when Solstice was upon them, as the sun appeared to stand still in its northern progression.
The axis of Stonehenge, which aligns with the monument's entrance, is oriented in the direction of the midsummer sunrise. The Teotihuacán Temple of the Sun, a pre-Columbian temple located in Mexico, was also oriented to the sun's passage at the Summer Solstice. During the time of the ancient Egyptians, Sirius (the dog star) rose on the Summer Solstice (today it rises August 10) heralding the beginning of their new year, just before the season of the Nile's flooding. Richard Hinckley Allen suggests that the star is connected with the dog because it was thought of by the ancients as the "guardian of the horizon and also the solstices" (Richard Hinckley Allen's Star Names: Their Lore and Meaning). The impact of the sun's journey was one that traversed all the world's population throughout all time. The ancients knew that life came from the sun, it was life giving, life supporting, without it life would be lost. The journey of the sun impacted life at every level in the course of time, only relatively recently with the advances of electricity, greenhouses, transportation networks, has human reliance on the passage of the sun been lessened. Even with this dependence lessening, in this technological age, necessity of the sun and its path is crucial to our existence, however it is not as apparent today to many.