Today, June 20th, 2024 at 1:50pmPST is the Estival (Midsummer) Solstice, a single moment in time when the Sun reaches it's highest annual position in the northern hemisphere sky, making it the longest day of the year in the northern hemisphere. However, if you are in the southern hemisphere, today is the shortest day of the year & the longest winter night.
The Sun's position in the sky determines the length of day that a location on Earth experiences, and is dependent on the tilt of Earth's axis & Earth's location on it's orbital path around the Sun. Earth is racing around the Sun on it's orbital "trackway" at 66,620mph, while the tilt of Earth's axis stays relatively consistent through the centuries.
The North Pole points to the North Star (Polaris), and that won't change enough to be apparent for a long time. It takes 21,000 years for Earth's angle of axial tilt to change by less than 2.5 degrees, so we won't notice any change in axial tilt as the Earth orbits around the Sun annually. Therefore the tilt of Earth does not cause the seasons. Earth's annual seasonal journey is the result of Earth's speeding along its orbital path while maintaining a relatively consistent axial tilt.
In June, the North Pole is pointing toward the Sun, so the Northern hemisphere gets more hours of sun light & experiences the summer conditions of hot, long days. In the north we are lucky to experience relatively mild summers compared to those of the southern hemisphere, due to the distance between the Sun and the Earth.
During the northern hemisphere summer, the Earth is further from the Sun, closer to Aphelion. The Earth is closest to the Sun at Perihelion, which occurs in early January. Summer temperatures in Africa, Australia & South America are extreme because the Earth is closer to the Sun while southern hemisphere days are long & the Sun is positioned high in the sky. Annual average temperatures on Earth are higher for the southern hemisphere than they are for the northern hemipshere.
Earth's seasons, equinoxes, and solstices are the result of Earth's orbit (revolution) around the Sun. Appreciate this long day, because as of tomorrow, the days will start getting shorter. Happy summer!
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