Today, Friday, began the fall semester known as “”master of classesAs astronomical calculations revealed that the autumn season began today, Friday, September 23, and lasts for 89 days, 20 hours and 44 minutes..
After the sun passes the summer solstice, the apparent movement of the sun begins to gradually move towards the south, and the slope of its rays decreases, until it reaches zero around the 23rd of September (autumn equinox), and the sun’s rays perpendicular to the equator.
This day is again the same length of night and day for all places on the surface of the globe, and autumn occurs in the northern hemisphere and spring in the southern hemisphere.
The situation must be reversed during the vernal equinox, and the apparent movement of the sun continues to move towards the south, and the slope of its rays on the perpendicular to the surface of the earth begins to decrease; The day becomes long and the night shortens in the northern hemisphere, while the opposite happens in the northern hemisphere, until the sun’s inclination reaches (-27′ 27°), at the winter solstice again, and its rays perpendicular to the orbit of Capricorn, and thus the Earth’s revolution around the sun is completed in 365.25 days approx .
To explain the reason for the occurrence of the four seasons, it comes as a result of the sun being in an apparent orbit relative to the stars of the heavenly background that appear fixed in the sky, this orbit is known as the zodiac circle, and as a result of the Earth’s rotation around the sun and the tilt of its axis at the level of its orbit, the four seasons occur, and in order they are winter, spring and summer then autumn“.
Autumn is a transitional season that moves us from the heat and humidity of the summer to rain and lower temperatures in the winter.
The autumn climate is characterized by moderation in temperatures, but it is punctuated by some cases of instability in weather conditions, which are air depressions centered on the Mediterranean Sea, accompanied by instability in the upper layers of the atmosphere that work on occasional heavy rains on the northern coasts, Lower Egypt and Cairo .
The south of the country, the Red Sea Governorate and South Sinai are sometimes affected by the extension of the seasonal Sudan depression, which leads to high humidity and works on heavy rains, which cause torrential rains in the mountainous areas in Sinai and the Red Sea chains and the south of the country.