Understanding the Sun’s Motion and the Reason for Seasons скачать в хорошем качестве

Understanding the Sun’s Motion and the Reason for Seasons

In this session, I discuss the nature of sunrises and sunsets and the sun’s motion across the sky. We know the sun rises in the east and sets in the west, but it also drifts eastward relative to the stars over a year. This drift takes approximately 365.25 days to return to the same sky location, which accounts for leap years. The Earth’s orbital motion and its rotation on its axis create differences in the sun’s apparent position. A solar day, measured from noon to noon, differs from a sidereal day, which is shorter by about four minutes. This difference causes the sun to appear to move against the backdrop of stars, tracing a path called the ecliptic. The zodiac constellations, through which the sun travels, include familiar names like Virgo, Libra, Scorpius, Sagittarius, and more. These constellations correspond to the sun’s position at different times of the year. Using Stellarium, I illustrate how the sun moves along the ecliptic and explain the solstices and equinoxes. The angle of the Earth’s tilt relative to its orbital plane creates seasonal changes. During summer solstice, the sun is high in the sky, casting short shadows, while during winter solstice, the sun stays low, casting longer shadows. The solstices mark the longest and shortest days of the year, and the equinoxes occur when the sun crosses the celestial equator. The reason for the seasons lies in the tilt of the Earth’s axis, not in the distance from the sun. The angle of sunlight impacts the intensity of heat received on Earth’s surface. A higher sun angle in summer results in more intense heating, while a lower angle in winter results in less intense heating. Understanding the interplay of these factors helps us grasp how the sun’s apparent movement affects our seasons.