Earth approaches perihelion in 2024
Earth's closest encounter with the Sun, "perihelion," is tomorrow.
Tomorrow, at 12:38 a.m. GMT, the Earth will reach its closest point to the Sun, known as " perihelion ." This event coincides with winter in the Northern Hemisphere.
Celestial Dance: Perihelion and Aphelion
At the beginning of each new calendar year, the Earth is on schedule to reach "perihelion" which occurs in early January. During this time, the Earth reaches its closest distance to the Sun, while around the middle of the year, specifically in early July, it reaches its farthest point, known as "aphelion".
The terms "perihelion" and "aphelion" were coined by the German astronomer Johannes Kepler, describing the orbital motion of the planets, borrowing words from ancient Greece.
In this regard, Eng. Majed Abu Zahra, President of the Jeddah Astronomical Society, explains that the Earth’s orbit around the Sun is elliptical, not circular. Therefore, the distance between us and the Sun varies throughout the year. During perihelion, the Earth is about 147,099,586 million kilometers closer to the Sun, compared to its position six months later during aphelion, at a distance of 152,096,155 million kilometers.
Effect on the apparent size and brightness of the sun
While the difference in distance between January perihelion and July aphelion is not large, it does cause the Sun to appear slightly larger and 7% brighter during perihelion. However, this phenomenon does not affect the duration of the seasons, as the four seasons are primarily caused by the tilt of the Earth's axis of rotation, not its proximity or distance from the Sun.
During winter, the North Pole is tilted away from the Sun, while in summer it is tilted toward the Sun. Although Earth's approach or retreat from the Sun is not responsible for the seasons, it does affect their length. When Earth is closest to the Sun, it moves faster in its orbit, about 30.3 kilometers per second, than it does in early July. As a result, winter in the Northern Hemisphere is the shortest of the four seasons.
Questions and Answers Section:
Q1: Why are there perihelion and aphelion on Earth?
A1: Earth faces perihelion and aphelion because of its elliptical orbit around the Sun, with perihelion being the closest point and aphelion being the farthest.
Q2: How does the Earth's distance from the sun affect the seasons?
A2: Earth's distance from the Sun does not directly cause the seasons; instead, it affects the length of the seasons. The closer proximity during perihelion results in a shorter winter in the Northern Hemisphere.
Q3: What is the importance of Johannes Kepler's contribution to astronomy?
A3: Johannes Kepler introduced the terms "perihelion" and "aphelion" to describe the orbital motion of a planet, which contributed greatly to our understanding of celestial mechanics.