The scientific and astronomical communities are eagerly anticipating a significant annual event next Saturday, January 3, 2026, when Earth reaches its perihelion, its closest point to the Sun throughout the year. This event is expected to occur at 8:00 PM Mecca time (5:00 PM GMT), a celestial phenomenon that recurs at the beginning of each calendar year, specifically during winter in the Northern Hemisphere.
Celestial mechanics: Why does distance change?
To understand this phenomenon, we must return to the laws governing planetary motion. As engineer Majed Abu Zahra explained, Earth's orbit around the sun is not perfectly circular as some might imagine, but rather elliptical. This geometric shape of the orbit, discovered by Johannes Kepler in the 17th century, means that the distance between Earth and the sun is not constant, but changes periodically as Earth revolves around its parent star.
At perihelion on Saturday, the distance between the Earth and the Sun will be approximately 147,099,587 kilometers. For comparison, this is about 5 million kilometers less than the distance Earth will reach six months later, on July 6th, when it will be at aphelion (its farthest point from the Sun), at which time the distance will be approximately 152,081,196 kilometers.
Does proximity mean higher temperatures?
A common misconception is that the Earth's proximity to the sun in January leads to higher temperatures. Scientific fact confirms that the distance between the Earth and the sun is not the determining factor in the four seasons. The primary reason for the seasons is the tilt of the Earth's axis at an angle of approximately 23.5 degrees. In January, the North Pole is tilted away from the sun, reducing the amount of direct solar radiation and causing winter, while the Southern Hemisphere is tilted towards the sun, resulting in summer.
However, the proximity of the Earth has other physical effects; the sun's disk appears 7% larger and brighter than at apogee, a difference that may not be easily noticeable to the naked eye but is observable with astronomical instruments.
The effect of the phenomenon on the length of the seasons
The phenomenon of perihelion directly affects the speed of Earth's orbit around the Sun. According to Kepler's second law of planetary motion, a planet moves faster when it is closer to its host star. Therefore, Earth travels in its orbit at speeds of up to 30.3 kilometers per second at perihelion, compared to a slower speed at aphelion. This increased speed makes winter in the Northern Hemisphere the shortest season, as the Earth covers the distance designated for this season in less time than in summer.
Solar observation and space technologies
This period presents a golden opportunity for amateur astronomers and scientists to study the Sun. Astrophotographers can capture images of the Sun's disk (using only safe filters) and compare them to images taken in July to clearly demonstrate the difference in apparent size. At the technological level, satellites play a crucial role in documenting these phenomena, such as the NASA/NOAA Discover satellite.
This satellite is located at the gravitationally stable Lagrange point 1 between the Earth and the Sun, at a distance of 1.5 million kilometers, allowing it to monitor the solar wind and capture stunning images of Earth showing the terrain, cloud cover, and ozone layer, enriching our understanding of the interactions between our planet and its parent star.
