CHARLESTON, WV (WVNS) – The Earth is closest to the Sun every year two weeks after the Winter Solstice, which is January 3rd or 4th. This measurement is called Perihelion, but why does it happen in the middle of winter?
Perihelion is the measurement of any planet, comet, or asteroid when it is closest to the Sun. The Earth and many other objects in space have orbits shaped like ovals, or ellipses. This means that at some point, they can be closer to what they are orbiting, like the Sun. The word comes from Greek and literally means around (peri) the sun (helios). Aphelion is the point at which an orbiting body is furthest from the sun. Likewise, Aphelion is the measurement of when it is farthest away. In 2023, Perihelion happens on January 4. To be more precise, the Perihelion happens at 11:17 A.M.
Logically, it would make sense that the Earth should be warmer when its closer to the Sun, but that isn’t the case. This highlights a fairly common misconception about the way that seasons work. The Perihelion is not connected to the seasons of the planet. California Academy of Sciences clarifies that from Perihelion to Aphelion, Earth’s distance varies by about 5 million kilometers (3 million miles), or about three percent of its average distance of 150 million kilometers (93 million miles), and that’s not enough to make any difference in the weather.
The seasons are actually the result of changes in the angle and duration of sunlight covering the planet’s surface. As the planet orbits the Sun, its axis maintains its tilt with respect to the stars, causing its orientation to the Sun to change over the year, and this affects the way sunlight shines on the northern and southern hemispheres. Right now, around the December solstice, the North Pole is tilted away from the Sun, so in the northern hemisphere, the Sun is low in the sky, illuminating the northern half of the planet at a shallower angle than at other times of the year. The Sun is also not above the horizon for as long as it is during the summer. This produces our winter weather, when the days are short and cold. In fact, on the December solstice, sunlight doesn’t even reach the North Pole, which is enveloped in a 24-hour long night.
Six months later, during the June Solstice, the reverse is true. That also happens to be Aphelion, when the Earth is farthest from the Sun.