On January 2, 2021, the Earth is closer the sun in its elliptical orbit than on any other day of the year, marking an annual event known as the perihelion.
The word helium is translated from the ancient Greek, meaning “near the sun.” According to EarthSky, Earth was expected to reach perihelion on Saturday morning at 8:51 am ET.
The sun it’s about 3% bigger in the sky on Saturday, not enough to be noticed with the naked eye. Remember: you should never look at the sun without proper eye protection and sunglasses are not a sufficient substitute for sunglasses.
The Earth’s orbit is not a perfect circle, that is, sometimes the planet is a little closer to our star and sometimes it is further away. The distance varies about 3 million miles throughout the year, almost 13 times the distance from Earth to the Moon.
The perihelion also marks the time when the Earth moves most rapidly in its orbit around the sun. Currently, the planet runs around the sun at almost 19 miles per second, about 0.6 miles per second farther than when it reaches its farthest point from the sun in July.
“If you run east at local midnight, you’ll move as fast as possible (at least in Sun-centered coordinates) to your location,” NASA said.
Because of this, summer in the northern hemisphere lasts about five days longer than winter, according to EarthSky. The opposite is true in the southern hemisphere.
Although the sun is most intense on Saturday, winter in the northern hemisphere is unaffected, due to the 23.5-degree tilt of the Earth’s axis. Being closer to the sun does not change the tilt of the Earth, so the north pole is still tilted toward the sun.
In six months, on July 5, the Earth will be at its furthest from the sun, known as its aphelion, which means “away from the sun.” In the perihelion, the Earth is about 91.5 million miles from the sun, and in the aphelion, it is about 94.5 million miles away.
Between perihelion and aphelion, there is approximately a 6.7% difference in the intensity of sunlight when it reaches our planet. According to NASA, this is one of the explanations for the more extreme stations in the southern hemisphere compared to the northern hemisphere.
The perihelion is not the only celestial event this weekend. Saturday night through Sunday morning also marks the summit of the Rain of quadrantid meteorites – one of the best of the year.