Earth is at perihelion – closer to the sun than any other day of the year

On January 2, 2021, Earth is closer to the sun on its elliptical orbit than any other day of the year, marking an annual event called perihelion.

The word perihelion is translated from ancient Greek, meaning “near the sun”. According to EarthSky, Earth was scheduled to reach perihelion on Saturday morning at 8:51 a.m.ET.

The sun is about 3% larger in the sky on Saturday – not enough to be seen 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.

Earth’s orbit is not a perfect circle, which means that sometimes the planet is a little closer to our star and sometimes it is further away. The distance varies by about 3 million miles during the year, which is almost 13 times the distance between Earth and the Moon.

Perihelion also marks the time when the Earth is moving the fastest in its orbit around the sun. The planet is currently running around the sun at nearly 19 miles per second – about 0.6 miles per second more than when it reached its farthest point from the sun in July.

“If you run east at local midnight, you’ll be moving 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 sunlight is more intense on Saturday, winter in the northern hemisphere is not affected, 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 always tilted away from the sun.

Six months from now, on July 5, Earth will be at its farthest point from the sun, known as its aphelion, meaning “away from the sun.” At perihelion, Earth is approximately 91.5 million kilometers from the sun, and at aphelion, approximately 94.5 million kilometers.

Between perihelion and aphelion, there is a difference of about 6.7% in the intensity of sunlight when it hits our planet. According to NASA, this is an explanation for more extreme seasons in the southern hemisphere compared to the northern hemisphere.

Perihelion is not the only celestial event this weekend. From Saturday evening to Sunday morning also marks the top of the Quadrantid meteor shower – one of the best of the year.