This weekend, the Earth will be at perihelion, the closest we get to the Sun in our orbit. Between perihelion and 6 months later at aphelion there is about a 6.7% difference in the intensity of the sunlight reaching the Earth, one of the reasons the seasons in the Southern hemisphere are more extreme than in the Northern Hemisphere. Perihelion is also when the Earth is moving the fastest in its orbit around the Sun, so if you run east at local midnight, you will be moving about as fast as you can (in Sun-centered coordinates) for your location. At its closest point, Earth swings to within 91,398,199 miles (147,091,144 km) of the sun. That’s in contrast to six months from now, when the Earth reaches aphelion – its most distant point – on July 4, 2020. Then we’ll be 94,507,635 miles (152,095,295 km) from the sun. In other words, Earth is roughly 3 million miles (5 million km) closer to the sun in early January than it is in early July.