This week the Earth reaches its closest point to the Sun of the entire year. At 05:20 GMT on 3 January, the Earth will draw to within 147,099,761km of the Sun. This is the point of its orbit known as perihelion. Six months from now, on 4 July, the Earth will be at the furthest point in its orbit, known as aphelion. The distance then will be 152,104,285km. So we are approximately 5m kilometres closer to the Sun this week than in the summer. This situation occurs because the Earth’s orbit is not a perfect circle, but is mildly elliptical. The seasons however do not follow this orbital pattern. They are governed by the Earth’s tilt. Even though we are closer to the Sun than at any other time of year, the northern hemisphere is tilted away. This lowers the Sun in the sky, meaning that the days are shorter and the rays of light we do receive are spread out over a wider area on the ground. These factors trump the slight increase in energy due to our increased proximity.
