1·The point in the orbit nearest the sun is called perihelion, while the point farthest is called aphelion.
在轨道上最接近太阳的点被称为近日点，而最远离太阳的点被称为远日点。
2·W hen the Earth moves from perihelion to aphelion, its radiation belts are expansion, and aphelion to perihelion contraction.
当地球从远日点运动到近日点时，地球辐射带向内收缩。