The sun focuses its radiation under the earth in different ways throughout the year. In some periods it is more inclined to the north, in others to the south, and there are also times when the two hemispheres are equally illuminated. The tropics are used in the location and demarcation of climates and seasons. The function of the tropics is to mark the zones of the Earth that receive the maximum solar radiation during the year. The tropics are regions of the Earth that lie roughly in the middle of the globe. All of these are describing which feature the tropic of cancer.