Tropic of Capricorn

The Tropic of Capricorn is an imaginary line of latitude going around the Earth at approximately 23.5° south of the equator. It is the southernmost point on Earth where the sun's rays can be directly overhead at local noon. It is also one of the five major circles of latitude dividing the Earth (the others are the Tropic of Cancer in the northern hemisphere, the equator, the Arctic Circle and the Antarctic Circle).

The Tropic of Capricorn is significant to understanding the Earth's geography because it marks the southern boundary of tropics. This is the region that extends from the equator south to the Tropic of Capricorn and north to the Tropic of Cancer.

Unlike the Tropic of Cancer, which passes through many areas of land in the northern hemisphere, the Tropic of Capricorn passes mainly through water because there is less land for it to cross in the southern hemisphere.

The Tropic of Capricorn crosses northern Chile and Argentina, Paraguay, and southern Brazil in South America. In Africa, it crosses Namibia, Botswana, South Africa, Mozambique and Madagascar. The tropic of Capricorn also passes through the middle of Australia.

In addition to being used to aid in dividing the Earth into different parts and marking the southern boundary of the tropics, the Tropic of Capricorn, like the Tropic of Cancer is also significant to the Earth's amount of solar insulation and the creation of seasons.

Solar insolation is the amount of Earth's direct exposure to the sun's rays from incoming solar radiation. It varies over the Earth's surface based on the amount of direct sunlight hitting the surface and it is most when it is directly over head at the subsolar point which migrates annually between the Tropics of Capricorn and Cancer based on the Earth's axial tilt.

When the subsolar point is at the Tropic of Capricorn, it is during the December or winter solstice and is when the southern hemisphere receives the most solar insolation. Thus, it is also when the southern hemisphere's summer begins. Furthermore, this is also when the areas at latitudes higher than the Antarctic Circle receive 24 hours of daylight because there is more solar radiation to be deflected south due to the Earth's axial tilt.

Tropical rainforests are found near the equator between the Tropic of Cancer and the Tropic of Capricorn. Even though they cover only six percent of the Earth's land surface, tropical rainforests are home to half of the world's plant and animal species.. Most rainforests in this region are, therefore, considered tropical. In the tropics there is little change in the weather throughout the year. It is always hot and there is usually between 1500-4000 millimetres of rain each year.