WHAT IS THE TROPIC OF CAPRICORN? - SCIENCE - 2025

The Tropic of Capricorn is the terrestrial parallel located approximately 23.5 ° south latitude. It joins the southernmost points, that is, the areas located furthest to the south on which the sunlight falls from a zenith (completely vertical) once a year.

The Tropic of Capricorn is thus one of the multiple imaginary lines that run horizontally (parallel) around the globe. These reference lines can be imagined as if they were belts that surround the Earth at different heights and that they get smaller as they get closer to the poles.

The parallel that is used as a starting point to locate the others is the equator, a circular line that surrounds the earth horizontally, dividing it into two halves or hemispheres (north and south).

Therefore, the Tropic of Capricorn is an imaginary reference line (parallel) that is located in the southern hemisphere of the earth. Specifically, this line is located at an approximate latitude of -23.5 ° (or 23.5 ° south) with respect to the equator, taking into account that latitude measures the distance at which a geographical point is with respect to the equator (latitude 0).

While the Tropic of Capricorn is located in the southern hemisphere of the planet, the Tropic of Cancer is its equivalent in the Northern Hemisphere or half of the globe located above the equator. Specifically, the Tropic of Cancer is located at a latitude of approximately + 23.5 ° or 23.5 ° North.

Through which countries does the Tropic of Capricorn pass?

By Maose, from Wikimedia Commons

Let's imagine the Tropic of Capricorn as a circle that crosses those areas further south of the Earth on which the solar rays can hit completely vertically. The imaginary line drawn would therefore pass through all those territories that are located at a latitude of 23.5 ° south.

Thus, the Tropic of Capricorn crosses geographical points located on three continents and in more than ten different countries that, ordered from west to east, are:

• America: Chile, Argentina, Paraguay and Brazil.
• Africa: Namibia, Botswana, South Africa, Mozambique, and Madagascar.
• Oceania: Australia and French Polynesia (a territory located in Oceania but belonging to France).

As a curiosity, it should be mentioned that Brazil is the only country in the world with territories located in geographical points that will be crossed by both the equator and the Tropic of Capricorn.

Of course, the imaginary line drawn along Earth's latitude 23.5 doesn't just cross dry land. On its journey, the Tropic of Capricorn also passes through three different oceans: Pacific Ocean, Atlantic Ocean and Indian Ocean.

Which countries are completely below the Tropic of Capricorn?

On the other hand, there are countries that are entirely south of the Tropic of Capricorn, without touching or exceeding this imaginary line with any geographical point. In the southern hemisphere, only three states have their entire territory below 23.5 ° south latitude marked by the Tropic of Capricorn.

Interestingly, this is a very small number compared to the 74 states that lie entirely above the Tropic of Cancer in Earth's northern hemisphere. This difference is due to a very simple reason: the percentage of land in the northern hemisphere is vastly higher than in the southern hemisphere.

The three countries that lie completely below the Tropic of Capricorn are, from west to east:

• Uruguay, the only country on the American continent located in an integral way further south of said brand.
• Swaziland and Lesotho, two very small countries located in southern Africa.

There is a very interesting debate surrounding the inclusion of a fourth country on the list: New Zealand. It is true that the main body of its islands is completely below the Tropic of Capricorn. However, there are small archipelagos dependent on the Kingdom of New Zealand that are located at coordinates above 23.5 ° south latitude: Cook Islands, Tokelau and Niue.

What is the origin of the name of the Tropic of Capricorn?

By Caliver, from Wikimedia Commons

The term tropic comes from the Greek (τροπικός) and means “back”. In the astronomical field, the word tropic is used to designate the latitudes located further north (Tropic of Cancer) and further south of the Earth (Tropic of Capricorn) on which the Sun can reach the zenith, that is, its greatest height. in the sky.

This means that, at a certain time of the year, the Sun falls completely perpendicular to the Earth's surface marked by the situation of the Tropic of Capricorn. The phenomenon is called solstice.

The origin of the name of the Tropic of Capricorn dates from about 2000 years ago. When in Classical Antiquity, the solstice was observed in the southern hemisphere, the Sun was in the constellation Capricorn, hence its name.

Currently, this star is not in this constellation when once a year it reaches its zenith in the southern hemisphere of the earth. However, the traditional name has been maintained throughout the centuries and to this day.

What is the Tropic of Capricorn for?

The Tropic of Capricorn is a parallel associated with a latitude that has had great relevance, even since Classical Antiquity. The latitude line around the Earth marked by said tropic is fundamental for disciplines such as Geography and Astronomy. Why?

Both sciences use the terrestrial zones delimited by the Tropic of Capricorn (and by its equivalent in the northern hemisphere, the Tropic of Cancer) as a reference to locate a series of natural phenomena. What anniversary occurs at this terrestrial latitude?

1- The Tropic of Capricorn and the December Solstice

The latitude line that the Tropic of Capricorn draws around the globe is also used as an imaginary reference to mark the lower limit of the tropical climate zone, the warm region of the planet.

In this way, in an associative way, those regions of the Earth that are included between the Tropic of Capricorn (23.5 ° south latitude) and the Tropic of Cancer (23.5 ° north latitude) receive the name of tropics..

However, it is important to bear in mind that the climatic boundaries represented by both tropics are only an indicative limit. The Tropic of Capricorn, as well as that of Cancer, is a rigid reference to latitude. However, there are more factors that influence the climate and that would justify the presence of areas in the tropics that do not have the climatic characteristics normally associated with this region.

Finally, the Tropic of Capricorn also serves as a reference to mark the upper limit of the southern temperate climate zone of the planet. This region would be delimited, in turn, in its lower part by the Antarctic polar circle.

References

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