Looking at a globe or a map of the world, we will seegrid of thin blue lines. Among them will be the main parallels of the Earth: the equator, two polar circles, and the Northern and Southern tropics. More about them we will tell in our article.
All meridians and parallels on our modelthe planets, of course, are conditional and imaginary. All of them were mapped for scientific and practical purposes. However, among them there are five very important parallels: the equator, the polar circles, the southern and northern tropics. The existence of all these fictional lines is directly related to real natural laws (physical and geometric). And knowledge of them is extremely important for a comprehensive study of geographical science.
The equator divides our planet into two equal halves.- Northern and Southern hemisphere. The location of this line is strictly perpendicular to the axis of the earth's rotation. This is the longest parallel of our planet: its length is 40 thousand kilometers. In addition, the Sun at the equator twice a year is at its zenith, and the entire equatorial region of the Earth receives the greatest amount of solar radiation per year.
Polar circles are parallels thatLimit phenomena such as the polar day and the polar night on the surface of the planet. These lines correspond to a latitude of 66.5 degrees. In the summer, residents living beyond the Arctic Circle have the opportunity to contemplate the polar days (when the sun does not set at all). At the same time, the heavenly body does not appear at all (the polar night) on the other side of the Earth. The duration of polar days and nights depends on how close a particular place is to the poles of the planet.
There are two tropics on our planet, and they are not heldby chance. Once a year, the Sun is at its zenith over one of them (June 22), and after another six months over the other (December 22). In general, the word "tropic" comes from the Greek tropikos, which translates as "turn". Obviously, we are talking about the movement of the Sun in the sky.
The northern tropic is located north of the linethe equator. It is also called the Tropic of Cancer. Where did this name come from? The fact is that two thousand years ago, the Sun at the summer solstice was in the constellation of Cancer (now the heavenly body in this period of the year is in the constellation Gemini).
Exact latitude of the Northern tropic - 23 ° 26 ′ 16 ″. However, its position changes over time due to changes in the Earth’s axis, nutation, and some other geophysical processes.
The Tropic of the North crosses the three oceans (Pacific,Atlantic, Indian) and three continents (Eurasia, Africa and North America). The parallel passes through the territories of twenty states, including Mexico, Algeria, India and China.
At the latitude of the tropic of Cancer is a number of cities. The largest of them are:
In addition, the Tropic of Cancer crosses several major rivers: the Nile, the Ganges, the Mekong, etc. Just south of this parallel is Mecca - the main sacred place of all Muslims in the world.
23 ° 26 ′ 21 ″ - this is the latitude of the Southern Tropic as of the beginning of this century. The position of this line is also variable in time. The tropic is very slowly shifting towards the Earth's equator.
Parallel also has its second name -Tropic of Capricorn. It crosses only 10 states that are located on three continents of the planet (South America, Africa and Australia). The largest city located on the tropic - Brazilian Sao Paulo. It is curious that this parallel crosses Australia almost in the middle, thus causing a substantial aridity of the continent.
Tropic of Capricorn decided to mark on the grounddifferent ways. The most impressive sign announcing the passage of the Southern Tropic is in Chile. In 2000, a huge 13-meter monument was built near the city of Antofagasta.
Now you know where the Tropic is located,what countries and continents it crosses. It is also called the Tropic of Cancer. It marks the northern latitude, over which the sun can rise to zenith. Mirrored to him in the southern hemisphere tropic of Capricorn.
