The main parallels of the Earth. The Northern Tropic and its geography

Looking at the globe or map of the world, we will see a grid 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'll talk about in our article.

The main parallels of the Earth

All the meridians and parallels on the model of our planet, of course, are conditional and imaginary. All of them were put on maps 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 fictitious lines is directly related to real natural laws (physical and geometric). And knowledge about them is extremely important for the comprehensive study of geographical science.

The equator divides our planet into two equal halves - the Northern and Southern Hemispheres. The location of this line is strictly perpendicular to the axis of earth rotation. This is the longest parallel of our planet: its length is 40 thousand kilometers. In addition, the Sun at the equator is twice a year at the zenith, and the entire near-equatorial region of the Earth receives the greatest amount of solar radiation per year.

Polar circles are parallels that limit on the surface of the planet such phenomena as polar day and polar night. These lines correspond to a latitude of 66.5 degrees. In summer, residents living beyond the Arctic Circle have the opportunity to contemplate the polar days (when the sun does not set at all beyond the horizon). At the same time, on the other side of the Earth, the celestial star did not appear at all (polar night). The duration of polar days and nights depends on how close a particular place is to the poles of the planet.

The North Tropic

There are two tropics on our planet, and they were not held by chance. Once a year, the Sun is at the zenith above one of them (on June 22), and six months later on 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 celestial sphere.

The northern tropic is located to the north of the equator line. It is also called the Tropic of Cancer. Where did this name come from? The fact is that two millennia ago, the Sun during the summer solstice was in the constellation of Cancer (now the heavenly body in the given period of the year is in the constellation of Gemini).

The exact latitude of the Northern Tropic is 23 ° 26 '16 ". However, its position changes with time due to changes in the slope of the earth's axis, nutation and some other geophysical processes.

Geography of the Northern Tropics

The northern tropic trail crosses 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:

• Dhaka (Bangladesh);
• Karachi (Pakistan);
• Bhopal (India);
• Guangzhou (China);
• Medina (Saudi Arabia).

In addition, the Tropic of Cancer crosses several large rivers: the Nile, the Ganges, the Mekong, etc. A little south of this parallel is Mecca - the main sacred place of all Muslims in the world.

Southern Tropic and its geography

23 ° 26 '21 "- this is the latitude of the South Tropic as of the beginning of this century. The position of this line is also not constant in time. The tropic is very slowly shifting towards the earth's equator.

The parallel also has its second name - the tropic of Capricorn. It crosses only 10 states that are on the three continents of the planet (South America, Africa and Australia). The largest city located in the tropics is the Brazilian São Paulo. It is curious that Australia, this parallel crosses almost in the middle, thus causing a significant aridity of the climate of the continent.

Tropic of Capricorn is usually celebrated on the ground in various ways. The most impressive sign, announcing the passage of the Southern Tropics, is in Chile. Near the city of Antofagasta in 2000 was built a huge 13-meter monument.

Finally

Now you know where the North Tropic is located, which countries and continents it crosses. It is also called the Tropic of Cancer. It marks the northern latitude above which the Sun can rise to the zenith. Mirror to it in the Southern Hemisphere is the tropic of Capricorn.