When we look at a globe or a map of the world, we see a grid of thin blue lines. Among them will be the main parallels of the Earth: the equator, the two polar circles, as well as the Northern and Southern tropics. We will tell you more about them in our article.
Main parallels of the Earth
All meridians and parallels on the model of our planet, 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 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 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 is at its zenith twice a year, and the entire equatorial region of the Earth receives the greatestthe amount of solar radiation per year.
Arctic circles are parallels that limit phenomena such as polar day and polar night on the surface of the planet. 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 below the horizon at all). At the same time, on the other side of the Earth, the celestial body does 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.
Northern Tropic
There are two tropics on our planet, and they were not held by 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 celestial sphere.
The Tropic of the North is located 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 precisely in the constellation of Cancer (now the heavenly body in this period of the year is in the constellation of Gemini).
The exact latitude of the Tropic of the North is 23° 26' 16″. However, its position changes over time due to changes in the tilt of the earth's axis, nutation and some other geophysical processes.
Geography of the Northern Tropic
The Tropic of the North crosses three oceans (Pacific, Atlantic, Indian) and three continents (Eurasia, Africa and NorthAmerica). The parallel passes through the territories of twenty states, including Mexico, Algeria, India and China.
A number of cities are located at the latitude of the Tropic of Cancer. The biggest ones:
- 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 Southern Tropic at the beginning of this century. The position of this line is also not constant in time. The tropic is moving very slowly towards the earth's equator.
The parallel also has its second name - the 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 is the Brazilian Sao Paulo. It is curious that this parallel crosses Australia almost in the middle, thereby causing a significant aridity of the climate of this continent.
The Tropic of Capricorn is customarily marked on the ground in various ways. The most impressive sign announcing the passage of the Southern Tropic is located in Chile. Near the city of Antofagasta, a huge 13-meter monument was erected in 2000.
Bconclusion
Now you know where the Northern 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 its zenith. Mirrored to it in the Southern Hemisphere is the Tropic of Capricorn.
