The earth's axis crosses the surface of the planet at the points of the geographic poles.

Geographic poles

As you know, the Earth has two poles: North (located in the Arctic Ocean in the central part of the Arctic) and South (located on the Antarctic continent). These places do not belong to any state.

The South Pole is the southernmost point of the planet, and the North Pole, respectively, is the northernmost. A person standing exactly on the pole (for example, on the South) takes any step towards the north.

The areas surrounding the poles are the coldest on the planet and are called the Arctic. There are also two seasons of the year: polar night and polar day. This is due to the fact that the illumination here differs from the rest of the planet due to the deviation earth's axis about 20° from the plane of the orbit.

Conquest of the poles

The conquest of the poles was very slow and did not occur until the beginning of the twentieth century. People have been trying to conquer the North Pole since the seventeenth-eighteenth century, since all the continents around were inhabited for a long time and swimming in the southern parts of the Arctic Ocean took place over the centuries. However, during the short Arctic summer, it was not possible to sail there by sea, and icebreakers did not exist then.

In this regard, the North Pole was mastered only in 1909. The success of the expedition of the discoverer Robert Peary was guaranteed, in many respects, by the fact that the northern coast of Greenland, located closest to the pole, was chosen as the starting point. Other explorers tried to reach the Arctic from Europe, and they simply did not have enough supplies to complete the trip.

Among others famous travelers who tried to reach the North Pole were:

• F. Nansen.
• W. Parry.
• F. Cook.
• C. Hall.

Exploration of the Antarctic began much later, because. the continent itself was discovered only in the first half of the nineteenth century. It was reached by the Russian expedition of Bellingshausen. Only a few decades after that, people first set foot on the land of Antarctica. In 1911, several pioneers went to the pole at once, and in the end, the victory went to the Norwegian R. Amundsen.

Major axis A= 6 378 245 m.

Minor axis b= 6 356 863.019 m.

Radius of a ball of the same volume with Krasovsky's ellipsoid R= 6 371 110 m.

Radius of a ball of the same surface with the Krasovsky ellipsoid R= 6 371 116 m.

The radius of a ball of the same circumference of a great circle with the length of the meridian of the Krasovsky ellipsoid R= 6 367 559 m.

Radius of a sphere, one minute of arc of a great circle of which is equal to a nautical mile (1852 m) R= 6 366 707 m.

When solving problems that do not require high accuracy, the compression of the Earth is neglected; take the earth for a ball.

ball radius selected based on certain conditions. For example, when measuring distances at sea, the radius of the ball R = 6366 km 707 m(L E= 39,983 km).

R SR = 6371.1 km(L E= 40,010.5 km).

2. Basic points, lines and planes of the Earth

Rice. 2.1. Basic points, lines and planes of the Earth

earth axis (Fig. 2.1) is an imaginary straight line around which the Earth makes its daily rotation (≈ 0.5 km/s = 0.464 km/s).

This axis ( P N P S) coincides with the minor axis of the earth's ellipsoid and intersects the surface of the ellipsoid at two points called geographic poles Lands: - northern – P N , – southern – P S .

north geographic pole (P N) is considered to be the one from which the Earth's own rotation is seen counterclockwise.

south geographic pole (P S) is the pole opposite to the north.

Equator plane - a plane perpendicular to the earth's axis and passing through the center of the ball (ellipsoid).

earth's equator - a line (circle) formed from the intersection of the surface of the ellipsoid with the plane of the equator.

Earth's equator (line EAQB) divides the globe into two hemispheres:

northern hemisphere (with P N);

southern hemisphere (with P S).

Planes of parallels - planes parallel to the plane of the equator.

Parallels - small circles formed on the surface of the earth's ellipsoid when its planes of parallels intersect.

Normal (plumb line) - a straight line coinciding with the direction of gravity at a given point. For T. WITH- the normal is a straight line SOS' passing through the center of the earth.

Planes of true meridians are the planes passing through the Earth's axis ( P N P S).

The meridian passing through the place of the observer is called the true meridian. (geographical) meridian of the observer

3. Main lines and planes of the observer

Rice. 2.2. Main lines and planes of the observer

The surface of the Earth observed by man is perceived as flat, therefore, certain imaginary lines and planes are used to orientate on a small area of ​​the Earth's surface. With the help of these lines and planes, many navigational problems are solved.

For orientation at any point on the Earth's surface, the following lines and planes are used, associated with the observer's place.

Vertical (plumb) line - straight Zn, coinciding with the direction of gravity at the observer's location.

Observer Zenith - dot Z intersection of a vertical line with an imaginary celestial sphere above the observer's head.

Observer's nadir - dot n intersection of a vertical line with an imaginary celestial sphere under the observer.

horizontal plane - any plane perpendicular to the plumb line.

The observer's true horizon plane - horizontal plane HH’ passing through the eye of the observer.

vertical plane (vertical plane) - any plane passing through a plumb line.

The plane of the true meridian of the observer - vertical plane MM’ , passing through the poles of the Earth and the place of the observer.

True (geographic) meridians - lines (circles) formed on the surface of the ellipsoid when its planes intersect the true meridians.

Observer Meridian - big circle R N AR S, formed by a section of the Earth's surface by the plane of the true meridian of the observer.

Line of the true meridian of the observer (noon line) – line NS intersection of the plane of the true meridian of the observer with the plane of the true horizon of the observer.

Initial (zero, Greenwich) meridian .

According to the International Agreement, since 1884, the Greenwich meridian has been taken as the initial (zero) meridian - the meridian that passed through the axis of the main telescope of the former Greenwich Observatory (existed 278 years 1675 ÷ 1953) in the suburbs of London (England).

Since 1953, the new Greenwich Observatory has been located in Herstmonceau Castle (south of England, 15 km from the coast of the English Channel, east of the zero meridian at 20′25″).

The zero (Greenwich) meridian divides the globe into the eastern and western hemispheres.

main directions.

The intersection of the plane of the true meridian of the observer and the plane of the first vertical with the plane of the true horizon forms two mutually perpendicular lines N–S and E–W in the plane of the true horizon. Line N–S is the noon line. It fixes the direction to the north and south geographic poles. The E–W line defines the east–west direction. Four mutually perpendicular directions in the plane of the true horizon: N (north), S (south), E (east - east), W (west) form the main directions. Relative to these directions, orientation on the surface of the Earth is carried out.

Such a system of lines and planes is called a horizontal coordinate system.

One of the two points of intersection of the Earth's axis of rotation with the Earth's surface

The place on Earth with the longest nights

One of the two ends of a magnet

One of two opposite ends of an electrical circuit

One of the two points of intersection of the Earth's axis with the surface, as well as the area adjacent to this point

Singular point of an analytic function

Peren. pronounced opposites.

Positive or negative current source terminal

Polar Station, Amundsen-Scott, USA

Limit, border, extreme point of something

Central, main point, place

Meridian meeting point

One of the extreme points of the proposed axis of rotation of the Earth

Both North and South

Point with zero latitude and longitude

The place where bears rub their backs against the earth's axis

. "plus" or "minus" on the battery

magnet end

Geographical navel of the Earth

Top of the Earth

American polar station in Antarctica

Russian refrigerator brand

. "+" or "-" batteries

Magnetic south or north

. "minus" batteries

Center in the Arctic and Antarctica

A place with zero longitude and latitude

He was conquered by Sedov and Nansen

. "edge" of the earth

Intersection point of the Earth's axis of rotation with the surface

One of the two ends of a magnet

Positive or negative current source terminal

The end point of something

. "+" or "-" batteries

. "end" of the earth

. "minus" batteries

. battery positive or negative

M. Greek. awn, each of the end points of the axis on which the ball rotates. Earth's poles, north and south (ostia midnight and noon), points earth's surface through which the imaginary axis of the earth passes; heavenly ostia, corresponding to the earthly points of the meeting of the earth's axis with the (imaginary) heavenly firmament. The height of the pole, the earth's ostium above the ovid (horizon), is equal to the latitude of the place. The poles of any great circle of a ball, the meeting points of its axis with the surface of the ball. Poles or ostia of a magnet, a galvanic column or an electric bank, etc., two opposite points or planes that have an opposite effect; in a magnet distinguish north and south poles, the ends with which a freely suspended magnet addresses these two cardinal points. The magnetic poles of the earth, the points near the awns, in which the greatest magnetic force is concentrated. The poles are also generally called the extreme points of forces opposite to each other (or mathematically, and - Pole or pole related to the pole. Polar, pole, core. Polar ice. Forces polar to each other, opposite. Polar star, closest to the northern awn, clearly visible to the simple with the eye of a star, in the constellation Ursa Minor. Polar circles, two imaginary circles separating the arctic belts around the poles; they are drawn by the end of the axis (ostium, pole) of the solar circle (ecliptic). Polarity property, the state of the polar, the attraction of opposite extremes and the repulsion of extremes of the same name. To polarize light or a ray of light, to change it by passing it through different media, in such a way that it reveals its duality. Oh, they're suffering. Polarization of light, action on vb. and fortune in German

The earth's axis crosses the surface of the planet at the points of the geographic poles.

Geographic poles

As you know, the Earth has two poles: North (located in the Arctic Ocean in the central part of the Arctic) and South (located on the Antarctic continent). These places do not belong to any state.

The South Pole is the southernmost point of the planet, and the North Pole, respectively, is the northernmost. A person standing exactly on the pole (for example, on the South) takes any step towards the north.

The areas surrounding the poles are the coldest on the planet and are called the Arctic. There are also two seasons of the year: polar night and polar day. This is due to the fact that the illumination here differs from the rest of the planet due to the deviation of the earth's axis from the plane of the orbit by about 20 °.

Conquest of the poles

The conquest of the poles was very slow and did not occur until the beginning of the twentieth century. People have been trying to conquer the North Pole since the seventeenth-eighteenth century, since all the continents around were inhabited for a long time and swimming in the southern parts of the Arctic Ocean took place over the centuries. However, during the short Arctic summer, it was not possible to sail there by sea, and icebreakers did not exist then.

In this regard, the North Pole was mastered only in 1909. The success of the expedition of the discoverer Robert Peary was guaranteed, in many respects, by the fact that the northern coast of Greenland, located closest to the pole, was chosen as the starting point. Other explorers tried to reach the Arctic from Europe, and they simply did not have enough supplies to complete the trip.

Other notable travelers who attempted to reach the North Pole included:

• F. Nansen.
• W. Parry.
• F. Cook.
• C. Hall.

Exploration of the Antarctic began much later, because. the continent itself was discovered only in the first half of the nineteenth century. It was reached by the Russian expedition of Bellingshausen. Only a few decades after that, people first set foot on the land of Antarctica. In 1911, several pioneers went to the pole at once, and in the end, the victory went to the Norwegian R. Amundsen.

The earth has a spherical shape, more precisely, it is slightly flattened along the edges at the points that are its poles. But this is not particularly noticeable on the scale of the planet, because it is assumed that the Earth is a ball, and its surface is taken as spherical.

Marking the Earth with meridians and parallels made it possible to accurately determine the coordinates of any object that moves (airplane, thunderclouds), or that occupies a certain place on the planet (city, island). This gave quite a lot of advantages for any objects moving in space. Previously, people were guided by the stars, by the position of the sun in the sky. It wasn't as accurate as using modern technologies although if you happen to be on desert island without the means so familiar to our lives - smartphones, tablets, laptops, respectively, without access to the Internet, without a navigator and other things, it would not be superfluous to know those very "inconvenient" methods for calculating coordinates.

You can use a navigation system into which the desired coordinates will be entered, and the autopilot devices will be able to move themselves where necessary, without a person. But first things first. Consider the main points and circles on the globe.

Some historical information

Questions about coordinates have preoccupied the minds of people for a long time, even before our era. Hipparchus and Ptolemy were prominent scientists in the development of the coordinate system. These people lived in the second or first centuries BC, but, nevertheless, they could already determine with dividing accuracy. These were the great people of their era, powerful geographers and astronomers. It was they who introduced the concept that we now call the coordinate system, and from their work it is already clear what it is. At that time, these people did not know that the Earth revolves around the Sun. Hipparchus suggested that the surface of our planet could be considered an ideal sphere, and using its example, he explained the various foundations regarding spherical geometry.

Globe - the most accurate model of the Earth

It is with the help of a globe that you can easily determine the coordinates of any country, island or other object. With its help, it is easiest to show what the meridians and parallels, geographic poles, other points and lines of the Earth are.

By the way, the first globe was created a long time ago, even before our era, and a certain Crates of Mallus made it in 150 BC, at the same time when Hipparchus and Ptolemy lived. Of course, a globe cannot show all the small details, but in general it allows you to perfectly describe the big picture of what our planet is, and perfectly demonstrates, for example, which points on the earth are called geographic poles,

On the globe it is easy to see where any country, sea, ocean, location of the continents, or even their topography is located. It depends on what will be depicted by the creator of this or that globe. It can be purely political, only with the division of the continents into countries and with the indication of large objects such as oceans. Most likely it will be a small decorative globe. The training instances contain much more information about geographic poles and geographical position any part of the world.

In general, there are three parameters by which the Earth is characterized in geographic coordinate terms. Therefore, consider the main points, lines and planes on the surface of the Earth.

What is the Earth's axis

Is it possible to take the Earth for a ball, then it becomes clear that it has such a line, which also serves as a creative line in a stereometric figure. What exactly are we talking about? This is a line, which is a diameter, rotating around which, a semicircle creates a whole sphere. What diameter in comparison with the Earth is called the axis. This is an imaginary line that does not really exist, but there is a daily rotation around it, and it is commonly believed that it passes through the North and South Poles.

Poles of the planet Earth

What points on earth are called geographic poles? They are the well-known cold deserted north and south poles. In solid geometry, what is called the "geographic pole" is the point at which the earth's axis of rotation (the diagonal of a spherical body) intersects the sphere. The last one in this case is

Through these two poles pass all the meridians, which will be discussed below.

What are parallels

Let's continue to consider the Earth as a sphere and define what the parallels are in this case. If we assume that the planet, like the ball, has a center, then the Earth's axis will pass through it and be divided into two equal parts, like a diameter into radii.

If we draw a certain plane that will pass perpendicular to the axis, then it will cross the sphere along a certain circle, that is, the Earth along a line called a parallel. The parallel, which has the largest diameter, passes through the center of the globe of the Earth, which is a large circle and is called the equator. It divides the sphere into two equal hemispheres. All similar circles that are created by planes perpendicular to the axis are also called parallels, but are small circles compared to the equator. And the lines passing through the geographic poles will be called meridians. By the way, it is thanks to the equator that our Earth is divided into two parts - northern and southern. Accordingly, there are geographic poles of the planet Earth, which are named depending on which part of the world they are in.

Meridian

If we draw a large plane through the axis itself and through the poles, we get a circle as a result, which is called the "full meridian". All meridians are the same in length, as they pass through a straight line and two points on it in different planes. Only their location changes.

The system of meridians and parallels, which are shown on the map and on the globe, is a degree network.

It is two-dimensional, since it is given by only two coordinates - the parallel coordinate and the latitude coordinate. So what are geographic coordinates? These are two numbers, indicators of latitude and longitude. These numbers are in degrees and minutes.

At the beginning of the article, it was said that the Earth is not quite a sphere, that it is slightly flattened. What is it expressed in? The length of the equator is 40075.7 kilometers, when the length of the meridian is 40008.5 kilometers. The poles are a little closer to the equator, although this is not very noticeable on a planetary scale.

Planes of the earth's spheroid

It is those imaginary planes that run parallel or perpendicular to the earth's axis that are the main ones. The area of ​​the plane that passes through the meridian is called, respectively, the plane of the earth's meridian. The most prominent of them is the Greenwich meridian. It divides the earth into the eastern and main plane, which passes through the equator and divides the earth into two parts - the northern and southern hemispheres.

Initial reference lines

All coordinates are calculated using conventional stereometry. Reference points are chosen, more precisely, reference meridian and reference parallel, from which the coordinates of any place on Earth are calculated. The zero meridian was chosen to be the one that passes through London, namely through the Greenwich Observatory. As a line, what is considered the origin geographical latitude, it is customary to take the longest meridian - the equator.

An interesting fact about the Greenwich meridian. There is a system for assigning certain coordinates to a point, and it is called the World Geodetic System-84, or WGS-84 for short, (84 is the year the system was adopted), which is used by the whole world, and in which the zero meridian is the ERS Reference Meridian, passing near Greenwich, just 5.31 arc minutes to the east.

What lines of the earth give latitude and longitude

Children at school often confuse these concepts - meridians and parallels, which of them is the width and which is the longitude. So, the equator is the origin of the geographic latitude, when the Greenwich meridian is the starting line for calculating longitude.

Geographic latitude can have values ​​from 0 to 90 degrees. Depending on which side of the equator the point is located, it is assigned the value of northern latitude or southern latitude. So, let's say New York has a latitude of 40 degrees 43 minutes north, and Sydney has a latitude of 33 degrees 52 minutes south. It is written as follows: 40 about 43 ', 33 about 52 '.

Similar to geographic longitude. It can also be calculated using degrees and minutes, but longitude has a range of values ​​from 0 to 180 degrees. It can be western if it goes west from the zero meridian, and eastern (similarly - east from the zero meridian).

As previously stated, the zero meridian passes through Greenwich and has a value of 0 degrees. And what points on the Earth are called the geographic poles of the planet and what are their coordinates? These are the points that have values ​​of ninety degrees in latitude and zero degrees in longitude.

Summing up

On the planet Earth, as well as on the sphere, there are basic points, lines and planes. What points on the earth are called geographical poles, we have already figured out. These are the points through which the diurnal axis passes. If the plane passes through this axis and crosses the geographic poles, then it forms the intersections of the Earth's sphere, which are called meridians.

There is a passing one in London, and several others that have a dimension of up to 180 degrees (there can be at least 180 of them). If a certain plane passes through the axis of rotation of the Earth, namely perpendicular to it, then their intersection with the sphere of the Earth is a parallel. The parallel with the greatest longitude is called the equator. It is he who is the initial for reading the latitude coordinates. All coordinates are measured in degrees and smaller fractions - minutes, seconds. There are sixty minutes in one degree, and sixty seconds in one minute. Two strokes are used to indicate seconds (such as for minutes).