Beyond the Equator: Southern Hemisphere Star Map
If, after living your entire life in the Northern Hemisphere, you suddenly find yourself on the other side of the equator - for example, in Australia, South Africa or New Zealand, the starry sky above your head on a clear night will seem unusual and even strange to you. After careful study, you will understand that the whole point lies in a completely different arrangement of the night luminaries in the sky. However, they are also grouped into easily recognizable constellations - constant guiding signs for travelers and sailors.
The constellations of the Southern Hemisphere received their modern names much later than, say, Big Dipper or Orion: the ancient Greeks, who systematized most of the groups of stars familiar to us, did not cross the equator, so in in this case this role fell to the share of European sailors, in XVII-XVIII centuries headed for India and South America.
Name of constellations
In total on stellar sphere visible from Earth, there are 88 constellations (all of them were finally approved by the International Astronomical Union in 1930); 40 of them shine over the Southern Hemisphere. Some of the constellations received names rooted in ancient Greek mythology: Centaur, Phoenix, Scorpion. Other names were taken from scientific and maritime terminology or simply from everyday life - for example, Microscope, Bake, Net, Octant.
Among the constellations of the Southern Hemisphere, there are no medium-sized ones: they are either small, compact groups of stars, or large ones, stretching across an impressive area of the celestial sphere. Yes, famous South Cross- Very small constellation, consisting of only four stars, which, nevertheless, are among the brightest in the night sky. Hydra, on the contrary, consists of 19 stars and dominates one of the relatively empty sectors of stars, stretching along the southern horizon from the constellation Libra to the constellation Cancer. Now it is the largest of the groups of stars, although until 1930 the constellation was still distinguished in the sky of the Southern Hemisphere Argo. However, astronomers came to the conclusion that Argo was too bulky and difficult to distinguish, so four new constellations arose in its place: Keel, Sail, Compass And Stern.
Southern circumpolar zone
Just as in the Northern Hemisphere, the southern stars move slowly across the sky during the night due to the rotation of the Earth around its axis. However, there is no such convenient “pointer” as the familiar Polar Star, and the imaginary point South Pole the world is located in the sky in the constellation Octant.
Southern circumpolar zone- this is the region of the celestial sphere located within 40º from the South Pole of the world; the stars related to it do not hide behind the horizon at any time of the night or year. (In fact, they do not leave the sky during the day, only their shine is naturally eclipsed by the radiance of the Sun; in near-equatorial regions they rise from the horizon in the east and slowly move westward during the night.)
Groups of stars that are entirely included in the southern circumpolar zone include the constellations of the Southern Cross, Chameleon, flies, Southern Triangle, Pavlina, Hours, Flying Fish and others.
Low on the horizon
Many constellations in the Southern Hemisphere appear in the sky only in certain time year - just as it happens in Northern. This phenomenon caused by a combination of inclination earth's axis with the movement of our planet in orbit around the Sun. For example, Keel And cup It is best to observe in the spring, when they rise high enough above the horizon. Libra and the Southern Cross - in summer, the constellation Phoenix and Capricorn- in the fall, and Eridani And Kita- in winter.
Such a cycle not only gives us the opportunity to determine what time of year or hour of the morning it is, but also greatly helps astronomers: by moving in the sky, the stars can take a more favorable position for observations - or, conversely, by leaving the field of view of telescopes, freeing up the desired area of the sky spheres.
Galaxy and nebulae
One of the most spectacular sights in a clear night sky is the jagged streak transparent light, stretching obliquely across celestial sphere. This Milky Way - our galaxy, the light of an uncountable number of stars, which travels to us for tens of thousands, or even millions of years. And although this huge formation has the shape of a spiral disk (at the end of one of the branches of which there is solar system), for us it remains a stripe, since we look at it from the side. The Milky Way is equally visible in both hemispheres, but its brightest part is in southern constellation Sagittarius.
Located so many light years away from us (63,240 AU or 9.463 x 10 12 km), all these luminaries, naturally, cannot be distinguished naked eye- just like the stars of other galaxies located even further away. However, these galaxies themselves can sometimes be seen without special optics: these are, in particular, Carina Nebula And Orion Nebula, located in the constellations of the same name. Besides, powerful telescopes at least a little, but they bring our neighbors in the Universe closer to us - it is known, for example, that the galaxy NGC 2997, located in the constellation Pump, like ours, is a gas-dust formation penetrated by myriads of stars.
Ptolemy in his work "Almagest" canonized the following 48 ancient constellations, which still bear the name Ptolemy. Zodiac constellations: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius, Pisces. Northern constellations: Ursa Major, Ursa Minor, Draco, Cepheus, Cassiopeia, Andromeda, Perseus, Bootes, Northern Crown, Hercules, Lyra, Swan, Charioteer, Ophiuchus, Serpent, Arrow, Eagle, Dolphin, Foal, Pegasus, Triangle. Southern constellations: Whale, Orion, River, Hare, Canis major, minor, Ship, Hydra, Chalice, Raven, Centaurus, Wolf, Altar, Southern Crown, Southern Fish. Ptolemy did not consider Coma Berenices a separate constellation.
Arab astrologers, in addition to lunar houses, gave various names for individual bright stars. Having become acquainted with the astronomy of the Greeks and translating Ptolemy's Almagest, they changed some of the names according to the positions of the stars in the drawings of the Ptolemaic constellations. Made in the 12th century Latin translation"Almagest" from Arabic, and in the 16th century - directly from Greek according to found manuscripts. The stars of the southern hemisphere, unknown to Greek astronomers, were divided into constellations much later. Some of them were planned by the Arabs.
There is no doubt that the navigators of the XV and XVI century(Vespucci, Corsali, Pigafetta, Peter of Medinsky, Gutman) during their travels to southern seas New constellations were gradually assembled. They were put in order by Peter Dirk Keyser. During his stay on the island of Java (1595), he identified 120 places southern stars and placed the figures of the constellations on them. The following 13 constellations were included, based on Keyser's inventory, in the atlases of Bayer (1603) and Bartsch (1624): Phoenix, gold fish, Chameleon, Flying Fish, Southern Cross, Water Snake, Fly, Bird of Paradise, Southern Triangle, Peacock, Indian, Crane, Toucan. Of these, the Southern Cross was known to Ptolemy and formed part of the Centaurus.
The current names of constellations and stars represent an amalgam of these lists and translations. Ancient drawings of constellations are completely lost. Only distorted figures on Arab globes of the 13th century have reached us; for example, on a globe in the Borghese Museum in Veletri (1225), in the Mathematical Society in Dresden (1279), in the London Astronomical Society, etc. early XVI century, the famous Renaissance artist Albrecht Durer painted the constellations according to their description by Ptolemy.
Unfortunately, not a single authentic copy of Dürer's drawings has survived. Dürer's drawings, modified by other artists, were reprinted in the star atlases of Bayer (1603), Flamsteed (1729). Then the figures of the constellations of the latest layout appeared. Currently, constellation drawings are no longer printed. The credit for banishing the “menagerie” from astronomical atlases belongs to Harding. He published a celestial atlas in 1823, where only the boundaries of the constellations were plotted.
Our planet is conventionally divided into four hemispheres. How are the boundaries between them defined? What features do the Earth's hemispheres have?
Equator and meridian
It has the shape of a slightly flattened ball at the poles - a spheroid. In scientific circles, its shape is usually called a geoid, that is, “like the Earth.” The surface of the geoid is perpendicular to the direction of gravity at any point.
For convenience, the characteristics of the planet use conditional, or imaginary, lines. One of them is the axis. It passes through the center of the Earth, connecting the upper and lower parts, called the North and South Pole.
Between the poles, at an equal distance from them, there is the following imaginary line, which is called the equator. It is horizontal and is a separator into the Southern (everything below the line) and Northern (everything above the line) hemispheres of the Earth. is a little more than 40 thousand kilometers.
Another one conditional line- Greenwich, or This vertical line, passing through the Greenwich Observatory. The meridian divides the planet into Western and Eastern hemisphere, and is also the starting point for measuring geographic longitude.
Difference between the Southern and Northern Hemispheres
The equator line horizontally divides the planet in half, crossing several continents. Africa, Eurasia and South America are partially located in two hemispheres. The remaining continents are located within one. Thus, Australia and Antarctica are entirely in the southern part, and North America- in the north.
The Earth's hemispheres also have other differences. Thanks to Arctic Ocean at the pole, the climate of the Northern Hemisphere is generally milder than that of the Southern Hemisphere, where the landmass is Antarctica. The seasons in the hemispheres are opposite: winter in the northern part of the planet comes simultaneously with summer in the south.
The difference is observed in the movement of air and water. North of the equator, river flows and sea currents deviate to the right (river banks are usually steeper on the right), anticyclones rotate clockwise, and cyclones rotate counterclockwise. To the south of the equator, everything happens exactly the opposite.
Even the starry sky above is different. The pattern in each hemisphere is different. The main landmark for the northern part of the Earth is the North Star, and the Southern Cross serves as a reference point. Above the equator, land prevails, which is why the majority of people live here. Below the equator total number The population is 10%, since the oceanic part predominates.
Western and Eastern Hemispheres
East of prime meridian The Eastern hemisphere of the Earth is located. Within its borders is Australia, most of Africa, Eurasia, part of Antarctica. Approximately 82% of the world's population lives here. In a geopolitical and cultural sense, it is called the Old World, as opposed to the New World of the American continents. In the eastern part there is a deep trench and the most high mountain on our planet.
The earth is located west of the Greenwich meridian. It covers North and South America, parts of Africa and Eurasia. It completely includes Atlantic Ocean and most of the Pacific. Here is the longest Mountain chain in the world, largest volcano, the driest desert, the highest mountain lake and deep river. Only 18% of the world's inhabitants live in the western part of the world.
Date line
As already mentioned, the Western and Eastern hemispheres of the Earth are separated by the Greenwich meridian. Its continuation is the 180th meridian, which outlines the border on the other side. It is the date line, where today turns into tomorrow.
On both sides of the meridian different calendar days. This is due to the peculiarities of the planet’s rotation. The International Date Line mostly runs along the ocean, but also crosses some islands (Vanua Levu, Taviuni, etc.). In these places, for convenience, the line is shifted along the land boundary, otherwise the inhabitants of one island would exist on different dates.
In geography, there is a conventional division of the Earth into hemispheres. In accordance with their location in relation to the equator (dividing line), they are called Northern and Southern. Each hemisphere has its own characteristics.
Hemispheres on the map
The Equator encircles the Earth, crossing Eurasia, Africa, and South America. Each of the remaining continents is located entirely in one of the hemispheres: North America - in the Northern, Australia and Antarctica - in the Southern.
Comparison
Let's look point by point at what is the difference between the Northern Hemisphere and the Southern Hemisphere.
- Temperature at the poles. Despite its name, the North Pole is less severe than the South Pole. What explains this? The fact that the zone North Pole is the ocean, and the Southern zone is Antarctica. Water is lower in level and conducts heat, unlike the solid, rising continent.
- Movement of air masses. In the Southern Hemisphere, the rotation of emerging cyclones occurs clockwise, and anticyclones rotate in a clockwise direction. opposite direction. Air flows in the other hemisphere rotate in the opposite direction.
- Seasons. While the warm summer season lasts in the Northern Hemisphere, Southern people have to survive the winter. And familiar to us winter months– this is summer on the other half of the globe.
- Fauna. Each hemisphere has its own unique animals. In Severny you can meet walrus, polar bear, and polar fox. In the South - kangaroos, hummingbirds.
- Distribution of land and water. The Northern Hemisphere contains vast land masses. This is the majority of the planet's landmass. A significant proportion of the other hemisphere is water.
- Population size. What is the difference between the Northern and Southern Hemisphere? The fact is that there are immeasurably more inhabitants of the Northern Hemisphere. Only 10% of the world's population lives in Yuzhny.
- Starry sky. In the field of view of people staying in the Northern Hemisphere, there is a set of stars and constellations that is different from the one that is visible to southerners. In particular, in the Northern Hemisphere there are important landmark The North Star, and in the opposite hemisphere the Southern Cross has the same meaning.