Equator
The equator of the earth is the adopted at its surface great circle on the plane ( the equatorial plane), the Earth's axis is vertical. The Earth's surface is divided by him into a northern and a southern half, where the Latin name " equalizer" ( old German for "equal " ) is derived. He is reference circuit for the parallel small circles that are used for dimensioning the earth in a north-south direction with the help of circles of latitude. He even has the latitude 0 °.
The intersection of the equatorial plane of the earth with the imaginary celestial sphere around the Earth is the celestial equator.
The geometry of the equator term is commonly applied to the ball in combination with a fixed through its center axis.
Earth's equator
Length of the equator
The length of the equator circle is 40075.017 km ( WGS 84).
The length of a nautical mile (abbreviated nm; engl nautical mile, NM. ) Was originally the equatorial bow over one minute of arc and totaled 1.853 km relative to a mean earth radius of 6,370 km.
States, cities and islands on the equator
The Earth's equator passes through the continents of Africa, Asia ( Indonesia ) and America ( South America) and the oceans (except the polar ). By Crossed continental states are:
- Africa Gabon
- Republic of Congo
- Democratic Republic of Congo
- Uganda
- Kenya
- Somalia
Island states, of which one or more islands are on the equator, are:
- São Tomé and Príncipe ( west coast of Africa )
- Indonesia
Island states with islands on both sides of the equator, the Maldives in the Indian Ocean and Pacific Ocean Micronesia and several other island groups.
Almost on the equator are the main cities:
- São Tomé (35 km north) São Tomé and Príncipe
- Libreville (40 km north) of Gabon
- Kampala (35 km north) of Uganda
- Quito (20 km south) of Ecuador
- Yaren (50 km south) of Nauru
Direct crossed by the equator are:
- The city of Macapa (Brazil )
- The cities Calacalí, La Concordia and San Antonio de Pichincha in Ecuador
- The city of Pontianak (Indonesia)
- The cities Maseno, Nanyuki and Nyahururu Kenya
- The city Makoua in the Republic of Congo
- , was until 2006 the only equatorial section on the whole year snow - the mountain massif of the Cayambe volcano in Ecuador
- The massif of the Wolf volcano on the Galapagos Islands
- Of Lake George and the north coast of Lake Victoria in Uganda
- The Rolas Island in São Tomé and Príncipe
- The UNHCR refugee camp at Dadaab Hagadera (Kenya )
Because of the slight periodic movements of the Earth's axis, the instantaneous equator be up to about 10 meters from the central equatorial away in one place.
Germany is from the equator 47.4 ° to 55.0 ° (about 5300-6100 km), Austria 46.4 ° to 49.1 °, Switzerland 45.8 ° to 47.8 ° and 46.2 ° South Tyrol to 47.1 °.
Equator, in behalf of states and provinces
Two States take on their behalf with respect to the equator, Ecuador and Equatorial Guinea.
After 1801 there was in South America for a short time France Equatorial (Equatorial France, southern expansion of French Guiana ), until 1958 there was also the colony of French Equatorial Africa
Equatoria has been used several times in the history as a province or state designation of a region in what is now South Sudan. Currently, three states of Southern Sudan Equatoria in their name ( Central Equatoria, Eastern Equatoria and Western Equatoria ).
Equateur is still the name of a province in the Congo.
Climate at the equator
On both sides of the equator, there is the climate of the tropics. Due to the high throughout the year the sun at the equator the radiation is high and almost constant. The consequences are an almost constant total cloud formation and a correspondingly constant precipitation levels. Characteristic of the so-called equatorial climate is a year of persistent mildness; Seasons like summer or winter, for example, in European standards do not occur. However, take care on the leeward side for longer drying times in high mountain near foehn winds.
Others
In addition to the geographical equator, there are laid down by the Erdmagnetpole magnetic equator and the climatological heat equator.
A common ritual in shipping on first crossing of the equator is the line ceremony.
Celestial equator
The celestial equator is the great circle on the imaginary celestial sphere on which it is intersected by the plane of the Earth's equator. In other words, if you would put a light bulb in the center of a glass globe, is the celestial equator just the projection of the Earth's equator to the apparent celestial sphere. It divides the celestial sphere into a northern and a southern half.
Since the Earth's axis is tilted relative to the plane of the solar system, the celestial equator intersects the ecliptic - the apparent plane of the orbit of the sun around the earth - currently at an angle 23.44 ° ( obliquity of the ecliptic ). The two intersections are called the vernal equinox or fall point, since there is the projection of the sun on the apparent celestial sphere to the day - and -night match in the spring or autumn in them.
Locations on the celestial equator are the declination 0 °, a polar distance of 90 °, its right ascension is measured in the equatorial coordinate system starting from the vernal equinox.
Since the Earth's axis executes a precessional motion, and the position of the celestial equator, and with it the direction of the vernal point in space changes over time.
Equator in a figurative sense
The term equator is also jokingly used as the ( imaginary ) boundary line:
- So the Weißwurstäquator denotes the imaginary boundary between ( Old ) Bavaria and the other, northern Germany, including Franks, although this is also part of the Free State of Bavaria
- The furnace equator: a border in China, is heated from the winter ( about the height of Shanghai)
- The border between the German food markets of Aldi Nord and Aldi Süd is called Aldi equator