North

For the homonymous articles, to see North (homonymy).

north is one of the four .

Etymology

Of Latin Septemtriones who means seven b?ufs. Formerly , that we call from now on Small Ourse, was called constellation of the seven b?ufs.

most brilliant of this constellation is itpole star, that which indicates north.

The north term is thus a out-of-date synonym of north, referring to this constellation which indicated the direction of north to Romans ; but the adjective septentrional who results from this very used remainder.

The expression North Pole indicate two different things:

• the geographical North Pole, located in the axis of rotation of the Earth, is fixed, in;
• the magnetic North Pole, whose position is pointed by the needle of one , moves according to variations of .

North (with one capital letter) the septentrional part of the world indicates (also called Far North with ) or of a country (e.g. : is a city of North, in opposition to is a city of the South).

North is also used to indicate the countries known as developed, in opposition to (or in certain cases Midday), which indicates the countries of , known as in the process of development or under development.

is the course more in north of Europe, in with 71°11 of .

Geographical and magnetic

There are two north. First is magnetic, the axis of symmetry cylindrical magnetic field, second is geographical, the axis of rotation of . They are not completely at the same place, the magnetic North Pole ofnorthern hemisphere is located at 1900 km of the geographical North Pole.

The difference in angle which one can observe on the compass between these two north is called magnetic variation. This difference varies with time.

On the traditional charts and in particular the charts of, the meridian lines (vertical black lines) point the true north (NG.), it is necessary thus to hold account of the magnetic variation to direct itself towards the chart with the assistance of compass (NM.) the sketch located on the left indicates the value of the variation for the chart and a year given, because the magnetic pole migrates permanently, reducing each year the value of the variation (0,8 degree/year).

Certain cartographers circumvented this complication by building charts holding account of this variation: north (N) of the chart as well as the vertical lines in blue or black point the magnetic north (same manner that the needle of the compass).

It would seem that the magnetic north was, 780 000 years ago, in the geographical south. And it would not be the first time. A new inversion is awaited in 2 000 years if the current magnetic field continues to weaken.