Meridians are the great circles of the Earth's sphere that cross the poles.
Meridian is a term that, according to the Royal Spanish Academy (RAE) , refers to what belongs to or is related to the time of noon . By extension, the concept is used as an adjective to name something that is very luminous or very clear .
Before entering fully into the analysis of the meaning, it is advisable to proceed to determine its etymological origin. Thus, it must be made clear that it is a word that emanates from Latin, and more precisely from the word meridianus . This is the result of the sum of two Latin words: meridies , which can be translated as “noon” and which in turn is composed of medius – synonymous with “middle” – and dies , which is equivalent to “day” .
Meridians as imaginary lines
Meridians, on the other hand, are the great circles of the Earth's sphere that pass through the poles . It can be said that meridians are imaginary lines , which are used to set the schedule .
The meridian that passes through the point where an observer is located is called the local meridian . This meridian can be divided into two semi-circles by the Earth 's axis of rotation: the superior meridian ( PM ) and the inferior meridian ( AM ).
Solar time is the measurement of time based on the apparent movement of the sun over the horizon. When the sun passes through the meridian, it reaches its highest point in the sky and noon is established.
The Greenwich meridian passes through the observatory of said English city.
Greenwich Observatory
The base meridian from which longitudes are measured is the Greenwich meridian . This imaginary circle that joins the poles stops at the old astronomical observatory in the English city of Greenwich and was adopted as a reference in 1884 .
From north to south, the Greenwich Meridian runs through the United Kingdom , France , Spain , Algeria , Mali , Burkina Faso , Togo and Ghana .
It is interesting to note that currently one of the greatest tourist attractions of this English city is the Royal Astronomy Observatory , which dates back to the second half of the 17th century . Thus, many visitors are encouraged to get to know it in depth and are amazed by the exhibitions that it includes inside, both of chronometers and all kinds of navigation tools. Of course, without forgetting that it has interesting clockwork and star and planet observation artifacts.
Other uses of the notion of meridian
In the field of astronomy there is also what is known as a meridian telescope , which is the one used to observe the stars and which is placed on a horizontal axis.
In addition to everything stated above, we would have to emphasize that there are other concepts that also use this word. Thus, for example, there is the so-called meridian plane , which is that plane that has the particularity of passing through what would be the axis of revolution of a surface.
Other uses of the notion of meridian refer to the sofa without arms or backrest ; to the stretcher ; and the nap that takes place after a meal.w