The Earth, a spherical body, can be conceptually divided into halves, known as hemispheres. Geographers commonly use imaginary lines to partition our planet into four distinct hemispheres. These divisions help in understanding global patterns and locations.
Horizontal Division by the Equator
The most fundamental horizontal division of Earth is the Equator, an imaginary line encircling the planet at 0 degrees latitude. This great circle is equidistant from both the North and South Poles, effectively splitting the Earth into the Northern and Southern Hemispheres. The Equator serves as a reference point for measuring latitude, which indicates how far north or south a location is from this central line, measured in degrees up to 90 degrees at each pole.
The Northern Hemisphere encompasses all land and ocean areas north of the Equator. It contains a majority of Earth’s landmass, approximately 67-68%, and is home to about 90% of the global population. Major continents such as North America, Europe, and most of Asia and Africa lie within this hemisphere, along with a small portion of South America.
The Southern Hemisphere includes all regions south of the Equator. It is predominantly covered by water, accounting for about 81% of its surface, with landmasses making up roughly 32% of Earth’s total land. It contains Antarctica, Australia, most of South America, and the southern part of Africa. The Earth’s axial tilt means that seasons in the Northern and Southern Hemispheres are opposite; for instance, when it is summer in the north, it is winter in the south.
Vertical Division by Meridians
The Earth is also divided vertically into the Eastern and Western Hemispheres using lines of longitude. These lines, called meridians, run from the North Pole to the South Pole. Longitude measures the angular distance east or west from a specific starting line, the Prime Meridian, in degrees.
The Prime Meridian, at 0 degrees longitude, passes through Greenwich, England. Its direct opposite on the globe, approximately at 180 degrees longitude, is the International Date Line. This line largely follows the 180-degree meridian but deviates in places to avoid splitting countries and islands into different calendar dates.
The Eastern Hemisphere is the half of the Earth located east of the Prime Meridian and west of the International Date Line. This hemisphere contains the vast majority of Europe, Africa, Asia, and Australia, encompassing a larger land area and population compared to its western counterpart. The Western Hemisphere lies west of the Prime Meridian and east of the International Date Line. It includes North America and South America.