Hemisfäärien

Hemisfäärien, or hemispheres, refer to the two halves of a spherical object, such as Earth, divided by an imaginary line called the equator. The term originates from the Greek words *hēmisphaira*, meaning "half sphere." Earth is divided into two primary hemispheres: the Northern Hemisphere and the Southern Hemisphere, separated by the equator. Additionally, the planet is also split into the Eastern and Western Hemispheres along the prime meridian, which runs from the North Pole to the South Pole through Greenwich, England.

The division into hemispheres is primarily used for geographic and navigational purposes. The Northern Hemisphere encompasses all land and water north of the equator, including continents such as North America, Europe, and Asia (except for parts of Russia and China). The Southern Hemisphere covers the area south of the equator, featuring regions like South America, Africa (south of the equator), Australia, and Antarctica. The Eastern and Western Hemispheres are less commonly referenced in everyday contexts but are useful in global mapping and time zone calculations.

Hemispheric divisions influence climate, ecosystems, and human activities. For example, the Northern Hemisphere experiences seasonal variations more distinctly due to its larger landmass, while the Southern Hemisphere tends to have milder seasonal shifts. The concept of hemispheres is also applied to other celestial bodies, such as Mars and Venus, though their divisions may differ based on their axial tilt and rotational characteristics. Understanding hemispheric distinctions is fundamental in fields like geography, astronomy, and environmental science.