emisfera

Emisfera is a term that denotes one half of a sphere, typically separated by a plane that passes through the center. In geometry, cutting a sphere along a great circle yields two congruent hemispheres; the concept extends to other spherical bodies, such as planets and stars, in astronomy and geoscience.

When applied to Earth, emisfera commonly refers to the four halves defined by latitude and longitude. The Northern Hemisphere lies north of the equator, while the Southern Hemisphere lies south of it. The Eastern Hemisphere lies east of the prime meridian up to the 180th meridian, and the Western Hemisphere lies west of the prime meridian up to 180th. The intersection of these splits yields four hemispheres; real-world boundaries can be irregular due to the international date line and territorial claims.

In astronomy, celestial hemispheres describe halves of the celestial sphere, such as the northern celestial hemisphere and the southern celestial hemisphere, used to map stars, constellations, and the visible sky from a given location. In climatology and ecology, hemispheric analyses compare patterns across the Northern and Southern Hemispheres, for example seasonal shifts opposite between hemispheres.

Terminology varies by language; emisfera may appear in some contexts as a variant spelling or loanword, while the standard term in English is hemisphere and the equivalent in Spanish is hemisferio.