cosmography

Cosmography is the branch of study that seeks to describe and map the structure of the universe. It focuses on describing the spatial relationships and distribution of celestial objects—stars, galaxies, clusters—and the geometry of space on the largest scales. Unlike cosmology, which addresses origin and evolution, cosmography emphasizes representation, coordinate systems, and measurements that place objects within a map of the cosmos.

Historically, cosmography grew out of celestial cartography in ancient and medieval astronomy, as people drew star charts and mapped the heavens relative to the Earth. In the modern era, it has become a data-driven practice, incorporating large-scale surveys that produce 3D maps of the universe, using distance indicators, parallax, and redshift to place objects in space.

Techniques include astrometric measurements for precise positions, standard candles and distance indicators for distances, and large surveys such as galaxy redshift surveys and all-sky surveys for distribution patterns. The resulting maps inform studies of the cosmic web, the large-scale geometry of the universe, and help visualize how matter is arranged on intergalactic scales.

Cosmography intersects astronomy, cartography, and cosmology. While closely related to cosmology, it remains primarily concerned with description and representation rather than theoretical interpretation. The term is sometimes used in philosophy or science communication to convey the human goal of mapping the universe.