{"dataset":{"slug":"extragalactic-structures","title":"Galactic Processes & Cosmic Structures","description":"The processes that shape galaxies and the large-scale structures they build — mergers, starbursts, feedback, the Local Group, clusters, superclusters, and voids.","version":"1.0.0","lastGenerated":"2026-06-29","license":"CC BY-SA 4.0","entityCount":12,"sources":["nasa"]},"entities":[{"id":"galactic_process:black-hole-feedback","name":"Black-Hole Feedback","type":"galactic_process","domain":"science","description":"The way an active central black hole regulates its galaxy — its winds and jets heating and expelling gas, quenching star formation, and explaining the tight link between a galaxy's black-hole mass and its bulge.","entryPath":"/galaxies/black-hole-feedback"},{"id":"galactic_process:galaxy-evolution","name":"Galaxy Evolution","type":"galactic_process","domain":"science","description":"How galaxies grow and change over cosmic time — assembling from smaller pieces, forming stars, exhausting or losing their gas, and transforming from blue, star-forming disks into red, quiescent ellipticals.","entryPath":"/galaxies/galaxy-evolution"},{"id":"galactic_process:galaxy-interaction","name":"Galaxy Interaction","type":"galactic_process","domain":"science","description":"The gravitational give-and-take of galaxies passing close without fully merging — drawing out tidal tails and bridges, triggering star formation, and, in a direct hit, punching out a ring galaxy.","entryPath":"/galaxies/galaxy-interaction"},{"id":"galactic_process:galaxy-merger","name":"Galaxy Merger","type":"galactic_process","domain":"science","description":"The collision and coalescence of two galaxies. Mergers trigger bursts of star formation, funnel gas to the central black hole, and can turn two spirals into a single elliptical — a driving force of galaxy evolution.","entryPath":"/galaxies/galaxy-merger"},{"id":"galactic_process:galaxy-quenching","name":"Galaxy Quenching","type":"galactic_process","domain":"science","description":"The shutdown of star formation in a galaxy, as it loses or is stripped of its cold gas, or has it heated by feedback — leaving a red, passively-evolving elliptical or lenticular of ageing stars.","entryPath":"/galaxies/galaxy-quenching"},{"id":"cosmic_structure:laniakea-supercluster","name":"Laniakea Supercluster","type":"cosmic_structure","domain":"science","description":"The vast supercluster the Milky Way belongs to, defined in 2014 by the flows of galaxies toward a common gravitational focus. It contains around a hundred thousand galaxies across half a billion light-years.","entryPath":"/galaxies/laniakea-supercluster"},{"id":"galactic_process:starburst","name":"Starburst","type":"galactic_process","domain":"science","description":"A phase of exceptionally intense star formation, forming stars far faster than a galaxy can sustain — often triggered by a merger or interaction and driving powerful galactic winds. M82 is the archetype.","entryPath":"/galaxies/starburst"},{"id":"cosmic_structure:bootes-void","name":"The Boötes Void","type":"cosmic_structure","domain":"science","description":"One of the largest known voids — an enormous, nearly-empty region of space containing very few galaxies, a vast bubble between the filaments and walls of the cosmic web.","entryPath":"/galaxies/bootes-void"},{"id":"cosmic_structure:coma-cluster","name":"The Coma Cluster","type":"cosmic_structure","domain":"science","description":"A rich, dense cluster of over a thousand galaxies. In 1933 Fritz Zwicky found its galaxies moving far too fast to be held together by their visible mass — the first evidence for dark matter.","entryPath":"/galaxies/coma-cluster"},{"id":"cosmic_structure:local-group","name":"The Local Group","type":"cosmic_structure","domain":"science","description":"The gravitationally-bound group of galaxies the Milky Way belongs to — dominated by the Milky Way and Andromeda, with the Triangulum galaxy and dozens of dwarfs. Andromeda and the Milky Way are approaching, and will merge in a few billion years.","entryPath":"/galaxies/local-group"},{"id":"cosmic_structure:sloan-great-wall","name":"The Sloan Great Wall","type":"cosmic_structure","domain":"science","description":"One of the largest known structures in the universe — an immense wall of galaxies stretching over a billion light-years, mapped by the Sloan Digital Sky Survey, part of the filamentary cosmic web.","entryPath":"/galaxies/sloan-great-wall"},{"id":"cosmic_structure:virgo-cluster","name":"The Virgo Cluster","type":"cosmic_structure","domain":"science","description":"The nearest large galaxy cluster, over a thousand galaxies bound together and centred on the giant elliptical M87. Its gravity draws the Local Group toward it, and it anchors our corner of the local supercluster.","entryPath":"/galaxies/virgo-cluster"}]}