🌐EnglishEnglishEspañolPortuguêsالعربية中文EntityQ4669818· pop 7· linked from 6 articlesabsolute horizonboundary in spacetime, defined with respect to the external universe, events inside which cannot affect an external observerAvailable in 7 languagesEspañol中文PortuguêsالعربيةBanglaCatalanvia Wikidata sitelinks · CC0ConnectionsFriedmann–Lemaître–Robertson–Walker metricEntityReissner–Nordström metricEntityCategoriesConcepts in astrophysicsGeneral relativityPhysical horizons