I advocate for why Wikimedia projects (especially Wikipedia, Wiktionary, Wikidata, and Commons) matter to the astronomy, astrophysics, and space science communities and I research how these resources are viewed and used by scientists, educators, curators, and students. I've spoken on this topic at universities, observatories, science museums, and conferences in the Netherlands, Austria, Greece, United Kingdom, Japan, South Korea, Hong Kong, and the United States. A small (slightly outdated) taste of this work is summarized by this learning pattern I wrote in 2018.