The file "myuniverse.owl" must be opened with Protege 5.5.0 . It contains an ontology about the celestial bodies and the relationships between them. There are classes like Planet, Star, Satellit with their relative classification by Nasa or the one found on Wikipedia. The main ObjectProperties are hasPlanetarySyste, hasGalaxy, hasSatellit, while the data properties talk about the radius, the mass and the luminosity in case of stars.
The files DL_queries.txt and SPARQL_queries.txt contain some query executed on the ontology