The Semantic Web for Earth and Environmental Terminology (SWEET) is a NASA-funded prototype to explore the technological challenges in making the semantic Web a reality for earth system science data and information. SWEET includes an extensive collection of ontologies written in the Ontology Web Language (OWL). These ontologies encompass both faceted (decomposed) concepts and integrative (unifying) concepts. Taken together, these enable a representation of the two science processes of reductionism and synthesis. SWEET stores ontology elements optionally in a DBMS (database management system), with a two-way translator between the XML and DBMS representations. SWEET also includes wrappers for large external online databases (gazetteers, earthquakes, etc.) to enable their contents be virtual components of the ontologies (http://sweet.jpl.nasa.gov).