Hierarchy classification:

1. top of the aat hierarchies
2. Associated Concepts Facet
3. Associated Concepts (hierarchy name)
4. scientific concepts
5. physical sciences concepts
6. astronomical concepts

Anotations

Scope note:

The physical universe beyond the earth's atmosphere, consisting of near vacuum with small amounts of gas and dust. Usage often excludes celestial objects, but includes the expanse in which celestial objects are situated.