=== Astronomical Object ===
Naturally occurring physical structures that exist in observable [[Space|space.]] [[Asteroid|Asteroids,]] [[Moon|moons,]] [[Planet|planets,]] and [[Star|stars]] are examples of single astronomical objects. [[Nebula|Nebulae,]] [[Star system|star systems,]] star clusters, and [[Galaxy|galaxies]] are examples of compound astronomical objects.
=== Astronomical Unit ===