 | This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these messages)
|
Locality in astronomy is in theory closeness of the observer relative to the observed astronomical phenomenon under consideration, and thus in practice the relative closeness of the phenomenon to the star system of the Sun.
Being local is an ambiguous condition, and always relative to the order of magnitude of the relevant phenomenon. The term "local" is commonly applied to structures on five successively larger scales beyond the roughly two-light-years diameter of the Solar System:
- The Local Interstellar Cloud containing the Solar System, roughly 30 light years across
- The Local Bubble of gas in turn containing it, 300 light years or more across
- The Local Arm, a.k.a. the Orion Arm (of the Milky Way galaxy), 3,500 light years wide, and approximately 10,000 long
- The Local Group, the group of galaxies that contains the Milky Way, 10 million light-years across
- The Local Supercluster or Virgo Supercluster, 110 million light-years across
This set index article includes a list of related items that share the same name (or similar names).
If an internal link incorrectly led you here, you may wish to change the link to point directly to the intended article.
If an internal link incorrectly led you here, you may wish to change the link to point directly to the intended article.