NASA, in collaboration with the astronomical community, names galaxies primarily through two methods: assigning descriptive names for particularly distinctive objects and utilizing catalogue designations for the vast majority.
Understanding Galaxy Naming Conventions
While there isn't a single "NASA naming committee" that assigns every galaxy a unique, popular name, the agency follows established astronomical practices and contributes to the ongoing cataloging of celestial objects. Most galaxies are not given unique, individual names like planets or stars; instead, they are identified by their designation in various astronomical catalogues.
1. Descriptive Names
For galaxies that are exceptionally prominent, unique in their appearance, or historically significant, descriptive names are often adopted. These names typically reflect a distinctive feature, location, or a well-known mythological figure.
- When Used: These names are reserved for galaxies that are easily recognizable and stand out due to their distinctiveness in location or visual appearance.
- Examples:
- Andromeda: Named after the constellation it appears in, and the mythological princess. It is a large spiral galaxy visible to the naked eye.
- Whirlpool: Known for its striking, swirling spiral arms, resembling a cosmic whirlpool.
2. Catalogue Designations
The most common way galaxies are identified is through their designation within astronomical catalogues. These catalogues systematically list celestial objects, assigning them alphanumeric identifiers based on their discovery, characteristics, or position. This method ensures a comprehensive and organized way to track and study countless galaxies across the universe.
- Prevalence: The vast majority of known galaxies are identified by their catalogue numbers rather than unique, descriptive names.
- Historical Context: One of the earliest and most influential catalogues of celestial objects, including galaxies, was compiled by Charles Messier in the 18th century. Objects in this catalogue are prefixed with 'M' (e.g., M31 for the Andromeda Galaxy, M51 for the Whirlpool Galaxy).
- Modern Catalogues: Today, many other extensive catalogues exist, such as the New General Catalogue (NGC) and the Uppsala General Catalogue (UGC), which provide designations like NGC 1300 or UGC 6697.
This dual approach allows for easy reference to well-known galaxies while providing a systematic way to categorize and study the billions of other galaxies in the cosmos.
Summary of Galaxy Naming
To summarize the two primary methods:
| Naming Method | Description | Examples |
|---|---|---|
| Descriptive Names | Unique names given to particularly distinctive or historically important galaxies. | Andromeda, Whirlpool |
| Catalogue Names | Alphanumeric designations from systematic astronomical surveys and catalogues. | M31, M51, NGC 1300, UGC 6697 |
