Galactic structure
The Thick Disk
A more extended, puffed-up disc of older, more metal-poor stars that envelops the thin disk. Its stars move on hotter orbits and formed early in the Galaxy's history, making the thick disk a fossil record of a more turbulent youth — perhaps heated by an ancient merger.
Galaxy, objects & concepts
Across the Galaxy
Knowledge connections
- Associated withThe Thin Disk
- Associated withThe Milky Way
- Associated withStellar Populations & Clusters
Sources
The primary and reference sources this topic draws on.
- NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.