Galactic structure
The Spiral Arms
The bright lanes that wind through the disc, marked out by gas, dust, and freshly-formed luminous stars. The arms are thought to be density waves — regions where orbits crowd together and trigger star formation — rather than fixed structures, so stars drift in and out of them over time.
Galaxy, objects & concepts
Across the Galaxy
Knowledge connections
- Associated withThe Thin Disk
- Associated withThe Milky Way
- Associated withThe Diffuse Interstellar Medium
- Associated withThe Thin Disk
- Associated withRadial Migration
- Associated withThe Galactic Magnetic Field
- Associated withMilky Way Explorer
- Associated withThe Milky Way
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.