Astronomy & Space Science · AST-512
Milky Way Rotation & Dark Matter: Structures & Vocabulary
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Structure
Structure of Milky Way Rotation & Dark Matter
A Galactic rotation curve plots orbital speed against distance from the center. Gas clouds, stars, and masers trace rotation across the disk, while satellite galaxies and halo objects extend mass constraints farther outward. The inferred dark-matter halo reaches well beyond the visible disk.
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- 01The Milky Way Galaxy — SummaryOpen source ↗
OpenStax Astronomy 2e
View claim-by-claim traceability3 verified claims
The rotation of the Milky Way shows that visible stars and gas do not account for all of its gravitational mass.
supported · checked Sep 22, 2026For a nearly spherical mass distribution, orbital speed depends on the mass enclosed within the orbit.
supported · checked Sep 22, 2026Measurements of neutral hydrogen, molecular masers, stellar velocities, satellite motions, and local stellar dynamics all require more gravitating mass than can be supplied by observed baryonic matter alone.
supported · checked Sep 22, 2026