The Milky Way Galaxy-Chapter 25

These flashcards cover key concepts related to the structure, components, and characteristics of the Milky Way Galaxy as discussed in the notes.

Milky Way Galaxy

Our home galaxy, which is a barred spiral galaxy containing billions of stars.

Spiral Structure

The arrangement of stars, gas, and dust in a spiral formation around the central bulge of a galaxy.

Herschel's Discovery

William Herschel's conclusion about the shape of the Milky Way based on star counts, indicating it has a disk-like structure.

Dark Matter

A nonluminous mass in the galaxy that can only be inferred from its gravitational effects; composition is currently unknown.

Supermassive Black Hole

A highly dense concentration of mass at the center of the Milky Way, specifically Sagittarius A*, estimated to be 4.6 million times the mass of the Sun.

Population I Stars

Younger stars found in the thin disk of the Milky Way that are rich in heavy elements.

Population II Stars

Older stars found in the halo and globular clusters of the Milky Way that have low abundances of heavy elements.

Differential Galactic Rotation

The concept that different parts of the Galaxy rotate at different rates, affecting stellar motion within the Galaxy.

Globular Clusters

Tightly packed groups of older stars found mainly in the halo of the Milky Way, often associated with Population II stars.

Sagittarius Dwarf Galaxy

A small galaxy currently being absorbed by the Milky Way, providing evidence of the Milky Way's past mergers.