3rd Part

Galaxies: Islands of Stars

A galaxy is a huge collection of stars, stellar remnants, gas, dust, and dark matter all held together by gravity. Galaxies are the major building blocks of the universe. Our own solar system is located within the Milky Way Galaxy, a large spiral galaxy.

Galaxies come in different shapes and sizes:

Spiral Galaxies: These are the most common type, with a flat, rotating disc and spiral arms extending from a central bulge. Our Milky Way and the Andromeda Galaxy are examples.

Elliptical Galaxies: These are oval-shaped and typically contain older stars with very little gas or dust, so star formation is minimal.

Irregular Galaxies: These lack a clear structure and are often the result of galactic collisions or gravitational interactions.