The document discusses different types of galaxies and astronomical terms. It defines an astronomical unit as Earth's distance from the sun and a light year as the distance light travels. It describes galaxies as groups of billions of stars that move through space together and lists spiral, barred spiral, elliptical, and irregular as types of galaxies.

1. ASTRONOMY
Study of heavenly bodies

2. Astronomical Unit – Earth’s distance
from the sun
LightYear – distance that light year
travels

3. Galaxy – group of
billion of stars that
moves through
spaces as a unit

5. SPIRAL GALAXY

7. BARRED SPIRAL GALAXY

9. ELLIPTICAL GALAXY

11. IRREGULAR GALAXY

54. Chromosphere