Across
- 3. a collection of planets, moons, and other objects that orbit a sun
- 4. the distance light travels in one year
- 5. a ball of very hot gas that gives off electromagnetic radiation
- 6. the total amount of energy an object produces as light
- 7. the study of outer space, including the stars and planets
Down
- 1. a huge system of stars, dust, and gas held together by gravity
- 2. a group of stars that forms a pattern
- 8. the curved path that an object takes around a central body, like a planet, moon, or star, due to gravity