1. A group of stars forming a pattern

2. A visible meteoroid

3. A planet that orbits a star outside our solar system

4. The emission of energy as electromagnetic waves

5. A state of matter in which atoms are stripped of their electrons

6. The collection of planets and other objects orbiting the Sun

7. The observation of stars and other celestial objects

8. The path followed by a celestial body around another

9. Relating to a galaxy

10. A hot, young star

11. A dying star in the late stage of its evolution

12. A cloud of gas and dust in outer space

13. A powerful and extremely bright star explosion

14. The natural satellite of Earth

15. The star at the center of our solar system