Question

1. change in frequency when source/observer is moving
2. apparent shift in position of object when viewed from different locations
3. very large and bright star has a hot core, used up most of its hydrogen
4. group of stars organized into a recognizable pattern
5. distance light travels in a year
6. object so massive that light cant even escape its gravity
7. body composed of gas that emits light
8. very luminous object that produces energy at a high rate

Explanation:

1. Doppler - effect in physics.
2. Parallax in astronomy (a branch of physics).
3. Red - giant star description in astronomy.
4. Constellation in astronomy.
5. Light - year definition in astronomy.
6. Black - hole description in astronomy.
7. Star description in astronomy.
8. Quasar or highly luminous star description in astronomy.

Answer:

1. Doppler effect
2. Parallax
3. Red - giant
4. Constellation
5. Light - year
6. Black - hole
7. Star
8. Quasar (or highly luminous star)