1. Unit 1 The Universe Vocabulary Review

2. a large celestial body that is composed of gas and emits light star

3. a graph that shows the relationship between a star’s surface temperature and absolute magnitude H-R diagram

4. a gigantic explosion in which a massive star collapses and throws its outer layers into space supernova

5. a star that has collapsed under gravity to the point that the electrons and protons have smashed together to form neutrons neutron star

6. a small, hot, dim star that is the left over center of an old sun-like star white dwarf

7. space and all the matter and energy in it universe

8. the brightness of a star as seen from Earth apparent magnitude

9. a collection of stars, gas, and dust held together by gravity galaxy

10. location on the H-R diagram where most stars lie; it has a diagonal pattern from the lower right to the upper left main sequence

11. a measure of how bright a star would be if it were seen from a standard distance absolute magnitude

12. the distance light travels in a year; about 9.6 trillion km light-year

13. a large cloud of gas and dust in interstellar space; a region where a star is born nebula

14. the Sun and all the planets and bodies that travel around it solar system

15. the actual brightness of an object such as a star luminosity

16. a relatively large spherical body that orbits a star planet