Unit 3 Vocab

1. A rotating disk of dust and gas that surrounds the core of a developing solar system
3. all existing matter and space considered as a whole
7. a broad band of light that can be seen in the night sky and that is caused by the light of a very large number of faint stars
8. unmanned device sent to explore space and gather scientific information
10. the amount or quantity of heaviness or mass
11. the path of an object around a particular point in space
14. the alternate rising and falling of the surface of the ocean that occurs
15. the distance light travels in one Earth year
16. an invisible force that pulls objects toward each other
20. a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction
21. the spectrum of frequencies of electromagnetic radiation emitted due to an atom or molecule transitioning from a high energy state to a lower energy state
23. shows the relationship between a star's temperature and its luminosity
24. two light nuclei merge to form a single heavier nucleus
25. the large rise and fall of the tide at or soon after the new or the full moon

2. the explosion of a star
4. an object that moves around a larger object
5. a place in space where gravity pulls so much that even light can not get out
6. a period of moderate tides when the sun and moon are at right angles to each other
9. The change in the way you hear a noisy object as it moves toward or away from you
12. how astronomers explain the way the universe began
13. the stellar core left behind after a dying star has exhausted its nuclear fuel
14. an instrument that allows people to see distant objects
17. an instrument that produces spectra from or by the use of electromagnetic waves
18. a measure of the amount of matter in a substance or an object
19. an enormous cloud of dust and gas occupying the space between stars and acting as a nursery for new stars
22. huge ball of hot glowing gases held together by its own gravity