Download stars and galaxies – study guide

CHAPTER 28 – STARS AND GALAXIES – STUDY GUIDE – ANSWER KEY
1. What is an asterism? A small grouping of stars in a larger constellation. Ex: the Big Dipper
2. Most stars are composed mainly of what two elements? hydrogen and helium.
3. If a star’s spectral lines are shifted towards the red end of the spectrum, then the star is moving
away from the Earth.
4. Objects moving closer to the Earth, shift the spectrum to the blue end.
5. The part of the electromagnetic spectrum that can be separated into colors of the rainbow is visible
light.
6. The unit most used by astronomers to express the distance to other galaxies is a light year.
7. All electromagnetic radiation travels and a speed of 300,000 km/sec.
8. Put the types of E.M.R. in order from longest wavelength to shortest wavelength
Long wavelength
Radio
Microwave
short wavelength
Infrared
Visible
Light
Ultraviolet
X Rays
Gamma
9. Stars A and B are the same size but Star A is hotter. Which one is brighter? Star A
10. Why does Polaris, the North Star, appear to be stationary as the Earth rotates? It lies directly
above the North Pole.
11. The color of the hottest stars is blue.
12. Any hot, bright sphere of plasma like the sun is called a star
13. The brightness of a star as we view it from Earth is the star’s apparent magnitude.
14. Galaxies are classified by their shape.
15. Name the three types of galaxies Spiral, Elliptical, and Irregular
16. What is the most accepted theory for the origin of the universe? The Big Bang Theory
17. Who came up with evidence for the Big Bang Theory? Edwin Hubble
18. What type of galaxy is the Milky Way galaxy? Spiral Galaxy
19. A galaxy is a group of 100’s of billions of stars.
20. The last phase (stage) for a small mass star is a white dwarf star
21. Hydrogen is the “fuel” of the sun.
22. By using a tool called a spectroscope astronomers can identify the elements in a star.
23. On an H-R Diagram, stars are classified by temperature and absolute magnitude.
24. What is the next stage of the sun? Red Giant
25. An example of a winter constellation is Orion.
26. White dwarf stars are hot, faint, Earth-sized stars.
27. A black hole is the densest object in the universe, and no light escapes.
28. The absolute magnitude is a measurement that compares the true brightness of stars.
29. What kind of spectrum comes from white light? Continuous
30. Some constellations can only be seen during certain seasons because the Earth revolves around
the sun.
31. A stellar nebula is composed of dust and gas.
32. The initial mass/size will determine the evolutionary course a star will take.
33. The sun is a main sequence star.
34. The explosion of a massive star at the end of its life is called a supernova.
35. The constellation that contains the “pointer stars” used to find Polaris is Ursa Major (Big Dipper)
36. The first stage in the life cycle of a star is called a (stellar) nebula.
37. Which type of galaxy has all its stars concentrated in the middle? Elliptical
38. Which type of galaxy is typically the faintest? Irregular
39. What does a light year measure? Distance
40. Which star will appear brighter in the night sky, a star with an apparent magnitude of 0 or a star
with an apparent magnitude of +1? Star with apparent magnitude of 0
41. Observing red shifts, most astronomers agree that the universe is expanding.
42. The further away a galaxy is from us the faster it is moving.
Use the diagram to answer the following questions
43.
Name the two brightest stars.
Rigel and Betelgeuse
44.
Which star is hotter, Vega or Capella?
Vega
45.
Which group of stars is the dimmest?
White dwarfs
46.
What group of stars does Arcturus belong to?
Red Giants
47.
At which position in the diagram would we find our solar system? B
48.
What type of galaxy is shown below? Spiral Galaxy
49-50. Label the constellations & the North Star in the diagram below.
(URSA MAJOR)
(URSA MINOR)