Name ________________________________________________ Class Period _______
Test Date:_________________
Test Review for Astronomy Unit
1. Which telescope did scientists use to show that most galaxies have black holes in their
centers? _________The Hubble Telescope_________________________________________
2. What is a light year? ___ distance light travels in one year_____________________________
______________________________________________________________________________
3. Is a light year a measure of time or distance?
____distance___________________________________
4. Why do we use light years instead of km to measure the distance to stars? The distances to
stars are so large that km is not a very practical unit. Light years is easier to calculate.
5. What is a spectrograph? A spectrograph breaks the light from an object into colors and
photographs the resulting spectrum. It helps us to get information about stars.
6. A scientist was looking at a star that was 20 light years away. All of a sudden the star went
dark. When did the star stop glowing? ____20 years ago___________________________
7. What are the three ways in which we classify stars? __size_______,
_____temperature__________, and ______brightness________
8. What are the largest stars called? _____super-giants_____________________________
9. What size star is the Sun? _____medium-sized star_______________________________
10. Compare absolute magnitude and apparent magnitude. Absolute magnitude is the
brightness the star would have if it were a standard distance from Earth and apparent
magnitude is how bright a star appears to be when seen from Earth.
11. Number the star colors from coolest to hottest (1 means coldest and 4 means hottest):
__3__ yellow __2__ orange
___4__ blue-white
___1__ red
12. After a white dwarf stops glowing, it becomes a ___black dwarf________.
13. How bright a star looks from Earth depends upon its ___distance from Earth______ and
__its actual brightness________.
14. According to the Big Bang Theory, the universe is ___expanding________
Because galaxies are moving ____away_______ from each other.
15. What evidence is used to support the Big Bang Theory? The shifting of light from galaxies to
the red end of the spectrum, the cosmic background radiation left over from the explosion, and
the abundance of the light elements (H and He) found in the universe.
16. Our solar system is located in the Milky Way galaxy, which is what type of galaxy?
__spiral galaxy_____.
Draw a picture of what it looks like:
17. Which type of galaxy has little gas and dust? ____Elliptical________
18. Which type of galaxy has a lot of gas and dust? ____Spiral____________
19. At what point in the life cycle of a star, do we consider it “born?” when nuclear
fusion starts ____________________________________________
20. All stars begin as a mass of gas and dust called a _ nebula (gravity holds it together _.
21. When the most massive stars explode, they form _Black__ __holes__.
22. An explosion of a giant or super-giant star is called a __Supernova__, and the material left
behind can form a ____neutron_____ star.
23. The lifetime of a star depends upon the star’s ___mass___. The larger the star, the
___shorter____ the lifespan; the smaller the star, the ____longer________________________
the lifespan.
Use the diagram to the right
To answer questions 24-27.
24. I’m thinking of a star that is blue-white, very bright, and a Supergiant. Which star am I
thinking of? _______Rigel__________________
25. Name all the yellow stars that are also Main sequence stars: Procyon, Sun, Alpha Centuri A,
Tau Ceti
26. Compare the North Star (Polaris) and Betelgeuse in terms of temperature, brightness, and
size.
North Star is hotter, Betelguese is a little brighter, both stars are supergiants
27. What pattern do you see in temperature and brightness among main sequence stars?
As the temperature of the main sequence star increases, its brightness increases.
28. I have a telescope that detects wavelengths up to 1.41 x 10-9 Hz. What type of waves can
this telecope see?
______Ultraviolet_______________________________________________________________
29. I have another telescope that detects wavelengths only up to 3.2 x 10-7 Hz. What type of
wave can this telescope see?
________Visible______________________________________________________________