1. Astronomy 1 Review

2. 1. A star starts off as a cloud of gases and dust known as a
Nebula
2. Gravity causes the nebula to collapse and form a
Protostar

3. 3. Identify the process that produces light and heat in a star?
Fusion
4. Explain what occurs in this process.
Hydrogen combines to produce helium and light and heat.

4. 5. What is the universe made of?
matter and space
6. How does a star begin its life cycle?
As a nebula
7. What type of star is the sun known as?
Main sequence

5. 8. A small, hot star is known as a
White dwarf
9. A super giant may explode to form either a neutron star or a black hole. This explosion is called a
Supernova

6. 10. Identify the name of the galaxy that our solar system belongs to.
Milky Way
11. Which star is closest to Earth?
The sun

7. As temperature decreases, brightness (luminosity) decreases.
12. Use the HR Diagram to answer the following questions.
B. Is the surface temperature of white dwarf stars higher or lower than red super giants?
Higher
White dwarfs have a temp of about 20,000 K while super giants have a temperature of about 3500K.
C. Describe the general trend between temperature and brightness for main sequence stars.
A. Most of the stars on the HR Diagram are classified as which type of star?
Main sequence stars
As temperature decreases, brightness (luminosity) decreases.

8. C. What type of star has a high temperature and a low luminosity?
13. Use the HR Diagram to answer the following questions.
B. The Herztsprung-Russell diagram classifies stars by their surface temperature and luminosity. If a star has a low surface temperature and is considered very dim, what type of star would it probably be?
Main sequence
C. What type of star has a high temperature and a low luminosity?
A. What type of star has a low temperature but a high luminosity?
Red supergiants
Temp = 2500 K
Lum = 106
White dwarfs
Temp = 30,000K
Lum = 10-4

9. 14. Use the HR Diagram to answer the following questions.
A. What is the approximate surface temperature of the sun?
4800K
B. List the color of the stars from hottest to coldest:
Blue, white, yellow, red
C. Would the surface temperature of white dwarf stars be higher or lower than red giants?
BLUE WHITE YELLOW RED
Higher

10. B A D C 15. Label the diagram of the sun below. A. Corona
C . Chromosphere
B. Photosphere
D. Core

11. 16. Identify the part of the sun being described:
Outer layer
Corona
b. Carries out fusion (produces light & heat)
Core
c. Gives off a red glow
Chromosphere
d. gives off light
photosphere

12. 17. Explain the difference between sunspots and prominences.
Sunspots are dark, cooler areas of the sun. Prominences are streams of flaming gas.
18. Eruption of charged particles that can interfere with communication if it reaches the Earth.
Solar flare
19. How do we calculate the amount of energy produced by the sun?
E = mc2

13. 20. Which model of the solar system describes our solar system
20. Which model of the solar system describes our solar system? Explain why.
Heliocentric model
The sun is at the center of the solar system and the planets revolve around it.
21. What was the first model called, that was proven incorrect? How did it explain the solar system?
Geocentric model
It described the Earth being at the center of the solar system and the sun and the rest of the plants revolving around it.

14. 22

15. 23. Identify the planet being described:
a. Living things found on this planet
Earth
b. Tilted on its side
Uranus
c. Has the most rings around it
Saturn
d. Earth’s twin
Venus
e. Is reddish in color because of iron
Mars
f. Has an atmosphere that mostly consists of carbon dioxide and is very hot.

16. 24. What is Pluto classified as?
A dwarf planet
25. What is revolution?
The motion of one object around another object
26. Identify an object that carries out this process.
The planets revolve around the sun.
The moon revolves around the Earth.
Asteroids and comets revolve around the sun.
27. Identify the smallest planet. Is it an outer or inner planet?
Mercury – inner planet

17. 28

18. 29. Identify the largest planet. Is it an outer or inner planet?
Jupiter – outer planet
30. Which planet is surrounded by rings? What are these rings made of?
Saturn – rocks and ice
31. How is a comet different from an asteroid?
A comet is made of rock, dust and ice, while an asteroid is a large chunk or rock. Both orbit the sun.
32. Explain what a shooting star really is.
A meteor (rocky object that enters the atmosphere) that burns up
33. What is a light year?
Distance light travels in one year

19. 34. Explain why we cannot describe Earth as perfectly round.
Its an oblate sphere. Flattened at the poles and bulges out at the sides.
35. What is the shape of Earth’s orbit?
Its an ellipse (oval/flattened circle)

20. 36 37

21. 38. When is the Earth at aphelion?
July – when it’s closest to the sun
39. When is the Earth’s orbital velocity the greatest?
January – at perihelion – when Earth is closest to the sun
40. Describe Earth’s path if gravity did not exist between the sun and the earth.
It would travel in a straight line.

22. 41
The larger the mass, the greater the gravity.
Mercury, Mars, Pluto

23. 42. Explain the difference between rotation and revolution.
When an object rotates, it spins. When an object revolves, it moves around another object.
43. How long does it take the Earth to complete 1 rotation?
24 hours/1 day
44. In which direction does Earth rotate?
West to East

24. 45
days/1 year

25. 46

26. 47. Explain when solar noon occurs.
When sun is at its highest point in the sky.
48. How long dies it take the Earth to revolve around the sun?
days/1 year
49. Explain the time it takes a planet to revolve around the sun as the distance between the sun and a planet increases.
The farther away a planet is from the sun, the longer it takes to revolve around the sun.

27. 50

28. 51 52

29. 53 54

30. 55
Rotation of Earth’s on it’s axis.

31. 56

32. 57 58

33. 59 60

34. 61

35. 62

36. 63. The Earth’s orbit around the sun is represented in the diagram below.C
C. At which letter does Earth have the greatest orbital velocity? Why? B
A – its closer to the sun
A. Which letter represents the Earth in perihelion? A
D. At which letter is there less gravity between the Earth and the Sun? Why?
B. Which letter represents the Earth in aphelion?
B – its farther from the sun B

37. 63. The Earth’s orbit around the sun is represented in the diagram below.C B
F. How long does it take the Earth to travel from Point A, back to Point A?
E. How many degrees is the Earth tilted on its angle?
23.5
1 year/ days