Astronomy Review Name: _________________________
1. Name the planets in order from the sun, going out.
Mercury, Venus, Earth, Mars,
Date: ____________________
Jupiter, Saturn, Uranus, Neptune
2. What is the meaning of AU? Astronomical Unit; defined as the distance from the sun to earth.
3. Which planet is smallest? Mercury______ Largest: Jupiter________
4. Which planet was redefined as a dwarf planet? Pluto______
5. What factor most affects a planet’s surface temperature?
Distance from the sun_______
6. What does gas giant mean? The planet is composed primarily of gas with a very small rocky core.
7. Name the rocky planets. Mercury, Venus, Earth, Mars_______________
8. According to science, how long ago was the earth formed? 4.5 billion years____________
9. What is planetary rotation? A body turning about its axis_____________________________.
10. What does revolution mean? A body orbiting another body, e.g. earth around the sun____.
11. Does the moon revolve or rotate around the earth? Revolve_______________________
12. What characteristic of the earth creates the seasons? Axial tilt________________________
13. What is the celestial sphere? An imaginary sphere in the sky that extends from all points on
Earth’s surface.
14. What is declination? The displacement of an object in the sky from the celestial equator________
15. What is fusion? A nuclear reaction in which hydrogen atoms are combined (fused) into helium_
16. What is right ascension? The eastward displacement of an object from the vernal equinox
17. Where is the Kuiper Belt located? Beyond the orbits of the 8 planets; Pluto is a Kuiper Belt object, as are many comets.
18. Where is the asteroid belt located? Between the orbits of Mars and Jupiter.
19. Where is the Oort Cloud located? Far beyond the Kuiper Belt near the outer limit of the Solar System .
20. Which planet has the most prominent ring system? Saturn________________________
21. Who first observed the first 4 four moons (Io, Europa, Ganymede, Calisto) of Jupiter with a telescope? Galileo; these moons are called the “Galilean moons.”___________________
22. The ancient Greeks believed the universe was GEO centric. (GEO = Earth)
23. What is the Heliopause? Considered to be the outer boundary of the Solar System.__________

24. Approx. how many stars are visible to the unaided eye on a dark night? 6,000
– 9,000_____
25. Relative to each other the distances to stars in constellations are usually Very different.______
26. Name 4 civilizations that contributed to our understanding of Astronomy.
Cambodians, Egyptians
Mayans, Indians,
27. Name 3 things that people in the past have used to the stars for: Navigation, calendars, religious mythology
28. What is a solar eclipse?
The sun’s light to the earth is blocked by the moon.____________
29. What is a lunar eclipse?
The sun’s light to the moon is blocked by the earth.____________
30. Why does the moon have phases? Because we see the moon as the sun illuminates it from different angles during the month.
31. What is a blue moon? The second full moon within a calendar month.______________
32. What is Astrology? The belief that the objects in the sky can foretell the future, people’s fortunes, etc. Astrology is NOT a branch of science.
33. Rank these in order from fastest to slowest as they travel across the night sky.
(1) Satellites; (3) Planets; (4) Stars; (2) the Moon
34. In terms of stars, explain the meaning of E = mc 2 . When hydrogen is fused into helium, some of the mass within the atoms is lost. This mass is transformed into huge amounts of energy, which the star emits as light, heat and other radiation.
35. What is meant by axial tilt? The angle at which the axis of a body lies in comparison to its orbital plane.
36. Explain Habitable Zone.
A planet’s distance from a star wherein liquid water can exist on its surface, presumably making the evolution of life more probable.
37. Which planet is experiencing an extreme greenhouse effect (much worse than earth)? Venus___
38. Is Saturn located more than, or less than one AU from the sun? More than; approx. 9.5 AU.___
39. In what season does Christmas occur in Australia? Summer; December occurs in the Southern
Hemisphere when axial tilt brings it closer to the sun.
40. An earth year is more than ___________ 365.000 days. a. Exactly equal to b. More than c. Less than
(This is why we have leap years.)