Astr 2100 Descriptive Astronomy
Samples Questions for Test 2


  1. Which planet has the highest orbital speed?
  2. Why did Copernicus still use epicycles in his heliocentric model of the Solar System?
  3. What provided the definitive proof that the heliocentric model of the Solar System had to be the correct one?
  4. Name the four Galilean moons of Jupiter.
  5. If we were to suddenly discover a new minor planet which is 50 AU from the Sun, how long would it take for this planet to orbit the Sun?
  6. What is Kepler's 1st Law?
  7. Why do the planets sometimes appear to move backwards across the sky?
  8. If your weight is 160 lbs on the surface of the Earth, what would it be if you are 12,000 miles above the Earth's surface? (Take the radius of the Earth to be 4,000 miles).
  9. What name is given to the shape of the orbit of a planet?
  10. What was Tycho Brahe's main contribution to the field of astronomy?
  11. Are you truly weightless in the Space Shuttle?
  12. Why do we think that there are planets around other star's?
  13. We have evidence of at least three planets orbiting around a single distant star. They have different sizes, different masses, and are different distances from the star itself. Which one has the longest year?
  14. Give 2 main observations that Galileo made? (There are actually more than 1.)
  15. If you lived on Jupiter, which planets could you see in the eastern sky at sunset?
  16. Is the Moon falling?
  17. How far would you have to be from the Sun to have a year exactly equal to 100 Earth years?
  18. A planet goes around a distance star. If the planet is 6 AU from its star, and makes one orbit in 12 Earth years, what is the mass of the star (in solar masses)?
  19. The planets Bert and Ernie orbit the same star. Bert's orbit defines the "Bertian year". If Ernie is 8 times further from the star than is Bert, how many Bertian years does it take for Ernie to make one orbit.
  20. According to Kepler, the planets move around the Sun in what shape of an orbit?
  21. What is an epicycle?
  22. You are the passenger in a car when it stops suddenly. You hit your head on the dashboard. What force pushes you forward into the dashboard?
  23. How do you determine the mass of a planet?
  24. How do you determine the mass of the Sun?
  25. How do you determine the mass of the Moon?
  26. What is meant by the term 'weight'?
  27. If we were to suddenly turn off the gravitational force provided by the Sun, what would happen to the Earth?
  28. Where would you expect to find
    1. Olympus Mons
    2. The Great Red Spot
    3. Valles Marineris
    4. Shepherd moons
    5. Phobos and Deimos
    6. Most of the asteroids
    7. Titan
  29. List the features which distinguish the terrestrial planets from the Jovian planets
  30. When was Saturn discovered, and by whom?
  31. When was Uranus discovered, and by whom?
  32. On the Earth your weight is 125 lbs. What would be your weight on a planet with 6 times the mass and 9 times the radius (both compared to the Earth.)
  33. Two moons orbit the same planet. Moon 1 is 6 x 108 m from the center of the planet, and moon 2 is 4 x 108 m from the center. If moon 1 orbits the planet in 36 days, how long does it take moon 2 to orbit once?
  34. A planet takes 8 years to orbit of star whose mass is ½ the mass of the Sun. What is the radius of the planet's orbit?
  35. What were the major contributions of
    1. Copernicus
    2. Brahe
    3. Aristarchus

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