1. Venus and Earth are much alike in terms of

2. SIZE

3. The model in which Earth is at the center of the system of planets is called the

4. Geocentric
System/Model

5. The heliocentric system gained support when Galileo observed that

6. Venus goes through phases similar to those of Earth's moon.

7. Which type of galaxy is the Milky Way?

8. spiral

9. The two factors that combine to keep the planets in orbit are

10. Gravity and Inertia

11. What do all of the inner planets have in common?

12. They are terrestrial planets.

13. Earth is unique amongst the planets because of

14. its oceans

15. How are the gas giants similar?

16. They are much larger than Earth and do not have solid surfaces.

17. Uranus is different from most other planets because it

18. rotates on its side.

19. The asteroid belt is located

20. between Mars and Jupiter (also can say between the inner planets and the outer planets)

21. Meteoroids usually come from

22. comets or asteroids.

23. When a meteoroid enters Earth's atmosphere, it produces a streak of light called a

24. meteor.

25. The ancient idea that Earth was at the center of the solar system was supported by

26. Ptolemy.

27. A meteoroid that hits Earth's surface is called a

28. meteorite

29. What will happen to a planet if it loses its inertia?

30. The planet will crash into the sun.

31. Where is the solar system located in the Milky Way galaxy

32. on one of the spiral arms

33. Which planet appears to be the smallest in size?

34. Mercury

35. Which planet rotates on its side?

36. Uranus

37. The region between Mars and Jupiter contain?

38. asteroids

39. The diagram below illustrates the revolution of imaginary planets around Star X. The period of revolution for planets A, B and C are 75, 200 and 300 Earth days respectively. Use the diagram to answer the question: Justify which planet travels around Star X in the shortest amount of time. (Write in complete sentences).