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Mercury, Venus, Earth, and Mars --- Inner Planet Q&A

March 25, 2026
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1. Which planets are called inner planets?

Ans: Mercury, Venus, Earth, and Mars

2. Why are they called inner planets?

Ans: Because they are located closer to the Sun than the outer planets

3. What are inner planets also called?

Ans: Terrestrial planets

4. Why are inner planets called terrestrial planets?

Ans: Because they have rocky surfaces

5. Which planets are rocky planets?

Ans: Mercury, Venus, Earth, and Mars

6. Which planets lie before the asteroid belt?

Ans: The inner planets

7. Which is the smallest inner planet?

Ans: Mercury

8. Which is the largest inner planet?

Ans: Earth

9. How many inner planets are there?

Ans: Four

10. Do inner planets have solid surfaces?

Ans: Yes

11. Which is the closest planet to the Sun?

Ans: Mercury

12. Which is the smallest planet in the Solar System?

Ans: Mercury

13. Which inner planet has the shortest year?

Ans: Mercury

14. How many days does Mercury take to revolve around the Sun?

Ans: 88 days

15. Which planet has no atmosphere almost?

Ans: Mercury

16. Which planet has the greatest temperature difference between day and night?

Ans: Mercury

17. Does Mercury have any moon?

Ans: No

18. Which planet is heavily cratered like the Moon?

Ans: Mercury

19. Which inner planet rotates slowly but revolves quickly?

Ans: Mercury

20. Which inner planet is nearest to the Sun and also smallest?

Ans: Mercury

21. Which is the second planet from the Sun?

Ans: Venus

22. Which planet is known as Earth’s twin?

Ans: Venus

23. Which is the hottest planet in the Solar System?

Ans: Venus

24. Which planet is called the Morning Star?

Ans: Venus

25. Which planet is called the Evening Star?

Ans: Venus

26. Which inner planet rotates in the opposite direction?

Ans: Venus

27. Which planet has a day longer than its year?

Ans: Venus

28. Which planet has thick clouds of carbon dioxide?

Ans: Venus

29. Which planet has the strongest greenhouse effect?

Ans: Venus

30. Does Venus have any moon?

Ans: No

31. Which is the third planet from the Sun?

Ans: Earth

32. Which planet is known as the Blue Planet?

Ans: Earth

33. Which is the only known planet to support life?

Ans: Earth

34. Which planet has liquid water on its surface?

Ans: Earth

35. Which inner planet has one natural satellite?

Ans: Earth

36. What is Earth’s natural satellite?

Ans: Moon

37. Which inner planet has oxygen-rich atmosphere?

Ans: Earth

38. Which planet has the densest atmosphere among habitable planets?

Ans: Earth

39. Which inner planet has moderate temperature suitable for life?

Ans: Earth

40. Which inner planet is largest and densest?

Ans: Earth

41. Which is the fourth planet from the Sun?

Ans: Mars

42. Which planet is called the Red Planet?

Ans: Mars

43. Why is Mars called the Red Planet?

Ans: Due to iron oxide (rust) on its surface

44. Which inner planet has the largest volcano, Olympus Mons?

Ans: Mars

45. Which inner planet has two moons?

Ans: Mars

46. What are the two moons of Mars?

Ans: Phobos and Deimos

47. Which planet is considered most suitable for future human missions?

Ans: Mars

48. Which inner planet has polar ice caps?

Ans: Mars

49. Which inner planet has a thin carbon dioxide atmosphere?

Ans: Mars

50. Which inner planet is most studied for possibility of past life?

Ans: Mars

51. Which inner planet is nearest to the asteroid belt?

Ans: Mars

52. Which inner planet has the highest average density?

Ans: Earth

53. Which inner planet has the weakest gravity?

Ans: Mercury

54. Which inner planet has the thickest atmosphere?

Ans: Venus

55. Which inner planet has the thinnest atmosphere?

Ans: Mercury

56. Which inner planet has the highest mountain/volcano in the Solar System?

Ans: Mars

57. Which inner planet has the largest canyon, Valles Marineris?

Ans: Mars

58. Which inner planet has the strongest surface gravity?

Ans: Earth

59. Which inner planet has clouds mainly made of sulfuric acid?

Ans: Venus

60. Which inner planet has the shortest revolution period?

Ans: Mercury

61. Which inner planet has the longest revolution period?

Ans: Mars

62. Which inner planet takes about 687 Earth days to orbit the Sun?

Ans: Mars

63. Which inner planet takes about 225 Earth days to orbit the Sun?

Ans: Venus

64. Which inner planet takes about 365¼ days to orbit the Sun?

Ans: Earth

65. Which inner planet takes about 88 Earth days to orbit the Sun?

Ans: Mercury

66. Which inner planet is often visible just before sunrise or after sunset?

Ans: Venus

67. Which inner planet is called Earth’s sister planet because of similar size?

Ans: Venus

68. Which inner planet is famous for global dust storms?

Ans: Mars

69. Which inner planet has a large iron core compared to its size?

Ans: Mercury

70. Which inner planet has the most suitable environment for human life?

Ans: Earth

71. Which inner planet is closest in size to Earth?

Ans: Venus

72. Which inner planet is the brightest planet in the sky?

Ans: Venus

73. Which inner planet appears reddish because of oxidized iron?

Ans: Mars

74. Which inner planet has a bluish appearance when seen from space?

Ans: Earth

75. Which inner planet is often called the most Earth-like in terms of day length?

Ans: Mars

76. Which inner planet has the least number of missions among the four?

Ans: Mercury

77. Which mission made India famous in planetary exploration?

Ans: Mangalyaan

78. Which mission first landed successfully on Mars?

Ans: Viking 1

79. Which mission mapped Mercury in detail?

Ans: MESSENGER

80. What does MESSENGER stand for?

Ans: Mercury Surface, Space Environment, Geochemistry, and Ranging