Space & Planets Quiz: questions and answers
Study every question with its correct answer and explanation.
1. Which is the largest planet in our solar system?
- A. Saturn
- B. Jupiter
- C. Neptune
- D. Earth
Answer: Jupiter
Jupiter is so big that more than 1,300 Earths could fit inside it.
2. Which planet is closest to the Sun?
- A. Mercury
- B. Venus
- C. Mars
- D. Earth
Answer: Mercury
Mercury is the closest planet to the Sun, and a year there lasts only about 88 Earth days.
3. Which planet is known as the 'Red Planet'?
- A. Jupiter
- B. Venus
- C. Mars
- D. Mercury
Answer: Mars
Mars looks red because its surface is covered in iron oxide — essentially rust.
4. Which is the hottest planet in our solar system?
- A. Mercury
- B. Mars
- C. Jupiter
- D. Venus
Answer: Venus
Venus is hotter than Mercury even though it is farther from the Sun, because its thick carbon dioxide atmosphere traps heat.
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5. Who was the first person to walk on the Moon?
- A. Yuri Gagarin
- B. Buzz Aldrin
- C. Neil Armstrong
- D. John Glenn
Answer: Neil Armstrong
Neil Armstrong became the first person to walk on the Moon in July 1969 during the Apollo 11 mission, followed by Buzz Aldrin.
6. Who was the first human to travel into space?
- A. Yuri Gagarin
- B. Neil Armstrong
- C. Alan Shepard
- D. Valentina Tereshkova
Answer: Yuri Gagarin
Soviet cosmonaut Yuri Gagarin orbited Earth aboard Vostok 1 on 12 April 1961.
7. Roughly how long does sunlight take to reach Earth?
- A. 8 seconds
- B. 8 minutes
- C. 8 hours
- D. 8 days
Answer: 8 minutes
Sunlight covers about 150 million km in roughly 8 minutes 20 seconds, so we always see the Sun as it was a few minutes ago.
8. Which planet is less dense than water — so it would float in a big enough bathtub?
- A. Earth
- B. Uranus
- C. Neptune
- D. Saturn
Answer: Saturn
Saturn's average density is only about 0.7 times that of water, making it the least dense planet in the solar system.
9. How many planets are there in our solar system?
- A. 7
- B. 8
- C. 9
- D. 10
Answer: 8
There are eight planets; the International Astronomical Union reclassified Pluto as a dwarf planet in 2006.
10. Which planet spins on its side, with its axis tilted by about 98 degrees?
- A. Neptune
- B. Saturn
- C. Uranus
- D. Mars
Answer: Uranus
Uranus is tilted so far that it rolls around the Sun on its side, giving each pole about 42 years of continuous sunlight.