- 1. The discovery of Pluto, a distant celestial body in our solar system, took place on February 18, 1930, when astronomer Clyde Tombaugh, working at the Lowell Observatory in Arizona, identified it while conducting a systematic search for a ninth planet, then dubbed 'Planet X'. Tombaugh employed a technique known as 'comparative astrophotography', taking two photographs of the same region of the night sky within a few days and comparing them for moving objects. Upon verification, the object was named Pluto, after the Roman god of the underworld, fitting for a planet so far from the Sun. Over the decades, Pluto was considered the ninth planet in our solar system, captivating the imaginations of astronomers and the public alike. However, as telescopic technology advanced, particularly with the discovery of other trans-Neptunian objects similar in size and composition to Pluto - notably Eris in 2005 - the astronomical community began to reevaluate what constituted a planet. This culminated in the International Astronomical Union's definition of a planet in 2006, which excluded Pluto from the ranks of planets, reclassifying it as a 'dwarf planet'. This decision was met with significant public and academic debate, prompting discussions about the nature of planetary classification and the criteria used to determine what an actual planet is. Pluto's reclassification sparked a renewed interest in the outer reaches of our solar system and the myriad of bodies that inhabit it, leading to ongoing exploration and research, including NASA's New Horizons mission that flew by Pluto in 2015, providing unprecedented images and data, rekindling the affection and curiosity surrounding the former ninth planet.
Who discovered Pluto?
A) Carl Sagan
B) Percival Lowell
C) Albert Einstein
D) Clyde Tombaugh
- 2. In what year was Pluto discovered?
A) 1950
B) 1940
C) 1920
D) 1930
- 3. Which organization reclassified Pluto as a dwarf planet?
A) NASA
B) NASA's Planetary Society
C) International Astronomical Union
D) ESA
- 4. What year did Pluto lose its status as a planet?
A) 1995
B) 2000
C) 2006
D) 2010
- 5. What is Pluto's largest moon called?
A) Charon
B) Titan
C) Ganymede
D) Europa
- 6. Pluto orbits the Sun at an average distance of what?
A) 29.5 AU
B) 39.5 AU
C) 59.5 AU
D) 49.5 AU
- 7. Which spacecraft visited Pluto in 2015?
A) Pioneer 10
B) New Horizons
C) Curiosity
D) Voyager 2
- 8. On what date did New Horizons fly by Pluto?
A) August 12, 2015
B) July 14, 2015
C) June 14, 2015
D) July 4, 2015
- 9. What is the primary composition of Pluto's surface?
A) Carbon dioxide ice
B) Nitrogen ice
C) Water ice
D) Rock
- 10. What is the estimated diameter of Pluto?
A) 3,000 kilometers
B) 1,500 kilometers
C) 2,377 kilometers
D) 2,000 kilometers
- 11. Who proposed the existence of Planet X, which led to the search for Pluto?
A) Neil deGrasse Tyson
B) Carl Sagan
C) Percival Lowell
D) Clyde Tombaugh
- 12. Which object was discovered in the Kuiper Belt that contributed to Pluto's reclassification?
A) Haumea
B) Makemake
C) Sedna
D) Eris
- 13. Pluto's orbit is tilted at what angle compared to the ecliptic plane?
A) 17 degrees
B) 30 degrees
C) 25 degrees
D) 10 degrees
- 14. What did the New Horizons mission discover about Pluto's surface?
A) It is entirely smooth
B) It has diverse geological features
C) It is barren and lifeless
D) It has no geological activity
- 15. What is the time it takes Pluto to complete one orbit around the Sun?
A) 50 years
B) 248 years
C) 365 days
D) 84 years
- 16. What is the main reason Pluto was reclassified?
A) It is too small
B) It does not clear its orbit
C) It has no moons
D) It is too cold
- 17. Which of the following spacecraft visited Pluto prior to New Horizons?
A) Pioneer 10
B) Voyager 1
C) Voyager 2
D) None
- 18. How was Pluto's atmosphere discovered?
A) Through a direct landing
B) During a stellar occultation
C) With ground-based radar
D) By telescopic imaging
- 19. Before its reclassification, Pluto was referred to as what?
A) First dwarf planet
B) Tenth planet
C) Ninth planet
D) Second moon
- 20. Pluto's atmosphere primarily contains which gas?
A) Oxygen
B) Carbon dioxide
C) Methane
D) Nitrogen
- 21. What is the primary objective of the New Horizons mission?
A) Explore Pluto and the Kuiper Belt
B) Study Mars
C) Observe Jupiter's moons
D) Investigate asteroids
- 22. Which of the following is a region inhabited by Pluto and similar bodies?
A) Oort Cloud
B) Heliosphere
C) Kuiper Belt
D) Asteroid Belt
- 23. Before the discovery of Pluto, which planet was considered the outermost planet?
A) Mars
B) Neptune
C) Uranus
D) Saturn
- 24. Pluto has how many known moons?
A) Seven
B) Five
C) Two
D) Three
- 25. Which observatory was used to discover Pluto?
A) Palomar Observatory
B) Mount Wilson Observatory
C) Kitt Peak Observatory
D) Lowell Observatory
- 26. What did Pluto's discovery contribute to astronomy?
A) It proved planets were larger than stars
B) It established a fixed number of planets
C) It confirmed the existence of all planets
D) It expanded our understanding of the solar system
- 27. In what constellation was Pluto discovered?
A) Gemini
B) Ursa Major
C) Canis Major
D) Orion
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