Question

question 7 of 10

which scientific development in the early 2000s affected how americans viewed the universe outside of earth?

a. pluto was reclassified as a dwarf planet.
b. the cosmic microwave background was discovered.
c. black holes were first reached by spacecraft.
d. a supernova was identified and studied.

Explanation:

Analyze the historical timeline of each option

• Option A: Pluto was reclassified as a dwarf planet by the International Astronomical Union (IAU) in August 2006, which is in the early 2000s. This fundamentally changed how Americans and the global public viewed the solar system and the universe outside of Earth.
• Option B: The Cosmic Microwave Background (CMB) radiation was discovered in 1964 by Arno Penzias and Robert Wilson, which is in the mid-20th century.
• Option C: Spacecraft have never reached or entered a black hole.
• Option D: Supernovae have been observed and studied for centuries (e.g., Kepler's Supernova in 1604, and many modern observations throughout the 20th century), not uniquely originating as a defining early 2000s development.

Identify the correct match

• The reclassification of Pluto in 2006 is the only scientific development listed that occurred in the early 2000s and directly altered the public's understanding of planetary bodies in our universe.

Answer:

• A. Pluto was reclassified as a dwarf planet. (Correct answer)
• B. The Cosmic Microwave Background was discovered.
• C. Black holes were first reached by spacecraft.
• D. A supernova was identified and studied.