Which achievement marked the start of the space age in 1957?

• A. Sputnik
• B. Apollo 11
• C. Moon landing
• D. Gemini 4

Answer: (A)

The main idea here is recognizing that the space age began with the first artificial satellite reaching orbit in 1957. When Sputnik 1 launched, it proved that human-made objects could be placed into orbit around Earth, signaling a new era in science, technology, and international competition in space. This milestone sparked rapid advances in rocketry, satellite communication, and space exploration, and it set the tone for subsequent programs and missions from both sides of the Cold War.

The later events listed—Apollo 11, the Moon landing, and Gemini 4—occurred after Sputnik and represent important milestones, but they do not mark the start of the space age. Apollo 11 achieved the first human Moon landing in 1969, and Gemini 4 featured an American spacewalk in 1965, both following the initial leap into space with Sputnik.