What event marked the true beginning of the space age?

The launch of Sputnik I on October 4, 1957, is recognized as the event that marked the true beginning of the space age. This was the first artificial satellite to be placed into orbit around the Earth, and it represented a significant technological achievement. The successful launch of Sputnik not only demonstrated the capabilities of the Soviet Union in space technology but also initiated the space race between the United States and the Soviet Union. Sputnik's launch had profound implications for science, technology, and military strategy, and it sparked increased interest and investment in space exploration and research. The event paved the way for subsequent missions and advancements in space exploration, including human spaceflight and deep space exploration.