Which satellite was the first man-made object to orbit the Earth, marking the beginning of the space age?

Sputnik 1

Launched on October 4, 1957, by the Soviet Union, Sputnik 1 ushered in a new era in human history, marking the beginning of the space age. This first artificial satellite, weighing about 83 kg and about the size of a beach ball, emitted radio signals that could be received on Earth, proving that orbiting the Earth was achievable. The success of Sputnik triggered the space race, prompting the United States to accelerate its own space program and ultimately leading to major advancements such as the Apollo missions and interplanetary exploration.