The first human-made satellite to orbit the Earth is Sputnik 1. Launched by the Soviet Union on October 4, 1957, Sputnik 1 marked the beginning of the space age and initiated the space race. The satellite was approximately 58 centimeters in diameter and transmitted radio signals that could be received on Earth. Its launch had significant geopolitical implications, showcasing Soviet technological capabilities and prompting other nations, notably the United States, to accelerate their own space programs. Sputnik 1 remained in orbit for about three months before re-entering the Earth's atmosphere, but its legacy continues to influence space exploration today.