What was the first artificial object to orbit the earth?

The first artificial object to orbit the Earth was Sputnik 1, launched by the Soviet Union on October 4, 1957. This spherical satellite transmitted radio signals back to Earth and marked the beginning of the space age, initiating the space race between the United States and the Soviet Union. Sputnik 1 remained in orbit until it re-entered the Earth's atmosphere in 1958.