Final answer:
Sputnik 1 was launched by the Soviet Union on October 4, 1957, signaling the start of the space race between the U.S. and the Soviet Union.
Step-by-step explanation:
The Soviet Union launched Sputnik 1, the first satellite, into space on October 4, 1957. This event marked the commencement of the space race, a period of intense scientific competition in space exploration between the United States and the Soviet Union. The launch of Sputnik 1 using an intercontinental ballistic missile (ICBM) launch vehicle not only served as a technological milestone but also demonstrated the Soviet Union's capability in space technology, which prompted the United States to accelerate its own space program.