Final answer:
The statement about the Soviet Union launching Sputnik 1 in 1957, which started the space race and influenced the U.S. to launch Explorer I soon after, is true.
Step-by-step explanation:
The statement provided describes the launch of Sputnik 1 as the event that started the space race. This is true. Sputnik 1 was the first artificial Earth satellite, launched by the Soviet Union on October 4, 1957.
It marked a significant milestone in space exploration and contributed to the expansion and intensification of the space race between the United States and the Soviet Union.
Following the launch of Sputnik, the United States accelerated its own space program, launching its first satellite, Explorer I, in January 1958.
The entry of these two superpowers into space exploration resulted in significant technological advancements and the establishment of agencies, such as NASA, for space research and travel.