Which one of the following is correct regarding Sputnik-1?

Which one of the following is correct regarding Sputnik-1?

اسپوٹنک-1 کے بارے میں مندرجہ ذیل میں سے کون سا صحیح ہے؟
Explanation

Sputnik-1, launched by the Soviet Union in 1957, was the first artificial satellite to orbit the Earth.

It marked the beginning of the space age and the start of space exploration.