Why was sputnik launched?

well, it's all called the Space Race. the united states and russia were racing against each other to who could go out in space and got to the moon first.

Sputnik helped identify the density of the upper atmosphere. It also helped understand radio-signal distribution in the ionosphere. It detected meteoroid strikes.
Sputniks purpose was to see how satellites could be put into space, and to monitor many things such as air density while in space. Sputnik was a spherical shaped craft with four antennas, and many measuring devices. Transmissions were sent to earth through beeping, which not only relayed information, but told Soviets more about how radio waves work in space. Another thing that made Sputnik's shape relevant to its use was its core. The main body of the craft was filled with Nitrogen; If Sputnik got hit by asteroids, astrologists would be able to tell and judge how much effect asteroids had on it. Sputnik was the first frontier in learning more about space and what it's like.