It seemed so odd that Americans would choose Sputnik to be so fearful of. It did nothing more than beep and orbit the earth. Why did it launch such a controversy and fear that it would lead to the Space Race/freeze the cold war further? Why Sputnik? Why not the Russian number stations, or Russian spy planes? Or, semi-related, why weren't Americans fearful of the omni-present Nazi U-boats off the East coast?
Sources would be great to look at in answers, although if some of you experienced Sputnik first hand please shed some light on the subject. Thanks!
Sputnik was the first artificial satellite. There were many reasons for countries to fear it.
It could have been used to spy on the them.
It could have been or carried a weapon.
It showed that Russia had beat us to that level of rocket tech. That means they had beat us to that level of of missile tech as the only difference between the two is ballistics trajectory and payload.
As to the other things, our planes were on par with Russian planes so we felt confident in our ability to defend ourselves in dog-fights. The Nazi's were already defeated at that point, and the number stations did bother many, but they had already moved into conspiracy theory territory by that point in time.
I would question the premise that Americans were afraid of Sputnik in a way that was incongruous with their general fear of the Soviet Union and nuclear war. The launch suggested that the Soviets had better rockets and better telemetry. Soviet espionage and conventional arms weren't as frightening as Sputnik was, because Sputnik demonstrated the Soviets' ability to put a (nuclear) payload anywhere they wanted it.
And since the Soviets got there first, it called into question our ability to effectively respond, which threatened MAD, which was assumed by many to be the only thing standing in the way of war.