Sputnik I became the first human-made object to be launched into orbit. It became the first artificial satellite to reach the orbit of the earth. Sputnik was designed like a ball with a size of 58 cm and launched by the Soviet Union. The Sputnik I was a technological success with its size, caught the world attention, especially Americans who were astonished by the achievement of the Soviet Union being a communist country.
It saw the end of the New Deal coalition. It saw the first important third-party candidacy. It saw the Republican Party become dominated by eastern moderates.
Because an infantry invasion of Japan, would have resulted in <em>Far</em> more casualties for both the americans and the japanese. Than the dropping of an atomic bomb.