The United States successfully developed the atomic bomb in 1945, and he immediately used it on Japan. These two loud noises of the United States made the world realize his strength, and at the same time made the Soviet Union realize that if it did not want to be suppressed by the United States, it must develop an atomic bomb as soon as possible.
The Atomic Bomb Advantage of the United States lasted only five years against the Soviet Union, and the Soviet Union's development process began only after the end of World War II, so why was he able to go so fast?
In fact, the Soviet Union was also exposed to the atomic bomb very early, but it was only collecting relevant intelligence, and did not go to war.2 It wasn't until the United States used atomic bombs that the Soviet Union realized the power of atomic bombs.
Although there was relevant information, Stalin found that there was no talent to use. The Soviet Union did not have any protection mechanism for high-end talents at that time, and even expelled them in large numbers. But Stalin was not flustered by this, claiming that excellent people worked for us for ideals.
Those who had been persecuted were revived by Stalin, and even if they could not be bribed with money, ideals and fame and fortune always impressed them. Coupled with the intelligence the Soviets received from the Manhattan Project, the atomic bomb was soon developed.