Ukraine ousted Khrushchev and became the Soviet leader from 1964 to 1982. Many prominent Soviet sports players, scientists, and artists came from Ukraine. On 26 April 1986, a reactor in the Chernobyl Nuclear Power Plant exploded, resulting in the Chernobyl disaster, the worst nuclear reactor accident in history. This was the only accident to receive the highest possible rating of 7 by the International Nuclear Event Scale, indicating a "major accident", until the Fukushima Daiichi nuclear disaster in March 2011. At the time of the accident, 7 million people lived in the contaminated territories, including 2.2 million in Ukraine. After the
Peaceful nuclear explosion that was used to measure and then help model global circulations in the atmosphere by following the movements of fallout aerosols. After the Van Allen Belts surrounding Earth were published about in 1958, James Van Allen suggested that a nuclear detonation would be one way of probing the magnetic phenomenon, data obtained from the August 1958 Project Argus test shots, a high-altitude nuclear explosion investigation, were vital to the early understanding of Earth's magnetosphere. Soviet nuclear physicist and Nobel peace prize recipient Andrei Sakharov also proposed the idea that earthquakes could be mitigated and particle accelerators could be made by