* Astronomy

The Limited Test Ban Treaty (LTBT) is a treaty prohibiting all test detonations of nuclear weapons except underground. It was developed both to slow the arms race (nuclear testing was, at the time, necessary for continued nuclear weapon advancements), and to stop the excessive release of nuclear fallout into the planet's atmosphere. It was signed and ratified by the governments of the Soviet Union and United Kingdom and the United States in 1963. 
The treaty went into effect on October 10, 1963.
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