U-238

Enrico Fermi had come to Chicago in the spring of 1942 to lead the effort to construct the world’s first atomic pile, of blocks of graphite and uranium metal. The Manhattan Project scientists under Fermi’s leadership worked for months in secret beneath the stadium stands at the University of Chicago, built their pile in November, and, on December 2, achieved a faint but hugely significant self-sustained nuclear reaction with it.

The Supreme Court ruled on December 21 to validate that new American tradition, the Las Vegas divorce, forcing the other states to honor these quickie agreements as binding.