Fritz Zwicky (February 14, 1898 – February 8, 1974) was a Swiss astronomer. He worked most of his life at the California Institute of Technology in the United States of America, where he made many important contributions in theoretical and observational astronomy.
In 1934 he and Baade coined the term "supernova" and hypothesized that they were the transition of normal stars into neutron stars, as well as the origin of cosmic rays. It was a prescient insight that had tremendous impact in determining the size and age of the universe in subsequent decades.
While examining the Coma galaxy cluster in 1933, Zwicky was the first to use the virial theorem to infer the existence of unseen matter, which he referred to as dunkle Materie 'dark matter'.
1.) "To base the unexplainabilty and the immense wonder of nature onto an other miracle (God) is unnecessary and not acceptable for any serious thinker." - Fritz Zwicky Diary entry, 1971., NNDB.com.  NNBD is not a reliable source for Fritz Zwicky and ignored directives to Fritz Zwicky's actual beliefs where he gifted and dedicated the Holy Bible, King James Version, to his youngest daughter, Barbarina. The false allegation of Fritz Zwicky's alleged Atheism is only found on NNBD by taking words out of context.