HALF LIFE. HOW LONG IT TAKES FOR HALF OF A RADIOACTIVE SAMPLE TO DECAY. MORE. NUCLEAR FISSION ... NUCLEAR FUSION. 2 SMALL ATOMS COMBINE INTO A LARGER NUCLEUS ...
Point sources radio surveys in 1950s. 1960 first optical counterpart found. 1963 Marten Schmidt identifies spectrum. High z implies high L (1013 L8) Background ...