Some 238U atoms, however, could absorb two additional neutrons (for a total of 17), resulting in 255Es, as well as in the 255Fm isotope of another new element, fermium. The discovery of the new elements and the associated new data on multiple neutron capture were initially kept secret on the orders of the U.S. military until 1955 due to Cold War tensions and competition with Soviet Union in nuclear technologies. However, the rapid capture of so many neutrons would provide needed direct experimental confirmation of the so-called r-process multiple neutron absorption needed to explain the cosmic nucleosynthesis (production) of certain heavy chemical elements (heavier than nickel) in supernova explosions, before beta decay. Such a process is needed to explain the existence of many stable elements in the universe.