Element Einsteinium, Es

Einsteinium as well as Fermium was discovered in the debris from the thermonuclear explosion in the Pacific Ocean in November 1952. Furthermore, this debris contains extremely heavy uranium and plutonium nucleus, such as ²²⁴Pu and ²⁴⁶Pu. Formation of such nucleus can only be performed if ²³⁸U traps several neutrons (from 6 to 17!) simultaneously. This allows to propose that together with heavy isotopes of uranium and plutonium some elements with atomic number higher than 98 can formed. This was proven by careful separation and studies of the debris from the thermonuclear explosion, especially those captured by coral in the vicinity of the explosion. New isotopes 253 and 255 of the new element Einsteinium were found.