London, May 3 : A team of physicists has detected a few exceptionally massive atoms in a solution prepared from natural minerals, which they say could be element 122, the heaviest element found till now.
According to a report in New Scientist, the heaviest element known to occur in nature is uranium, which contains only 92 protons, putting it 30 places below the putative new element in the periodic table.
The new finding came about when Amnon Marinov of the Hebrew University of Jerusalem led a team that analysed a purified solution of thorium (element 90) by running it through a mass spectrometer, which can measure the mass of individual atoms.
The thorium should have an atomic mass close to 232 (including neutrons), but the team saw a handful of counts with a much greater mass - just over 292, which is heavier than any known atom.
Though Marinov considered the possibility that hydrocarbon molecules from oil used in the experimental apparatus might have caused the signal, the tests found no contamination.
"Every molecule that can be found in the lab has slightly lower mass," Marinov told New Scientist. "Instead, mass could fit element 122, in a variety, or isotope, containing 170 neutrons; or possibly element 124, in an isotope with 168 neutrons," he added.
Calculations show that both of these isotopes should be very unstable, undergoing some form of radioactive decay in a matter of nanoseconds.
So Marinov suggests that the nucleus could be in a particular kind of excited state - highly deformed and spinning, which he believes could last much longer.
If even this faint trace of the stuff remains after 4.5-billion years in Earth's rocks, it would have to have a half-life greater than 100 million years.
If a very stable superheavy isotope does exist, it is likely to contain more neutrons than the one claimed by Marinov's group, which has 170. An "island of stability" is thought to exist around isotopes with 184 neutrons, but none have yet been synthesised.