“We have always known that, throughout the centuries, people have wondered where the edge of the physical world is. This limit changes all the time in accordance with our knowledge. Years ago, the elements beyond the first 100 on Mendeleev's Periodic Table were believed not to exist, that their half-life periods were so short that there was no sense in talking of them,” said Yury Oganessian, the scientist co-ordinating the experiment, told RIA-Novosti news agency.

“It is now clear, however, that this is not the case. These regions, earlier considered to be uninhabited, have ‘islands of stability’,” he added, stressing that these “islands” are inhabited by so-called super-heavy elements.

The scientists fired ions of Calcium-48 at the target of Berkeley 249 in the unique U-400 magnetic-resonance accelerator at the Joint Institute for Nuclear Research to obtain a new element. Six events of the birth of element 117 were recorded during the experiment.

Oganessian said that as yet only single atoms of the transuranium super-heavy elements can be synthesized.

“We have not attained the peak of stability yet. If these elements turn out to be long-lived, they will likely exist in nature, in cosmic rays striking Earth."

The scientist did not comment on the further practical value of the experiment. Plutonium is so far the only widely used transuranium element, as it is the key component in the production of nuclear weapons and as fuel for nuclear reactors.

“We have managed to expand the borders of the physical world,” the scientist said.

The new element, synthesis of which began in June 2009, is yet to receive an official name.