SAN FRANCISCO — American and Russian scientists announced on Monday that they had discovered a superheavy element, known as 118, albeit one that has only existed in three different atoms lasting a fraction of a second over months of experiments.
Scientists discovered the last naturally occurring element on the periodic table in 1925 but have since sought to create new heavier elements.
In the latest experiments, scientists at the Lawrence Livermore National Laboratory in California and the Joint Institute for Nuclear Research in Dubna, Russia, bombarded californium with calcium ions to create 118 — the heaviest ever created in such experiments.
"I think of this like any other journey to a new place. Why do you want to go to the moon? Why do you want to go to the top of Mount Everest?" Nancy Stoyer, a member of the Livermore team, said in explaining the significance of the discovery. "Finding it is something new, it is something interesting.
"Finding it experimentally helps the theorists understand what really works for their theory and gives us more things to look for."
Scientists said they found their first superheavy element 118 atom in 2002, then found another two atoms in 2005 in a second round of experiments in which they fired 10 to the power of 19 calcium ions at the californium.
In the end the atoms of element 118 — also known as ununoctium — lasted 0.9 milliseconds, researchers said.
An announcement in 2002 from a Bulgarian-born researcher and others at the Lawrence Berkeley National Laboratory in California that they had found element 118 was later shown to have been a fraud.
"We selected a completely different nuclear reaction, performed with completely different people in a different laboratory," Ken Moody, the Livermore team leader, told reporters. "Everything we do is checked and double checked.
"The data analysis is performed by both us and our Russian colleagues. We do everything that we can possibility do to both avoid the possibility of intentional fraud and of mistaken handling of the data."
The last new elements discovered, 113 and 115, were announced in 2004.
The Livermore-Dubna team says they are now looking to discover element 120, so high school and college science labs may still have to replace their periodic table posters again in the future.
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