Take a look around: Every single thing you see is made up of elements in the periodic table. Ever since scientists first cobbled together these catalogs of nature’s building blocks in the 19th century, they have wondered if there was any end to the elements and their variants, called isotopes. It’s a profound question at the heart of the physical universe.
Nowadays, we have 118 elements on the books, distinguished by the number of protons in their nuclei. About two dozen of these elements, however, do not occur in nature.
Over the years, physicists have conjured new, short-lived and typically supersized elements (as defined by their atomic number, or proton count)by smashing atomic nuclei together in particle accelerators. Hordes of interesting isotopes also have emerged from these colliders.
Each new record-setting “superheavy” element tacked on to the periodic table gives us insight into natural laws and their limits. Meanwhile, isotopes — variants of an element with different numbers of neutrons in their nuclei — can have distinct properties that make them scientifically and industrially valuable. For example, the most frequently used isotope for medical imaging is an isotope of technetium, the first element ever artificially synthesized in 1937. And many smoke detectors contain an isotope of americium, a man-made, radioactive superheavy element originally forged in 1944.
