This artist’s impression shows the decay of a lutetium-149 nucleus into a ytterbium-148 nucleus and a proton
© Getty / University of Jyväskylä
Physicists in Finland have created a pumpkin-shaped atomic nucleus that throws off protons in a rare kind of radioactive decay. Lutetium-149 has the shortest half-life of any of a group of radioactive elements called proton emitters. It loses half its radioactivity in a mere 450 nanoseconds. Lutetium is a rare-earth element that occurs as a silvery metal with 71 protons and 71 neutrons in its nucleus. It usually occurs alongside the metallic element ytterbium in Earth’s crust.