Although the search for the element with atomic number 61 began in 1902, it was not until 1947 that scientists conclusively produced and characterized promethium, which is named for a character in Greek mythology. It is the only naturally radioactive rare earth element, and virtually all promethium in the earth’s crust has long ago decayed into other elements.Today, it is largely artificially created, and used in watches, pacemakers, and in scientific research