Recent breakthroughs in timekeeping technology may redefine the second, a unit of measurement critical to modern life, including GPS and communication systems. In September 2024, researchers in the United States achieved a significant milestone by developing a nuclear clock based on thorium-229, which measures transitions occurring within an atom's nucleus.
Traditionally, the second has been defined since 1967 by the transitions of cesium-133 atoms, occurring 9,192,631,770 times per second. However, the newly developed nuclear clock promises a frequency approximately one million times greater than that of cesium. This leap in precision could enhance GPS accuracy and enable scientists to investigate extremely rapid processes with unprecedented detail.
The journey to this advancement involved overcoming substantial technological hurdles, particularly in creating frequency combs capable of measuring the rapid transitions in thorium's nucleus using ultraviolet light. This innovation not only paves the way for more accurate timekeeping but also holds potential implications for fundamental theories in physics, such as general relativity and quantum mechanics.
As the quest for precision continues, the era of the cesium second may soon come to a close, ushering in a new age of time measurement that could transform various scientific and technological fields.