For years, atomic clocks
have been considered the most accurate devices
for tracking the slow march towards obsolescence, a subatomic particle vibrating a given number of times per second with relatively few issues. Now the reliability crown might be passed to the nuclear clock, which in addition to sounding gnarly, could prove to be less susceptible to errors from outside stimuli. It goes like this: although an atomic clock will measure a certain number of vibrations per second, external forces such as ambient electric and magnetic fields affect the electrons used in atomic clocks, causing mishaps. The particles used in nuclear clocks that are measured for vibrations -- and thus timekeeping -- can be excited with a relatively low-energy ultraviolet light, allowing for fewer variations from the aforementioned fields. To wit, Corey Campbell and colleagues at the Georgia Institute of Technology in Atlanta have devised a scheme that uses lasers to carefully control the spatial orientation of the electron orbits in atoms. A nuclear clock containing a thorium nucleus controlled in this way would drift by just one second in 200 billion years, the team claims. Before nuclear clocks become a reality, researchers must identify the precise frequency of light needed to excite thorium nuclei; but this is what grad students are for, right?
[Image credit: University of Colorado / Science Daily