One other neat use of really accurate clocks: measure if the fundamental constants drift relative to each other. https://onlinelibrary.wiley.com/doi/full/10.10

One other neat use of really accurate clocks: measure if the fundamental constants drift relative to each other. https://onlinelibrary.wiley.com/doi/full/10.1002/andp.201800364 https://onlinelibrary.wiley.com/doi/full/10.1002/andp.201800...