[time-nuts] Why we can't calculate atomic energy levels and how we do it anyways

[Attila Kinali]

Moin,

A few years ago, in a discussion on atomic clocks, someone asked
why we have to measure energy levels of atoms and their related
frequencies instead of calculating the exact value and use
that instead.

I just found a decent video that explains the problem in simple
terms and how we get around it to get good approximations:
https://www.youtube.com/watch?v=55c9wkNmfn0
(The second half of the video are unrelated Q&A)

			Attila Kinali

-- 
The driving force behind research is the question: "Why?"
There are things we don't understand and things we always 
wonder about. And that's why we do research.
		-- Kobayashi Makoto