New atomic clock loses only one second every 300B years
What’s the most precise clock I can buy, as an overpaid computer programmer?I suppose anything that shows a human time representation is out of the question.  It wouldn’t be able to incorporate legal changes to time such as let’s insert a leap second! or days are now divided into 32 hourlets!.I would settle for an output that shows elapsed seconds from an agreed upon datum.  I guess having a human readable time would be fine but the science part is more interesting.With a clock of such precision, how could I synchronise it?  Or rather: is there something better than NTP that Serious Clock Owners(tm) use?Perhaps what I want is a clock with reasonable-ish accuracy but incredible longevity.   Having a long running independent mechanical source
of time is appealing, and kind of orthogonal to having an ultra accurate but electrical one.