From: Georgi Guninski <guninski@guninski.com>
   >This bugs me.
   >Since 2009 it is known that the value of the dimensionless constant Pi
   >changes over time:  [1]https://arxiv.org/abs/0903.5321 [1]
   That's a FUNNY article!!!
   Seriously, however, there are indeed examples of fundamental physical
   "constants" which may vary over
   time. [2]http://io9.gizmodo.com/5642233/ask-a-physicist-is-the-fine-str
   ucture-constant-really-constant
   One minor motivation to develop really precise clocks, accurate to 1
   part in 10**18 (Ytterbium lattice clocks, for one example
   [3]https://en.wikipedia.org/wiki/Atomic_clock   ) is that it is
   possible that two different such clocks (each using a different type of
   atom), a few meters apart on a desktop, could show a variation in rate
   over a reasonable period of time, say a month or a year.
   [4]× (BUTTON) (BUTTON)
   Put more simply, suppose you could compare the frequency of two such
   clocks, with different types of atoms, and express that result to a
   precision of one part in 10**18.  A month or a year later, you do the
   same comparison, you might discover that the ratio of frequencies are
   different by a few parts in 10**18, or perhaps much larger.
   This would be a laboratory verification of a recent astronomical
   observation, a one-part-in-100,000 change over a period of 6 billion
   years:    [5]http://www.physicscentral.com/explore/action/constant.cfm
       If that rate of change were constant, it would be one part in 600
   trillion per year.  If an equivalent laboratory variation rate could be
    compared to a precision of 10**18, that would be 1600 units per year,
   or 133 per month, or perhaps 4 per day.  [6]×
   (BUTTON) (BUTTON)
   [7]× (BUTTON) (BUTTON)
              Jim Bell

References

   1. https://arxiv.org/abs/0903.5321
   2. http://io9.gizmodo.com/5642233/ask-a-physicist-is-the-fine-structure-constant-really-constant
   3. https://en.wikipedia.org/wiki/Atomic_clock
   4. file:///var/lib/mailman/archives/private/cypherpunks/attachments/20170401/ecb47b76/attachment-tmp.html
   5. http://www.physicscentral.com/explore/action/constant.cfm
   6. file:///var/lib/mailman/archives/private/cypherpunks/attachments/20170401/ecb47b76/attachment-tmp.html
   7. file:///var/lib/mailman/archives/private/cypherpunks/attachments/20170401/ecb47b76/attachment-tmp.html