[seqfan] Re: More digits of ?

[Richard J. Mathar]

ada> Date: Mon, 23 Aug 2021 15:01:10 -0400
ada> From: Alonso Del Arte <alonso.delarte at gmail.com>
ada> To: Sequence Fanatics Discussion list <seqfan at list.seqfan.eu>
ada> Subject: [seqfan] More digits of ?
ada> ...
ada> Some landscaping companies use ? = 3.14, and twenty digits seems to be
ada> overkill for most scientific applications.

The number of "applicable" digits of Pi is given by the ratio
of the radius of the "known" universe (15 billion light years currently)
over the quantum scale, "Planck length" of 10^-35 m, which is about
1.4e61. So 62 digits suffice.
See e.g. https://en.wikipedia.org/wiki/Observable_universe
and https://doi.org/10.12942/lrr-2013-2 .