I have asked many academics and received no answer, but this group always
seems to have answers, so here goes:

if there were no such thing as an hour, what is the optimum or ideal width
of a time zone?

Time zones are a compromise between a continuously changing standard time
that is represented by local solar time; and a global standard time with
everyone setting their clocks to GMT. Before time zones, Philadelphia set
their clocks 12 minutes different than did New York city. Both of those
systems have problems.

In the late 19th century, a compromise solution was proposed: time ZONES,
with a constant standard time within each zone, and a big change at the
zone boundary. This concentrated all the problems at the boundaries,
places like White City. If time zones were wider, there would be fewer
boundaries around the globe, fewer problem places, but within zones
standard time would get too far from solar time. Narrower zones allow
closer correspondence between solar and standard time, but more of those
troublesome time zone boundaries.

We divide the day into 12 hours, and the night likewise into 12 hours,
because the Romans like the dozen, 12 has so many common factors. And the
Earth rotates 15 degrees per hour, so that's why the average time zone is
15 degrees of longitude wide. But what if we had no hour, just 1440
minutes per day. It would be amazing luck if the idea time zone really if
60 minutes, or 15 degrees wide. So, a puzzle: Without a unit called an
hour (= 60 minutes), what would be the ideal width of a time zone?

David