> We have had to invent a way of compensating for the variable rate of spin such that "midday" is still the middle of the day and "midnight" is still the middle

> We have had to invent a way of compensating for the variable rate of spin such that "midday" is still the middle of the day and "midnight" is still the middle of the night. Just granularity of timezones causes 30min offset of civil 'midday' and 'midnight' to astronomical one (more with political borders of timezones instead of strict 15°). DST adds another 1h of offset. If we want adjustments so these concepts would not slowly drift away, we can just shift timezones once per few thousand years.