> Suppose that instead we had historically used sunrise as our reference. No need to suppose. That’s how many cultures have marked the day. That’s why Jewish s

> Suppose that instead we had historically used sunrise as our reference. No need to suppose. That’s how many cultures have marked the day. That’s why Jewish sabbath is sunset to sunset. However your plan does suffer one drawback—time zones would need to change with latitude too. And what about the polar regions?