Hello Everyone
Until now we have been discussing how the Halacha determines the beginning and endpoints for night and day and how it defines the intermediate periods of twilight and dawn. What we learned is that in the Halacha, as well as as in everyday life these terms of day, night, twilight and dawn are related to the presence and absence of sunlight as the days go through the usual 24 hour cycle by which we measure our days.
Today we will discuss how the Halacha relates to the extreme conditions at the polar regions of the earth. There, during winter and summer the sun does not rise and set relative to the horizon. Without sunrise and sunset how do we determine such fundamental times such as the time that Shabbat begins and ends?