science

Jewish law in the polar regions

Jewish law in the polar regions is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Jewish law in the polar regions rather than just read about it. In short: The observance of Jewish law (halakhah) in the polar regions of Earth presents unique problems. Many mitzvot, such as Jewish prayer and Shabbat, rely on the consistent cycle of day and night in 24-hour periods that are commonplace in most of the world.

Key takeaways

Jewish law in the polar regions belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Jewish law in the polar regions to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Jewish law in the polar regions from memory before moving on to harder problems.

Reference excerpt

The observance of Jewish law (halakhah) in the polar regions of Earth presents unique problems. Many mitzvot, such as Jewish prayer and Shabbat, rely on the consistent cycle of day and night in 24-hour periods that are commonplace in most of the world. However, north of the Arctic Circle (and south of the Antarctic Circle), a single period of daylight can last for a month or more during the summer, and the night lasts for a similar length of time in the winter. For religious Jews who live in or visit these regions, the question is how to reconcile the observed length of days in the polar regions with common practice elsewhere in the world. Should a "day" be defined solely based on sunrise and sunset, even if these events do not occur for long stretches of time, or should the definition of a polar "day" be consistent with the length of a day in the rest of the world? The problem was first identified in the 18th century when Jewish émigrés began to move in greater numbers to the northern parts of Scandinavia. A number of different opinions on the question have been presented in responsa and are reviewed in a 2005 essay by Rabbi J. David Bleich, and in a 2007 article by Rabbi Dovid Heber.

Scope of the problem The definition of a "day" in polar regions affects mitzvot that must be performed during the day, or at a particular time of day. It also affects the passage of time in the Jewish calendar for the purpose of observing Shabbat and other Jewish holidays.

Mitzvot performed during the day Many ritual mitzvot may be performed at any time during the day but not at night, or vice versa. In addition, a lender is required to return clothing used as collateral to a poor borrower if he needs it to sleep at night, and an employer must pay a day laborer his wages on the same day that the work is done.

Time of day The most familiar mitzvah that depends on the time of day is Jewish prayer. The morning Shema must be read between dawn and three variable hours after sunrise. (A "variable hour" is one-twelfth of the time between sunrise and sunset, or according to another opinion between dawn and the appearance of stars at twilight. Variable hours are longer than 60 minutes in the summer, and shorter than 60 minutes in the winter.) The prayers of Shacharit, Mussaf and Minchah are also limited to certain hours of the day. The evening Shema and Ma'ariv, though acceptable at any time of the night, should preferably be done in the first half of the night. It is possible that during very long days of the polar summer, evening prayers are not recited, and during very long nights of the polar winter, daytime prayers are not recited.

Days of the week The passage of days from one to the next most prominently drives the observance of Shabbat on every seventh day. During the polar summer, hundreds of hours can pass without sunset, and it is possible that this entire period is just one day of a week. However, since Shabbat is observed on the same day throughout the world (allowing for differences in time zones), it stands to reason that Shabbat should be observed simultaneously even in polar regions.

Pre-modern background The Bible, Talmud, and individual pre-modern Jewish writers do not address this issue, because Jews of this period did not visit the polar regions and were unaware of its distinctive nature. However, the section in Talmud regarding the "desert wanderer" has been used by modern authorities to analyze this issue. The Talmud contains the following discourse:

Rav Huna says, if a man is wandering in the desert and he does not know when is the Sabbath, he should count six days [as weekdays] and keep one day as the Sabbath. Hiyya bar Rav says he should keep one day as Sabbath, then count six days [as weekdays]. ... Rava says, on each day he may do whatever he needs in order to survive, except for his Sabbath. But should he die on the Sabbath? He could prepare extra food the day before his Sabbath, but that might be the real Sabbath. So every day he may do whatever he needs in order to survive, even on the Sabbath. How is the Sabbath recognizable to him? By kiddush and havdalah [which he performs on his Sabbath but not on other days]. Rava says, if he knows which day he departed on the journey, he may do work on the same day of the week [i.e. 7 or 14 days after he departed, because he certainly would not have departed on a Sabbath]. The law is in accordance with the first opinion, that a confused desert wanderer keeps six "weekdays" followed by one "Shabbat", but he may not perform activities forbidden on Shabbat on any day except to aid his own survival. The law is based on a principle that a person who is unaware of reality should create his own Sabbath while acting out of concern that the real Sabbath may be on a different day.

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Jewish law in the polar regions

Start with the simplest possible case. Write down what Jewish law in the polar regions claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Jewish law in the polar regions before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Jewish law in the polar regions ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Jewish law in the polar regions

In research: Jewish law in the polar regions appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Jewish law in the polar regions in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Jewish law in the polar regions is common in secondary-school and first-year university syllabi. It links to neighbouring topics Jewish law and rituals, Polar regions of the Earth, Time in religion, so understanding it makes those chapters shorter.
In everyday life: Look for Jewish law in the polar regions outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Jewish law in the polar regions in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Jewish law in the polar regions means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Jewish law in the polar regions out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Jewish law in the polar regions in simple terms?

Why does Jewish law in the polar regions matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Jewish law in the polar regions?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Jewish law in the polar regions.