According to Jewish law, Shabbat begins at sundown. During Ramadan, Muslims fast from sunrise to sunset. But what do you do if the sun does not set?

Many religions set their time by the sun. Jewish mitzvot (religious duties) require prayers in the morning, afternoon, and evening. The state of the sun defines morning, afternoon, and evening: you should not say morning prayers after noon, for example. Shabbat, the Jewish sabbath, begins right before sunset on Friday and carries through until three stars are visible in the sky on Saturday night. During Ramadan, adult Muslims eat before dawn (sahūr), fast during daylight hours, and then eat again after sunset (iftar).
This reliance on the sun introduces an interesting problem: what should you do if the sun doesn’t set?
At the North Pole and at the South Pole, the sun rises just once a year and sets just once a year. Lands within the Arctic and Antarctic Circles see days that last for a month and hundreds of hours between sunrise and sunset. What does this mean for religious law and custom?
Well, the answer is predictably complicated. For Ramadan, some people observe the fasting time even if that means twenty hours without food. Others switch to the time in Mecca for their fasting schedule, or go with the daylight hours of the nearest city.
An article by Rabbi Dovid Heber (see the fourth link below) identifies four Jewish responses to the challenge of the poles:
- Use the time from your point of departure as the standard.
- Treat 6am as sunrise and 6pm as sunset.
- Treat the sun’s low point as sunset, even if it doesn’t actually set.
- Just don’t go that far north or south!
All this gets even more complicated when you consider the special problem of outer space. A Jewish astronaut orbiting the Earth sees sixteen sunrises a day – giving them two 90-minute Shabbats every twenty-four hours. This is not just hypothetical: the Israeli astronaut Ilan Ramon remained observant while in orbit. He used the point of departure method, keeping Shabbat according to Cape Canaveral time.
There have been eleven Muslim astronauts to date, and at least two of them were up during Ramadan. One did not fast, and the other used the time from their point of departure. Muslim astronauts faced some additional complications: how do you pray facing Mecca? How do you pray if you cannot kneel? In 2007 a team of clerics compiled a guide to Islam in outer space titled “Guidelines for Performing Islamic Rites at the International Space Station” to answer these questions.
- Jewish law in the polar regions
- Ramadan
- Arctic Ramadan: fasting in land of midnight sun comes with a challenge
- Where does one pray when there is no day?
- How to Observe Judaism in Outer Space?
- Guidebook issued for Muslims in space
- Muslims in outer space
- A guideline of performing Ibadah at the International Space Station (ISS)
One could temporarily leave one’s religion for the duration of the stay.
I see what you did there.
Oh fuck no. You don’t get to stop there. You can’t just rip the bandaid off and walk away. It’s either solar-occurrence-religious-mandates are garbage, or you gotta declare at the gate and show how God intended you to observe while traveling at .95 the speed of light away from your primary star. You didn’t even touch on “what happens if I’m pulled into the singularity of a black hole during a holy month.” It’s either broke-ass-pre-modern mysticism, or show me the math.