On Earth, we pray facing Jerusalem. On another planet, it makes sense to pray facing Earth. However, since planets move relative to each other, Earth might not be always in the same direction. In particular, the direction of the Earth might be "above" or "below".

How then can a synagogue be constructed on another planet? Should it perhaps face the nearest spaceport, since that's where one would go to reach Earth?

(I should say this question is not quite hypothetical. I am a sci-fi writer. I would very much like to get the halachic side of the story right. I am also aware of this answer regarding whether the Torah is OK with us leaving Earth at all. I think it is safe to say Hilonim would be leaving Earth regardless, and they would want a synagogue.)

  • Even in an Earthly Synagogue, we don't pray towards Jerusalem, we pray towards the front/ark. The fact that those often (purposely) are the same direction is a happy coincidence. There are plenty of Synagogues on good ol' Mother Earth where the congregants don't face Jerusalem. Apr 24, 2018 at 23:09
  • 10
    @Salmononius2 the Gemara (Berachos 30b) and Shulchan Aruch (OC 94:1) say that one who prays outside the land of Israel should face the land of Israel when he prays.
    – Dov F
    Apr 24, 2018 at 23:27
  • 5
    What about a round, gravityless synagogue with a floor that automatically rotates in the right direction?
    – Dov F
    Apr 24, 2018 at 23:39
  • The same question applies, and is far more practical, for someone who is on the space shuttle. You are orbiting the earth; the earth is orbiting the sun. On a simpler level, which way do you face when davening on an airplane or bus or any vehicle that changes direction?
    – DanF
    Apr 25, 2018 at 3:02
  • @DanF See OC 94:4 Apr 25, 2018 at 8:41

2 Answers 2


I suppose it's a fascinating question, but for me the answer seems to be a bit easier. It's quite the same, when someone doesn't know where is mizrach. In this case you should focus your concentration on Hashem without turning to a specific direction (Orach Chayim 94:3 based on Berakhot 30a):

ת"ר סומא ומי שאינו יכול לכוין את הרוחות יכוין לבו כנגד אביו שבשמים שנא' והתפללו אל ה'

The Sages taught in a Tosefta: A blind person and one who is unable to approximate the directions and, therefore, is unable to face Jerusalem in order to pray, may focus his heart towards his Father in Heaven, as it is stated: "And they shall pray to the Lord" (Kings I. 8:44)*

The Kitzur (Orach Chayim 18:10) repeats this ruling. You should pray as if you were standing in the Jerusalem Temple (Orach Chayim 95:2). But based on the comments, I'm quite sure that these Jews will eventually find a way to turn towards Jerusalem!

* Translation from Sefaria


Why would the rules be any different than on the Earth? If you can locate Jerusalem (in this case, the Earth), face that direction. If not, it doesn't matter. The construction of the synagogue there should facilitate facing the Earth, regardless of the direction. It may include a technology that tracks the Earth and illuminates a light at the side of the room in that direction.

  • The issue would be that it’s sometimes not possible to face towards the earth/ Jerusalem even if you know where it is. Because it might be below the ground (can you pray face-down on the floor?) or above your head.
    – Zarka
    Aug 31, 2020 at 7:38
  • @Zarka that issues applies on earth too, like in hawaii
    – Double AA
    Aug 31, 2020 at 17:48
  • @DoubleAA Not really.
    – Zarka
    Aug 31, 2020 at 21:02

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