I know this is a hypothetical question, but let’s say living conditions become too difficult on Earth and people begin colonizing other planets such as Mars. Would there be any concerns in Jewish law with doing so?
The Aish Rabbi Replies
Thank you for the fascinating question. Such questions have actually been discussed for many years, when such topics were pure science fiction. Some even asked if man is permitted to blast off into space at all, for did not King David state in Psalms, “And the heavens are the heavens of God, and the land He gave to the sons of man” (115:16)? More recently, and actually on a practical level, the Israeli astronaut Ilan Ramon of blessed memory asked how he could observe Shabbat on a space shuttle which circles the Earth every 90 minutes!
Although such questions have been posed many times, most of the issues raised have no clear resolution. To begin with, when would a person observe Shabbat? Would the days of the foreign planet count for halachic days? These certainly do not seem to be the “days” defined in the Torah – and in fact are not the 7 days God spent creating the world (which is what Shabbat commemorates). And furthermore, some planets rotate extremely slowly (such as Venus, 243 days), while some rotate quickly, in a small fraction of a day. (Martian days happen to be only slightly longer than Earth days.) And as above, the same question is posed regarding space shuttles, which can have artificial days of virtually any length of time, if they have “days” at all.
A very similar question is posed regarding the many mitzvot which depend on the time of day – such as prayer and wearing Tefillin, and which depend on the calendar date, such as the holidays. How does one calculate the days and seasons? Based on the planet or spaceship he is on? Based on the times of the place on Earth he departed from? Based on Jerusalem? Or does he not observe such mitzvot at all?
Some suggest comparing this question to a somewhat less exotic one which occurs on Planet Earth. Say a person travels (or lives) close to a pole, so that the sun never sets certain times of the year and never rises on others (or alternatively, at certain times it does not become fully dark or light). How can he pray arvit, the evening services, and when does Shabbat begin and end? This question too has no clear resolution, but the most accepted ruling actually would not help extraterrestrials – that the point at which the sun begins dipping down from the midpoint of its path is “sunset” and when it reaches its lowest point is “midnight”. Thus, even at the poles, halachic times follow the earthly sun.
My father of blessed memory, R. Azriel Rosenfeld, pointed out to me one reason why Jews could never colonize other planets. Even if the calendrical issues could be satisfactorily resolved, one thing could never exist on another planet: a mikvah (ritual bath)! These may only be constructed directly attached to the ground (of Planet Earth), and from natural water. The surfaces of other planets, even if usable, would not have the true status of “ground” as defined by the Torah. Thus, family life would not be possible anywhere other than Earth.
My father also pointed out to me a humorous science fiction story on this subject. (I wasn’t able to find it online just now.) Orthodox Jews were living on a badly overpopulated future Earth. They were unsure if it was within their rights to depart for a different, more hospitable planet. At last they concluded that they were allowed to, based on Deuteronomy 30:4: “If your dispersed will be at the ends of heaven, from there the Lord your God will gather you and from there He will take you.” Thus, we can be assured that God will bring us to the promised salvation wherever the Jewish people may be!