Dispersed in the uttermost parts of heaven: Interplanetary colonization according to Jewish ethics, prophecy, and law

By Dr. Yonathan Reches

Interplanetary human colonization is becoming an imminent prospect. Among other endeavors, NASA is laying out plans for the Lunar Gateway and SpaceX is preparing to launch manned missions to Mars as early as 2024. But what do these efforts mean for our souls as people and as Jews? Judaism, which has always been at the avant-garde of the human conscience, must now grapple with the question of what our tradition has to say about the exploration and colonization of extra-terrestrial planets and moons.

Earth and sky, food and water.

Torah divides the world into shamaim (שמים), the heavens, and aretz (ארץ), the Earth. Physically, the Earth is a life-sustaining assemblage of solids and liquids and the heavens consist of an atmospheric layer, overlain by an endless vacuum (which does contain non-vacuous inclusions such as planets, stars, and nebulae). The spiritual division is more fundamental: “Thus saith the L-RD: The heaven is My throne, and the earth is My footstool” (Isaiah 66:1). Does this mean that if we only could travel far enough into the skies, that we would eventually encounter a physical G-d seated on a throne?

Our tradition eschews seeking G-d in the physical heavens. Following the Great Flood, all of humanity came together in Babel and, with the invention of brick and mortar, sought to build a tower “with its top in heaven” (Genesis 11:3-4). In the rabbinic consensus, this is seen as an idolatrous and eventually disastrous attempt to physically reach G-d. Clearly, Babel offers a model of how not to approach shamaim. Yet Torah does not provide much delineation between the physical heavens and the spiritual ones. For our ancestors who had not developed any capacity for flight—much less for space travel—the two meanings of shamaim were functionally the same. In the Year 5779, they are difficult to disentangle.

The shamaim are literally the sham-maim (שם-מים), the there-water. This name dates back to the separation of the waters (Genesis 1:7-8), where “firmament,” rakiah (רקיע) refers to the same physical space as shamaim, but distinct in that the firmament is vacant, whereas the heavens (repeated in Psalm 148:4) are filled with a portion of the waters of creation. Where are these waters now?

There is a pshat manifestation of H2O on other planets and moons, a necessary condition for human life. The life-giving symbolism of water is a common theme in scripture, such as the parched wilderness of Shur (Exodus 15:22), which refers to the absence of Torah as a life-giving force (Bava Kamma 82a). So the drash of the “waters above the heavens” is the literally universal manifestation of Torah.

Besides water, human life requires food. In the story of Joseph, food appears in three pairs of dreams: Joseph’s dreams (Genesis 37:7 and 9); the dreams of the chief butler and the chief baker (Genesis 40:9-11 and 16-17); and the dreams of Pharaoh (Genesis 41:1-7). In each pair, one dream is centered around grain. The baker’s baskets of bread represent his own life, taken from him by Pharaoh. Pharoah’s stalks of grain represent the life and the bounty of Egypt. Joseph dreams once that he and his brothers are collecting grain in the field and his brother’s sheaves all rise and bow to his. Then he dreams that the Sun, the Moon, and eleven stars (or planets) all bow to him. The parallel between planets and sheaves of grain hints to the habitability of foreign celestial bodies. But Earth, being innately habitable and best suited to our needs, stands in the center and the other planets bow to it.

The Earth hath He given to the children of men.

To an atheist, the eating of a piece of fruit is a perfectly amoral action. To a faithful Jew, the use of any of the Earth’s resources is only permissible because of G-d’s consent in one of the earliest acts of creation: “[R]eplenish the earth, and subdue it; and have dominion over the fish of the sea, and over the fowl of the air, and over every living thing that creepeth upon the earth” (Genesis 1:28). Is this divine mandate limited to the Earth only, out of all celestial bodies? The dominion over of hashamaim (עוף השמים) certainly seems to indicate that the physical heavens are ours to govern as well.  

On the other hand, in his book, Sham Derech, Rabbi Simcha Broida argues that the divine sanction is limited to the physical aretz and writes that a human on the Moon, “is not permitted to do there anything whatsoever,” as she would be committing a theft against G-d. According to Rabbi Bentzion Firer, Torah has no foothold on any extraterrestrial body and one cannot perform the mitzvot there. Murder on the Moon would be perfectly permissible (which begs the question of why the proverbial theft there would be prohibited). Then again, there was also a time when Jews thought it was only possible to do mitzvot in the Land of Israel. When the Temple was destroyed, we realized that we could be Jews anywhere: that the essence of our humanity depends on the state of our souls and not the location of our bodies.

Not all rabbis agree with Rabbis Broida and Firer. The Lubavitcher Rebbe was asked in 1961 whether Psalm 115:16 prohibited exploration of the Moon. He responded that space exploration was entirely permitted and explained: “The stars, planets, moon, etc. are not called Heaven, since Heaven is something spiritual, whereas those planets are physical and belong in the physical universe.” If so, the physical shamaim are part of the spiritual aretz, and we have the divine sanction to inhabit them. In his book, Im Esak Shamaim, Rabbi Levi Yitzhak Helprin argues that mitzvot can be observed in space, though most of the mitzvot which depend on time and place are not required there.

“Both these and those are the words of the living G-d. However, the halakha is in accordance with the opinion of Beit Hillel” (Eruvin 13b), or by parallel in this case, with the opinions of Rabbis Schneerson and Helprin. Wherever a Jew draws breath, there does Torah live.

It is human nature to fear the unknown expanse. We built the Tower of Babel, “Lest we be scattered abroad upon the face of the whole earth” (Genesis 11:4). The use of the “whole earth,” kol ha’aretz (כל הארץ), as in Genesis 1:26, suggests the Tower as a defiance of G-d’s commandment to inhabit the Earth. For the first time, the new craft of masonry had given humankind the choice of isolating or propagating. This possibility gave rise to a new moral obligation to spread out into communities and to create a diversity of culture, language, history, and trade. Just so, technology will be the midwife of a new moral imperative to explore Space.

The profits of such a venture for the vantage of the human spirit are immense. Imagine standing on the surface of the Moon during Rosh Chodesh, shrouded in darkness and seeing a fully-lit Earth. Your view will be the opposite of an Earthling’s: a New Moon means a Full Earth and a Full Moon means a New Earth. And still, this is exactly when both an Earthling and Moonling Jew will bless kiddush levana, to remember that a sliver of light and renewal will always emerge, even from total darkness.

For my sake the world was created.

We have seen that the habitation of other planets is permitted and possible, even virtuous. Still, there are moral perils involved with leaving the safety of one’s home in favor of the peril of an unknown wilderness. In his 2004 NYT article, “Life (and Death) on Mars,” Physicist Professor Paul Davies proposed that the trailblazers of Martian colonization should be sent on one-way missions, where they would certainly meet untimely deaths, in order to spare the operational difficulty of returning them to Earth. Another scientist, Professor Lawrence Krauss, supported this suggestion in his own 2009 NYT article, “A One-Way Ticket to Mars,” with an informal survey of his colleagues, who indicated an overwhelming willingness to undertake a one-way trip to the Red Planet.

While the privileged and well-educated fantasize about suicide missions to Mars, who is destined to be left behind to tend Planet Earth? The taxes and environmental resources that pay for space travel are drawn from every member of society, yet disproportionately benefit the privileged few. There has not yet been even a single black crew member to inhabit the International Space Station. The first-ever space walk by two women was recently canceled by NASA due to a shortage of women’s space suits.

Exploring the universe is the right decision, but perhaps is being done for the wrong reasons. Already, interplanetary colonization is largely driven by a real but dangerous need, which Davies terms, “a precious insurance policy against catastrophe at home.” If human life on Earth were destroyed, life could be preserved elsewhere and Earth could be “reverse-colonized.” In terms of dry utility, this is a sound plan. Morally, it is dangerous.

Bold exploration will not do as a substitute for sustaining the habitability our own Planet Earth, which G-d created as a gift and a trust for the human race (Kohelet Rabba 7:13). The utilitarian view of other planets as insurance for our own poisons our love of the Creator through His creation and casts our own humanity as a mere corporeal existence, rather than an extension of the divine presence.

What would it look like to cash in the insurance plan proposed by Professor Davies? Sanhedrin 4:5 teaches that the value of every human life is so great that each person must say, “For my sake ‎the world was created.” And yet we know that no technology will ever make it possible to safely evacuate every human from this planet. If we resolve that the preservation of the species is a more noble end than the preservation of billions of lives, then humanity is already lost.

In a way, Earth seems destined to become for all of humanity what the Land of Israel has long been for the Jews: a home that only some of us can occupy some of the time. The exile of the Jews appears in many prophecies, including Isaiah 11:12, Jeremiah 29:14, and Ezekiel 20:41. Its only mention in Torah, Deuteronomy 30:4, is also the only mention of exile in the sky: “If any of thine that are dispersed be in the uttermost parts of heaven, from thence will the L-RD thy G-d gather thee, and from thence will He fetch thee.” But people don’t live in shamaim. Or do we? Could Torah be prophesying an exile from Earth and a later return?

Humans envision ourselves as bold explorers venturing off into space. We don’t like to imagine ourselves running back home to our Mother Earth, but if we approach our future with even a scrap of humility then it is clear that we must make sure there’s something worth returning home to.

Dr. Yonathan Reches is a Program Manager in the US Air Force Space and Missile Systems Center in El Segundo, CA and a member of the Ikar Community. During his undergraduate studies, he was involved with Hillel at the University of Oklahoma and formed a lasting bond with the Dallas Jewish community. The views expressed in this article do not necessarily represent the views of the Air Force or the United States.


Torah likens Joseph’s eleven brothers to eleven stars. The author dedicates this article to the memory of the eleven stars of the Tree of Life Synagogue, brothers and sisters in blood, who were murdered on 18 Cheshvan 5779, which was 27 October, 2018: Joyce Fienberg, Rich Gottfried, Rose Mallinger, Jerry Rabinowitz, Cecil Rosenthal, David Rosenthal, Bernice Simon, Sylvan Simon, Daniel Stein, Melvin Wax, and Irving Younger.

May their memory be a blessing.