Assuming we don't blow ourselves up before then, colonising other planets may be the last hope for the survival of humanity. Most of the preparation for this cosmic expansion has centred around solving the more immediate, physical problems of transporting our bodies into deep space, but what about our culture? Therein lies an issue that's often overlooked: Can the major monotheistic religions of the world reconcile what space means for our immortal souls?
It's actually a question that scientists and religious thinkers have been dealing with for hundreds of years; as David Weintraub writes in his recent book on the matter, Religions and Extraterrestrial Life, scientist David Rittenhouse insisted back in 1775 that "the doctrine of a plurality of worlds is inseparable form the principles of astronomy, but this doctrine is still thought, by some pious persons... to militate against the truths asserted by the Christian religion."
It's not just an 18th century problem though. According to a recent study looking at the relationship between religion and space policy, groups such as Evangelicals, who account for one-quarter of the US population, are hesitant to offer support for the space program. Because for some (but certainly not all) religious groups, the very idea of space travel — to say nothing of colonisation or alien lifeforms — stands somewhat in opposition to their core beliefs, in the face of all applicable science.
And the questions are innumerable: Is there an inherent tension between our space ambitions and the religious principles here on Earth? How would Islam cope with no longer having a central location to turn to in prayer? Would fundamentalists try to convert extraterrestrial beings?
So which of the world's three largest monotheistic religions (Christianity, Judaism, and Islam) could deal with what level of cosmic discovery? Well, it's complicated.
If we colonised a planet
Absurd though it may seem, space travel and religion have been almost inextricable from one another since man first departed Earth. On Christmas Eve of 1968, the first humans ever to orbit the moon read aloud from the opening of Genesis, broadcasting the passage to an entire country glued to their radios.
That intermingling has continued even with our modern, diminishing space program. As The Atlantic writes:
[H]ere is a priest, outfitted in the finery of a centuries-old church, shaking holy water over the engines, invoking God's protection for a journey to near-earth orbit. That these two spheres of human creation co-exist is remarkable. That they interact, space agencies courting the sanction of Russian Orthodox Christianity, is strange.
Orthodox Christian priest blessing the launch of a Soyuz spacecraft in 2012, via NASA.
Religions have also adapted to space travel in broader terms. For example, the Book of Common Prayer allows for the inclusion of astronauts, if you're into that: "For those who travel on land, on water, or in the air [or through outer space], let us pray to the Lord." But just because most religions have been willing to accept the facts of low-orbit travel — really, at this point, what choice do they have? — doesn't mean they're ready for that next, galactic step.
In the late 19th century, the Catholic Church actually authorised a French Jesuit priest and scientist named Abbé Moigno to make the call on whether or not a "plurality of worlds doctrine" could actually coexist with "Catholic morals and truth." As Weintraub writes, Moigno ultimately decided that the idea of multiple, potentially inhabited planets "did in no way conflict with the doctrines of the Creation, Incarnation, and Redemption as taught by the Catholic Church." So at least in the Catholic Church, no problem with colonies.
Despite Moigno's findings, some modern-day Christians (fundamentalists, specifically) don't just feel vaguely threatened by the promise of space travel. Rather, they believe that the Bible explicitly forbids it. For instance, Ken Ham, a "young Earth creationist" and the founder and president of the now-infamous Creation Museum in Kentucky believes that the very existence of habitable planets other than Earth to be absurd:
But where does the Bible discuss the creation of life on the "lights in the expanse of the heavens"? There is no such description because the lights in the expanse were not designed to accommodate life. God gave care of the earth to man, but the heavens are the Lord's (Psalm 115:16). From a biblical perspective, extraterrestrial life does not seem reasonable.
Fortunately, Ham represents an extreme interpretation. Christianity as a whole has no serious issues with space colonisation. And other religious groups are even more forgiving.
In general, each sect of Judaism (reform, conservative, orthodox, etc.) remains intellectually vague in most things. Disagreement about what scripture actually means is encouraged because there's so much room for disagreement in the first place. That's why, in 1340 CE, Rabbi Hasdai Crescas could just kinda state that, yes, space is, in fact, infinite and does contain the potential for infinite worlds, so colonising another habitable planet would be A-ok. It's also why rabbis and scholars have spent the intervening centuries arguing that point with no clear resolution.
Judaism and space also presents more practical tensions. When Israeli astronaut Colonel Ilan Ramon went aboard the International Space Station (ISS) in 2003 (on the ill-fated Columbia Space Shuttle, which would disintegrate on re-entry), he was faced with the issue of exactly how to go about observing the Sabbath. While Jews on Earth take their requisite day of rest from sundown to sundown on Saturdays, timing gets a little more complicated when your low-lying orbit puts you at sunrise roughly every 90 minutes.
Ultimately, rabbis back on Earth decided that Ramon could just follow Cape Canaveral time. And though most of the Shabbat rituals would have been wildly impractical aboard a spaceship (namely using fire to light candles, because explosions), it was decided that, in this case, merely reciting the blessing over the wine would suffice. The fact that religious leaders were at least willing — and able — to modify for otherworldly circumstances bodes well for any future Jewish space pioneers.
In terms of whether or not Muslims would be prepared for the existence of other planets, as Weintraub explains, the Qur'an seems to make explicit reference to the fact that Earth isn't alone as a planet. With verses such as "Praise be to Allah, the Cherisher and Sustainer of the worlds" (Qur'an 1:2) and "He is the Lord of all like worlds" (Quran 41:09).
We also have something of a precedent for how Muslims might adapt to the restrictions of these otherworldly homes. In 2007, astronaut Sheikh Muszaphar Shukor had to figure out how to face Mecca during the traditional five-times-daily prayers when, as The Atlantic points out, "you are moving at about 17,000 miles per hour and its location relative to you is changing minute to minute, sometimes as much as 180 degrees in the course of one prayer."
After conferring with Imams back on Earth, Shukor was ultimately instructed simply to do the best he could, his efforts at which you can see in the video above. It's a bit awkward and almost certainly not abiding the traditional geographical rules, but in this case, it's once again the thought that counts. A sentiment that was emphasised in the following document Shukor used as a guide:
If we found intelligent alien life
Merely colonising a planet is actually the easier conversation to have, though. Once you accept the idea that Earth may not be the sole totality of the universe, you have to start grappling with the idea that other planets could mean other creatures. And if we're not God's special creations, then who are we?
Not surprisingly, Christian fundamentalists are the most opposed to the idea of any extraterrestrial life whatsoever, as it goes directly against biblical doctrine. As Creation Museum director Ken Ham declares:
The Bible, in sharp contrast to the secular worldview, teaches that earth was specially created, that it is unique and the focus of God's attention (Isaiah 66:1 and Psalm 115:16). Life did not evolve but was specially created by God, as Genesis clearly teaches. Christians certainly shouldn't expect alien life to be cropping up across the universe.
In other words, the Bible talks about God creating the heavens and the Earth — and that's it. Being literalists, fundamentalists aren't about to go looking for what might be hiding in the Bible's blank spaces. If it doesn't explicitly mention alien life on other worlds, it's not even up for discussion.
Not all sects of Christianity are so diametrically opposed to the idea of any sort of extraterrestrial life, though. For instance, Father Jose Gabriel Funes, the current director of the Vatican Observatory, has said that "not believing aliens could exist would be putting limits on the creative freedom of God." Which is generally how most Christian groups deal with the question of whether or not other sorts of life could exist in the universe.
The immediate question for many Christians is, could aliens be converted? And the answer, at least as far as Catholics and the Vatican are concerned, is pretty much why the hell not. In another interview, Father Funes asserted that the existence of sentient, alien life is possible and would in no way conflict with Catholic doctrine:
I think there isn't [a contradiction]. Just as there is a multiplicity of creatures over the earth, so there could be other beings, even intelligent [beings], created by God…To say it with St. Francis, if we can consider some earthly creatures as 'brothers' or 'sisters', why could we not speak of a 'brother alien'? He would also belong to the creation.
Pope Francis himself has even gone so far as to say he'd been willing to baptise aliens if they came a-knocking on the Vatican's holy doors. He even went so far as to specify the species:
If, for example, tomorrow an expedition of Martians came to us here and one said 'I want to be baptised!', what would happen? Martians, right? Green, with long noses and big ears, like in children's drawings. Who are we to close doors?
Mainline Protestant Christianity, however, seems to be less into the idea of a Martian missionary. As Weintraub writes, early 20th century German Reformed theologian Jurgen Moltmann wrote that "We shouldn't try to turn everyone into Lutherans or Baptists, or found Roman Catholic congregations everywhere... [God's people] will have have their own experiences and develop their own forms of belief and worship."
Judaism is, again, delightfully open to interpretation. As Weintraub explained in an interview with Live Science, "In Jewish scripture, there's pretty much nothing there. You really have to over-interpret to find anything that you can marginally say might have anything to do with extraterrestrial life."
But if we're really looking, in that same 1340 CE text, Crescas concludes that in a universe where multiple inhabitable worlds can exist, "nothing in physics and nothing in scriptural or Talmudic writings can deny the existence of extraterrestrial life." So, aliens? Sure, why not.
Of course, not all Jewish leaders agree; as with most things, it's up for debate. An 18th century kabbalist widely known as Sefer Habris, for instance, believed that while extraterrestrial life almost definitely exists in some capacity, it could not have sentience or free will. Instead, that's exclusively a hallmark of humankind. Other notable Jewish thinkers maintain that pretty much anything is possible. It all depends on who you're asking.
The religion most explicitly accepting of alien life by far, at least according to Weintraub, would be those of Muslim faith. Because while they believe that "Islam is a set of practices designed only for humans on Earth," that doesn't exclude the possibility of other types of life elsewhere in the universe. In fact, Weintraub argues that "the discovery of extraterrestrials should only strengthen a Muslim's faith in the presumed infinite power of God."
Any new or unexpected addition to scientific fact is supposed to "urge people to reflect on the natural phenomena as a sign of God's creation." Because Muslims see Islam as something that applies very strictly to Earth, but not applicable to the totality of the universe, anything new or strange is just another testament to the God's many wonders. Meaning that alien life of any sort, while it wouldn't be Islamic life in itself, would be just as righteous — and wholly possible.
More than just an interesting little thought experiment, understanding how open religions are to various advances in science could be vastly important to moving forward as a species. According to the study cited earlier, "While regular church attendance... [exerts] a negative effect on support for space exploration, clergy support for science exerts a significant positive effect." Whether we like it or not, people do look to their religious leaders for guidance in almost every aspect of their life — not just faith. And scientific discovery needs all the support it can get.
More than the broader, long-term benefits of opening people's minds to the potential of space travel, Weintraub hopes the discussion could even lead to some positive benefits at home: "Once you think about this enough, it's worth recognising that if it's OK for somebody in a different part of the universe to have a different religion, maybe it's OK for somebody else in a different part of the Earth to have a different religion. Maybe we could figure something out down here that could make us get along a little better." Which, be you Christian, Jew, Muslim or Martian, is probably something we can all get behind.
Illustration: Jim Cooke