More recently, the Christmas story has intersected with astronomy in questions about how to think about Christian theology now that we are aware quite how big the universe is, especially if it may contain a great deal of other life. We don’t know whether that’s true, of course, but given we now know that planets common around stars, and there are billions of billions of stars in the universe, the probabilities seem to tilt towards other life, at least as I see it. 

Suggestions surfaces from time to time that the world’s religions have arrived late to the party, when it comes to thinking about life beyond Earth. The astronomer and broadcaster Carl Sagan made that claim, for instance, in his best-selling book Pale Blue Dot. In fact, the earliest discussions of life beyond Earth I know about from Christian writers come from the mid-fifteenth century (and they stretch even further back in Judaism and Islam, to give two other examples). Christian writers have written on the subject ever since. If few gave us more than a paragraph here or a page there, that’s usually because the prospect of other life did not worry them enough to warrant more. They noted the prospect cheerfully, and moved on.   

Until the twentieth century, the prospect of parallel Nativities on other planets was rarely in view. In a sense, it didn’t need to be. It’s a consistent Christian position to say that God joined his life to all creation in joining it to one species of rational animal on Earth, just as God joined his life to all humanity in being born in a stable, in a wayside town, in a backwater province of the Roman Empire.  

One erudite early exploration of multiple Incarnations comes in a poem from the 1920s by the Roman Catholic poet Alice Meynell, entitled ‘Christ in the Universe’. More recently, Meynell’s topic has become perhaps the central theme in thinking theologically about life beyond Earth. My own book (Astrobiology and Christian Doctrine, 2023) looks at the prospect of life beyond Earth from the perspective of all of central topics in Christian doctrine (creation, sin, redemption, revelation, the Trinity, and so on), but the largest section is on Christmas and possible parallels. I am sympathetic to the idea that God would also unite himself to another natures, alongside the human nature he took up in Christ: not because I think that would be necessary, but because it might be fitting. It might be fitting for God to deal with other species as intimately as God has dealt with us, so that they might see ‘God made visible’ in their own nature, as we see God made visible in ours. 

Hiding in plain sight in the Nativity stories is another key to Christian thinking about life beyond, namely the angels. It’s not that I think that angels are aliens, or that alien life is angelic. In fact, being a disciple of St Thomas Aquinas, I’m inclined to view angels as entirely immaterial, and so very much not examples of biological life. But angels are useful for thinking about other biological life beyond Earth nonetheless, because of what they mean for the Christian imagination. The angels show that there’s always been space in that imagination for rational creatures other than human beings. They show that Christianity has never imagined that we’re the sole object of God’s love, or even the most glorious of species.  

The Christmas story has its cosmic elements: the star, glory in the highest heavens, and the angels, reminding us that wonderful though humanity is, it has no monopoly on rational life. My hunch, as much as my hunch matters, is that if there is other life then they too may see God face-to-face in their own Incarnation. Even if we find evidence of life beyond Earth, however, it’s not going give us much detail. The balance of gases in the atmosphere of a planet around another star might indicate life, but not much else about it. The prospects for interplanetary comparative religion are far off indeed. Alice Meynell had the right idea, when she recognised that one of the joys of the life of the world to come will be learning the stories of God’s dealings elsewhere: 

But in the eternities, 

Doubtless we shall compare together, hear 

A million alien Gospels, in what guise 

He trod the Pleiades, the Lyre, the Bear. 

  

O, be prepared, my soul! 

To read the inconceivable, to scan 

The myriad forms of God those stars unroll 

When, in our turn, we show to them a Man. 

 Alice Meynell