In early February, NASA announced new results suggesting that a sizable number of planets are orbiting other stars in our Milky Way galaxy. Scientists are using the Kepler Space Telescope to measure tiny variations in the light of distant stars, which could represent planets passing between a star and the telescope. Observers identified 1235 “planet candidates” within Kepler’s field of view. Like someone looking through a soda straw, Kepler stares at 1/400^th of the total galaxy, which gives it a view of some 156,000 stars. Extrapolating from this 1/400^th to the whole galaxy, the number of potential “planet candidates” becomes large, compared to previously available data. Around fifty-four of those candidates seen so far in Kepler’s sliver of the sky are thought to be in the habitable zone between too cold for life, and too hot. While the number of galaxies in the universe is not known with precision, the current estimates range from 100 billion to over 200 billion. So, the number of habitable planets in the universe could be vast.

Or it could be much smaller. Substantial work remains to be done using other instruments to confirm which planet candidates are in fact planets, habitable or not. “Habitable” here is an elastic word that does not mean inhabited, and the unknowns far exceed the knowns: whether such life exists, whether (if it does) it is intelligent or self-aware, whether it would be interested in communicating, whether it likes baseball, bacon and eggs, beer and wine, and cheese, or has features that would make it worth meeting, etc. But the recent evidence is still intriguing and, very possibly, a step forward in our understanding of the universe.

This is not the first time in recent years that evidence has emerged to support the plausibility, though not the fact or likelihood, of life on other planets. And each time, news reports assert that such findings call into question Christian, especially Catholic, teaching. Little explanation of why this should be so is provided, though montages of the pope and ET adorn the newspapers and television screens, and dark allusions to the persecution of Galileo and Giordano Bruno abound. Certainly those were episodes of error by the institutional Church, yet the faith persisted alongside scientific exploration. But many Christians do seem to wonder if their belief could survive definitive proof that life exists elsewhere in the universe.

       Brother Guy Consolmagno, S.J., Vatican astronomer

The Catholic faith, of course, would not just survive but thrive in the event of such a discovery. To begin with, God is truth. If the truth is that other forms of life exist in the universe, then that truth can certainly be encompassed by Catholic faith. The Catechism quotes Gaudium et Spes:

methodical research in all branches of knowledge, provided it is carried out in a truly scientific manner and does not override moral laws, can never conflict with the faith, because the things of the world and the things of faith derive from the same God. The humble and persevering investigator of the secrets of nature is being led, as it were, by the hand of God in spite of himself, for it is God, the conserver of all things, who made them what they are.

Recent Christian writers such as C.S. Lewis and Walker Percy have explored the possibilities of life on other worlds in their fiction while keeping their faith. The Vatican held a conference on the prospect in 2009: no one walked away rending garments over the intractable theological problems raised. The engaging Vatican astronomer, Brother Guy Consolmagno, S.J., has given many patient interviews to breathless reporters seeking their Pulitzer in connecting astronomical findings to the demise of Catholicism. He and others who have seriously studied both astronomy and theology see no great danger. Surveying Lewis’ science fiction, Father James Schall concludes in The Order of Things that, whether such life exists or not, the absence of contact with other worlds by the billions of souls who have passed their lives on Earth tells us that our purpose here does not depend on finding life there, even as our capacity to know all things leads us to explore the possibility. 

Perhaps other habitable planets are there for us only to observe and wonder about (all we are likely to do for the foreseeable future), perhaps to visit and inhabit using physics and engineering not yet foreseen, perhaps to meet their inhabitants. About 1500 years of scientific exploration ago, St. Augustine taught that if we encounter verifiable facts of nature that contradict our interpretations of Scripture, we need to reexamine our scriptural conclusions; doing so strengthens rather than debilitates our faith. And, of course, there is Scripture itself. In the Gospel of John, Jesus says, “And I have other sheep, that are not of this fold.” Perhaps he was speaking of the various tribes of Israel, or of Gentiles spread to the ends of the Earth. Or, as Christian science-fiction fans have pondered, perhaps His other sheep are light-years away.