Vatican Observatory



Societas Jesu – University of Arizona – Tucson AZ 85721 USA

Extraterrestrial intelligent Life, Extraterrestrial life, Vatican Observatory

This article first appeared in The Tablet in April, 2004; we first ran it here at the Catholic Astronomer in 2015

Astrobiology, so the joke goes, is like theology: an academic discipline where highly educated people argue for years about a subject no one can prove exists. It’s been around a long time under a variety of different names – exobiology, bioastronomy – but only when NASA decided a few years ago that the search for life was a winning strategy to get funding did the field start to get more than begrudging respect. And so, the last week of March [2004], I joined more than 700 scientists gathering at the NASA Ames Research Center for the fourth Astrobiology Science Conference.

Cover image of "Would You Baptize an Extraterrestrial" Book

The setting was both inspiring and cautionary. NASA Ames is located at the old Moffett Field Naval Air Station in California’s Silicon Valley: our meeting was in a large tent in the shadow of the enormous hangers built in the 1930s to house dirigibles. One could not help but wonder just how similarly ephemeral the material at the meeting would look in seventy years’ time.

I helped organize a session on the ethics of exploration with Connie Bertka, the director of the program for the Dialogue on Science, Ethics, and Religion at the American Association for the Advancement of Science (AAAS). The panelists included the historian of science Steven Dick; ecologist Margaret Race; NASA’s moon-rock curator, Carl Allen; philosopher Kelly Smith; theologian Richard Randolph; and astronomer Dave Grinspoon.

The sheer cost of doing the science to look for life is one issue with an ethical dimension raised by the panel. It’s not a choice of either/or, feed the poor or search for life on Mars; there’s good reasons to do both. But how do you choose how much to spend – time, money, human effort – on each? It’s not only a decision that governments must make; it is also one that each individual makes, constantly. Do I become an economist or an astronomer? Do I work on a scientific paper this morning, or write another column for the Tablet? Do you spend the time to read this column, or turn the page?

Exploration can be dangerous. The ships of the Renaissance not only brought spices from the east; they also brought the plague. In returning samples from Mars, do we expose Earth to alien life? But meteorites from Mars, and elsewhere, rain down on us all the time. To what degree must we sterilize samples returned from Mars? What if doing so destroys some of the very scientific data we went to the trouble of fetching the rock for? When is it ethical to kill Martian life?

Visiting other worlds creates another set of ethical problems. As one speaker noted, the human animal, full of e-coli and whatnot, is notoriously “leaky;” humans on Mars inevitably will release bacteria into its biosphere. And at what point – if ever – do human beings have the right to “terraform” another planet, to deliberately alter its environment? We’ve been doing that to planet Earth for years, with decidedly mixed results.

Along with the physical dangers, a more subtle danger comes with exploration: dangerous ideas. Few plagues can do as much damage as a half-baked philosophy in the wrong hands. Discovering life elsewhere will inevitably alter everyone’s world-views, to a greater or lesser extent. Short of closing our eyes, how do we prepare ourselves, and our culture, for the shift? Science fiction may be more important than we realize in defining the debate.

Indeed, the impact on Christianity of finding alien intelligent life was a question I got more than once at the meeting. How does our understanding of the salvation of Jesus Christ, God and man, change when we find a race of aliens, neither God nor human?

It’s a question I hesitate to answer simply because there are so many unknowns. (That, of course, doesn’t seem to have hampered anyone else; Paul Davies quotes many different answers in a recent Atlantic Monthly article.) Is there alien life? We don’t know. Are there alien intelligences? We don’t know. Would they be in need of salvation? We don’t know. Would we even be able to communicate with them? We can’t communicate with dolphins – or each other, at times – here on Earth.

I am confident there are no extra Persons hiding in the Trinity, a new one for each alien race. The Word, as John’s Gospel tells us, was there In The Beginning, the one spot in space-time common to all time lines. And this same Word was with God, and was God, the God of whom Psalm 85 says, “the heavens are Yours, the earth also is Yours; the universe and all that is in it – You have founded them.”

Would that Word be spoken in different ways, to different alien cultures? The idea of multiple incarnations strikes some people as ludicrous, other people as inevitable. But after all, The Word becomes incarnate a million times a day, at every Mass.

For those demanding a Biblical answer to whether Jesus will speak to alien races, I quote John 10:16, in the famous Good Shepherd passage: “I have other sheep that do not belong to this fold. I must bring them also, and they will listen to My voice. So there will be one flock, one shepherd.”

I admit, my reading of that passage is tongue-in-cheek. (Traditionally, the “other sheep” are the Gentiles, not ETs.) And yet, by asking these questions, we are already forcing ourselves to confront the very nature of the salvation of Christ; who He is, and what it means to us. And to admit that, here too, we don’t know it all. It’s one more example of how a scientist works every day, proceeding on nothing more than the hunch that there’s something there to study; something to believe in.

Extraterrestrial intelligent Life, Extraterrestrial life, Vatican Observatory

As I have been putting together these reflections on faith and science in the classroom, there has been a topic looming in the background as the proverbial elephant in the middle of the room: What happens to Christianity if we discover intelligent life on another planet? This question is both compelling and loaded. First off, we need to break down this question into a series of clarifying questions.


  1. What do we mean by life?
  2. What do we mean by intelligent life?
  3. Is intelligent life synonymous with human life?
  4. How do we understand the difference between human life and other kinds of life?
  5. Can we conceptualize a type of intelligent life that isn’t human life?
  6. What does it mean to be made in God’s image and likeness?


From these questions, we can develop another series of clarifying questions.


  1. What is the role of science in defining life?
  2. What is the role of philosophy in defining life?
  3. What is the role of theology in defining life?
  4. How has defining life been treated by different cultures (including legal definitions)?
  5. What is the ultimate “litmus test” when defining life?
  6. Is defining life based on understanding physical characteristics of a living thing (like dissecting a frog in a lab), encountering a living thing (entering into some type of relationship with something), or both?


And these are just the beginning questions! Needless to say, the question of what will happen to Christianity if we find intelligent life on another planet is not as simple as some may presume. One of the glairing problems with the question is that the only example we have of life is on our planet. Therefore, could there be a type of intelligent life that is so different from anything we know on Earth that there is no way of conceptualizing what this life may be like?


As a a Catholic Priest whose primary ministry is to walk with my parishioners in their faith life, my gut inclination tells me that the discovery of intelligent life on another plant, dwarf planet, or moon that is similar to human life would be met with two responses: First, an initial shock and fear that this discovery will be the death of Christianity, and, second, with time and patience, a deeper understanding of our created world will emerge that will deepen, enrich, and strengthen Christian faith.


Cover image of "Would You Baptize an Extraterrestrial" Book

The reason I think the response of Christians to intelligent life would move from fear to a deepening of our faith is because this is how the spiritual life works in so many other aspects of life. When someone starts to understand the moral implications of the decisions they make in life, there can be an initial shock that things they once thought were okay to do actually have deep moral implications both personally and socially. Any seminarian or college theology student that has studied the Doctrine of God quickly realizes that their confident, unwavering understanding of God they brought with them to seminary or university is suddenly dismantled when encountering the theological tradition of understanding who God is. Does this dismantling lead to the loss of faith? For some whose faith gets rattled in the face of this dismantling, it can lead to a loss of faith. However, for those who persevere through this humbling of our belief, a deeper and more grounded understanding of God can also emerge. It is a good reminder to us that questioning one’s faith is not a bad thing, but is often necessary to strengthen our faith. In many ways, how new discoveries impact one’s faith has less to do with the initial data that may dismantle one’s current beliefs and more to do with the patience and fortitude we are willing or unwilling to embrace in light of this data, prayerfully deepening our understanding of faith.


Below is a series of videos that explore the question of life and how these discoveries may or may not impact faith in God. The first video is a discussion with Lynn Rothschild and Vatican Observatory Scientist Juan Pablo Marrufo. Lynn is a world renowned scientist in the study of the potential of life outside of our Earth and Juan Pablo’s area of expertise is in the dialogue between faith and science. In their discussion, Lynn and Juan Pablo explore multiple aspects of the exploration of life outside of our common home. The second video is a discussion between Br. Guy Consolmagno and Fr. Chris Crobally on both the scientific exploration of life and the need to encounter and be in relationship with life. The final video is from the AAAS dialogue between science, ethics, and religion on the exploration of space.

Happy Monday!

A Discussion Between Lynn Rothschild and Juan Pablo Marrufo on the Potential of Life Outside of Earth.

A Discussion Between Br. Guy Consolmagno and Fr. Chris Corbally on Life Outside of the Universe.

Space and Exploration: Humans in a Vast Universe from Nathan Clarke on Vimeo.