Can you tell me about your path in science to where you are today?
It was probably not until high school, as I was preparing for college, that I narrowed into wanting to do some sort of science. I thought the best questions of science were in Physics, but I was better at Chemistry. At Caltech, I started out trying to double-major in Chemistry and Physics, partially doing what I was good at and partially trying to get at these big questions that I was interested in concerning the origins of the universe, of the planets and stars. Unfortunately, I realized was that I was still not very good at Physics and still much better at Chemistry. This was a bit of a personal dilemma, until I discovered Astrochemistry, the application of chemistry to astrophysical puzzles, during my sophomore year. I have been doing that ever since. I enjoy the tools of Chemistry very much, but I was not as inspired by the questions of Chemistry research as I was by the questions in Astronomy research.
In your research now, how do you get to bring the tools of physics and chemistry together?
The research that we do in my group tries to figure out how the chemistry and physics interact as planets are forming, and how the chemical environment within which planets form affects the future state of the planet: its size, its chemical composition, whether it’s likely to be hospitable to life, etc. With more probes in the solar system and more direct observation of the material around young stars where planets form—all in the past 15 to 20 years—we have a lot more data, which pushes us to understand the theory better as well. In the past five years, new telescope technology has further revolutionized the field to the point where we can take chemical pictures of the birth environments of new planets.
What are your some of your favorite findings and implications of your research?
On the theoretical side, I think the biggest realization was how important the chemical structures of these [pre-planetary] discs are for the composition of the mature planet. For example, the carbon-oxygen ratio, or oxidation state, of a planet is to a large degree set by the environment where the planet forms. On the observational side, a few years ago we found the biggest organic molecules detected in discs to date, which has opened up the field of exploring the organic chemistry as planets are assembling. I am also proud of my thesis work, where I showed that laboratory experiments can be used to a greater extent than previously realized to quantify the strange chemistry that establishes chemical compositions in planet-forming disks.
In your field, do you think about the origins of life, both on this planet and potentially in other parts of the universe?
It is something that I think about, and that is the big-picture motivation for the studies we do. We want to understand the origins of planets, which can help the people who study the chemistry of the origins of life put constraints on their models. Understanding why a certain kind of planet forms around certain kinds of stars is needed to inform the models that ask how often we get planets that are hospitable to life. Even though every study we do is a tiny, tiny piece of the puzzle, [understanding the origins of life] is definitely the ultimate puzzle that I think everyone in the field has in the backs of their minds.
Do you think it’s likely that other hospitable planets exist?
In terms of planets that are hospitable at the basic level—that is, that are temperate, have some access to water, can sustain a water-based chemistry, and have access to organic molecules—I think we’re going to find that those are very common. We don’t have the data to say for sure yet, but I would say that the data we have all points to the chemical environment that the solar system formed in being fairly common.
Now, what we don’t know is how often, given the minimum requirements, life actually originates. I hope that it’s a common process. I think a universe teeming with life is one that I find more attractive. Also, I think our only chance at understanding our own beginnings is if this is a common enough process that we find life elsewhere. Right now, it’s all very speculative how the transition from inorganic or very simple organic chemistry to life happened here on earth.
Do you think that finding life elsewhere in the universe threatens Christian faith?
When it comes to non-rational animals, I don’t see any theological issues whatsoever. In that sense, finding a weird bacterial species on Mars would be equivalent to finding another weird bacterial species on earth.
When we get into rational life, however, interesting questions emerge. I do not believe that the possible existence [of other rational life] would threaten our unique relationship with God. If you believe in angels, as I do, then you already believe there is more than one intelligent creature in the Cosmos, and they have of course helped, not harmed our relationship with God. However, I think there are possible tensions with our belief in the Incarnation and how we are saved through it. But I hope that the perceived tensions turn out not to be too severe, and that extraterrestrial life exist.
Can you tell me about how you came to the Catholic faith?
I was baptized into the Swedish Lutheran church, but not in a family that practiced faith in any visible way—we didn’t go to church, for example. Growing up, I took God’s existence for granted until my confirmation process, during which my certainty that God exists became less and less. After my teenage years, I went from having some sort of belief in God to being an agnostic. But I never jumped all the way into atheism, really for two philosophical reasons. One was that I had a very strong sense of moral realism, and the other was the belief that my will exists and is free, and both of those are hard to explain and understand in a purely materialistic universe.
I didn’t have any big religious experience while I was at Caltech, but I did meet many more Christians than I had ever known in my life before. (Sweden is a very secular country.) Even if we didn’t have many discussions about it, I think just having Christian friends kept the question of God alive. Then, during my senior year, I started wearing my confirmation cross again. I started believing in God in some vague way, and at the same time I was given C.S. Lewis’s The Screwtape Letters by a friend. I read and really enjoyed it, then went ahead and ordered myself The Abolition of Man, also by C.S. Lewis. That one was really important because it crystalized the reasons why I had not been able to go all the way to atheism before, especially the idea of moral realism: that there are some things that are evil not because a majority of people think they’re evil, not because we have evolved to believe them evil or that I think them evil, but because they are actually evil. And likewise, there are some things that are objectively good.
By this time, I had left Caltech and begun my Ph.D. in Leiden, the Netherlands. The next book I ordered was Mere Christianity, which is a dangerous book to read if you are trying to stay agnostic, especially if you’re primed, as I was. (I think another thing that made me very primed was a love of The Lord of the Rings from a very early age, which is a remarkably Christian book.) Being well-primed, I got through about half the book before acknowledging that I believed what C.S. Lewis believed.
A year later, my brother gave me G.K. Chesterton’s Orthodoxy, and that was another formative book—not as emotional or dramatic as reading Mere Christianity, but it made me realize that I was probably on a journey towards Catholicism. When I walked into a Catholic church and went to Mass for the first time after I moved back to Cambridge, Massachusetts, it was an incredible sense of homecoming, which really reminded me of what I had been reading in Chesterton—the sense of adventure and homecoming all at once. I think that was ultimately what cemented it, that combination of intellectual conversion through reading Chesterton and others with that very strong sense of peace and homecoming when I actually did go into a Catholic church.
Have you ever felt your faith challenged or strengthened by your work?
I’ve definitely had no challenges to my faith, either in the work I do or by my colleagues or my environment. However, one thing that I hadn’t realized until recently is that it’s very tiring being in an environment where the assumption is that you’re not Christian. It takes a lot of energy to be the sole carrier of your Christianity, and in my case Catholicism. You constantly have to remind yourself or are reminded that this is not the norm. This is in no way a criticism towards any of my colleagues—they’ve all been incredibly nice and supportive about me being very open about my faith. But it’s always up to you to stay faithful, since you don’t have the natural support that comes from a religious community. I do notice whenever I go to a Catholic university or to Catholic conferences how energized and peaceful I feel, which has opened my eyes to how much energy it takes to constantly be in a secular environment—which is what the natural sciences are today.
Why do you think secularism is the norm in the natural sciences?
I think it’s really the norm among the intellectual elite, rather than being anything peculiar to the natural sciences—though I don’t know what the data says. I heard a very interesting lecture from Peter Harrison, a historian of science and religion, about the shift from the beginning of the modern scientific project, which had a very strong theistic motivation. All the scientific greats you can think of at that time were very open about the fact that their motivation, which was to do science to understand God’s creation better, and they thought that the laws of nature are prescribed by God. But a separation happened in the 19th century, and the laws of nature were separated from the law-giver. I’m not sure I understand the sociology of that, but I have never felt the temptation to move in that direction.
At the same time, I haven’t felt that I’m Catholic or Christian because of the science I do. Astronomy is great because it does remind me about the wonder of the universe and its mystery; but it’s not something that is particularly motivating for my relationship with God.
Why do you think the idea of a conflict between science and faith persists for many students?
I don’t think students come into college with an intellectually rigorous reason for why there should be a conflict between science and religion. I think they just pick it up because when they see things about science and religion in media, it’s always a conflict. The Catholic leadership is very clear that there is no conflict between science and religion, yet many Catholic students I talk to think that to be good Catholics, they can’t take seriously some scientific claims. So I think it’s something they’ve subconsciously absorbed through society rather than deeply thought about. Most of the time when I talk to students, we can very quickly remove major barriers. For example, a common one is, how can you accept that there are miracles and at the same time do science? I think this misunderstands both natural laws and miracles.
How do you define natural laws and miracles, and how do you reconcile them?
My understanding of natural laws is that they describe the common relationships between bodies and forces in the universe, and they work with incredible regularity and precision, such that it actually makes sense to call them “natural laws.” Now, you could imagine a petty and evil God who enjoys throwing a wrench into those natural laws at random times. The God who created the universe could certainly create a fake or inconsistent experimental result. But that does not seem to be the kind of miracle that God does, and the miracles described both in tradition and in scripture are always there for a reason: to help people believe. No one is going to get closer to God by having to redo their experiment an extra time. It makes sense to me that God respects the regularity of the universe that makes it understandable and predictable for the rational beings He has made. And it seems that miracles are very rare for precisely this reason: to respect the intelligibility of the universe to us.
Is there anything else you’d like to add?
I feel like there are so many stories of Christians that have had a great struggle in academia and for whom living out their faith has been problematic in different ways. While these people do exist and those struggles are real, I want people to know that this is not always the case. I have had a smooth and joyful journey being very open about my faith at the very secular place that Harvard is. And by being open about my faith, I’ve had many meaningful encounters at Harvard and many good discussions with my colleagues. I think it’s important to have both kinds of stories out there—academia is often painted as a very dark environment for Christians, but it doesn’t have to be.