Pickerel Frogs and Proxima-b

A little over a year ago, my family and I were living in New Jersey while I was on research leave. Taking advantage of being in this new place, I went hiking with my children on an impossibly serene day. My son was climbing boulders, but mostly he marveled at the red-tailed hawks circling overhead. After feasting on carrots and oranges, we followed a persistently trickling stream beside our trail down to a pond. In the natural silence of walking in the woods, corybantic croaking caught the ear of my then four-year old daughter, Greta. Her head cocked to the side. She had a look on her face like when familiar friends call out and surprise you because you weren’t expecting them to be present just now. “What’s that?” she said.

“Frogs. Or toads, maybe.” I replied, a bit confused.

Greta marveled at my stupidity for a moment; then a hint of disgust emerged from her pursed lips. Thinking I hadn’t taken her seriously, she did her best impression to warn me I was on thin ice and would soon find myself in serious trouble. “Daaad…” she intoned, “Frogs live at the cottage. What’s that sound?”

She had heard and seen the sources of such croaking many times before near the river by our home in Kansas and during the summer where we stayed with family in Michigan, but these were clearly local phenomena that could not so easily recur on the East Coast. I did my best to explain that frogs and toads live in lots of places and there are lots of different types. Some of them live in Michigan and some of them live in this pond. Greta remained vehemently skeptical, and I received the withering look of doubt that makes a parent suspicious of what they claim to know. My amateurish inability to name the type of amphibian from its croaking was also eroding any confidence she felt in my expertise on this subject.

I suggested we follow the sounds to see if we could spot the croakers. We all scoured the banks, creeping quietly so we could hear the mysterious noise that Greta was sure could not possibly be croaking. Sure enough, my son found about half a dozen Pickerel frogs perched on shallow stones with their heads and backs poking out of the water. He called us over, glad to have found them, and ran off. Greta, however, crouched down; her head returned to its cocked position of surprise—maybe even awe—and she stared very quietly for the rest of the time we were there. You could see how hard it was for her to wrap her mind around the idea of frogs in New Jersey.

Her surprise made me think of my own recent research projects: considering the religious implications of astrobiology. As a theologian, when I tell friends and relatives that I am working on astrobiology I receive a whole series of puzzled, skeptical looks like the one Greta gave to me. The look usually precedes a tenuous confirmation that they had just heard me correctly: “You mean, you’re thinking about aliens….”

If there’s one thing you should know about astrobiology, it is that it is about much more than just discovering aliens. Of course, finding some sort of life-form beyond the Earth, most likely microbial life, would be outstanding. However, astrobiology is centrally concerned with a much bigger question: what makes any place in the universe habitable? Or, what are the fundamental conditions necessary for life to arise in different places in the universe? It’s these issues of habitability that are most relevant for my own work.

Moreover, even if astrobiology is not primarily about finding elusive little green men, this doesn’t mean it lacks moments of head-tilting awe. For instance, I imagined that same head-cocked surprise that Greta showed in the face of frogs affecting the research teams finding scores of exoplanets in unexpected places of late. In August of 2016, an article appeared in Nature announcing the finding of an Earth-sized exoplanet in the habitable zone (the zone where liquid water might appear on the planet) around Proxima Centauri. It is the closest exoplanet we will ever find and it was surprising that it was there.

Scientists had not been looking at these M class dwarf stars for exoplanets much; many assumed these stars were too small to have planets around them. Moreover, these stars are much cooler than our own Sun (a G class star). To put this in perspective Proxima Centauri is approximately 2,700 degrees Kelvin cooler than our Sun, only 0.1% as bright, and only 14% as large. An exoplanet, let alone a habitable exoplanet just should not have been there—yet there it was. In February of 2017, the surprises continued as NASA made a significant announcement with regard to another nearby system of exoplanets around a dwarf star: Trappist-1. Of the seven exoplanets in this system that is only 40 light years from the Earth, three were Earth-sized and in the habitable zone. ¹The official papers on these discoveries are as follows, but there is a treasure trove of pieces that make this research accessible to the general public. See Guillem Anglada-Escudé et al., “A Terrestrial Planet Candidate in a Temperate Orbit around Proxima Centauri,” Nature 536, no. 7617 (August 25, 2016): 437–40, doi:10.1038/nature19106; and Michaël Gillon et al., “Seven Temperate Terrestrial Planets around the Nearby Ultracool Dwarf Star TRAPPIST-1,” Nature 542, no. 7642 (February 23, 2017): 456–60, doi:10.1038/nature21360.

These two exoplanet discoveries are not just simple intellectual curiosities. About three quarters of the stars in our galaxy are just these sorts of stars. Imagine how many exoplanets could be (galactically speaking) right around the corner from us. A little like finding Pickerel frogs in abundant, unexpected places, Proxima-b and other exoplanets have been popping up with amazing frequency. So what does it mean to find something in a place we just don’t expect to find it?

Greta seemed to have an answer to this question. Tired and warm from the afternoon sun, we rolled down the windows and headed home in the car. My daughter was staring idly out the window letting her hand be pushed gently up and down in the wind; I asked her if she liked hiking. She nodded gently, but then sat up right as though something bit her in the back to ask, “Will we go see the frogs again?”

“Maybe.” I replied, mustering my best parental non-commitment.

Luckily, it was enough to be satisfying. “I hope so;” she added, “its a big deal that frogs aren’t just at the river and the cottage. I’m gonna tell the neighbors.”

And so, many encounters with my daughter over the next month began, “We went hiking and saw frogs! I’ve seen them here and at the cottage.”

For her, there is little doubt that this was a world-shifting discovery to be shouted from the mountaintops (something she would do if we let her). Others clearly needed to know this vital information: frogs live in Kansas, Michigan, and New Jersey. At first, I just assumed that this event was a widening of her worldview: a new fact at her disposal to impress the dull-witted adults who ceased to wonder at the marvels of the world that at least she was still appreciating. But, as her intentness on sharing this news of Jersey frogs persisted it was clear this was not just some fact to be trotted out. These frogs had changed the way she felt about this place. In a visceral sense the space between her and the world had been transformed, but for the life of me I was not sure why.

One of the many adopted grandmothers at the local Christian congregation we were attending had become the latest recipient of Greta’s “Good News according to the Existence of Frogs” saga. Noticing her passion, she asked Greta, “What does it mean that frogs are here in New Jersey?”

Without even looking up from her coffee-hour cookie Greta plainly stated, “This place can be our home. Homes have frogs, so we aren’t just visiting now.”

Children have a knack for connecting events that adults all too easily keep disparate. Now it was my turn to stare with my head cocked in surprise. This place was transformed. It became home. In that moment, where the Pickerel frogs rested on rocks at the water’s edge, a new depth was opening up between Greta and this place that she had been thrown into for the year. The croaking of frogs became a symbol for calling her more deeply into this place. That ‘Gospel According to the Existence of Frogs’ should be shouted from the mountain tops.

Every religious tradition I have encountered has some way of affirming that the world is not ever banal. For me, this happens in Abrahamic cosmogonies that show us the world as a teeming, fecund space of God’s creation in which we have meaningful existence. This is a world that reveals its depth through encomiums to skies set apart from the waters for flying things to fly, to dry land for creeping things to creep upon, to behemoths that roam amidst the trees and plants of every kind, and to the fellowship of humankind bearing the image of God. God provides in these cosmogonies for flourishing of creatures in a panoply of diversity. That is most certainly good.

It is tempting simply to see exoplanets as the next verse in these hymns of praise to the majesty of the cosmos. After all, there is no shortage of exoplanets. Over 3,400 are confirmed to date and each year more are being confirmed than in the previous year. Knowing exoplanets may be hiding around dwarf stars and with the launch of missions like TESS (Transiting Exoplanet Survey Satellite) and the James Webb Telescope, we can expect to be hearing much more from NASA about these distant—and sometimes not so distant—planets beyond our solar system. In this sense, Proxima-b or the Trappist-1 system are symbols for the creative power of God. Certainly, this is a valid interpretation.

Yet, Greta has made me wonder if there is not something more at work here as well. Maybe exoplanets and the many discoveries of astrobiology are doing more than just widening our worldviews. Perhaps they, like those Pickerel frogs for Greta, are symbols that call to us. Not only do they drive us out into understanding the immensity of the cosmos, but they also root us more deeply on this particular, pale, blue dot—transforming our sense of what it means to be at home on the Earth and recognizing our calling to be responsible stewards in its midst.