Our theme for the month of March is “light.”

I remember one of my Sunday school teachers—the most professorial one—drawing a line across two consecutive whiteboards with a dry erase marker. Then he turned around and the line doubled back on itself, returning to where it started. He wrote “Earth” on one end of the lines and “Moon” on the other.

“What the evolutionists don’t tell you,” he said, “is that we’ve only ever measured the speed of light in two directions. We shine a laser beam at the Moon” (he gestured along the line), “and the light bounces back” (he gestured back), “and we time how long it takes. And that’s how we get the speed of light, or c. As in E=mc2.”

The problem with this measurement method, he explains, is that the light beam could be pulling any number of inconsiderate hijinks along the way. Maybe it goes half-speed on the way to the Moon and then 1.5-speed on the way back. Maybe it zips to the Moon at 3c and plods back Earthward at 0.6c. Maybe it—[more high school algebra problems ensue].

The point of these maybes is to solve the Distant Starlight Problem, which has long haunted those (like my Sunday school teacher) who claim that God created the universe about 6,000 years ago. If the cosmos is only a few millennia old, how can we see stars that are millions and billions of light years away? How has the light had time to get here?

One classic solution is the apparent age theory. The logic goes like this: God created Adam as an adult human with only the appearance of having previously been a child and endured adolescence. Therefore, God might also have created the universe to look old without actually being old. In the case of starlight, God might have created the rays of light already en route to us. When we gaze at the Andromeda Galaxy, 2.5 million light-years away, we’re not actually looking into the universe’s past, as scientists tell us. Instead, we’re seeing a kind of photograph or simulation of the galaxy as it never really was. The universe, on this view, is God’s planetarium.

But this raises all sorts of theological problems. Is God deceiving us? Maybe! The stronger versions of apparent-age creationism even insist that God planted dinosaur bones and other fossils in the ground to test our faith—to ensure that we have to consciously choose biblical revelation over scientific data. For some fundamentalist Christians, this is consonant with God’s demanding, hard-nosed character. But for others, even my soulwinning Baptist church, it’s a bit too far.

Another option is to point out, as several articles on the creationist Answers in Genesis website do, that “the secularists have the same sort of problem.” The universe’s background temperature is too uniform to have balanced out in the mere 13.7 billion years since the Big Bang. To explain this, “secularists” proposed the theory of inflation—an extremely rapid period of expansion shortly after the Big Bang, ensuring even temperatures across vast distances. From the creationist point of view, inflation is a way of forcing the universe to fit the Big Bang model. Why not just believe that God created the universe as it is now, uniform temperatures and all? 

This was the tack my Sunday school teacher was taking. Because we haven’t measured the one-way speed of light, he said, we don’t know whether light from Andromeda even needs 2.5 million years to get to us. The constant speed of light is an assumption forced on the data in order to confirm the universe “secularist” scientists already believe in: godless, naturalistic, wholly material, coldly indifferent to us. But we who knew better could believe both that God had created a young universe and that the light we were seeing had really come from the stars. 

The creation science industry, led by organizations like Answers in Genesis, is adept at these kinds of arguments: either frighteningly adept or laughably adept, depending on your perspective. But what is definitely frightening is the way creationists link these issues to others, so that believing in a young earth becomes both a reason for and a reflection of your orthodoxy, your conservative politics, your view of scripture, your salvation. And scholars have revealed creationism’s links to some of the most destructive forces of the last century: virulent anticommunism and climate change denial.

I understand the threat my Sunday school teacher saw in what the “evolutionists” were offering. An old universe was a crack in the system, a glimpse of fundamentalism’s inadequacy. An icy patch atop the slippery slope. My own path away from fundamentalism began with such a slip, thanks not to evil secularists but to my church-attending, John Piper–reading geophysicist grandfather. A tiny patch of ice indeed.

The one-way speed of light lecture was another slippery spot. I didn’t know enough astrophysics at thirteen (I know, what was I doing?) to separate its kernel of truth (there’s no way to synchronize clocks in two different spots, so it’s technically true that we can’t measure the speed of light in one direction) from its questionable interpretive layers (this does not throw into question the evidence for an ancient universe). For that, look here. But I felt that Sunday morning that something was wrong, that the world and God were being forced together like two matching poles of a magnet, and that one of them needed to be flipped around.

Other major shifts in my values and beliefs have come with their own one-way-speeds-of-light: moments when something feels wrong enough that, even when I don’t notice at the time, my feet start to slip. Those moments, I think, are gifts: signs that our friends and teachers and wonders and loves have prepared us to notice, even subconsciously, when the world is demanding something more of us. And in that way—and only that way—I’m glad I learned about light’s unidirectional fickleness.

Photo credit: Wikimedia Commons user Adam Evans (CC BY 2.0 DEED)

Josh Parks

Josh Parks graduated from Calvin in 2018 with majors in English and music, and he is currently a PhD student in religious studies at the University of Virginia. When not writing, he can be found learning the alto recorder, watching obscure Disney movies, and making excruciating puns.