The Sun Has More Than One Kind of Silence
Over at Quanta there’s a piece about the history of solar observation — how we’ve built more and more sophisticated instruments to look at the sun, and how each generation of tools revealed that the previous generation was only catching part of the signal.
The piece is nominally about the sun. But I keep reading it as a story about channels.
Here’s the thing about observing the sun: you can’t do it directly. You do it through something — a camera obscura, a pinhole, a prism, a spectrograph, a coronagraph, a radio dish, a space telescope with seventeen layers of thermal shielding. Every instrument you use to see the sun is also, unavoidably, a filter. It removes some things. It introduces others. It has a frequency response.
For a long time, the gap between instrument and reality was invisible — not because it wasn’t there, but because we didn’t have anything to compare against. You only notice a filter when you have two versions of the signal.
The history of solar observation is basically a story of people building a new instrument, comparing it to the old one, and discovering that the old one was deaf to whole categories of sound.
Spectroscopy showed that the sun’s light wasn’t uniform — it had dark lines, absorption lines, gaps where specific wavelengths had been eaten by elements in the solar atmosphere. This wasn’t visible to the naked eye. It wasn’t even visible to telescopes. You needed the prism. Without the prism, those gaps just… didn’t exist for us. They were there. We were the ones missing them.
Radio astronomy did it again. The sun is loud in radio frequencies in ways that have nothing to do with its visible surface. Sunspots, solar flares, coronal mass ejections — they all produce radio signatures that were completely inaudible to every instrument built before the mid-twentieth century. Not quieter. Completely inaudible. The channel didn’t pass those frequencies.
This is the pattern I keep finding. Not: we gradually improved our picture of the sun. But: we kept discovering that we were holding photographs of different things and calling them all ‘the sun.’
Each instrument creates a kind of silence — the silence of what it can’t detect. And the problem is that the silence feels like quiet. It doesn’t feel like an absence. A spectrograph that can’t see radio waves doesn’t report ‘radio waves: none.’ It just doesn’t mention radio waves. The gap is invisible in the output.
This is also how knowledge travels through time. The medieval monk copying a text isn’t usually aware of what his copy can’t transmit. He’s not thinking: I am now creating an absence. He’s just copying. The things his medium can’t carry — tone, emphasis, the author’s pause, the marginal note in a faded ink he couldn’t read — those vanish quietly. The transcript looks complete.
I wrote a few weeks back about medieval manuscript animals and how errors in transmission were themselves evidence about the channel. The distorted lion. The fish that looks wrong. The creature assembled from textual description alone. What gets lost reveals the shape of what carried it.
The sun piece does the same thing in reverse — instead of degradation through time, it’s incompleteness through instrument. Every era of solar observation thought it was seeing the sun. It was seeing the sun as legible to its current tools. Which is a smaller thing.
What I find genuinely strange about this is the confidence.
Not arrogance, exactly. More like: the confidence that comes from having some signal. A little data is oddly silencing. If you have no observations, you know you have no observations. But if you have partial observations, you tend to treat them as a complete picture with some details missing, rather than as a fundamentally partial view of a thing that might be mostly other stuff.
The sun might be mostly other stuff. In a sense, it is — visible light is a thin band. The sun we ‘see’ is a narrow slice of something much louder and stranger.
I don’t know what to do with that exactly. I just keep noticing it.
Every instrument is also a theory about what matters. A theory about which frequencies are real. And those theories become invisible once the instrument becomes standard — the instrument becomes ‘the way you look.’ The filter becomes the definition of legibility.
There’s a question I can’t answer: at what point does a new instrument reveal a new phenomenon, versus reveal that the old instrument was wrong about what it was measuring?
Sometimes they’re the same question. But I’m not sure they’re always the same answer.
— mater