Iused to watch my father solve math proofs, in the hour before dinner, seated in his wingback chair. Numbers clean in their meaning, clear in their signification of some known entity. What I also watched my father do: record the world around him. Or, record the world around me, when as a child I dictated notes to him about what I saw on nature walks. An acorn top as fairy hat. A leaf as discarded boat. The known entity rendered strange, but no less true, no less real.

For a long time, each of my beginnings is a tearing. When the egg inside my mother splits in two to become my sister and me. When the doctors cut us from her. When they carry us apart. When my sister dies, but I go on living. When a surgeon takes a scalpel to my back. When a surgeon takes scissors to the nerves inside my spinal column. When a surgeon cuts my heel cords. Then my hamstrings. Then, later on down the line, repeats the severing again. Every time I am remade, there’s ripping, breaking, blood. I am a little more a fragment, a little less whatever I once was.

I like that all bodies, fragmented and otherwise, are a matter of matter. That it’s all a matter of arrangement. Because you and I are both obsessed with meaning and order when we weren’t born of it. That meaning and order assert themselves despite the chaos of origin. I find this hopeful. The endless ways our bodies could have been opened. The endless ways we are cleaved, and how cleaving is meaningless, but to experience it is not. That we are only what we make, what we’re made of, the edges of our bodies clear and clean as longhand math proofs. That bodies can’t, on the surface, mean, but that we need them to in order to keep living. We are invested in their histories and stories and accumulations. How simple and devastating and necessary the world we’ll make in order to make sense of this one. That we’ll make up a world as we go.

Binary stars are what we call two celestial bodies orbiting a common center of mass. You can’t always tell that there are two stars in the system. Depending on the angle and the glare, one star might appear, for a long time, to be moving around an empty space: its companion invisible, only inferred. In the binary system J0806, two white dwarf stars orbit one another every 321 seconds. Scientists think the stars are about sixteen hundred light-years away, are spiraling in toward one another, will eventually merge into one.

In my mid-twenties, I become melodramatically overwhelmed by the fact that the world will die. That it is dying. That all around me, everything I love, or imagine I might love, will vanish. Yet humans build things anyway. We are so invested in continuance, even when continuance is a myth. I am, in my mid-twenties, melodramatically moved by this too: that we do it all regardless.

I mentioned this once to my mother, how sad it made me to consider that it would all be lost—the languages, our history, even the record of our cruelties. I think it’s kind of nice, she said. We get to start over. Someone else gets to do it all differently. That we are spiraling toward or away from this, that there must be a moment of convergence between collapse and generation. That even if I press my hand against yours there is always a sliver of space between the two that belongs to neither one of us.

In the months after we meet there are hundreds of miles between us, and we send the same note back and forth like we’re waiting for the wonder to grow stale: Where have you been? How did it take us this long to discover one another in the universe? While often we’re just talking about teaching, oversleeping, to-do lists, needing to make dinner, I never stop feeling dumbstruck by our luck. How it settles in inside our friendship, our ordinary lives. We trade poems while we try to finish manuscripts. Each fragment has a corresponding fragment. Each star a corresponding star.

Is this what it feels like to believe that meaning is a force? Fathomless: without measure.

The letters start because we’re both at natural pausing points with other projects. They start like a joke: wouldn’t it be funny if we just wrote a book where we talked to each other?Then, very quickly they are not a joke at all: Dear M— / The dream where I am legless / is not a nightmare, and I am not / afraid there… Because your first language is my first language: you had / already been picked up, / held down, put under, / and refashioned; / you were already / dreaming your body. Every beginning is a tearing, until this one.

We write a book about loss, and I’m laughing. Your poem appears in my inbox, full of knives. At the same minute a message flashes on my phone: I killed us again, sorry! I can hear you like an electrical current underneath the ground.

We fathom something and then ruin it. I kill us and I’m sorry. But I mean I’m sorry to have taken the shape of something deliberate and taken us out of the equation. I want the space beyond us, the space that refuses us. Collaboration as a rearranging of matter into a shape that that has a weight beyond its parts. I mean that I imagine there is something in the between-ness of making that weighs something, though it’s indiscernible. The poem that wheels beyond itself, that wheels beyond the edges of what either of us can fathom.

I know you don’t believe in God, which is only strange to me because you feel like proof.

Dear M—, dear maker, dear miracle, dear mishap, dear misshapen, dear mistake. Dear monster, dear marvel. Dear marked and measured. Dear meaning. Dear moment, dear minute. Dear miscalculation. Dear matter. A world whose accumulation I can’t touch. A visible binary star.

You fly across an ocean to visit, and after months and miles your cab pulls up to the apartment gate. There, when the door opens, is the fact of you: suddenly a matter of matter. A world whose accumulation I can brush the surface of. A visible binary star.

My hands grip the handles of your wheelchair as we zip around London, and every time a cab driver tries to fold your chair into his trunk I want to scream don’t touch that or be gentle because this is what makes the world possible in a way he can’t fathom, in a way he can’t register. And I hate watching you watch them fold the frame roughly, and so I hurry to take the chair apart and put it back together before they can. I put my body between your chair and other bodies. We orbit wordlessly this way, in a binary system whose rhythm no one recognizes, whose existence no one sees.

Because you and I are both obsessed with catalogs and classifications, cabinets of curiosities and their arrangement, we spend much of our time together attending to strange collections: amputation saws spanning four hundred years, the tail feathers of so many kinds of birds pinned to parchment with the names penciled below, human hearts suspended in formaldehyde, the faces of women photographed working in a textile mill, rocks pulled smooth and shining from various stratifications of the earth. One thing I love: how thin the membrane is between the ordinary and the astonishing, how I can watch your face change as you pass through it. How often one of us will reach back and pull the other through the window with her. How, if you’re leading, I land someplace I never would have ended up alone.

At the Natural History Museum, we see the fossil that first linked dinosaurs and birds. Tiny bones and the imprint of feathers in a sheet of rock, and then the mirror image, the corresponding sheet: the space the bones left when they cleaved the rock apart. The evidence so small we almost miss it. A thing I love about the world: how arbitrary and accidental and lucky our survival. How we’ve landed here in spite of ourselves.

Someone wields a chisel and our understanding of evolution changes. Someone else wields a surgical knife and the human body is illuminated. They cleave a thing apart—create two from one—and light enters the space between.

As the poems we wrote together make their way into the world, we sometimes ask one another who wrote these? Always in a whisper. They wheel through that sliver of untraversable space between our hands, which is why sometimes I feel as if I hardly know them. This is also why I love them in an utter, stunned, and startled way I’ll never love a thing I make alone. Between us is an opening that isn’t any kind of wound, an opening that yields a thing so much larger than itself.

Often, the museums are dimly lit, and I have to bend close to the placards to read descriptions of the objects. Often, you are two steps away, and we oddly mirror each other as we make our way through, doubling back to see the same thing more than once. The glass that protects each object reflects our faces together as we try to look inside: two faces superimposed on a plant pressed between plates, the leaves still green, our faces floating improbably among them.

A light enters the space between us and makes things strange again: the discarded leaf I saw on the ground as a child floats back to me here, and in this light it is alive. In this light, the scars that wind my legs aren’t the traces of a wound but the records of the moment light first entered my body’s dark and someone looked inside, turned a starless expanse into a glistening landscape of tissue and organs.

This is what I mean when I look up at the skylight in the attic of the ancient operating theater and think God.

I’m delighted someone else gets to do it all differently. That all of this will vanish and someone else will look inside, and what they see will be beyond measure. What we know will be rearranged and someone else will record what it becomes. That they will behold the world around them and make meaning out each fragmented part.

In the attic of the ancient operating theater there are two lights and two small tables, and all the emptied bottles of ether are blue or bruise black like the bottom of a river, and they all say poison. There are two of us, and you’re two steps above me, and you’re looking down at the theater below, then up at the ceiling, up at the sky.

At the museum, we peer inside a glass case full of knives, our faces in the glass, the light dim and low. A sliver of space between us when one of us doubles back, pauses, and the other says, I know.

Read more of Molly McCully Brown and Susannah Nevison’s collaborative work at poets.org.