I learned from Bernadette that there are two ways a star can go supernova. The first is in a double star where one partner dies first, turning into a white dwarf, and the surviving partner swells in grief and dumps mass onto the compact star. But the atoms of compact stars can only hold up to a certain limit. The resulting explosion destroys both stars and nothing is left except a thin nebula, returning the atoms to space.

The other type of supernova is a massive short-lived star desperately trying to keep the fusion burning. When one fuel is burned to its ash, the star burns the ashes, forging new elements deep within. Hydrogen to Helium, Helium to Carbon, Carbon to Neon, all the way up to Iron. Iron, the ultimate ash, accumulates until it becomes too heavy and the core collapses, releasing a huge burst of energy.

I first heard Bernadette’s explosive laugh one day in the Science Library (where I work) and saw her curly mane of red hair framing an angelic face with bright blue eyes. When she checks out a book on stellar interiors, she tells me about the star Betelgeuse and how it could supernova soon—sometime in the next couple of decades. “Of course that means it actually used up its fuel and exploded centuries ago, but the light hasn’t reached us yet. Astronomers are bad at distinguishing past and present.”

Our first date is at the Hayden Planetarium watching a flight through the Orion Nebula. “Those dark areas,” she whispers, her lips brushing the ridges of my ear, “are terrible places to hide a starship. They only look dark because they’re light-years thick. The density in that part of space is less than the density of air on the moon.”

I couldn’t be more in love.

We walk down Central Park West after the show, and she points to the sky. “Can you see Betelgeuse there?”

I could, surprisingly. And a few other bright stars poking through Manhattan’s light pollution.

She turns to face me, reaching inside my unbuttoned coat to wrap her arms around my waist. “I really hope I live to see it blow.”

“You said twenty years. We won’t even be fifty by then. That’s plenty of time.”

Bernadette pulled away and started walking south, her gaze on her feet. “It might be a hundred years from now, or maybe a thousand if I’m totally wrong. But I’m going to hang on until it blows. I am Betelgeuse.”

We sit on a bench by the outer wall of the park and talk about books and movies and games we like—lots of overlap, some new things for each of us to try. “I need to get home,” she says without making any move to get up. She holds my hand before she stands and leans in for a long, deep hug.

We walk west past a few blocks of brownstones, and everything she talks about always comes back to astronomy, no matter how loose the connection, like when she started talking about Edwin Hubble’s misguided attempt at classifying galaxies with a diagram that looked like a tuning fork after we passed a street musician with a QR code on his open guitar case.

She stops by a glass tower, the entrance door level with the street. “This is me. Will I see you at the library tomorrow?”

We kiss, then reluctantly part. “You know where to find me.”

She opens the door, which clicks at her touch, then leans against a wall waiting for the elevator. She looks exhausted. I want to help her.

Bernadette didn’t come to the library the next day. But while I was thinking about her and her comment about the tuning fork, I suddenly saw my own project on reorganizing obsolete classification schemes in a new light. She wasn’t there on Tuesday, but I still felt good because my advisor thought my idea was brilliant. When I get to my shift on Wednesday, I see her sitting at a table with some other astronomy grad students I recognize, sitting in a wheelchair at the end of a table, a clear tube running to her nose.

She looks up and waves. “I pushed myself a little too hard the other day. I needed to rest.”

I think I see fear in her eyes, wondering if I’m going to not want to date anyone in a wheelchair. “Bring your chair on our next date, if you like. Whatever makes you comfortable.”

“How about my place tomorrow so we can play Jupiter Running?”

We dated for a year, defended our dissertations within a month of each other, then got engaged and applied for academic jobs at any school hiring both an astronomer and a librarian. Bernadette said the two-body problem for academic couples is even harder to solve than the three-body problem in physics.

But the dark mass growing inside Bernadette grew more massive and she collapsed one night in June on our evening stroll, me pushing her chair. I was talking since she was having trouble getting the energy to string more than three words together. Still, she still managed to finish a paper the next week, claiming Betelgeuse was even closer to the end of its life than previous estimates, even her own dissertation.

Then Betelgeuse exploded in September, visible to the east of the sun during the day. I took Bernadette out to Central Park to see it, but her phone buzzed the whole time—so many requests for interviews she had to start turning them down.

A few days later, after she had somewhat recovered from the exertion of the interviews, we go out at three AM to see the star casting shadows on the pavement. I sit beside her holding her hand. She’s too tired to talk but I see the wonder in her eyes and the joy in her smile. She never takes her eyes off Betelgeuse even though I hardly take my eyes off her. When dawn breaks, I get us breakfast from a halal cart, and we go to bed.

That afternoon I woke up but Bernadette didn’t.

Somehow, I didn’t let her death take over my life. I broadened my job search area and landed a job at a school in the western part of the state, a place with dark skies and a great observatory. They gave me a key to one of the telescopes so now I can go up and look at the growing Betelgeuse nebula whenever I want.