From the author: This story is about time travel, but mostly it’s about how sometimes people in a relationship change at different rates, and how sometimes they’re not quite in the same inertial frame of reference.
After the sharp pop of resistor discharge, Alexander flung open the chamber door. Maria stood, head down, her straight black hair hanging over her face, bracing her arm on the wall.
"Maria! Oh, thank God you're okay! I'm sorry, something went wrong and it took me a few minutes...here, sit down."
He moved to help her, to comfort her. When his arm slid around her back, she stiffened and pulled away. She ignored his hand and stepped out onto the lab floor.
"The machine didn't track you like it was supposed to. I had to do it manually, took me an extra ten minutes." Now that he could see her clearly, her face looked different somehow. Thinner. Tired, maybe. "Was it...difficult?"
She turned and slapped him hard across the face.
It was so unexpected, that Alexander didn't even have time to flinch. It knocked the breath out of him in a sharp huff.
"You absolute asshole," said Maria, tears spilling down her cheek. "After all this time, you should have just left me."
"Relativity" refers to the fact that all events are relative to an observer in a frame of reference. Two events occurring simultaneously to one observer may occur at different times for another. This is known as "relativity of simultaneity".
Maria had collected herself in his office, standing on tiptoe to stare out the tiny window onto the grass quad. Office space was highly contested at the University of Chicago, and even the tiny, ill-placed window was a mark of distinction for someone under 30.
"God, this place," she said. "I'm sorry, it's just so disorienting."
"You'll feel better with some food. Let's go get some Pho."
She shook her head. "You know, I never liked it. You did, that's why I pretended."
Her laugh was like acid.
They walked instead to the only Italian restaurant, not talking the entire way. Maria couldn't stop looking around at everything. Sometimes she would shake her head and chuckle to herself.
They sat in a booth and took the menus.
"I think we could use a bottle," said Alexander. "Merlot?"
"I thought it was your favorite –"
She ordered pinot grigio and chicken marsala. Alexander ordered broccoli alfredo.
"Maria, I want to apologize. You've obviously been through something that I can't understand –"
She laughed that acid laugh again, but then she softened and took his hand. It was the first time she had touched him.
"I'm sorry. I know you did what you could. And you did it! I made it to 2070. It actually worked." She sounded tired rather than triumphant. "It was December 2081 when you pulled me back."
Her words washed over Alexander like a bucket of cold water.
"But I...Maria, it was only ten minutes..."
"For you. For me, it was eleven years."
Their food came, which gave Alexander time to think. The machine had not tracked Maria properly. When he had manually tuned the device to relocate her, he had been extremely lucky to have found her in the timestream at all. Why had he assumed immediately after for him would be immediately after for her?
Alexander clenched her hand tighter until the waiter left.
"My God, Maria! It must have been terrible. I know it's not enough, but I am so, so sorry." And then, after a few seconds: "I love you."
Maria squeezed him back and then withdrew her hand. She did not answer with her customary, "I love you too."
She took a deep breath. "I knew I would come back, just not when. I found...records. Of my death. In the past." She corrected herself. "Present."
"Why didn't you come back yourself? If you were trapped there, why did you wait for me to do it?"
Maria sat forward suddenly.
"That's just it. Alex, there's no time travel in the future. No record of your work at all. Even after I realized, I thought maybe if I could read your papers and worth through the parts I didn't know...but there were no papers. Or...anything else."
She trailed off, then started again as animated as before. "You are still going to publish, right?"
"Of course! I mean, with your permission, of course. But, despite our setback, we did it! You're the first time traveler! Why would we not tell the world? We're going to be the most famous people in history."
Maria bit her lip. Suddenly she threw her napkin on the table next to her untouched dinner and stood up.
"We have to go back to the lab. Right away."
"Maria, what's going on?"
"Something must happen to prevent this from getting out. You're right; we would be the most famous people in history. But we weren't. We have to get everything: hard drives, paper copies, anything. We have to keep it safe."
Later, after they had boxed up anything necessary to his research except the machine itself, they went to his apartment and made love.
Based on the everything that had happened, Alexander had expected Maria to be hesitant or cold, but she wasn't. If anything, he was the reluctant one.
It had only been three days since they had made love, at least from his subjective time, but this Maria was an entirely different person. She was more eager, but slower. More giving, but more demanding too. Her body was softer, her hair smelled different. Afterwards, Alexander felt vaguely guilty, like he had cheated on his Maria.
Maria lay next to him in the bed, not quite touching him. She spoke low.
"I'm worried we can't change anything. I'm worried it's all one timeline, and anything we do now can't change the future I was in."
"Was it terrible? Does something happen?"
"No, no, nothing like that." She chuckled. "Actually, you'd be surprised at how much is the same. I'm just worried about you."
"You said I'd never published the work, but that doesn't make sense. Why wouldn't I? Maybe in that timeline you never came back, and I thought it didn't work."
Maria shook her head. "I told you, I knew I'd come back and die in this timeline. The only timeline. But..."
The "But" hung in the air between them.
"There's something else you're not telling me. Did you find me in the future? You must have gone to see me; I could have helped you get back."
She was quiet for a long time, but Alexander's heart was racing. There was something she didn't want to tell him, and it was about his future.
"I didn't at first. When I first got there, it was hard for a while. We didn't plan on a long trip. I didn't have anything. I had a little money in my pocket, but I needed a place to stay. I had to find a job, I had no records...Anyway, I kept expecting to come back at any moment.
"I didn't know if it would cause some kind of paradox. I didn't want to know our future, or cause something to happen that wasn't supposed to happen. I..." she faltered. "I didn't want to see us old. Or not together."
"And we weren't together?"
She rolled her back to him and pulled the sheet over her shoulder.
"You weren't there at all," she said softly.
He might not have heard her if he wasn't so still, hanging on her every word.
"With me, there were records. I bought a house. I got married. Am going to get married. I had a death certificate." She cleared her throat. "You didn't have one. You didn't have anything. After the time I left here, you didn't publish any papers, get any traffic tickets, so much as win a blue ribbon at the fair for your prize pig. Nada.
"I could only think of two possibilities: one, that you came after me. Maybe that was naive--"
"Or two," she continued, overriding him, "that someone found out what you had done, and made it disappear."
They were both silent then. Alexander didn't know who fell asleep first, but when he opened his eyes, it was morning.
It follows from relativity of simultaneity that time may appear to move differently relative to the speeds of observers in different frames of reference. This is called "time dilation".
Maria grabbed her coat. Alexander sighed.
"You're going out again tonight?"
"Yeah, well, what am I supposed to do, stay here and watch you make graphs and type?"
"You didn't used to mind."
Maria exploded. "I don't care what I did or didn't used to do! That was a long time ago for me, and you can't keep throwing it in my face. I'm me right now, and I want to go for a walk!"
"I just like having you around. What's wrong with that?"
"What's the point? You hardly even know I'm in the room."
"It's nice! It's romantic."
"It's weird, and immature."
Alexander closed the lid of his laptop a little harder than he meant to.
"Find, forget work. What if we watch a movie?"
"I don't want to watch a movie. I want to go for a walk."
"But we used to--"
"Alex, damn it, I'm trying here! I'm trying. We've been dating for what, 2 years?"
It stung Alexander that she didn't know, but before he could say so, she continued.
"I was gone for eleven years. Eleven. I've known people that don't even exist anymore longer than I've known you. I've...been with people longer than I've been with you. People I'll never see again. And I'm trying really damn hard not to hold that against you."
Alexander sighed. "Maria, believe me, I'm trying too. I'm adjusting, but it's just taking me a minute. You've changed so much--"
"That's the problem, Alex. I've changed. You haven't."
Maria stepped outside and slammed the door.
Time and space are not independent concepts, but rather a single entity called "spacetime". One consequence of this is "length contraction" in which the physical dimensions of an object may be different (larger or smaller) made by an observer in a different frame of reference.
By the time Maria said, "Alex, I'm moving out," Alexander wasn't really surprised. That didn't stop him from pleading.
"Please, Maria! I know I've been busy with the research, but you're the one who's been pushing me to get it ready."
"It's not that. I just need a little distance, okay? It doesn't mean we're over, it just...I can't slip into my old spot like a hand in a glove. I've got to make a new spot."
"Maybe you could if you tried harder! You don't want to see our old friends, do the things we used to do--"
Maria chopped the air with her hand, cutting him off, but she didn't take the bait. Instead, she said, "I can't do it again."
Alexander winced. "I know, I'm sorry. I didn't mean to bring it up again."
"No, not the fight. This." She spread her arms indicating the apartment. "Waiting. Trying not to get close to someone because every minute I'm expecting a change. Going through the world like a ghost, killing time until whatever is going to happen to you happens. Being...stuck."
"Then don't be stuck! Please, Maria, stay with me. I know you don't think I'm changing, but I am. And this thing that you think is going to happen...maybe it doesn’t."
The old Maria might have caved, might have deluded herself, might have convinced herself she was being foolish. Might not have known what she wanted.
Maria kissed him. "You're a great guy, Alex. I need some time to figure out a few things, but I'm finally going to go figure them out instead of waiting for them to come to me."
She took only her coat, and she left.
One upside of relativity is "gravitational lensing", in which light bends around super-massive objects. This quirk allows observers to see objects, which would otherwise be impossible to see.
I assume it is you who finds this note, since there was no reference to a missing person report in the future.
I've thought a lot about what you said the last time we spoke; analyzing data has always been a strong suit of mine.
I have come to the unfortunate conclusion that you are right about everything. As long as I am here, you will be trapped by me and by the ghost of who you were. As long as you are here and not with me, I will be trapped by that ghost as well.
If it is true that the future is immutable, then my research is not published by 2081. If I stay, then I am taking a chance that this is true. Instead, I am taking the only chance that either of us has.
I am taking it all with me to 2082. I would like to say that I'll return, older and wiser, as you have. But I realize now that would just be another trap. Go, buy your house, get married. You don't need to wait; I will not be back.
I only hope that my future contains someone as wonderful as you.
This story originally appeared in Analog.