21 September 2022

"Hey prof, you know time stuff, right? Quick question."

Professor Abel frowned slightly and closed his eyes, pressed his fingertips against his temples. In the wake of the announcement last month, he'd become a bit of a minor celebrity. The most immediate effect of this was that he'd spent much of the past three weeks trying to explain the basics of temporal mechanics to inquisitive parties, with varying degrees of success. His enthusiasm for the whole thing was wearing dangerously thin. "Let's hear it."

The student hesitated. "You know the grandfather paradox? Like, if I go back in time and kill my own grandfather before my father is born. What happens if I really do that?"

Abel nodded. He'd fielded this one a lot. "The short answer is that you can't."

The kid was undeterred. "Yeah, I read that, but none of the articles talk about the big problem," replied the kid. Nick, that was his name. A decent student. Not one of his best. "What if I did manage to go back and, like, find my own grandfather, and then I point a gun at him and pull the trigger. I mean, what happens? Do I disappear, or..."

Abel watched the last few stragglers from his class as they filed out. One girl dropped her phone and bent over to pick it up, affording him a criminal display of cleavage. His mind began to wander; he wished he weren't on the wrong side of forty.

Presently he became aware that Nick was waiting for a response and he tried to refocus. "You couldn't do it. It's impossible." Abel paused, collecting his thoughts. "But it's not as though there's any one step involved that you wouldn't be able to carry out---well, nothing a priori. Given the motivation and resources, you could make it back to your grandfather's time. The rest of it would be straightforward, ethical issues notwithstanding.

"But time loops are every bit as binding and immutable as gravitational attraction.

"As a whole, it's impossible to carry out because you're here. You already didn't shoot him, and therefore there's no sequence of future events that could result in his premature death. Once you grok the physics, the paradoxes melt away, and the question itself becomes a non sequitur. You'd literally have a better chance of walking outside and jumping into orbit.

"But you could get it in your head to try anyway, and that's where things become interesting," said Abel, warming up to the explanation. "The universe would actually seem like it were deliberately conspiring against you at every turn. But no, you wouldn't just disappear. Reality is far more creative than that. Our current understanding is that the obstacles you're most likely to encounter are those events that were most probable to begin with.

"Bear with me, I've got examples. For instance, the building with your time inverter might lose power, or you might have written down the wrong address for your grandfather. Maybe you make it all the way there but the gun jams, or maybe you get hit by a car when you walk out the door that morning. Nothing overtly sinister or inexplicable. Aside from that, it could be almost anything, and the only guarantee you'd have is that it wouldn't seem suspicious on its own. I'm sorry I can't give you anything more definitive than that, but this is the only plausible theory we've got."

The boy seemed unhappy with this answer. "I guess I got it. But I thought of something else, too. What if the fact that I'm here now doesn't prove anything after all? Because what if I go back and shoot him, and instead of changing things here and giving you paradoxes and stuff, it makes, like, a parallel universe where I'm never born?"

This was another concept that Abel had run into a fair amount in recent days, so he was prepared. The question was essentially gibberish predicated on a gross misunderstanding of quantum mechanics, but you didn't become a professor without learning how to give good answers to bad questions. "Nice thought, but the problem there is that any internally consistent set of axioms we've come up with that can incorporate time-like loops ultimately necessitates a single-universe model, or the math doesn't work out. Even if there are some sort of 'parallel realities,' or a multiverse, or whatever you choose to call it, it won't make a difference. We're effectively isolated---at least, where time travel is involved. We're stuck with our one timeline."

Nick spent a moment digesting this, then said, "Guess it's a good thing we can reuse it, huh?" Still, Nick seemed unhappy with the answer. He was starting to object, but someone called over to him, so he thanked the professor and excused himself. As Abel finished packing up his things, he resolved to write a primer on this stuff to share with anyone else who buttonholed him. The core theory and its possibilities were endlessly fascinating, but answering the same half-dozen questions over and over was not.

"Dr. Abel?"

He looked up from his briefcase to find the room empty but for a man he didn't recognize, standing by the doorway. The man was maybe in his late forties. He was slightly soft around the middle but stood with a posture and bearing that screamed military. He wore an understated dark suit and carried nothing.

"Yes, I am. What can I do for you?"

"I'm not sure. Perhaps nothing, but perhaps a great deal," said the man, stepping closer and offering his hand. Abel shook it. The man had a confident, efficient, single-pump shake. Military-esque. Abel was less than surprised. "I've spent several days meeting with scholars in your field. They all tell me that you're the best."

Abel more or less agreed, but adopted an appropriate level of modesty. "I suppose that's fair, but a lot of that is luck. I sunk a lot of time over the past decade into following the theoretical work, back when everybody thought the whole thing was a pipe dream. That gave me a bit of a head start on everyone who's been playing catch-up since the announcement."

"As far as I can tell, that's pretty much everyone but you," the man said.

"Well---yeah, pretty much. Except for J.D. and his team at Berkeley, of course. It was all I could do to keep up with what they were publishing. It's a smart group of kids they've got down there, it truly is." Abel looked pointedly at his watch. Between classes and a flurry of speaking engagements, he had plenty on his plate already without getting entangled in some governmental affair. "Come to think of it, if you're chasing down a consult for something, why not go straight to the source? I know they're under some pretty stringent security now, but you strike me as someone with connections. And if not, I could maybe shoot him an email and put in a good word for you."

The man raised an eyebrow but remained silent for several moments. He seemed to be considering something. After a glance back toward the empty doorway, he spoke, quietly. "Doctor, nobody's seen J.D. or his team in over six days."

"What do you mean? Last I heard, nobody's seen J.D. or his team for about a month now, since right after they went public. I think they're still locked up in that god-awful army complex outside Berkeley. 'For their own protection,' that's the party line. It was all over the news, not sure how you missed it."

"Air Force."


The man sighed, took a phone out of his breast pocket. "It's a U.S. Air Force complex, not Army." He traced a couple of small gestures on the phone and held it up for Abel to see. The screen was displaying an ident indicating that Abel was standing in front of one Colonel Jack Shaffer, USAF Liaison. He knew that Shaffer's phone was locally broadcasting authcodes, that his own phone would notice this and automatically query a central government server for verification. He could check his phone now and instantly see whether this man was truly Colonel Shaffer, but doing so would be a breach of etiquette. Besides, under the circumstances, he found little reason to doubt it.

Shaffer tucked his phone away and continued. "And it really was for their protection. You remember how crazy it was those first few days? After the demonstration vid got leaked on the Tube and everyone saw it was the real deal? People literally thought J.D. was going to somehow consign humanity to oblivion, or flat out incite the wrath of God. A lot of people. The NSA logged more credible death threats in one week for J.D. alone than they had on record for anyone else in the country over the past twenty years. If we hadn't moved to secure them when we did, I assure you that things would have ended suddenly and tragically."

Abel was taken aback. He'd known the situation had been tense for a while there. Daily protests-turned-riots, plenty of political and religious leaders calling for J.D.'s imprisonment while the issues were discussed. A few of the fringe elements openly proposed assassination, but Abel had only laughed at the time. He'd written it all off as groupthink and reactionary posturing in a brave new world. More to the point, he'd corresponded with J.D. a number of times over the years, and knew the guy to be pleasant and mild mannered. The notion of anyone seriously wanting to do him harm was difficult to wrap his head around.

But so far Shaffer had asked for nothing, and Abel was inclined to give him the benefit of the doubt. "Say I take your word for it. With your connections, you must know what they were up to these past few weeks, right? My imagination's been running wild."

"I've told you what I can," replied Shaffer. "Hell, I've told you more than I should have already. SOP would've been to make you sign an NDA before giving you the time of day. But your background check came back spotless, and in any case, I'm operating with some fairly wide latitude here due to the time-sensitive nature of the situation."

"In other words, you don't know." Abel tried not to sound disappointed.

"I'm saying that if I did, I couldn't tell you." Shaffer shrugged. "Though as it turns out, you're right. The tech stuff is someone else's department. My job has more to do with greasing the wheels between the USAF, Homeland Security, and a few other entities, making sure things run smoothly, silently, and securely." He gestured expansively. "Alas, things have not gone as smoothly as we would like. Look, I'll level with you, Professor. Bringing you on board was not Plan A. That said, we're way, way beyond Plan A at this point, and it's just possible that your cooperation will improve our chances of resolving this mess, so I hope you will agree to provide it."

Abel wondered at exactly how desperate the man was. Shaffer's expression remained stoic, but his words struck Abel as a genuine plea, and he was inclined to help if he could. "Okay. You said J.D.'s team went missing a week---"

"Hey, prof!" Nick had reappeared in the hallway. "Just wanted to ask if it would be cool if I turned in my project proposal two days late. I've got a camping trip scheduled since like forever. White Mountains, it's gonna be awesome."

"It'll be a ten point deduction. I went over that on the first day. Check your syllabus."

"Yeah, fine. Thanks," he said, and drifted off down the hall.

Shaffer seemed to have second thoughts about their venue. "That's enough talk here. If you want to help us---if you want to help J.D.---we should leave immediately." He cut off Abel's protests. "We can have anything you need from your apartment overnighted, and I've already spoken to the Dean about a sub for your classes. You'll have to decide now, though."

Abel looked at the stack of ungraded exams on his desk. He thought about watching J.D. on the Tube a month ago, all shyness and stammers at the press conference. He thought about time travel.

Really, it was no decision at all.

>> Chapter 2