“OK, Kara. There’s something I’ve been meaning to ask you for a while now.” Lena sat down next to her girlfriend on the sofa, and gently took the smartphone from her hands.
Kara looked up, a little startled, and began to nervously adjust her glasses. “Um … sure, Lena, you know you can ask me anything, right?”
Her smile was slightly less brilliant than usual. Their status as “officially dating” was only a little over a week old, and there were still plenty of unexplored corners in the relationship, and unknown facets of each others’ personalities.
“It’s OK, Kara, I’m not going to drop any bombs on us.” She leaned in for a quick kiss. “I just want to understand things. You know how I get once I start to focus on an idea, right?”
Kara rolled her eyes. “You have the most obsessive mind I’ve ever seen. I wouldn’t want to be a puzzle you were trying to solve; I’d never stand a chance.”
Lena chuckled. “Well, actually …” she drew out the words as she grinned playfully at Kara. “You kind of are the puzzle that I’m trying to solve today.” She took Kara’s hand in her own.
Kara widened her eyes in mock terror. “Oh crap! What am I gonna do now? I’m doomed!”
Lena smiled and squeezed Kara’s arm. “You’re Kara Zor-El, Mistress of the great House of El, and you were slated to be the youngest-ever inductee into the Science Guild, the history of which went back thousands of years. Before you told me you were Supergirl, I only ever saw the adorable, slightly goofy Kara Danvers who I secretly fell in love with. I never suspected you were one of the most advanced intellects on the planet – if not the most advanced. You have no idea how sexy that is to me. I want to understand the things that you understand … at least the things that you can entrust to a human. I don’t want you to violate any Prime Directive Krypton may have had.”
Kara smiled at the Star Trek reference. “Lena, I trust you with anything. But I think that you may find that at least some of the knowledge I have, while it may be interesting, will not be very practical or useful given humanity’s current technical capabilities.”
Lena looked at Kara for a long moment. “I kind of figured that there would be limits. And I can respect that some of those limits are going to be more social than scientific, in the same sense that you shouldn’t hand a loaded AR-15 with full-auto enabled to a stone-knives-and-bearskins primitive. I fully expect that it would take years for you to explain everything that you know about how the universe works beyond Earth’s current scientific understanding, and many more years for me to fully understand it. I’m not asking for that. There are just some things that really keep me awake at night, thinking about how to understand them. I’m hoping you can help.”
Lena’s expression was so sincere, her eyes so bright and focused on Kara’s own, that Kara knew she couldn’t refuse anything Lena might ask. “Of course, Lena. Ask me anything, and I’ll do my best to help you understand whatever I know.”
“Well, ever since I first heard of Superman, and even more so since I met you, I’ve been trying to figure out how you fly. I always felt like if I asked Superman, his answer would have been ‘I just do it.’ I know Krypton had a much deeper understanding of physics than humanity has, and I suspect that a lot of what humanity knows as theoretical physics was much more fully developed on Krypton, to the point of real-world technological applicability. Again, I’m not asking you to violate any Star Trek-type Prime Directive, but I’m really dying to know how you do it. Can you tell me? Please?”
Kara smiled. “You know, in all the years I’ve been on Earth, you’re the first person to ask me that. And not only that, you’re probably one of the only people I could talk to about it who might actually understand what I’m talking about. I’ll be delighted to tell you what I can, but you might want to sit down – it might take a while.” Kara sat down on the sofa, and gestured for Lena to sit next to her. “So I’ll be skirting the whole Prime Directive thing by avoiding any actual equations, but you are definitely smart enough to take what I say and start working on them.” Kara looked steadily into Lena’s eyes. “Are you sure you’re ready for this?”
Lena felt a chill run down her spine at the thought of being the first human to see beyond the veil, to what she suspected was either confirmation or negation of Einstein’s theories, and possibly even a glimpse of a Grand Unification theory. She took a deep breath to steady herself, and nodded. “I’m ready.”
Kara grinned at her girlfriend. “Your heart is going crazy, Lee. I’m not going to introduce you to some kind of Universal Consciousness or anything. It’s only science.”
“I know, Kara, but I love science, and I love learning new things. This is going to be the newest, most amazing science I’ve ever been exposed to. You can’t blame me for being excited.” Lena caressed Kara’s forearm, gripping it nervously for a second before bringing her hand back to her lap.
“OK, then, here we go. First, you should know that while the theory behind what I’m going to explain to you is fundamentally based on Kryptonian science, the fine points and the way they actually apply in the real world are things I worked out on my own since I’ve been here on Earth. Kryptonians couldn’t fly on Krypton.”
Lena leaned forward, her eyes wide. “Holy cow, I never even thought of that. And you’ve figured it out? All by yourself?”
Kara blushed at the praise, smiling. “Well, I was genetically engineered to maximize my mental acuity, so I really kind of cheated.” She chuckled softly and took Lena’s hand. “In order to explain my flying, I need to give you a little background. You know the Standard Model theory that explains the Big Bang origin of the Universe, and Guth’s theory about the initial inflation of space itself, right?” Lena nodded. “And I know you’ve seen the Hubble Ultra Deep Field Image, because you showed it to me. So, keeping those theories in mind, if you could instantaneously teleport to the most remote galaxy in that image, and set up a Hubble-type space telescope there, and take another deep field image in the direction away from Earth, what do you think you would see?”
Lena looked at Kara for a moment, nonplussed. “More galaxies, of course.”
“Ten points to Ravenclaw. So human scientists have determined that the Universe is about 14 billion years old, right? And the farthest objects in the Deep Field Image are about 13.5 billion light-years away, which is logical. So the most distant visible objects in the deep image taken from that galaxy you teleported to are going to be about 13.5 billion light-years further away. As are the objects seen from the next galaxy, and the next, and so on. Are you with me so far?”
Lena nodded, seeing the direction this was going. “Yes, you’re pointing out that the inflation phase of the Big Bang was pervasive, and resulted in a universe that is effectively infinite.”
“Yes, but also no. This is one of the parts where I’m going to leave out some math. Humanity is very close to figuring out how to prove this, but I can tell you with great confidence that the universe is infinite. Now, if you just accept that for the purpose of this discussion, where does that place Earth’s physical location in relation to the universe as a whole?”
Lena thought for a minute. “OK, I’m not sure if I’m going in the right direction with this, but in an infinite system, every point can be described as the center, right? So Earth is at the center of the universe?”
Kara beamed. “Exactly. No matter what direction you go, there is the exact same amount of universe as there is in any other direction. The important thing to consider for this discussion is that this includes an infinite amount of mass, because as we’ve already pointed out, you’ll never run out of galaxies. The next thing to consider is the gravitational force exerted by an infinite amount of mass. The formula that Newton came up with for gravitational force is essentially correct for our purposes. If you use an infinite mass for one of the terms in the numerator, the force becomes infinite, right?”
Lena spoke up at that. “But in this case, to get to that infinite mass, the force has to travel an infinite distance, so the infinity-squared term in the denominator would more than cancel out the numerator, wouldn’t it?”
Kara smiled her best Lena smile. “You might think so, but it doesn’t. One of the things that human science hasn’t quite worked out is that in an equation that describes a physical phenomenon like gravitational attraction, it matters at a fundamental level which variable is being modified. Equations let us define convenient terms that we use to describe things like force or motion. Mass and distance and the like are fundamental properties that don’t need to be defined beyond setting parameters for measurement. In an equation, the doubling of any one fundamental value is not the same as doubling a different fundamental value. In other words, one gram does NOT have the same relationship to two grams as one meter has to two meters. You – humanity, that is - will not be able to physically discover or verify this until you develop instruments capable of measuring gravitational radiation directly. The ultimate effect in the case we are discussing is that the two infinities do not cancel each other out, and the only reason Earth is not being accelerated in some random direction is because we are at the center of an infinitely large, infinitely dense sphere. The gravitational force cancels itself out in every direction.” Kara paused, waiting for Lena to indicate that she was with her.
“So you’re not looking at the local effects here. I mean, obviously Earth’s gravity is still effective. And the effects of the moon and the sun haven’t been cancelled out. And it’s evident that gravity is the operating force that keeps the Milky Way rotating coherently, right? So at what scale does this cancellation come into play?” Lena scrunched her brow in concentration. “I mean, even at the largest scale we can observe, we have found gravitationally dependent mega-structures. Groups of galaxies forming these huge bubble-like arrangements, rotating around a common center…” Her voice trailed off as she imagined the scales involved.
“OK,” Kara began, “Here’s where the background comes in. Everything you just said is true. But consider that everything you can observe, everything that comprises those megastructures, is within the part of the universe that is close enough for its light to have reached Earth in the time since the universe formed. In the inflation phase, all of the objects potentially visible from Earth were close enough to each other that their mutual gravitational attraction had already been established. Other parts of the inflating universe were far enough away, and inflation was rapid enough, that the connection never happened, and what we can refer to as the “local” part of the universe is affected by the rest of the universe as though it is all concentrated in a point, or a singularity. There are an infinite number of these point/nonlocal pairings overlapping throughout space, but to an observer inside the universe, there is only one, centered at the observer’s location.”
“Just like every point is the center of an infinite universe…” Lena felt like she was beginning to understand.
“Exactly.” Kara smiled, proud that Lena was picking this up so quickly. “So now we come to my flying. In the strictest sense, I don’t fly at all. I fall. When I came to Earth and was exposed to the radiation from your star, Sol, something in my cellular function changed. In addition to the obvious enhancements to my physical strength and resistance to physical damage, my senses were greatly amplified. Some of those improvements are more or less common knowledge at this point – super hearing, and telescopic and microscopic vision for example. But most people don’t know that I can tell which shirt has been worn by a person, even after multiple washings, just by smelling it. I can read the writing on a newspaper by feeling a photograph of it with my fingertips. I can follow a trail underwater by tasting the traces left behind by whatever I’m following. And my other senses have been similarly affected.”
“Wait, what?” Lena interrupted. “That’s all five already. Hearing, sight, smell, touch, and taste. What other senses do Kryptonians have?”
Kara’s smile grew. “The same as humans, Lena. We all have a sense of time, a sense of balance, a sensitivity to magnetic fields, the ability to sense where our various body parts are relative to the rest of ourselves… and most of our senses can be broken down into multiple derivative senses, like color vision versus black-and-white vision. All of mine have been cranked up to eleven. But the most important one for flying is my sense of balance. Balance is how we detect and adjust to gravity. I can feel the gravity waves from every direction, just like we talked about earlier. I can feel the infinite mass all around me, even though it’s billions of light-years away. But even more than just feeling it, I can choose to focus on specific parts of it, while ignoring other parts. Just like listening to one person’s voice in a crowded bar, I can filter out the gravitational effects in one direction and allow myself to be affected by gravity from the other direction. I literally just let the universe suck me around.”
Lena’s eyes were as big as saucers. “Oh my God, Kara, that’s incredible! If we could figure out how to replicate that effect, we could have artificial gravity! The implications are unlimited!”
“I’ve done a few experiments. You know the basic equations. If I allow a completely linear acceleration, with infinite mass in front and no counteracting pull from behind, how fast could I go?”
Lena blinked. “Holy shit, Kara. You’d be relativistic almost instantaneously. You’d be a like bunch of photons. Jesus, I can’t – what the hell would happen?”
“So I went out into the desert one time, and gave it a try. I didn’t go full out or anything, but I punched it a lot harder than I had ever done before. For the shortest interval I could manage, which was something like a tenth of a second. My path was mathematically straight, and I accelerated from zero, heading due west to subtract about a thousand miles per hour from my speed. I left a plasma wake, probably some free quarks in the upper atmosphere. I was able to decelerate to zero and reverse course somewhere around the orbit of Saturn, and came back a little slower. For me, it took a total of less than ten seconds. For everyone on Earth, it took almost three hours.”
“OK, stop. I need to process this.” Lena’s eyes were darting back and forth as she mentally digested what she had heard. “You just told me that you can literally accelerate to the speed of light almost instantaneously, completely without inertia or reaction mass. Holy crap, just knowing that’s even possible is going to drive me crazy. There has to be a way to replicate the effect on a space ship. This opens up the whole galaxy, Kara! I mean, literally any star in the Milky Way is within reach! Even other galaxies…” Lena’s voice trailed off. “Wait a minute. Time dilation. Shit. This is only going to be practical in a very local region of space, isn’t it?”
“That’s right. If I had let myself go for just one minute of subjective time, I wouldn’t have made it back to Earth for thousands of years of objective time. On the other hand, a practical method of accessing these forces would enable viable colonization of compatible planets within fifty or so light-years of Earth – whatever length of time would be tolerable. There are twelve stars within ten light-years, and more than a hundred and fifty within 20 light-years. Rao, Krypton’s sun, is about 24 light-years away, and within that distance of Earth there are about 200 stars. There are a good number of potentially habitable planets in there; enough to allow humanity to expand for quite some time. But as you said, time dilation will make meaningful colonization beyond a fairly local region – or even meaningful exploration – impossible until faster-than-light travel is developed.”
“Don’t tell me you’ve got that figured out, too. That would make me crazy, unless you could give me some kind of hint, to point me in the right direction to work on it…?” Lena fluttered her eyelashes flirtatiously.
Kara laughed at Lena’s antics. “I’m so sorry to disappoint you, but unfortunately that’s not in my bag of tricks. Kryptonian scientists had been working on theoretical possibilities for ages – wormholes, folded space, warp bubbles, you name it. Nothing had panned out by the time Krypton exploded. The pods that Kal and I were sent off in were prototypes – our other interstellar craft were larger and slower, built for exploration and diplomacy. We had pretty much reached the practical limit for slowship exploration, which for us was about 20 light-years when we used cryogenic storage for personnel. Kal was in cold sleep for his trip. I was supposed to be, but my pod was knocked into the Phantom Zone before it activated. But anyway, we never did figure a way around the lightspeed barrier. Two of the six other intelligent races we had interacted with seemed to have developed ways to beat the speed limit, but they were very Prime-Directive-y with us about it. I think there’s some kind of interstellar secret society or something that you can only join by figuring out how to outrace a photon.”
Lena smiled and leaned in to Kara’s shoulder, taking her hand and lacing their fingers together. “So since you don’t know the secret to faster-than-light travel, you can’t violate any Prime Directive by telling me about it, right?”
“Nope,” Kara grinned at her. “There’s nothing there to tell.”
“And we’re sure it’s possible, since your friends can do it, yeah?”
“I’m sure of it. They never came out and said it, but our records showed them getting around without time dilation issues. There’s only one way to do that.”
“And any ideas a mere human might come up with - not mentioning any names - in conjunction with a random Kryptonian - again, not mentioning any names – would be new material, not subject to any kind of interdiction?”
Kara’s smile grew again. “And any technology derived from those ideas would be fully patentable. I can see right through you, and I don’t even need X-ray vision.”
Lena swatted her arm playfully. “That’s not where I was going, silly. Though I wouldn’t complain if that was where we ended up. I just want to do some original science with my brilliant girlfriend.” She kissed Kara’s cheek. “I love how smart you are. It’s an incredible turn-on for me. And I can’t imagine anything that would make me happier than working with you on something like this.” Lena cupped Kara’s chin and gently turned her face so they were eye to eye. In her most serious voice, with sincerity oozing out of every pore, she solemnly asked, “Kara Zor-El Danvers, will you be my lab partner?”
Kara dissolved in helpless laughter. Lena’s smile threatened to bruise her cheeks as Kara gasped for air. After three or four unsuccessful attempts to respond, punctuated by fits of giggling and guffaws, Kara finally managed to speak. “Of course I’ll be your lab partner, you goofball. Oh my Rao, I’ve never laughed so hard in my life. You’re crazy, and I love you for it. We’re gonna have so much fun with this.” She pulled Lena in close and kissed her. “And we’re gonna have so much fun with this, too…”