FUTURES: Breaking The Light Barrier – How space-time waves are propelling warp drives from fiction to fact
by A’liya Spinner
A Wrinkle in Space-Time
The warp-ship Chariot careened through the empty void of space, past the last reaches of lonely Pluto and towards the star-studded blackness of the “Between”— the vast, unoccupied space that separated solar systems. From the rounded bridge of the Chariot, the Between looked tiny, reasonable. But the expansive nothingness between those twinkling dots, the crew knew, was a voyage of tens of thousands of years.
Or, at least, it would have been just a decade or two before. Since then, technology had evolved to concoct a solution to the seemingly ungraspable limit of the speed of light, and now the Chariot was about to take its maiden voyage before the eyes of the entire world, and test if all those theories, trials, and simulations were really true. If humanity could, at least, break the light barrier and venture into and past the Between.
“Status on the Bubble?”
The helmsman— who was responsible both for navigation and for monitoring the warp-ship’s propulsion systems on the Chariot’s skeletal crew (to limit casualties incase of disaster)— looked up as the captain broke the tense silence. She glanced down to her console, at the monitors and dials and nodes. Everything was still within safe parameters; lights were green; alarms were silent.
“T-minus forty-five seconds,” she answered the captain, “electromagnetic plasma fields in place. All systems operational.”
“Good,” he answered, “keep ‘er steady.”
The helmsman nodded, but did not reply. The silence on the bridge was almost deafening except for the beeping and whirring of machines. Scientists both honored and terrified to be included on the mission crowded a monstrous steel amalgamation of instruments, monitoring and recording everything that happened inside and outside the craft. A representative from the United Nations sat, fidgeting, beside the captain, unsure what to do with her hands. The engineer who had pioneered the Chariot’s design and argued with the international government until he was allowed to be aboard her maiden flight paced in the back, watching diagnostics flash across impossibly complicated diagrams that he had long since committed to memory.
“T-minus fifteen seconds.”
The captain leaned forward in his seat. The helmsman’s hands shook, just barely, at the controls. Beyond the bridge’s window, the Between was beginning to be obscured by amorphous veins of plasma.
“T-minus ten seconds…”
The warp-ship shuddered as it drew in the last of its energy stores. The rumble of its traditional engines died away, replaced by the roar of electromagnetic current rushing through the reinforced walls.
The Chariot had become wreathed in energy, heat, and light.
“Two… one. Bubble ready, sir.”
The captain rose, standing amid his crew and vibrating warp-ship. Invisible to the eye, he knew space was beginning to fold in around the Chariot, preparing to severe them from Earth— from the universe as they knew it. He flicked his hand forward and breathed deeply.
自科幻小说诞生以来，超光速旅行（FTL）一直是科幻小说的主要内容，它有各种名称，如《沙丘》（1965）中的 “space-time folding“，《星际迷航》（1966）中的 “warp“，《星球大战》（1977）中的 “hyperdrive“，以及此后书籍、电影和游戏中无数的其他名称。但是，尽管它很受欢迎，科学界早已一致认同，超光速旅行在现在和将来都只是纯粹的虚构。甚至爱因斯坦在创建他著名的相对论时也补充说，没有什么东西能比光粒子移动得更快。随着时间的推移，这一理论受到了挑战，有人认为，虽然我们永远无法在真空中无障碍地达到或超过光速，但我们有可能加速在空气、水或其他物质中旅行的比光速更快的粒子——这已被证明是可能的。然而，使用极端的能量来推动这些粒子通过水，使它们在类似的环境中比光粒子移动得更快，这只是在技术上比光快。这种方法仍然没有使我们更接近在太空真空中比光速更快的目标。
Faster-than-light travel (FTL) has been a staple of science-fiction since the genre’s conception, known by a variety of names such as “space-time folding” in Dune (1965), “warp” in Star Trek (1966), “hyperdrive” in Star Wars (1977), and countless other monikers in books, movies, and games since then. But despite its popularity, the scientific community has long agreed that FTL travel is and always will be purely fiction. Even Einstein, when creating his famous Theory of Relativity, added that nothing could move faster than light particles. Over time, this theory was challenged by the idea that maybe, while we can never meet or exceed the speed of light unobstructed in a vacuum, we could potentially accelerate particles faster than light travelling through air, water, or other matter— which has been proven possible. However, using extreme amounts of energy to propel these particles through water so that they move faster than light particles in a similar environment is only going faster than light by technicality. This method still brought us no closer to traveling faster than light in the vacuum of space.
然而现在，可能有另一种方法。哥廷根大学研究员Erik Lentz提出了一种最终超越这些极限的方法–孤子。孤子是一个定义宽泛的科学术语，用来描述一个自我维持的、孤独的波包。与其他随时间改变形式的波不同，孤子有一个特定的形状，不会消散（这被称为克尔效应。）正因为如此，孤子能够永久地保持一个恒定的速度，而不会在互动过程中失去能量。伦茨提出，利用我们已经掌握的技术，时空结构可以被安排在一个孤子内部，形成一个 “曲率泡泡”。与物理物质不同，时空几乎可以以任何速度和方式弯曲和伸展；人造孤子将收缩它前面的空间，扩大它后面的空间，允许它里面的任何东西比光速更快，而不违反任何物理规律。
Now, however, there may be another way. A new theory by University of Göttingen researcher Erik Lentz proposes a method of finally exceeding these limits— a soliton. Soliton is a loosely-defined, scientific term used to describe a self-sustaining, solitary wave packet. Unlike other waves, which change form over time, solitons have a specific shape that does not disperse (this is called the Kerr effect.) Because of this, solitons are able to permanently maintain a constant velocity without losing energy during interaction. Lentz proposed that, using technology already available to us, the structure of space-time could be arranged inside a soliton to form a “warp bubble”. Unlike physical matter, space-time can bend and stretch at virtually any speed and in any way; the artificial soliton would contract space in front of it and expand space behind it, allowing anything inside of it to travel faster than light without breaking any physical laws.
How is this different?
高级推进实验室的研究人员阿列克谢·博布里克和吉安尼·马尔泰尔表示，大多数超光速计划都遵循一个包含现有正负能量的一般模型，但伦茨的想法是自成一体的。它建立在理论物理学家米格尔·阿尔库比埃尔于1994年提出的理论之上，即压缩和扩展空间时间是服从广义相对论的规则的，因为尽管你对外部观察者来说比光速更快，但你在 “曲率泡泡”内的运动速度会更慢，消除了以不可能的速度推动航天器的需要，而只是减少了它需要的旅行距离。这一概念在马德琳-朗格尔1962年的著名科幻小说《时间的皱纹》中得到了探讨，书中提到的皱纹是对时空结构的折叠，这能够使旅行者走捷径穿越浩瀚的太空。在这本书处于构思阶段时，这还远远不可能，但伦茨相信，他关于在孤子泡泡内重组时空的理论是超光速旅行的可行解决方案。这种内部配置甚至有可能通过在孤子内部配置一个最小潮汐力的区域来解决 “双胞胎悖论”——即其中一个以接近光速旅行的双胞胎将比他们在地球上的兄弟姐妹衰老得慢。假设，时间在泡泡内和泡泡外的进展速度是一样的，当旅行者回到地球时，两个双胞胎的年龄依然是一样的。
Most FTL schemes follow a general model that incorporates existing positive and negative energy, according to Advanced Propulsion Laboratory researchers Alexey Bobrick and Gianni Martire, but Lentz’s idea is in a class all of its own. It builds on a theory broached in 1994 by theoretical physicist Miguel Alcubierre that compressing and expanding space time is obedient to the rules of General Relativity, because although you would be traveling faster than light to an outside observer, you would be moving at a slower rate inside of the “warp bubble” itself, eliminating the need to propel a spacecraft at impossible speeds, and simply reducing the distance it needs to travel. This concept was explored in Madeleine L’Engle’s famous 1962 science-fiction novel, “A Wrinkle in Time”, in which the titular wrinkle is the folding of space-time fabric to send travelers on a shortcut across the vastness of space. At the book’s conception, this was far from being possible, but Lentz is confident that his theories on restructuring space-time within soliton bubbles is a workable solution to superluminal travel. This inner configuration could potentially even solve the “twin paradox”— wherein one twin travelling at close to the speed of light ages slower than their sibling on Earth— by configuring a region inside the soliton with minimum tidal forces. Hypothetically, time would progress at the same rate inside the bubble as out of it, and both twins would be the same age upon the traveler’s return to Earth.
Lentz’ proposal is especially important because it is one of the only theories for FTL travel that does not require the usage of negative energy, something that Alcubierre’s theory still relied on. In order to do this, the spacecraft would need to be immense, as negative energy is created when particles and antiparticles are separated by the pull of a concentrated mass and an imbalance is formed. But even if the theory is sound, the application is not. Alcubierre’s warp drive would’ve required the mass of the entire visible universe to propel itself. In 1999, a physicist named Chris Van Den Broeck proposed a more “reasonable” formula that expanded the volume of the warp bubble without changing its surface energy. This, however, still required the drive to have a mass equivalent to that of the sun’s, an improvement, but still well beyond the bounds of feasibility.
Erik Lentz’s warp bubble, too, requires vast amounts of energy— but positive energy only, which can be created through conventional means, such as nuclear fission. Right now, Lentz’s soliton wave requires thirty orders of magnitude more energy to create than is possible with modern nuclear technology, but he is hopeful that energy-saving mechanisms proposed in earlier research can potentially lower that amount to a much more reasonable range, at which point it may be possible to start building physical prototypes of his theoretical engine.
What’s stopping us?
The major obstacle between us and a functioning prototype of Lentz’s warp bubble is, as already mentioned, the energy cost. But, provided that can be solved, there are still some concerns that are only now being raised because of the newness of this theory— and there will be many more discovered in the future, without question. One such issue, for example, which was raised with the Alcubierre warp drive and was not solved by Lentz’s positive-energy variation, is that while the bubble is in operation, it is impossible for the passengers inside the fold of space-time to communicate with those outside of it. This brings up questions as to how a crew could operate and control such a craft, especially in potentially hazardous zones of debris, asteroids, or other obstacles that those inside of the bubble are unable to see. As of now, there are no known solutions to this problem, although we will undoubtedly see more serious conversations centered around faster-than-light steering surface as the technology to create these superluminal bubbles becomes closer to fruition.
The second major barrier is the creation of the soliton bubbles themselves. As well as requiring massive amounts of energy to propel and operate them, wave packets of space-time are not easily made. Lentz believes that the stress-energy of conducting electromagnetic plasma may be sufficient to create his solitons, but unfortunately, plasma made in modern laboratories is several orders of magnitude too small to produce anything of the scope Lentz describes. In his original paper, Lentz states that this could possibly be solved by further theoretical work at the interface between plasma physics and our understanding of general relativity.
But, even if that proves impossible, there may be another way— by “catching” solitons that have already been created. When aging stars in a particular size range exhaust their fuel, they collapse and go supernova, forming incredibly dense neutron stars. During this collapse, their magnetic field lines are trapped and compressed to incredibly high field strengths; neutron stars with especially powerful fields are called magnetars. Magnetars are the astronomical source of regular gamma ray bursts, and some scientists believe that the ultra-magnetized plasma surrounding these stars may spontaneously create Lentz solitons, which are then propelled away from the star at extreme speeds. Such events could be observed with the right gravitational wave detectors or radio interferometry, and thus may lead us to finding and possibly “catching” a soliton that already exists somewhere in our universe.
Time and Travel
The applications of a device capable of FTL travel are both obvious and limitless; it would revolutionize our ability to reach, research, and resettle on nearby planets, such as Mars. It would also, for the first time, grant us the ability to leave the confines of our solar system, and explore the galaxy beyond. Not only does this give us the chance to study more planetary bodies, stars, and astral formations, but make new and rare resources available to us with which to better care for our own planet and create more sustainable technology.
And— as fiction has speculated about in many forms— possibly discovering life in some form beyond planet Earth. Even if we cannot physically meet an alien race, sentient or primordial or wherever in between, warp technology makes us able to send messages and information across extreme distances very quickly (on a cosmic scale, at the least), which would expand the range of our probes and communication network to the point where perhaps we can observe or exchange phone numbers with our extraterrestrial neighbors.
These devices, however, could be useful on Earth, too. Earlier, it was mentioned that the soliton could be constructed to minimize tidal forces, but what if one could be made that does just the opposite? Dr. Sam Baron, a metaphysicist and Associate Professor at Australian Catholic University, expressed doubt that Erik Lentz’s machine could ever fly, and instead considered how the technology could be implemented as a time-manipulating device. By structuring the warp bubble just right, Baron postulated that time would pass slower or faster than it did in the outside world. The practical uses for this are boundless— growing crops overnight, prolonging the lives of terminally ill patients until a cure can be found, speeding or slowing reactions, decomposition, and even adaptation to aid in its study. Baron even proposed that rotating space-time bubbles inside of a warp drive could create a battery capable of storing immense amounts of energy.
无论它是用于时间还是旅行，或者两者兼有之，很明显，时空操纵和 “曲速驱动器 “正越来越接近于走出科幻小说，成为现实。与任何如此年轻的技术一样，我们很难预见到最切实在等待我们的陷阱，但一旦一个想法被带到公众和科学的视野中，它就很少被放弃，而且几乎从未被遗忘。尽管它不会以英勇的 “企业号”飞船的形式出现，但在我们的有生之年，超光速旅行将继续成形和盛行。也许我们甚至会活着看到——或成为——第一个走出太阳系、进入伟大的未知世界的人类。
Whether it’s used in time or travel or both, it’s clear that space-time manipulation and the “warp drive” is getting closer and closer to leaving science-fiction and becoming a reality. As with any technology so young, it’s hard to foresee the pitfalls that most certainly await us, but once an idea is brought to the public and scientific eye, it’s rarely given up, and almost never forgotten. Although it won’t be in the form of the gallant Starship Enterprise, superluminal travel will continue to take shape and prevalence in our lifetime. Perhaps we will even live to see— or be— the first humans to venture beyond our solar system, and into the great unknown.