Can We Travel Faster than Light?

from Through the Wormhole; Humans have always gazed up at the stars. For thousands of years, we thought they were as close as the Sun and the Moon almost close enough to reach out and touch. But now we know just how vast the Universe is. The closest star is about 25 trillion miles away. The fastest spacecraft we have today would take more than 10,000 years to get there. To become true citizens of the cosmos, we have to do something that physics says is impossible. We have to travel faster than a beam of light. Sean Carroll is a theoretical physicist from the California Institute of Technology. The mysterious nature of light gets his mind racing. The speed of light is 186,000 miles per second, or 670 million miles per hour. Nothing goes faster than the speed of light. It really is the maximum speed limit for everything in the Universe. These strange rules for how light moves inspired Albert Einstein to rewrite the basic laws of the Universe. He realized that space and time were not fixed and absolute but connected and relevant. It was an idea that led to the most famous equation in history "E" equals "MC" squared. Because we can never move faster than light, we're stranded in the solar system, with the stars impossibly far away. This man believes he can help us escape our cosmic prison. He think he's found a way to bend Einstein's rules and allow us to reach the stars. Miguel Alcubierre, a physicist in Mexico City, has invented the warp drive. The warp drive is a way to get from one place to another that's very different from the way we normally do it. One man does believe in negative energy. He even claims he's created it in his lab. The warp drive. It sounds like science fiction, but the idea of surfing across the Universe in a warping bubble of space would make perfect sense to Einstein. There is one snag. A warp drive can only function with a mysterious power source negative energy. And today, most scientists believe negative energy is just an unproven theoretical concept. But Steve Lamoreaux, an atomic physicist at Yale University, has made it his mission to track down this exotic form of energy, and he believes the answer is all around us in the fabric of space itself. Steve's discovery may only be a baby step towards warp drive, but he's confirmed that Miguel Alcubierre's warp drive theory does not violate the laws of physics. The energy needed to warp space and propel a warp drive forward actually exists. But he's also opened the door to something else the wormhole, a rip in the fabric of space itself. If this theoretical object exists, you could enter it in one place and emerge moments later clear across the galaxy. But are wormholes more than a science-fiction fantasy? And, if so, how would we know where they would take us? Now one physicist is daring to enter these strange portals and plot a course through the wormhole. We've all heard of wormholes. They're cosmic shortcuts that put alien worlds practically on our doorstep. But how would we actually build one? And how would we use one? Travel by wormhole requires exotic technology and the courage to jump into the unknown. Our planet is riddled with passageways. We regularly travel through strong, stable tunnels cut through massive mountains. Well, here we're entering a nice, solid tunnel. It's made of looks like concrete and reinforced steel. Very solid. A reliable means of transportation. I drive my car in. I'm gonna come out. I know what's happening at all times. Physicist Steven Shu is fascinated by the concepts of stability and instability, be they in the stock market, in real-estate values or in space-time wormholes. One of the fundamental properties that we look at in physics when we look at a particular system is whether that system is stable or unstable. An example would be a pen which is balanced like this. It might be okay when it's exactly balanced, but even a slight bump will send it into a drastically different state. We decided to look at whether one could build a wormhole that had nice properties such as its behavior is predictable and it's stable. Those are two criteria you'd like to have for a real wormhole. The rules of building wormholes start with Einstein's theory of relativity, which tells you how to bend and shape space as if it were a flexible sheet. Imagine this sheet of paper, and imagine that you're an ant living on this sheet of paper. If you want to travel from this point to this point, you might have to walk all the way from here to here. But if the paper were curved, the long way around would involve walking all the way around the paper like this. But you can imagine that there would be a little Tube connecting this point directly to this point, and the ant could just slip through. Wormholes in science fiction have gaping entrances that a starship can dive into. But those two-dimensional renderings gloss over the true architecture of wormholes. In this two-dimensional analogy, the opening of the straw is just a circle. But, because we live in three dimensions, the opening of the wormhole would actually be like the interior of a bubble. This is what the mouth of a real wormhole might look like if they are lurking somewhere out there in space. But Steven wondered if we might be able to build our own from scratch. A cosmic engineer would first create two mouths and connect them. Then, he would drag one of the mouths light-years away but the tunnel between the two mouths is not part of our space and could remain very short. It's a simple idea, but the vast amount of negative energy needed to keep the wormhole's mouth and tunnel from collapsing is tricky stuff to control. It's very challenging to stabilize a wormhole. All wormholes, as far as we know from general relativity, require this kind of special negative energy exotic matter. The question is whether that matter itself can be stable. Steven crunched the numbers on how negative energy would react with normal matter on the fringes of the wormhole to discover whether they could coexist in a stable way. And we've proven mathematically they're unstable. That would be a very dangerous device to use, because once you bump it a little bit, the entire device could just fall apart. If I try to get into an unstable wormhole, it's like trying to put my finger into this bubble. It'll just pop. The negative energy needed to keep a wormhole open is inherently too unstable. A man-made wormhole would collapse the instant someone tries to step inside. But there might be another way. Not by using cosmic shortcuts that we have built ourselves, but by searching for microscopic ones that could be hiding all around us. Just as empty space is fizzing with microscopic pulses of energy, some theorists believe it could also be riddled with microscopic holes. There could be quantum wormholes that are just left over from the Big Bang, or at very, very short distances, you could have little fluctuations where space-time just connects to itself in a funny way, and that would be a quantum wormhole. If they just happened as a little fluctuation, they would be incredibly tiny, like 10 to the minus-35 meters. Microscopic quantum wormholes are quantum fluctuations in space that perpetually appear, disappear, and reappear again. Since we don't have to construct their portals, Steven suspects they might be safe to enter. But before you try jumping into one, be aware there's a catch. Quantum mechanical things are fuzzy. They're intrinsically random and unpredictable. So if we were in a quantum wormhole, we might be shaken around, and we wouldn't quite know where we're gonna come out. You wouldn't want to get into a tunnel that might end in the bottom of the pacific ocean or on a mountaintop that you didn't want to be on. Quantum wormholes have no estimated times of arrival, and your destination is unknown. You could end up anywhere or anywhen. Traveling faster than light through a wormhole would be a risky ride. You've got to be willing to roll the dice. But there may be a safer way for the cautious traveler. Imagine being able to move from here to there without ever moving at all. Well, Mankind's first journey to the stars looks a long way off. We won't master the technology of wormholes and warp drives for centuries at least. But there's another way to zip around the cosmos. We could turn our bodies into information and send that information from place to place at the speed of light. Chris Monroe and Steve Olmschenk are quantum physicists at the University of Maryland. They are pioneers of teleportation. Their work is all about making connections between events taking place in two separate locations events which normally have no connection whatsoever. A scientist is turning the laws of physics upside down. And if he's right, the speed limit Einstein slapped on the Universe might have to be changed. We live in a Universe with a speed limit 670 million miles per hour. Well, that's what Albert Einstein said. But what if Einstein was wrong? John Webb has big plans. He wants to rewrite the laws of the Universe. John is an astrophysicist at the University of New South Wales. The bar codes he studies are not on packages of lettuce, but on light coming from distant galaxies. If you split the light coming from these galaxies into a rainbow, you'll discover that certain colors are missing. When light passes through atoms of interstellar gas, it can interfere with this exchange of photons and knock an electron out of its orbit, but only if the light has exactly the right amount of energy. So John began searching the heavens for glowing clouds of gas billions of light-years away. He used the Keck Telescope in Hawaii to look at the northern sky, and the Very Large Telescope in Chile which looks out on the southern sky. Electromagnetism is the force that is transmitted by light. So if the strength of electromagnetism is not constant, it means that the properties of light itself are changing. If John Webb is right, he's overturned one of the basic laws of the Universe. Once the laws of physics are allowed to vary in those equations, things have to be rewritten. So it's back to the drawing board for certain fundamental principles in physics. Could Einstein be wrong? Could the speed of light be different in different parts of the cosmos? On the other side of the world, one cosmologist is sure the answer is "yes." He believes that light can move much faster than we think, and that, out there in the Universe,

The spaceship actually stands still inside the bubble of space-time
The spaceship actually stands still inside the bubble of space-time

Traveling faster than light through a wormhole would be a risky ride
Traveling faster than light through a wormhole would be a risky ride

The experiment Time Machine
The experiment Time Machine

Two atoms of an element called ytterbium
Two atoms of an element called ytterbium
  there are superhighways to the stars. Back at the dawn of the Space Age, it was all about having the right stuff. The first people who journey to the stars will need it, too. They will be venturing into the absolute unknown, and, perhaps for the first time, traveling faster than light. Theoretical physicist Joao Magueijo thinks that there may be regions of outer space where faster-than-light travel is possible. He developed this radical theory because without it, he couldn't explain the way the Universe looks. When we look out into the Universe, everything looks the same in every direction. This is a problem, because during the time the Universe has lived, there really isn't enough time for light to travel around for features to be shared around the Universe, and this we call the homogeneity problem. Joao's theory solves the homogeneity problem just as effectively as cosmic inflation. But it also thumbs its nose at Einstein's golden rule. This does not exactly contradict Einstein's principle that the speed of light is the speed limit. We're only saying that the speed limit changed throughout the life of the Universe. And Joao's theory means there might be a way to break today's cosmic speed limit, because there could be pathways through space where the speed of light remains faster. These pathways are called cosmic strings. Under the varying speed of light theory, light traveled faster in the beginning of the Universe, and cosmic strings could be regions where this higher speed limit is still in force. The idea is that, in the first moments of the Universe, tiny fractures formed in space-time.     Since then, these fractures expanded along with everything else in the cosmos and are now billions of light-years long. Cosmic strings might serve as high-speed lines cutting across regions where you would otherwise be moving at a crawl. You could think of cosmic strings like the Tube in London where, on the surface, there is a speed limit, but obviously down there there isn't one. On the surface, Einstein's limit is the law. The Tube below is the cosmic string a faster way across town. If you could fit a spacecraft into the corridor of high speed limit created around the cosmic string, fast travel throughout the Universe would become possible. Cosmic strings have yet to be found, and the variation in the speed of light is still just a theory. But slowly and steadily, scientists like Joao Magueijo and John Webb are chipping away at Einstein's cosmic speed limit. You begin to wonder, what if it changes from place to place in the Universe, or maybe it was different early on in the Universe's history, and if the speed of light is changing, then a lot of what we think about physics could be different in the early Universe to today. Around the world, scientists are testing new technologies and probing deep into the heart of physics to uncover new laws of the Universe, to find a way for us to escape our island Earth. We are still a long way from becoming citizens of the cosmos. The stars remain almost unimaginably far away. But wherever science goes next, our hopes to explore this final frontier will never be dimmed. And, one day, we will reach it, because what man can imagine, man can do.
List with pictures of the scientists, in order of their appearance in Through the Wormhole Can We Travel Faster than Light? documentary, who share us their knowledges:
Sean Carroll
Sean Carroll (theoretical physicist, CalTech)
  Miguel Alcubierre
Miguel Alcubierre (physicist, Mexico City)
  Steve Lamoreaux
Steve Lamoreaux (atomic physicist, Yale University)
  Steven Shu
Steven Shu (physicist)
  Chris Monroe
Chris Monroe (quantum physicist, University of Maryland)
  Steve Olmschenk
Steve Olmschenk (quantum physicist, University of Maryland)
  John Webb
John Webb (astrophysicist, University of New South Wales)
  Joao Magueijo
Joao Magueijo (astrophysicist, theoretical physicist)