What Travels Faster Than the Speed of Light?
One frequent question I get is whether we can break the light barrier—because unless we can break the light barrier, the distant stars will always be unreachable.Most textbooks say that nothing can go faster than light, but that statement actually should be qualified: The answer is yes, you can break the light barrier, but not in the way we see in the movies. There are, in fact, several ways to travel faster than light:
1. The Big Bang itself expanded much faster than the speed of light. But this only means that "nothing can go faster than light." Since nothing is just empty space or vacuum, it can expand faster than light speed since no material object is breaking the light barrier. Therefore, empty space can certainly expand faster than light.
2. If you wave a flashlight across the night sky, then, in principle, its image can travel faster than light speed (since the beam of light is going from one part of the Universe to another part on the opposite side, which is, in principle, many light years away). The problem here is that no material object is actually moving faster than light. (Imagine that you are surrounded by a giant sphere one light year across. The image from the light beam will eventually hit the sphere one year later. This image that hits the sphere then races across the entire sphere within a matter of seconds, although the sphere is one light year across.) Just the image of the beam as it races across the night sky is moving faster than light, but there is no message, no net information, no material object that actually moves along this image.
3. Quantum entanglement moves faster than light. If I have two electrons close together, they can vibrate in unison, according to the quantum theory. If I then separate them, an invisible umbilical cord emerges which connects the two electrons, even though they may be separated by many light years. If I jiggle one electron, the other electron "senses" this vibration instantly, faster than the speed of light. Einstein thought that this therefore disproved the quantum theory, since nothing can go faster than light.
But actually this experiment (the EPR experiment) has been done many times, and each time Einstein was wrong. Information does go faster than light, but Einstein has the last laugh. This is because the information that breaks the light barrier is random, and hence useless. (For example, let's say a friend always wears one red sock and one green sock. You don't know which leg wears which sock. If you suddenly see that one foot has a red sock, then you know instantly, faster than the speed of light, that the other sock is green. But this information is useless. You cannot send Morse code or usable information via red and green socks.)
4. The most credible way of sending signals faster than light is via negative matter. You can do this either by:
a) compressing the space in front of your and expanding the space behind you, so that you surf on a tidal wave of warped space. You can calculate that this tidal wave travels faster than light if driven by negative matter (an exotic form of matter which has never been seen.)b) using a wormhole, which is a portal or shortcut through space-time, like the Looking Glass of Alice.
In summary, the only viable way of breaking the light barrier may be through General Relativity and the warping of space time. However, it is not known if negative matter exists, and whether the wormhole will be stable. To solve the question of stability, you need a fully quantum theory of gravity, and the only such theory which can unite gravity with the quantum theory is string theory (which is what I do for a living). Sadly, the theory is so complex that no has been able to fully solve it and give a definitive anwer to all these questions. Maybe someone reading this blog will be inspired to sovle string theory and answer the question whether we can truly break the light barrier.
Shameless Screen Grab courtesy of Big Think
And as a Bonus Delight;
Breaking the Speed of Light and Contemplating the Demise of Relativity
Einstein was in his mid-20's when he published his special theory of relativity which become an absolutely essential tool for scientists, physicists, theorists and experimentalists around the world today. Some of the concepts that were introduced were time dilation, length contraction, and his famed theory of mass-energy equivalence with the introduction of E = mc2. One of his other concepts, and the subject of this blog entry, was Einstein's introduction of the cosmic speed limit which states that no physical object or information can travel faster than the speed of light in a vacuum.
Shortly after the publishing of his special theory of relativity, he immediately began working out equations that encompassed geometric views of gravitation and introduced new and exciting concepts that replaced Newtonian mechanics, which had lasted 250 years. Scientists had been able to calculate low energy effects of gravity for centuries with Newton's theory, but until Einstein, what actually caused it had remained a mystery. Einstein's general theory showed the world that gravity was caused by the bending of space and time. So in short, it's not a gravitational force that is holding us all firmly down to the ground but it's space that is actually pushing you down. The theory explained such phenomenon as the bending of light by gravity and opened up the entirely new field of cosmology. The theory also made entirely new predictions, such as the Big Bang theory and also black holes, which continue to be a rich source of research for scientists.
Needless to say, Einstein's theory has with stood the test of time for almost a century and if there's one data-point out of place, we would have to throw the entire theory out. So everywhere we look into the heavens, Einstein's theory of general relativity comes right on the spot.
Last week, an international team of researchers and scientists reported that they have recorded sub-atomic particles appearing to travel faster than the speed of light. Over a period of three years, neutrinos were shot from the particle accelerator at CERN in Switzerland to a detector in Italy (the OPERA - Oscillation Project with Emulsion Tracking Apparatus) about 500 miles away. What the team found interesting was that the neutrinos arrived around 60 nanoseconds quicker than the light would have traveled. This recent result from the accelerator at CERN, which seems to contradict Einstein's theory of relativity, has generated enormous interest, among scientists as well as the public. However, not much has been written about precisely what this means for relativity itself.
Special Relativity of 1905, as discussed above, is based on the idea that the speed of light is the same, no matter who measures it, as long as you move smoothly and do not accelerate. This violates Newton's common sense notion that there is nothing special about the speed of light. Hence, something has got to give. So, our common sense notion of the universe must change if light speed is the same no matter how we measure it, whether it is coming toward us, away from us, or sideways. What gives is space-time. Hence:
- Time gets slower in a rocket ship as it goes faster.
- You get heavier as you approach light speed.
- You get squeezed the faster you move.
All of the effects above have been observed. For example, our GPS satellites slow down a bit as they whiz overhead, just as Einstein predicted. There is also cosmic waves and particle accelerators that are also used to verify this fact.
If you get heavier the faster you move, then the energy of motion has turned into mass. The precise amount of kinetic energy that turns into mass is easily calculated using relativity (the derivation is 1 line long) and that result is the most celebrated equation in science, E = mc2.
So why is light speed the maximum speed in the universe? As you approach the speed of light, bizarre things begin to happen such as:
- Time Stops
- You are Infinitely Heavy
- You are Infinitely Thin
If you exceed the speed of light, then you get nonsense such as:
- Time Might go Backwards
- You are Heavier than the Universe
- You have Negative Width
For these reasons, Einstein stated that you cannot go faster than the speed of light. This also affects general relativity, which is the foundation of cosmology, since (for small distances) general relativity reduces down to special relativity. Hence, both are wrong if the recent CERN experiments are correct. Not only is cosmology, nuclear physics, atomic physics, laser physics, etc. all in doubt, but also the fundamental theories of particle physics are also thrown in doubt. The Standard Model of particle physics (containing quarks, electrons, neutrinos, etc). is also based on relativity and would also mean that string theory, my field, may also be wrong. String theory has relativity built-in from the start and the lowest octave of string contains the entire general theory of relativity.
So you can see why physicists are breaking out in a cold sweat contemplating the demise of relativity. Not only will all textbooks have to rewritten but we will also have to recalibrate all our physics calculations, not to mention all of our theories of both nuclear, atomic physics and cosmology. What a headache! So, I think most physicists are holding their breath, wishing that the recent CERN experiment is shown to be flawed and something of a false alarm. However, there is the slim chance that the result holds up. Then relativity may fall and we will have to await the coming of the next Einstein who can make sense out of it all -- In retrospect however, This is How Science is Done.
Shameless Screen Grab courtesy of Big Think
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-Lord Malignance
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