|Originally posted by bdb55
That means that the energy found in one can of soda pop (140 kilocalories) could accelerate 7.16X10^11 electrons to the speed of light.
Woah! Woah! Woah! Here's to hoping that you're joking.
The section below is from here: http://homepage.sunrise.ch/homepage/...pace-time.html
Contemporary physics states that no object should be able to travel faster than the speed of light
c = 299'792'458 m/s (metres per second).
Although the value of c appears to be enormous when compared with conventional traveling speeds, it suggests a limit which renders a practical realization of interstellar travel improbable. Whereas another planet in our solar system is reachable within minutes or at least hours at the speed of light, a journey to the nearest star system Alpha Centauri would already demand a traveling time of several years. Surely, the question remains: Are faster-than-light speeds possible? At the present time most scientists believe that the correct answer should be "no". However, it has to be emphasized that there is no definite proof for this claim. Actually, whether superluminal speeds are possible in principle depends on the real structure of the space-time continuum, which contemporary physics ignores, however. Basically, there exist two distinct notions of space-time in physics, both of which represent a possibility:
Galilean Space-Time (GST)
Minkowski Space-Time (MST)
Briefly, whereas Galilean space-time allows the realization of faster-than-light speeds, at least in principle, Minkowski space-time does not. What is the reason for this difference? In the next sections it is exposed that the key point is the conception of global time, ie. the physical significance of the term simultaneity. In fact, what does it mean when we call two spatially separated events "simultaneous", actually? What we need is a clear physical notion of past, present and future, not only on a local but on a global level.
It is important to note that without some definition of global time the physical quantity speed (and thus light-speed) has no definite meaning anyway. Why? Consider an example: Imagine an object moving from position A to B. Its speed v is given by the formula
Here, the start time t(A,start) and the finish time t(B,finish) are read off from two spatially separated clocks: one clock is located at point A and the other one at point B. Now, the difference of the two times in the denominator t(B,finish) - t(A,start) is an indefinite expression, unless there exists a rule how to synchronize both clocks, because clock B ignores the "current" time at clock A at first. But, in fact, the decision in favour of a particular synchronization rule is pure convention, because it seems impossible to send an "instantenous" (infinitely fast) message from A to B like "Initialize the clocks now!". Thus, the actual quantity of speed is conventional too, depending on the particular choice of the simultaneity definition.
The question concerning global time is also important in the context of different reference frames. What is a reference frame? A reference frame R is simply a coordinate system of some observer. (For instance, let us imagine a physicist experimenting in his laboratory.) The observer attaches to all physical events personal coordinates, ie. space coordinates x, y, z (where?) and a time coordinate t (when?). Another observer in his personal reference frame R' attaches to all physical events another (not necessarily equal) set of coordinates x', y', z' and t'. (Let us here imagine another physicist who is working in a train moving with constant velocity v with respect to the reference frame R.) While two events may appear simultaneous in reference frame R (happening at equal time t), does this still hold in reference frame R' (at equal time t')? And while the physical laws have a particular form in frame R, does one obtain the same formulas in frame R' also? The answer is given by a theory which relates the new coordinates x', y', z', t' to the old ones x, y, z, t. Essentially, this is what a theory of relativity is all about.
Remark: For a better understanding of the distinct space-time concepts it is fruitful to study a geometrical representation of space-time, the space-time diagram (see below). In this picture four-dimensional space-time is reduced to two dimensions. Instead of three space x, y, z and one time coordinate t, one uses only one space and the time coordinate, x and t, respectively. (Obviously, it is much more easier to draw and think in two than in four dimensions.) For reasons of convenience the units are chosen such that the speed of light equals unity c=1. Hence, a light ray, which is described by x=+ct or x=-ct, appears as a straight line in the (x,t)-plane at 45° or 135°, respectively.
The reader is encouraged to reconstruct the arguments by studying the space-time diagram. Remember that the x-axis is the line of simultaneity (ie. with constant time t=0), and that the t-axis is the line of constant position (x=0).
Although, from a paper in Galilean Electrodynamics:
"IS THE VELOCITY OF LIGHT CONSTANT IN TIME?"
by Alan Montgomery, Mathematician
218 McCurdy Drive, Kanata, Ontario K2L 2L6 Canada
Lambert Dolphin, Physicist
1103 Pomeroy Avenue, Santa Clara, CA 95051
The possibility that the velocity of light, c, is not a fixed constant is reconsidered by statistical analysis of the historical measurements collected from four sources. Our hypothesis testing of the selected data shows the measured value of the velocity of light has decreased over the past 250 years.
going back to the original question, I'm sure that if we wait long enough and drink enough soda while listening to this cable, their claims will not be ridiculous. But for now, I think we'll just have to settle for a less silly claim, like maybe something like this: "By adjusting the cable, you can introduce alternative realities into your listening session in which music may go backwards and your food may try to eat you."