06 Feb

a few questions

What is energy made of? When someone says “that has potential energy”, or “electrical energy” or “nuclear energy”, you know exactly what they mean, but what is energy actually made of? Can you extract energy from some action and show it to someone? Can you draw energy? Possibly a silly question… – maybe “energy” is an example of a “meta-attribute” (something which does not physically exist, but only exists in context)

Why does refraction happen?The usually metaphor used to describe refraction is a model car rolling along on a smooth surface like Lino, and encountering a rougher surface such as carpet, at an angle. Because a car is multi-dimensional in shape, part of the car will move onto the carpet before the rest, which causes that part to slow down, which causes the entire car to turn towards that side of the car (thus, the car is “refracted” by the carpet). Light, however, is usually portrayed as a single point which is travelling really fast. Does a point have sides? When entering a refractive object, can part of a photon be said to be “in” the slower medium, while the rest is still outside? If so, then I understand refraction, but it seems to me that light needs to be explained a bit more clearly in school…

Is the speed of light a constant or not? There have been reports of scientists recently slowing light to a crawl. Surely, that makes the speed of light a variable? Or, is c (the letter used to describe light-speed in physics) not actually “the speed of light”, but “the maximum speed of light”?

When approaching the speed of light, does “time” actually slow? It seems to me that if the speed of light is the fastest speed possible, then that can cause perceived time dilation while moving, without inventing actual malleable time. For instance, imagine a simple action such as passing a cup from one hand to another. Easy – takes a second. However, imagine you are now sitting in a spaceship travelling at the speed of light. Logically, you cannot now pass a cup from hand to hand, as simple vector math will show that be doing that, the cup will actually be travelling faster than c. Similarly, if perceived time depends on, say, an electron “ticking” around an atom, then at the speed of light, time must seem to stop altogether, as the electron will not be able to orbit the atom, as part of that orbit will be travelling faster than c. (similarly, as you /approach/ c, time will appear to “slow down”, when in fact, it just takes longer to perform any task, including thinking)

Am I wrong? Enquiring minds want to know…

6 thoughts on “a few questions

  1. Ok… this is filed under philosophy – that complicates things somewhat, but I’ll still attempt to answer based on basic physics perspective. I should not do this, since I think you’ve though about this a lot more than I ever have, and I’ll be cornering myself pretty quickly šŸ™‚

    We need to start with the third question; whether the speed of light is constant or not. It is not. c is actually “the speed of light _in vacuum_”, not just “the speed of light”. When going through something other than a vacuum (which, in physics, should be considered to be the lack of anything which might somehow affect “the light”) the speed of light is different.

    This also answers a part of your second question; the part whether “the medium affects the speed of light” – it does. To answer the question more fully, we need to understand that all matter is mostly built of nothingness – all that matters is the gravitational powers; not the atoms themself. The light is actually moving between the atoms of any given medium. Due to the impossibility of determining both the speed and position of a particle at the same time, we might as well say that yes, it is possible for a one-dimensional particle to be both inside and outside something in three or more dimensions at the same time. However, the medium is not as important as the powers caused by the atoms of the medium that affect the light particle in question – after all, the light particle seldom “hits” the atoms, it goes past them guided by the forces.

    Then the first question, “what is energy made of”. That’s simple; it’s the mass multiplied by the speed of light in a vacuum squared. So, you can draw energy as easily as you can the two aforementioned – that’s philosophy … or insanity, whichever suits your taste better šŸ™‚

    The last question requires that we take into the equation an outside observer for whom the time travels at a standard rate. From his/her viewpoint, the time for those nearing the speed of light appears to slow down. For those traveling, the time dilation does not appear to happen, since as the time slows down, it is their time slowing. In actuality, if they were observing the outside observer who is continuing to go on at the standard rate, his/her time would appear to be speeding.

    This also somehow solves the problem of passing a cup while traveling at (near)lightspeed. Compared to the standard rate observer, the cup would appear to be traveling at more than the speed of the traveller nearing the speed of light. However, for you, the one nearing the speed of light, the cup is only moving at the speed your hand can move it away from you – you, the traveller, are not the outside observer.

    To sum everything up, time essentially does stop while traveling at the speed of light. As time can only be accounted from moving from somewhere to somewhere else, and as the speed of light in a vacuum is one of the components of calculating energy, when you travel at the speed of light, your energy at that point is infinite, which means you have all the mass in existence, meaning that you have no need to travel to anywhere, since you already are everything there is, and time can not be calculated.

    Philosophical enough? Feel free to knock me down my rocker at any time šŸ™‚

  2. Marku, whenever I think of relativity, my hair raises. I wish my brain would just leave me alone and do something more productive than ponder silly things that I’ll never get to test for real.

  3. On refraction, I remember reading about the properties of light you might also find interesting. It was on dead paper, so I don’t have a reference. So, if you look at the path the light takes between two points, it is the shortest line in a single type of environment. If there are more “matters” to pass through, like in a box of half air, half water, refraction happens, but this broken line is still the shortest possible one between the two points (as in, taking the shortest time).

    I’m not sure if the above description made sense, but if you think about the “slightly” more complex paths a photon can travel from a distant star to your eyes, it sounds incredibly spooky. One attempt to explain “how” is even less imaginable: if you consider *all* paths (not just the possible ones), they all cancel out, leaving only the one we see. So in a quantum-reality, maybe every (impossible) photon path is real and happening, we just experience the resulting, single, perfect path.

  4. That actually does make sense. I need to think about it more, but the same idea could also explain gravity, if you were to think of “space” as a matrix of points, and to assume that large mass reduces the number of “links” between the points of the matrix (an idea that occurred to me while walking to work one day). I could be wrong.

  5. I need to think about *that* a bit more šŸ™‚
    I managed to remember a few books (dead paper, eh, where was I šŸ™‚ that helped to improve my attitude towards relativity and cosmology:
    Stephen Hawking: A Brief History of Time; George Gamow: Mr Tompkins in Wonderland [newer: Mr. Tompkins in Paperback]; and a more obscure one: P.W. Atkins: The Creation.

  6. on further thought, increasing (not decreasing) the number of nodes around a large mass (maybe that’s what “mass” means – the number of nodes connected to an object?) would cause things to bend towards it

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