Prime Eval, Part 13 – Light

After reading Richard Feyman’s book, QED, I got to thinking about the recent spate of astronomy articles on Specifically the ones about finding ever more distant, older galaxies. According to the Feynman diagram, electrons randomly emit and absorb photons, and photons are particles that act like waves. So, here you have this galaxy, which has millions of stars, and each star has an uncountable number of electrons that are firing off photons all over the place. And some of those photons are aimed in the direction that Earth is going to be in 16 billion years.

And now, for 16 BILLION years, those poor little photons are zipping along, waiting to intercept another electron in order to move on to the next phase of emit and absorb. Naturally, some of those photons will run into cosmic dust, or other high velocity particles, along the way and be re-radiated, but there will be 16 billion year old photos that were never absorbed. And, if Feynman is right and photons are particles, these are 16 BILLION years’ old particles. If they had decayed, they’d have to reconstruct themselves again right away, and keep doing that along the entire trip.

One of the side corollaries of Einstein’s E=mc^2 formula is that as an object approaches light speed it gains mass (according to my physics professor in 1982; who knows, maybe the definition of mass has changed since then). And what travels at light speed? – Light! But, if light is made up of photons, and photons are particles that act like waves (as Feynman said), and those particles have mass, why don’t photons have infinite mass when traveling at light speeds? Additionally, if you slowed them down to less than light speeds, would the mass of photon particles go to 0?

There have been a few videos on youtube purporting to show what our solar system would look like to a ship traveling at light speed. A few commenters have complained that the math used in these simulations is for out-of-date formulas for General Relativity. Me? I’m wondering what the universe would look like to that 16 billion-year-old photon…

Which brings me to instantaneous travel. The thing about light is that it isn’t instantaneous. It may look that way at short distances, but as we know, light takes time to go from point A to point B. In fact, the speed of light is close to 3.00×10^8 m/s. The reason this is important is that by knowing how long something is going to travel, you know where it’s going to stop. That is, if you get into a car in Chicago, and drive around 8 hours in a northwesterly direction, when you stop you’ll be in (or right around) Minneapolis. Draw a line from Chicago and Minneapolis, specify a velocity for the car, and you’ll easily be able to determine where along that line the car will be if you stop it at time “t”.

But, if you invoke instantaneous faster-than-light transportation, the time taken from point A to point B is going to be 0 (or to any other point along your line). And if it’s zero, you’ll have no way of controlling where you are along that directional line. In fact, you will be on every point of that line simultaneously, and when you stop, you could end up anywhere (or, you turn into an infinitely thin plasma and end up nowhere at all).

So, if you look at Star Trek-style transporters, they can’t be instantaneous, because you wouldn’t be able to control where you reappear. And if they are near light-speed, you’re creating what is effectively a death ray (both for what you’re teleporting and what you’re aiming the teleporter at). I still argue that it’s better to melt down your passengers at point A, and just transmit the recipe for recreating them with a 3D printer at point B…

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