"Speed of Light"

[freyar]

It's looking at the physics by only interpreting the endpoint events: A photon is emitted; somewhat later, somewhere else, subject to spacetime, curvature, interference, and probabilities, a photon is absorbed. That the photon crosses space is looked at as a bookkeeping detail: Figuring out where the photon will be absorbed. The intrinsic event is the emission and absorption, together as one unified event, which happens to occur at two different points in space-time.

That's what you might do if you were making a simulation, and only cared about the emit and absorb steps. Computation of the path that the photon took (or could take) would be a way of figuring out where the absorb occurs.

That's a reasonable picture, but I don't think any physicist I know would consider emission and absorption as a single event. In particular, "event" is usually defined to mean a point in space-time.

I should mention, though, that is the quantum mechanical picture. That is how we describe physics at the microscopic level, but, in many contexts, it's much more useful to use the approximate picture of classical mechanics, in which the photon really does follow a definite path.

 

[Scott DeWar]

So, A thought: Energy never really disappears, or is destroyed, right?It 'changes to a different form of energy' If I recall being told. Is there a way to follow the path using the Femto-cam technology?

 

[Umbran]

That's a reasonable picture, but I don't think any physicist I know would consider emission and absorption as a single event. In particular, "event" is usually defined to mean a point in space-time.

Not as such. You can have a single Feynmann diagram for a particle-antiparticle pair annihilating to a photon, and that then emitting to a particle-antiparticle pair, which is close....

I should mention, though, that is the quantum mechanical picture. That is how we describe physics at the microscopic level, but, in many contexts, it's much more useful to use the approximate picture of classical mechanics, in which the photon really does follow a definite path.

Goodness, yes. You'd only use such a treatment for very short-range interactions. When you're talking about a photon that travels a light year, a mile, or even a few inches, you generally use the classical approach.

 

[Janx]

Yep. Massless particles are special.

I'm just extending my "what if the limit is because it's a simulation" idea here.

Is it possible that things like Photons exist because they artifacts of a rendering (aka display) proecess rather than actual matter?

consider in a video game (like minecraft), all the matter is modeled and effects are dealt with. Then, the rendering step kicks in to compute what is displayed to the viewing portal (the player's screen based on it's relative position in the game universe).

As Minecraft actually has to project rays from light sources to computer light/dark levels as it renders the image, what if the proposed universal simulator has to project photons from pertinent objects, in order to compute what the individual observers (us) see?

Thus, these things are massless and have odd properties (like always traveling at c relative to the observer regardless of how fast the observer is traveling) because they serve functional purposes for the simulation?

I'm not actually wholly enamored of the recent "universe is a simulation" movement, but there are ideas that are interesting from it.

 

[Bullgrit]

Something that twists my noodle:

Shoot a beam of light (like in the camera demonstration above), and you can see the beam from the side (90 degrees off its line of fire) -- that means photons are coming off the beam to the camera lens. I presume photons are being deflected off molecules toward the camera, and the beam is not *producing* more photons. Yes?

But the TED video, when showing the around the corner viewing potential, seems to show photons hitting a surface and "exploding" into more photons.

Bullgrit

 

[tomBitonti]

I'm just extending my "what if the limit is because it's a simulation" idea here.

Is it possible that things like Photons exist because they artifacts of a rendering (aka display) proecess rather than actual matter?

...

I'm not actually wholly enamored of the recent "universe is a simulation" movement, but there are ideas that are interesting from it.

(Text omitted.)

Yeah. There turn out to a number of conceptual problems which clear up with a computational approach. (Consider entanglement as the universe using lazy / deferred initialization.)

While not strongly advocating that approach, I do find it to be a curiously useful approach. But maybe, that's because I do software, and the meaning of "computation" is pretty wide.

There are problems: What about photons which vanish into space, never to encounter anything?

 

[Scott DeWar]

Something that twists my noodle:

Shoot a beam of light (like in the camera demonstration above), and you can see the beam from the side (90 degrees off its line of fire) -- that means photons are coming off the beam to the camera lens. I presume photons are being deflected off molecules toward the camera, and the beam is not *producing* more photons. Yes?

But the TED video, when showing the around the corner viewing potential, seems to show photons hitting a surface and "exploding" into more photons.

Bullgrit

I am guessing the sight of the 'photon bullet' in the coke bottle was diffused light from being scattered by the water. I am further guessing that a light beam in a vacuum would not have anything diffusing it and therefore no viewing from the side, as noticed when you look perpendicular to a line of sight between a star and earth, you can't see the beam or as long as it is not shining through an exploded star, 'dust motes'.

 

[Janx]

(Text omitted.)

Yeah. There turn out to a number of conceptual problems which clear up with a computational approach. (Consider entanglement as the universe using lazy / deferred initialization.)

While not strongly advocating that approach, I do find it to be a curiously useful approach. But maybe, that's because I do software, and the meaning of "computation" is pretty wide.

There are problems: What about photons which vanish into space, never to encounter anything?

As I figure, if Umbran said "yes, it could be that", it doesn't mean photons confirm the existance of a universal simulator. Just as coal being useful for making torches, doesn't mean coal exists for the purpose of such (in minecraft anyway).

It would strike me as a wasteful process to compute the path of photons that don't go towards observers. If it goes off to empty space, nobody's going to see it. However, from an object oriented approach, you don't know that until the photon goes forever and doesn't actually hit anything (or travels max diameter of the universe in its last projection/deflection)

Though I also don't know that I would need photons to travel in a simulation. As in a videogame, something is visible, the moment it is unobstructed. Light travels effectively instantaneously. Of course note, the video game is computing what's visible at 50-60 frames per second (at least on my PC for MC). Assuming the Universal Simulator is just time slicing (at say c frames per second), what technical purpose is served to model photons, instead of just showing me whatever's in front of my eye in each frame? I'm surmising that it might need to be some kind of performance optimization (so we don't have to check all 100 bajillion objects in the universe to see if I can see them to render an image for my eyes).

 

[Bullgrit]

Wonder if anyone has studied images of the universe for duplicate galaxies on opposite sides of us, to determine if we're seeing wrap-around.

Bullgrit

 

[Scott DeWar]

I took a peek the other day . . . . I will let you know what I saw when I catch up to myself. I had to borrow a bit of energy to do this so now I have to pay it back.