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platoprime t1_j8jp0pp wrote

>The question being, we're able to describe the physical wavelength in nanometers of these waves that apparently aren't oscillating in space so much as they oscillate between electric and magnetic fields. ...how do you assign a unit of length to that?

Okay I see your confusion. The electric and magnetic fields are overlaid on top of space so they are 100% physically oscillating up and down and side to side as they move through space. If you're talking about motion through one of the fields you're talking about that motion occurring through space.

After all a field is just a value assigned to every point in space.

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Grand-Tension8668 OP t1_j8jz4i7 wrote

u/shikuto's comment got me to sort of picture how EM fields are waves (they're traveling through space as they oscillate, after all, which is all a wave is), but it's still surprising to me to say that the change in polarity is actually a locational change, if that's what you're saying.

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platoprime t1_j8k2kyv wrote

No I don't mean to say polarity is spatial movement. Polarity is a change in the intensity of the electromagnetic field along a line over time.

However it's important to understand that photons are not localized until they interact with something. When they travel through space they don't have definite positions or momentums.

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karantza t1_j8kcf9s wrote

It's definitely not a locational change, but it does have a direction and "intensity", which drawings often represent as if it were a distance.

The electromagnetic field is a vector field, so it points in a real direction, and that gives us polarization. So as light travels in a straight line, oscillating in intensity between the E and B fields over time, those fields do have a direction, but no distance offset from the beam path.

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shikuto t1_j8m27fx wrote

It looks like you managed to tag someone with a 1-character difference from my username. I wonder what the chances of that are. Anyhow, I’m the one that supplied the assistance, not the innocent u/shikoto - please leave them out of this. I will take the punishment.

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