Since there is no time from the perspective of a photon, there is only one photon everywhere at anytime. Our perception of multiple photons is incorrect. Its just multiple timelines with the same photon.
Does light have an infinite lifetime?
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Re: Does light have an infinite lifetime?
#62Earlier quoted context omitted.
I believe proton decay is still considered hypothetical, and the electron is pretty confidently believed to be stable; https://profmattstrassler.com/articles-and-posts/particle-ph... is a good overview.
> I believe proton decay is still considered hypothetical Definitely. > [link] is a good overview That overview seems to overstate the likelihood of proton decay. In fact, it has it backwards. The default position is that protons are stable, per the standard model, not that they're susceptible to decay.
> The default position is that protons are stable, per the standard model, not that they're susceptible to decay.
It's only the "default" in the sense that the simplest model explaining data gathered to date (the standard model) predicts no decay. However, most physicist do not believe the standard model is the last word (and surely it cannot be when you go to the Planck scale), and many models post-SM models predict proton decay. I would guess if you surveyed high energy physicists, you'd find the majority expect the proton does in fact decay, so it's the "default" in that sense.
Re: Does light have an infinite lifetime?
#63Where do the photons that hit my retina go when I finish with them? If they have infinite lifetimes then does each one carry a memory of it's creation event? When I burn a log in my fireplace and a cinder flares and pops creating a spark, does the photon exist after the spark energy flares out and the cinder is no longer illuminated enough to be detected by my eyes? If photons are infinite then harvesting light would…
Feynmann is very clear that the photons bouncing off a mirror are not the same ones that hit it. They are absorbed by electric oscillators (free electrons in the material) and destroyed; then new ones are created and emitted. He's also careful enough to point out that electrons don't really have an identity that would allow you to meaningfully define "not the same". :)
It could be the same electron after all. Although probably not.
One electron theory. https://youtu.be/9dqtW9MslFk?si=qdWGUyJnDRCOns9F
Re: Does light have an infinite lifetime?
#64Earlier quoted context omitted.
My understanding is that photons don't have a life the way we do. They move at the speed of light and thus time does not advance for them. They cannot change between emission and absorption, no matter the distance. Always bends my mind to think about it.
> They move at the speed of light and thus time does not advance for them. Isn't it more accurate to say that photons move at the speed of causality , when the medium is a pure vacuum? Because in some other medium like glass, the speed of light is slower than the speed of causality. So my follow-up question is: do slower photons (such as those propagating through a fiber-optic strand, or water) then experience the ad…
There is no such thing as slow photons, photons always travel at the speed of light.
When light enters a medium there are two mostly (but not entirely) equal ways to think about what happens, one is to view light as a purely electromagnetic wave that interacts with atoms and causes the atoms to oscillate. This oscillation produces its own electromagnetic wave that interferes with the original wave. The result of this interference will be an electromagnetic wave with the same frequency, same amplitude, and travelling in the same direction as the incoming light but shifted backwards and it's that shift backwards that gives the appearance of light slowing down.
That explanation is pretty good and accounts for almost everything except for the latency of light through a medium.
If that's what you want to model, then it's better to think of light as made up of photons instead of being a wave, and then when photons enter a material they no longer exist as independent particles but through a process of absorption and reemission by electrons in the material become particles called polaritons. Polaritons do have mass and hence travel slower than the speed of light.
Neither of these explanations are perfect, but the full explanation is ridiculously complicated and there's no suitable metaphor for it. If you are interested in knowing the edge latency of light through a medium, then the polariton explanation is appropriate. If you want to know the "bandwidth" explanation of light through a medium, then the wave explanation is appropriate.
Re: Does light have an infinite lifetime?
#65Earlier quoted context omitted.
But at a reflection event you aren't producing a new photon, you are only reflecting a portion of the original determined by the refractive indices of the reflection interface. At that interface, part of the original photon is reflected and the rest is transmitted across the interface as a new photon and both have a modified bandwidth relative to the parent photon. So the one you see reflected is the same photon afte…
That would imply a frequency shift, which clearly doesn't happen (mirrors don't redshift the light that hits them).
I balked at that too, because infinite mirrors and mirror houses also don't show any wavelenght shift no matter how many reflections they do. They do change perceived amplitude, as no mirror is perfectly reflective.
Re: Does light have an infinite lifetime?
#66Anybody care to attempt a TL;DR of this?
Re: Does light have an infinite lifetime?
#67From the perspective of a photon, there is no such thing as time. It's emitted, and might exist for hundreds of trillions of years, but for the photon, there's zero time elapsed between when it's emitted and when it's absorbed again. It doesn't experience distance either.
Re: Does light have an infinite lifetime?
#68Earlier quoted context omitted.
Electrons aren't unique in not having identities. Photons of the same wavelength are similarly fungible if I remember right, though it's a little more defensible to call the reflected light not the same photons since the original photons are transformed to something we don't call photons before photons are produced again.
But at a reflection event you aren't producing a new photon, you are only reflecting a portion of the original determined by the refractive indices of the reflection interface. At that interface, part of the original photon is reflected and the rest is transmitted across the interface as a new photon and both have a modified bandwidth relative to the parent photon. So the one you see reflected is the same photon afte…
A photon is indivisible that’s the quantum nature of light. You aren’t reflecting a part of it. To do so is a classical wave interpretation of light. The photon after reflection is not the same photon.
Re: Does light have an infinite lifetime?
#69Earlier quoted context omitted.
Feynmann is very clear that the photons bouncing off a mirror are not the same ones that hit it. They are absorbed by electric oscillators (free electrons in the material) and destroyed; then new ones are created and emitted. He's also careful enough to point out that electrons don't really have an identity that would allow you to meaningfully define "not the same". :)
Electrons? We were just told that there is only one single electron in yesterday's posts. It's almost like they don't know what an electron is
It’s a true statement that they don’t know what the electron is. In the standard model the electron is a point particle with no volume.
Re: Does light have an infinite lifetime?
#70From the perspective of a photon, there is no such thing as time. It's emitted, and might exist for hundreds of trillions of years, but for the photon, there's zero time elapsed between when it's emitted and when it's absorbed again. It doesn't experience distance either.
Something about this doesn't make sense. This means that, from its own perspective, every photon is emitted at time T at location x, then absorbed at time T at location y, meaning there is no time "in between" those... yet somehow, at a distinct point in between those events, an object can get in the way and block the photon from reaching point y. Meaning you have two points in time that have the same value but aren't identical? How does that work, mathematically? Do you need nonstandard calculus or something to make sense of it?