Nature of photons presented in high school text books

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Discussion Overview

The discussion revolves around the nature of photons as presented in high school textbooks, particularly their association with the visible light spectrum and the implications of photons existing across the entire electromagnetic spectrum, including radio waves, x-rays, and gamma rays. Participants explore various aspects of photon behavior, wave characteristics, and the conceptual existence of photons.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants question why textbooks primarily associate photons with visible light, suggesting that other parts of the electromagnetic spectrum also consist of photons.
  • There is a proposal that transverse waves could take on a helical shape rather than a flat wave pattern, with some participants expressing this view as more realistic.
  • Concerns are raised about the existence of photons, particularly regarding the finite number of photons in the universe and their divergence from a light source, potentially rendering it invisible to telescopes.
  • One participant asserts that light waves in a vacuum are sinusoidal and unpolarized, aligning with established physics across various fields.
  • Another participant clarifies that "light" can refer to electromagnetic radiation beyond the visible spectrum, such as infrared and ultraviolet light.
  • A participant discusses the random emission of photons from stars and how this affects their detection by telescopes over time.
  • There is a distinction made between classical waveforms and the internal characteristics of photons, with some skepticism about the meaningfulness of questioning the internal structure of a photon.
  • One participant emphasizes that the detection of photons is probabilistic, noting that weaker sources require longer observation times to detect photons reliably.
  • A definition of photons as the elementary particles responsible for electromagnetic phenomena is provided, highlighting their role as carriers of electromagnetic radiation.

Areas of Agreement / Disagreement

Participants express differing views on the nature of photons, their association with various parts of the electromagnetic spectrum, and the implications of their existence. No consensus is reached on several key points, including the shape of waveforms and the conceptual understanding of photons.

Contextual Notes

Participants acknowledge various assumptions regarding the behavior of photons and the definitions of light, which may affect their arguments. The discussion includes unresolved questions about the internal structure of photons and the implications of their finite existence.

hl_world
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Why did textbooks (when I was in high school 5 1/2 years ago) always associate photons with the visible light part of the EM spectrum. Wouldn't the radio, x-ray, gamma, etc. areas of the spectrum exist as photons too?

What about the transverse waves; would it not form a helix shape instead of the classic wave pattern on a flat plane? The former seems more realistic to me.

Do photons REALLY exist? Think about it - a particle of which there would be a finite number of in the universe. A light source emits a certain number of photons per 3 dimensional degree. Eventually, wouldn't said photons diverge enough that would render the light source invisible to any telescope (because no photons are available to enter the lens). It makes me think that radiation energy exists as a longitudinal wave (like sound through matter medium) but with some other unseen, unfelt, unknown medium.

Your thoughts?
 
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From what I recall, "light" has erroneously been equated to "visible light."

I believe that in the simplest environment, a local vacuum, light waves (free photons) are sinusoidal and unpolarized.

The photon model fits with the vast majority of experimental and theoretical physics, from quantum mechanics to general relativity, from electromagnetism to thermodynamics.
 
I always thought "light" meant visible light. Ie, X-rays aren't light, they are x-rays. But all are forms of em radiation.
 
"Light" is sometimes used for electromagnetic radiation just beyond visible light, i. e., "infrared light" or "ultraviolet light."
 
i see what you mean by the point of no photons available to enter the telescope and what happens is light is not emitted by the start at any specific direction but photons are emitted at random directions every second or fraction of a second, and during this the photons emitted by the light reaches every possible region in the universe and since the number photons emitted is very large it looks like the star is emitting the photons in all directions, that is why sometimes the telescopes point at the same astronomical objects for seconds,minutes and sometimes hours.
 
Last edited:
hl_world said:
Why did textbooks (when I was in high school 5 1/2 years ago) always associate photons with the visible light part of the EM spectrum. Wouldn't the radio, x-ray, gamma, etc. areas of the spectrum exist as photons too?
Yes.
hl_world said:
What about the transverse waves; would it not form a helix shape instead of the classic wave pattern on a flat plane? The former seems more realistic to me.
You need to make a distinction between a classical wave (or the wavefunction of a photon if you like) and the internal field of the photon itself. You can get classical transverse waves and you can get classical helical waves (one just has a linear polarisation, while the other has a circular polarisation). Asking what the internal field of a photon however is like asking what the internal mass/charge distribution of an electron is - a question that, to me, doesn't make a great deal of sense.

hl_world said:
Do photons REALLY exist?
Yes.
hl_world said:
Think about it - a particle of which there would be a finite number of in the universe. A light source emits a certain number of photons per 3 dimensional degree. Eventually, wouldn't said photons diverge enough that would render the light source invisible to any telescope (because no photons are available to enter the lens). It makes me think that radiation energy exists as a longitudinal wave (like sound through matter medium) but with some other unseen, unfelt, unknown medium.

Your thoughts?
Probabilistically, the weaker a source the less photons per unit time will strike the detector. Thus the weaker a source, the longer we need to look to see a photon, which is a fairly well understood imaging principle. In practice our ability to detect a source is limited by the number of false positives (or dark counts) a photon counter tends to generate.

Claude.
 
In physics, the photon is the elementary particle responsible for electromagnetic phenomena.It is the carrier of electromagnetic radiation .
 

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