So I was thinking about Light, right ?

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    Light Thinking
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Discussion Overview

The discussion revolves around the nature of light, specifically its speed, energy, and how these relate to solar energy capture. Participants explore theoretical implications and analogies, questioning the relationship between the speed of light and the energy carried by photons.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants note that while light travels at a high speed, the energy it carries is not directly related to its speed but rather to the number of photons and their wavelength.
  • One participant compares photons to bullets, questioning whether the size of photons affects their energy, suggesting that more photons would equate to more energy.
  • Another participant clarifies that photons are massless and that traditional kinetic energy concepts do not apply to them due to their lack of mass.
  • Some participants express confusion about the implications of speed on kinetic energy, with references to the energy equation for photons (E = hf) being emphasized.
  • A later reply cautions against visualizing photons in classical terms, suggesting that such analogies may lead to misunderstandings.

Areas of Agreement / Disagreement

Participants generally agree on the distinction between the speed of light and the energy carried by photons, but there remains some disagreement and confusion regarding the implications of these concepts and the appropriateness of classical analogies.

Contextual Notes

Participants express varying levels of understanding regarding the relationship between photon energy, speed, and mass, indicating potential limitations in their assumptions and definitions.

Who May Find This Useful

This discussion may be of interest to those exploring the fundamentals of light, energy transfer in solar applications, and the conceptual challenges of quantum mechanics versus classical physics.

RagingPineapple
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...and I was wondering,

Light travels at 670,616,629mph, which is rather fast.

For light to travel that fast, it must carry a huge amount of energy, surely? So, if that's the case, why do we get so comparatively little from current solar energy mediums?

Are there any ideas or theories that might help get more out of it?
 
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RagingPineapple said:
...and I was wondering,

Light travels at 670,616,629mph, which is rather fast.

For light to travel that fast, it must carry a huge amount of energy, surely? So, if that's the case, why do we get so comparatively little from current solar energy mediums?

Are there any ideas or theories that might help get more out of it?

Light travels the same velocity whether it is dim (single photon) or intense. Don't confuse the speed of light with the energy carried by that light. The energy carried ratios with the number of photons and the inverse of their wavelength, and has nothing to do with the speed of the photons.
 
How does that work? I suppose I'm thinking of it in terms of a bullet, an object going that fast would be pretty hazardous. And I suppose a bigger bullet at the same speed would obviously carry more energy.

So is it the case that photons are just stupidly small, and the more you have the bigger the bullet? Or am I thinking of this wrong?
 
Photons are massless. I think you're thinking in terms of, something massive that was going that fast would have a great deal of inertia. (Though something that's massive cannot reach the speed of light.)
 
RagingPineapple said:
How does that work? I suppose I'm thinking of it in terms of a bullet, an object going that fast would be pretty hazardous. And I suppose a bigger bullet at the same speed would obviously carry more energy.

So is it the case that photons are just stupidly small, and the more you have the bigger the bullet? Or am I thinking of this wrong?

For photons, each individual photon carries an energy of E = h \nu where h is Planc's constant, and \nu is the frequency of the photon in Hz.

http://en.wikipedia.org/wiki/Photon

The total energy in an electromagnetic wave is the sum of the energy in the individual photons making up that wave (or composite waves).
 
But, given the speed they're going, wouldn't there be a lot of kinetic energy?
 
Deathwing said:
But, given the speed they're going, wouldn't there be a lot of kinetic energy?
As berkeman stated, the energy of a photon is E = hf. Speed is not a factor.
 
Deathwing said:
But, given the speed they're going, wouldn't there be a lot of kinetic energy?

Since they have no mass, the kinetic energy equation is irrelevant.
 
RagingPineapple said:
I suppose I'm thinking of it in terms of a bullet,

Don't think of photons as like bullets. They're quintessentially quantum objects, and you quickly run into trouble when you try to visualize them in classical terms.
 

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