So I was thinking about Light, right ?

In summary, the conversation discusses the speed and energy of light and the potential for harnessing solar energy. It is explained that the speed of light does not affect the energy carried by photons, which is determined by their frequency. The concept of photons being massless and their energy being purely electromagnetic is also mentioned. The conversation concludes with the reminder that photons should not be thought of as classical objects like bullets.
  • #1
RagingPineapple
21
0
...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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  • #2
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.
 
  • #3
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?
 
  • #4
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.)
 
  • #5
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 [tex]E = h \nu[/tex] where h is Planc's constant, and [tex]\nu[/tex] 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).
 
  • #6
But, given the speed they're going, wouldn't there be a lot of kinetic energy?
 
  • #7
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.
 
  • #8
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.
 
  • #9
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.
 

1. What is light?

Light is a form of electromagnetic radiation that is visible to the human eye. It is made up of particles called photons that travel in waves at a constant speed of 299,792,458 meters per second.

2. How does light travel?

Light travels in straight lines, known as rays, until it is either absorbed or reflected by an object. It can also bend, or refract, when it passes through different materials with varying densities.

3. What is the nature of light?

The nature of light has been studied and debated for centuries. It is considered both a wave and a particle, known as wave-particle duality. This means that light behaves like both a wave and a particle, depending on the situation.

4. What are the properties of light?

Light has several properties, including wavelength, frequency, and speed. It also has a dual nature, as both a wave and a particle. Light can also be described by its color, intensity, and polarization.

5. How does light interact with matter?

Light can interact with matter in different ways, such as absorption, reflection, and transmission. When light is absorbed, it transfers its energy to the matter, causing it to heat up. When light is reflected, it bounces off the surface of an object. When light is transmitted, it passes through the object without being absorbed or reflected.

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