Exploring the Limitations and Effects of Light's Energy and Wavelength

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In summary: CMBR photons... happened to cause a collision. This is also not very likely, because neutrinos are very difficult to detect and because the CMBR photons would have to be very weak in order for them to have any effect.
  • #1
ubavontuba
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Hello,

I tried attaching this question in another forum's related thread, but no one has responded. I hope you don't mind me starting a new thread here. I think this forum is more suited to the question anyway.

Here's the question:

What are the energy and wavelength limitations of light? If you were to project the lowest energy beam possible from a fixed location and then accelerate away from that location traveling along the beam, what would happen? Would the beam always be hypothetically detectable?

Is it possible for the energy level to drop so low that spin might be affected?

Is it possible for the energy to drop so low as to affect the time dilation between the source and the accelerating vessel (essentially severing the reference frames)?

What are the upper limits? If you were to project the highest energy beam possible and then accelerate toward it, what would happen? That is, if you're accelerating toward a high-energy beam at relativistic velocity, what unusual effects (if any) might you see?
 
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  • #2
There is no theoretical lower limit below which EM radiation could not be detected. There are, of course, enormous practical problems.

If you are moving with relativistic velocity toward a beam of EM radiation, its photons would appear severely blueshifted. Each photon's momentum, as measured in your frame, would be enormous. The resulting radiation pressure would act to slow you down.

This same effect is the cause of the so-called "GZK cutoff" in the energy spectrum of charged cosmic-ray particles. For an ultra-relativistic charged particle, even the weak photons of the cosmic microwave background radiation are blueshifted enough to impart significant changes in momentum, thus slowing down such high-velocity particles.

- Warren
 
  • #3
Warren,

Thanks for the response.

chroot said:
There is no theoretical lower limit below which EM radiation could not be detected. There are, of course, enormous practical problems.
So, the energy will never drop so low that it "disappears" into the cosmological constant, CMBR, zero-point field, or some such?

If you are moving with relativistic velocity toward a beam of EM radiation, its photons would appear severely blueshifted. Each photon's momentum, as measured in your frame, would be enormous. The resulting radiation pressure would act to slow you down.

This same effect is the cause of the so-called "GZK cutoff" in the energy spectrum of charged cosmic-ray particles. For an ultra-relativistic charged particle, even the weak photons of the cosmic microwave background radiation are blueshifted enough to impart significant changes in momentum, thus slowing down such high-velocity particles.
This makes me wonder... could inertia be partially affected by all the high-energy photons zinging around in the universe? Would it tend to cause an acceleration, deceleration or equilibrium?

Also, what is the current thinking regarding the GZK paradox? And, wouldn't this effect tend to scatter light from distant sources?
 
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  • #4
ubavontuba said:
So, the energy will never drop so low that it "disappears" into the cosmological constant, CMBR, zero-point field, or some such?

That isn't what I said at all, is it? No, it's not. What I said is that there is no theoretical lower (frequency) limit below which EM radiation cannot be detected.

If you have an EM wave with a wavelength of 10,000 light-years, it'll take a receiver 10,000 years to see a single cycle of it. You certainly couldn't use such a wave to transmit much information, because the maximum symbol rate would be 20,000 years per bit. The wave characteristics of the signal would be quite difficult to detect over any baseline less than 10,000 years, because the wave would appear to be a very close approximation to a static field over any (humanly) reasonable period of time.

You can, of course, measure whether or not a static electric field exists in your laboratory, by simply watching what electrons do under its influence. It would be very difficult, practically, to detect the rate of change of a 10,000 light-year wavelength wave, however.

This makes me wonder... could inertia be partially affected by all the high-energy photons zinging around in the universe? Would it tend to cause an acceleration, deceleration or equilibrim?

I don't know what you mean by inertia being "partially affected."

Also, what is the current thinking regarding the GZK paradox? And, wouldn't this effect tend to scatter light from distant sources?

The GZK paradox is currently "unresolved," though the most commonly proposed solutions are pretty mundane. Ultrarelativistic particles could be created relatively near the Earth, thus suffering CMBR photon interaction for only a short distance. This isn't very likely, because any process which could create such particles would probably be very obvious if it were in our neighborhood -- it would probably kill us, for example.

Another proposed solution is that very high-energy neutrinos are created elsewhere in the universe. Neutrinos have such a small interaction cross-section (and only interact weakly) that they could travel enormous distances without ever interacting with anything, until some weak interaction transfers their energy to another particle which shortly hits Earth.

- Warren
 
  • #5
chroot said:
I don't know what you mean by inertia being "partially affected."

I was wondering how high-energy photon interaction at atomic scales (since electrons and such are moving at relativistic speeds) might affect/contribute to inertial properties.

Anyway, I found this recent and interesting http://arxiv.org/PS_cache/physics/pdf/0602/0602132.pdf [Broken] on the GZK paradox.

What do you think of it?
 
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1. What is light energy and how does it work?

Light energy is a form of electromagnetic radiation that is made up of particles called photons. It is able to travel through space and can also pass through certain materials, such as air and glass. When light interacts with matter, it can be absorbed, reflected, or transmitted, which determines how it affects the object it encounters.

2. What are the limitations of light energy?

Light energy has some limitations, such as its ability to travel through certain materials. For example, light cannot pass through opaque objects, like walls, and is also affected by the particles in the air, which can cause it to scatter. Light energy also has a speed limit, known as the speed of light, which is approximately 299,792,458 meters per second in a vacuum.

3. How does the wavelength of light affect its energy?

The wavelength of light is directly proportional to its energy. This means that as the wavelength increases, the energy decreases and vice versa. This is because shorter wavelengths of light have higher frequencies, which means they have more energy. This is also why ultraviolet light has more energy than visible light, and gamma rays have more energy than ultraviolet light.

4. What are the effects of light energy on living organisms?

Light energy has various effects on living organisms. For example, plants use light energy during photosynthesis to convert it into chemical energy, which is essential for their growth and survival. Light energy also plays a role in regulating our circadian rhythm, which controls our sleep-wake cycles. Additionally, too much exposure to certain types of light, such as ultraviolet light, can be harmful to living organisms.

5. How is light energy used in technology and everyday life?

Light energy is used in various technologies, such as solar panels that convert sunlight into electricity. It is also used in fiber optic cables to transmit data and in lasers for cutting and welding. In everyday life, light energy is used for lighting, communication through devices like smartphones and televisions, and in medical imaging techniques like X-rays and MRIs.

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