Why Are Visible Light Waves So Puny?

In summary: It used a similar principle as a CD player - you put a mirror in front of the "horn" (the part that emits the microwave radiation) and the mirror reflects all the microwaves back into the horn, amplifying them 10,000x.
  • #1
This is purely a question I know little or nothing about light and the whole EM spectrum for that matter I was just wondering something. Why are visible light waves so puny compared to other frequencies on the EM spectrum. What I mean is that I can send a pulse to an antenna and emit let's say microwaves which travel so far they can be picked up on the moon. Now if I can do that with microwaves why can't I do it with light?

When I turn on the light bulb do light waves actually travel thousands of miles through the air only they are so sparse that they cannot be picked up by the human eye? With that question in mind here's another thing I was wondering. Since information can be encoded (modulated) into radio and microwaves can other EM waves be similarly modulated? For example could I broadcast messages over EM waves in the visible light spectrum? I've never heard about gamma rays being used for this either.

Sorry for this flurry of questions but here's one last thing I was wondering about waves. Since light waves can be beamed in a straight line as in a laser can other EM waves be beamed like a laser? Could I say beam radio waves to my next door neighbour in a straight line without the possibility of anyone intercepting those radio waves without getting right in front of the radio beam? Could this also be done with longitudinal waves like say sound?
 
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  • #2
MadmanMurray said:
Why are visible light waves so puny compared to other frequencies on the EM spectrum.
I suggest you don't play with lasers

When I turn on the light bulb do light waves actually travel thousands of miles through the air only they are so sparse that they cannot be picked up by the human eye?
How far away are the stars that you can see with your bare eye?

Since information can be encoded (modulated) into radio and microwaves can other EM waves be similarly modulated? For example could I broadcast messages over EM waves in the visible light spectrum?
This message is almost certainly being sent over light = fibre optics.

I've never heard about gamma rays being used for this either.
gamma rays are strongly absorbed by air and most materials, they are also difficultto generate and focus.


Could I say beam radio waves to my next door neighbour in a straight line without the possibility of anyone intercepting those radio waves without getting right in front of the radio beam?
Yes that's what's done with microwaves, they do spread out more than light but that's just because it's not worth the cost of making a large enough dish to make a more collimated beam
 
  • #3
Thanks for the concise answers. I didn't even think about fiber optic cables. What I had in mind was messages conveyed on laser beams through the air but if it can be done through fiber optic cables then I assume it can be done through the air.

I assume its hard a difficult task intercepting these direct microwave transmissions then.
 
  • #4
You can do laser beams through air - it's called 'free space optical' but compared to microwaves it's a lot more susceptible to atmospheric conditions (rain fog etc) and slower and a lot less reliable than fibre

The spread out of a beam depends on the size of the lens/dish, since a lens is so much larger than the size of a visible wavelength it's easy to make a very colimated beam. A microwave antennae 1-2m diamter doesn't give a very collimate beam - it might be 10s of m wide at the next tower, you try and collimate as much as possible because it reduces the power needed (more power/m^2 at the recevier) rather than snooping.
 
  • #5
Before the invention of the LASER there was the MASER - microwave amplification by stimulated emission of radiation. In other words, a "microwave" laser.
 

1. Why is visible light considered "puny" compared to other types of waves?

Visible light waves are considered "puny" because they have a relatively small wavelength and energy compared to other types of waves, such as radio waves, microwaves, and x-rays. The wavelength of visible light ranges from approximately 400 to 700 nanometers, which is much smaller than the wavelengths of these other waves. Additionally, the energy of visible light is lower than that of other types of waves, making it less powerful and less capable of penetrating through materials.

2. What determines the color of visible light?

The color of visible light is determined by its wavelength. Each color in the visible spectrum corresponds to a specific range of wavelengths, with red having the longest wavelength and violet having the shortest. When all of the colors are combined, we see white light. When certain wavelengths are absent, we see different colors or shades of light, such as in a rainbow.

3. How does the human eye perceive visible light?

The human eye perceives visible light through specialized cells called rods and cones. Rods detect the intensity of light, while cones are responsible for color vision. When light enters the eye, it is focused by the lens onto the retina, which contains these cells. The cells then convert the light into electrical signals that are sent to the brain, allowing us to see the world around us.

4. What is the relationship between visible light and electromagnetic radiation?

Visible light is a type of electromagnetic radiation, which also includes radio waves, microwaves, infrared radiation, ultraviolet radiation, x-rays, and gamma rays. These waves all have different wavelengths and energies, and they make up the electromagnetic spectrum. Visible light falls within a specific range of wavelengths within this spectrum, making it a small part of the overall range of electromagnetic radiation.

5. How is visible light used in science and technology?

Visible light has many important uses in science and technology. It is used in photography, where light sensitive chemicals are used to capture images. It is also used in fiber optics, which transmit data using visible light through thin glass fibers. In astronomy, visible light is used to study the properties of stars and galaxies. And in medicine, visible light is used in imaging techniques such as X-rays and MRI scans to see inside the human body.

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