Faster than the speed of light, electromagnetism, UV light, optical lens.?

Question

1- When people say "nothing can travel faster than the speed of light", to what exactly do they refer? Do they simply mean the narrow band of visible light that is perceived by humans? What about UV light band and Gamma rays etc.?

2- If visible light /could/ be accelerated, electromagnetically, into the ultraviolet spectrum or beyond, would it become 'invisible' to the naked human eye (ie. Project Rainbow/Philadelphia exp.)?

3- /If/ something where already 'invisible' to the naked eye, using electromagnetism to accelerate the system's energy into the UV spectrum or beyond, would it be possible to 'see' it by viewing the objects electromagnetism with a specially adapted UV sensitive lens?

4- How would one construct such a lens to view UV energy (either near or far)?

Cheers.

http://www.weather.nps.navy.mil/~psguest/EMEO_online/module2/EMSpec.gif

Answer 1

You have misunderstood the difference between frequency and velocity.

All frequencies of electromagnetic radiation - including visible light, radio waves, gamma rays etc - travel at the same velocity in the same medium.

You can change the frequency of light, moving it into the gamma ray or ultraviolet spectrum, but all this does is proportionally change the wavelength. The *velocity* of the light does not change.

Velocity *does* change when light moves into a different medium. This is why it's more correct to talk about 'the speed of light in a vacuum', although the difference between this and speed in (eg) air is not great.

Answer 2

1. All of that is electromagnetic radiation, and yes, it travels at the maximum speed possible, aka the speed of light.

2. You can't "accelerate" light into a different spectrum, light always travels at the same speed (unless you slow it down, which is possiblle). Spectrum depends on the wavelength and the energy of the electromagnetic wave. You can change those.

3. You can transform the invisible parts of electromagnetic spectrum into the visible light. That's how you can see all those radio, infra-red, UV and X-ray pictures of distant galaxies.

4. Ask the astronomers.

Answer 3

Can you change frequency? You can not accelerate electromagnetic energy such as light. It is already moving at the speed of light. This is why people are saying your question does not make sense. You can change the apparent frequency by moving towards or away from a light source. This is known as blue or red shift.

You can focus UV using glass or mirrors. It will have to be a special blend of glass that doesn't block UV. However you can't see it. You'd need a camera sensitive to UV to convert it to something your eyes could see. This is known as a UV telescope.

Answer 4

1)They mean "nothing can travel faster than the propagation of electromagnetic waves in a vacuum" In a vacuum all E&M waves travel at the same speed c. So we have hypothisized and so far the theory is working pretty well.

2) If you add energy to an electromagnetic wave it increases in frequency, it does not go faster. You have to watch out for folks taking liberties with physics!

3) To try to be generous to your notion, E&M waves are "red shifted" when the relative motion of emitter and receiver is away from each other. Theoretically if you were to "recede" fast enough from a source of invisible UV, that light would be shifted toward the red enough for you to see it.

4) UV and longer wavelengths are imaged using reflective optics (mirrors) and electromagnetic detectors of various types.

Answer 5

The correct statement is "nothing can move faster than the speed of light in a vacuum".

1) They mean NOTHING. including UV light, Gamma rays. Nothing.

2) how do you "accelerate" light? meaningless question, no answer.

3) meaningless question, no answer.

4) meaningless question, no answer.

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