scott wrote:
>>>> (I still can't figure out why you can use an oscilator to make radio 
>>>> waves, but not light rays...)
>>>
>>> Lasers?
>>
>> I don't actually know how those work. I was under the impression that 
>> it works by exciting atoms so that they emit photons - much the same 
>> way a lump of iron glows if you put it in a hot fire. (But with some 
>> mirrors in there to ensure the light only travels in one direction...)
> 
> Photons from a glowing lump of iron (or even an LED) have all different 
> wavelengths and all different polarisations.  Photons from a laser all 
> have virtually the same wavelength and polarisation, it's very different.

True. But - at least according to Wikipedia - it's still due to making 
electrons jump between different energy levels in atoms (rather than 
building an electronic oscilator). It's just a lot more controlled than 
a whitehot lump of iron...

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