Orchid XP v8 wrote:
>>>>> (I'm guessing that due to the absurdly long wavelength, most 
>>>>> objects would be too blurry to see.) 
>>>>
>>>> Indeed, that's kind of the point. That's why you can listen to the 
>>>> radio indoors.
>>>
>>> You can see light indoors too. Not because it has a short wavelength, 
>>> but because certain substances do not absorb it.
>>
>> That's why you can listen to the radio in the dark.
> 
> I'm not sure what you're talking about, but I know what I'm talking 
> about: Different materials absorb different wavelengths.

I'm being sarcastic, is all.

> There are 
> materials that absorb visible light, and others that let visible light 
> pass through it unaltered. 

Yes.

> Presumably the same thing applies to *every* 
> wavelength - which ought to include radio waves. You can listen to radio 
> indoors because not all of your house is made of metal (AFAIK the only 
> thing that absorbs radio waves).

I'm pretty sure a couple kilometers of concrete would do the trick too.

> That's nothing to do with the size of a 
> radio wave, it's to do with what materials do or don't absorb it.

It has to do with both. Any amount of non-conductive surface smaller 
significantly than a radio wave is unlikely to absorb it, unless you happen 
to be very unlucky in the choice of your sizes. The reason that far fewer 
materials absorb radio waves is that they're very long and hence low energy. 
You need a substance where the electron gap bands are very close together 
(like free electrons in a conductor's surface) to capture radio waves.

> Now, what kind of a picture you could make with a "light" having a 2 Km wavelength,
I have no idea.

http://universe.chimons.org/contents/Radio.jpg

-- 
Darren New, San Diego CA, USA (PST)
   Yes, we're traveling together,
   but to different destinations.

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