>> This is a *stupidly tiny number*. If you asked POV-Ray to render this, 
>> and you sent out a million, billion, trillion rays, every single 
>> damned one would completely miss such a tiny object. It seems 
>> astonishing to me that such an absurdly minute object is visible at 
>> all - but Wikipedia claims it is...
> 
> Good job the real world isn't a backward raytracer then :-)

Yeah. Because then we wouldn't be able to see stars... which... would be 
bad... somehow. I'm sure. :-)

I guess it's simply the case that all the light gets focused onto a 
point smaller than a single light sensor, which never the less registers 
that there's some light there. (Also, presumably no lense can ever be 
optically perfect...)

The part that really puzzles me as that even on the clearest, most 
cloudless night, there are, like, maybe 3 stars visible in the entire 
sky. And yet mankind has names for hundreds and hundreds of stars, many 
of which are claimed to be "visible to the naked eye".

I can only presume this must be due to light pollution. (I'm not saying 
that MK's street lighting is inefficient, but... you *can* tell where 
the city is from about 15 miles away just by the fact that one entire 
side of the night sky is glowing at the exact wavelength of the Sodium 
D-line...) Still, even on school caving trips in the middle of nowhere, 
I don't recall seeing many stars in the night sky. I presume they're 
still there, we just can't see them any more.

> I suspect even a true point source (ie no physical size) was sending out 
> the same amount of light from that distance, you would be able to see 
> that too.

Well, photons are quantum, right?

(Interestingly, I'm told it *is* possible to make a light source that 
emits individual photons, one at a time, on que. And that when you do 
this, things like the double-slit experiment still show multiple waves 
interferring and reinforcing - despite this being obviously 
impossible... Wave-particle duality is weird!)

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