Foz,I reckon its measured like this.... You know when your car breaks down at dusk on the side of the road and you only need 15 mins of daylight to fix it.Well you can always gurantee that your only gunna have 8 mins of bloody light.
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Westy. Some people I know are like slinkies. They look really funny when you push them downstairs !
Yeah, well I reckon dark is simply the absence of light, same as cold is the absence of heat. So if dark is simply the absence of light, then it ain't goin' nowhere in which case speed ain't got nuthin' to do with it.