"WingFlaps" wrote in message
oups.com...
On Nov 13, 3:42 pm, Mxsmanic wrote:
The beam
of a good quality laser (highly collimated, that is) will hardly spread
out at
all over a distance of a few thousand feet and thus may still be only a
millimetre or two in diameter.

Complete ********. Just buy a laser pointer and measure the spot size
after 50'. It's already cm wide. The cavity of laser diode is just
too short to produce such high degree of collimation...

Garden-variety laser pointers aren't the same as the newer high-powered
green lasers, though, are they? (For example:
http://www.greenlaserbeam.com/ )

-c
not a physicist.