Blog post: swansont: I Wonder if They Called "Bank Shot"

Scientists Bounce Laser Beams Off Old Soviet Moon Rover

Neat.

One thing that I don't quite get is this:

If they mean that it spreads out, then it depends on where the beam is focused. Using a beam focused on the moon, (or at twice that distance so the return beam was still converging) would probably be hard, and definitely be an incredibly silly way to do the experiment, since a small beam means you'd have to know precisely where the target was. Using a beam that was expanding (unless you have a laser that has a kilometer-scale beam output) is the right way to do it, so you're forced by expediency into using an expanding beam with it's decreasing intensity, but that's not the same as saying it's inherent to the laser.

If the claim is something else, then I don't get it at all.

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