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by maxden 1813 days ago
This page linked earlier [0] relates one possibility to the 'Bethe formula', where depending on the energy of the beam (proton in their example) you can control where the burst appears.

[0] https://www.otherhand.org/home-page/area-51-and-other-strang...

1 comments

Maybe. But that article is talking about beams of massive particles -- not beams of massless photons, which is what lasers are.

The fact that the particles have mass and decelerate is what produces the sharp drop in velocity: the slower it goes the more it slows down per unit of time or of distance traveled. Like a bullet travelling through water. So you get that nice sharp asymptote in the position-vs-time graph.

I don't think that webpage is applicable to light or other photon beams. Photons can't slow down unless they encounter a change of medium -- but that's basically projecting onto a physical "screen"... the laser operator can't influence the depth position of the screen. But thanks for the link, it's the first time I've seen a "3D projection technology" that had a coherent answer to the depth-control question. Maybe the Navy is using massive-particle beams instead of lasers and the Forbes journalist just doesn't know the difference. Or maybe it's deliberate disinformation, like how fusion weapons were named "hydrogen" bombs.