Senior HTF Member
- Feb 9, 1999
Laser beams are the only way to bounce light off the Moon because only they are concentrated enough to remain tightly focused during the round trip of roughly half a million miles.
I feel compelled to quibble here I'd rather say "directional" than "concentrated." Laser beams can be highly directional; they spread out very little over distance. They are also extremely bright (large energy for the spot size, compared to other light sources). This is useful since, as the article says, the reflected light is much reduced after the round trip. (But, "concentrated" is a pretty good way to express all that concisely.)
Mmm... squishy goodness in the moon....