Anyone doubting that we land on the moon can point their own laser at the mirror. Mirror is going to reflect whether you are a scientist or a poet, a democrat or a republican, a boy or a girl or anything in between. So when in doubt, reach for a laser.
I don't believe it's that easy, the return is in the order of single photon level for a large zap.
Yeah, it is not that easy. It was just an expression.
I have used laser (in 1970's) to measure length of a hallway about 100 feet long. 100 feet was short so I used split beam and interference based on wave length. But I still needed the laser to be stable and well aimed. I had a hell of a time doing it.
(When my neighbor's trees were not so tall...) Viewing a fairly low grade (90mm reflector) telescope aimed at the moon, I know a truck is passing by on the next street by the vibration of my telescope.
To aim a laser at that mirror on the moon and get a reflected signal is certainly not something done outside a well built astronomy-lab/observatory. And of course one has to account for the diffraction due to air movement before we even get the bloody photon there, and back.
So, there is a hell of a lot of stuff to account for to make the bloody thing work. Point is, we (human) left something there that many universities at the time used. That is proof we were there.
EDITed a zillion times. (Too late in the day, can't write worth a damn...)