Microscopic footage of a needle moving across the grooves of a record
Wow!  I never knew the needle move side-to-side!  I always assumed phonograph needles moved up and down.Edit:  Ben explains this in the video; there are actually two axes of movement, sort of diagonal to the plane of the disk, each of which encodes one channel of a two-channel stereo recording.  I'm sure many LP fans already know this, but it's a revelation to me.BTW, Ben Krasnow is a heck of a guy.  A true polymath and a generous teacher.