stupid question about turntables

How do you get stereo sound from a vinyl record and a turntable?

Not even sure if this belongs here, but never having owned one, I am not exactly sure how they work other than a moving coil connected to a needle sliding up and down and outputting a corresponding signal. Where does the other channel come from?

Again, sorry if this is so stupid, but it doesn't seem obvious to me right now.


Generally speaking, after about 1957 all records were recorded in stereo. For a while there were mono and stereo versions of the same records, but by the late '60s this was pretty much a thing of the past.
Stereo records are recorded with a V-shaped groove. The modulations on one wall constitute one channel. A stereo cartridge doesn't detect the signal by moving straight up and down, but more at a 45 degree angle (for one channel). The magnets and coils are positioned such that the 45 degree motion causes a signal in one set of coils or the other, depending on which way the stylus is moving. Obviously, the motions get pretty complex, but in practice it works quite well indeed.