Why can’t a space station in orbit be tethered to the ground?

Readers answer other readers' questions on subjects ranging from trivial flights of fancy to profound scientific concepts

If a space station were in a geostationary orbit, why couldn't it just be tethered to the earth with a cable that could be ascended and descended by astronauts? This isn't rocket science.

Paul Coates, Insch, Aberdeenshire