[Greg Anos]

One of the joys of the old S/F is the "when the world was young" sense of the times they were written in.

Let me give an example from Heinlein.

One of the Juveniles is Time For The Stars. A pair of twins acting as telepathic communications for a sub-light exploration of nearer stars, looking for habitual worlds. A valid premise in 1956. Today. its a joke! Within 50 years, if we bother, we will have mapped all the nearer stars' planets from the comfort of our own solar system. No need for exploration ships into the "unknown".

Who'd have thunk that in the mid 1950's?

Now obsolete, but still entertaining.

Today, there are fewer and fewer "reaches" for the imagination. We've already looked at so many former ones.