Thank you for posting it. I first reading this story as a teenager. I remember it having an impact on me in a way few stories do. I have re-read it many times since then and it can still take my breath away every time.
I came here to say precisely this. I didn't even know Asimov at the time; I started with some of Arthur C. Clarke's stuff). Years later I had to hunt it down to find it again, and that resumed my love affair with Asimov.
It's hard to believe he was 21 when he wrote Foundation. Easier to believe when you see how profound he could be in such short bursts as with OP.
