Carl Sagan

The line most people meet first is the one about perspective: the idea that seeing Earth as a single small point changes how you weigh everything on it. That framing — the cosmic perspective, and the Pale Blue Dot — is what keeps Carl Sagan circulating in clips and quotations decades after his death in 1996.

He was an astronomer and astrophysicist, born in Brooklyn in 1934, and he worked as much on how ideas are explained as on the ideas themselves. His early output paired conceptual rigour with an attention to clear expression that is uncommon in technical fields. Later writing widened out, taking on historical, social and technical questions rather than staying inside a narrow specialism. Where he was challenged, the disputes tended to sharpen his positions into more exact statements.

By the end of his life he functioned as a point of reference — someone whose work held a balance between new thinking and continuity with what came before. What survives is less a fixed set of conclusions than a way of asking questions, which is why the material still reads as usable rather than archival.