No two people exactly duplicate each other’s mental stores of items. One person may know A and not B, another may know B and not A, and either knowing A and B, both may get the idea—though not necessarily at once or even soon. Furthermore, the information may not only be of individual items A and B, but even of…
The O’Neill cylinder is named after an American physicist and space scientist who sought to engage his students by getting them to think about big problems—space settlement, in particular. He also led symposiums where the concepts behind large, permanent space habitats—including the cylinder that bears his name—were…
In 1967, British scientists found a much nearer intense radio source turning on and off with astonishing precision, its period constant to ten or more significant figures. What was it? Their first thought was that it was a message intended for us, or maybe an interstellar navigation and timing beacon for spacecraft…