Dyson VS Sagan on Nuclear Winter

I do not wish here to get into a technical argument about the details of nuclear winter. I will merely summarize my own struggles with the technical issues. I spent a few weeks in 1985 trying to make nuclear winter go away. The phrase "go away" here is used in the sense customary among scientists. To destroy a new theory, you try to find a simple situation where the theory predicts that something happens and you can prove that the same something does not happen. Then you say that the thing pr...

 The Comet Loss Cone

To understand why comet showers occur, we go back to the Oort Cloud. The theory of comet showers was worked out by Jack Hills, an American physicist now at Los Alamos. He realized that the movements of the comets in the Oort Cloud are not entirely random. Comets in the cloud are generally moving in random directions, but if a comet happens to be moving in an orbit almost exactly toward the Sun, it will not survive for long. A comet in an orbit coming close to the Sun may get boiled away and d...

 The Not-Believing-In-God-Glasses

But then I thought, "But I don't know how to not believe in God. I don't know how you do it. How do you get up, how do you get through the day?" I thought, "Okay, calm down. Let's just try on the not-believing-in-God glasses for a moment, just for a second. Just put on the no-God glasses and take a quick look around and then immediately throw them off. So I put them on and I looked around. I'm embarrassed to report that I initially felt dizzy. I actually had the thought, "Well, how does the...