I went into this expecting the Sun to have been more or less constant for the whole history of life, wobbling a bit with sunspot cycles. That is wrong, and it is wrong by a lot. It is also a question that answers itself slightly sideways. The Sun is getting brighter, dramatically so. It is barely getting hotter. Those are different things, and the gap between them is the interesting part. ...
Last October I asked whether you could engineer a human, or any mammal, to run on sunlight the way a plant does. I expected a biology answer, something about genes and organelles and immune rejection. What I got was arithmetic, and the arithmetic ends the argument before biology gets a turn. The answer everyone gives is the weakest one Search this question and the first thing you will read is that humans cannot photosynthesize because we have no chloroplasts and produce no chlorophyll. ...
Flying from Auckland to Santiago takes about eleven hours. Coming home takes closer to thirteen. The explanation everyone reaches for is that the Earth spins eastward, so on the way east the destination comes to meet you, and on the way back you have to chase it. This is wrong, and it is wrong in a way I find genuinely satisfying, because the thing people are blaming turns out to be responsible after all. Just not for the reason they think. ...