Fact Check

I asked whether intelligent life on another planet would follow anything like our evolutionary path, or whether humans are a one-off. Everybody who answers this question reaches for the same argument, and I reached for it too before I checked it. It is a good argument. It is also, in the specific form everyone uses, wrong. The argument everybody makes Evolution repeats itself. Give it the same problem twice and it finds the same answer twice, so the features that keep reappearing on Earth are the features we should expect anywhere. ...

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. ...

You have heard this one. Every seven years, every cell in your body has been replaced, so you are a physically new person, and the coffee stain you feel guilty about was technically spilled by somebody else. It is a lovely thought and it is not true. Some of the cells reading this sentence have been with you since before you were born. We know that with unusual confidence, and the reason is grim and wonderful. Between 1955 and 1963 the world tested nuclear weapons in the atmosphere, and in doing so accidentally wrote a date stamp into every living thing on the planet. ...

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. ...

I wanted to 3D print an adapter so my Bosch POF 1200 AE router would run along a Makita guide rail. To do that I needed the base plate geometry: the diameter of the centre hole, and where the three mounting screws sit. I assumed this would take about four minutes. Bosch sells the router, Bosch sells a guide rail adapter for it, so Bosch must publish the plate dimensions somewhere. ...

I recently learned that pistachios are supposedly classified as dangerous goods when shipped because they can spontaneously combust. This is a nearly perfect random fact. Pistachios look harmless. Their most aggressive normal behaviour is refusing to open properly and making you destroy a fingernail. The idea that a container full of them belongs in the same regulatory world as explosives and flammable chemicals is wonderful. It is also only partly true. ...