What everyone knows about asteroids

I just read a 1992 piece by Niven and Pournelle, extolling the glories of capitalism, and talking about how awesome Columbus was, and suggesting that if only those evil governments like the US government would stop being so annoyingly anti-capitalistic, people would go to space in order to get rich. (Title of essay: “Where Next, Columbus?”)

But the reason I’m posting about this piece isn’t about any of the above; it’s to warn against being too confident about what you think everyone knows.


In this year 1992 AD, anyone worth talking to has at least a vague notion that the wealth of Fantasyland is to be found in space. Test this for yourself. Ask a bright friend:

What killed the dinosaurs? (Giant meteoroid impact.)

How does anyone know? (High iridium content in the clay laid down at that time. It’s vaporized asteroid. Meteoroids are rich in metals of the platinum family.)

Iridium? That’s valuable, isn’t it? (Yeah.)

…I’ve been more or less a space enthusiast for, oh, 40 years or so, and I’ve read a little about Chicxulub and the K-T boundary event. I did not know any of the things in that parenthetical about iridium and asteroids until today. (It’s possible that I had seen some mention-in-passing of iridium in the boundary layer at some point, but I definitely never took the further step of thinking “That implies that asteroids are valuable!” …Of course, sf has been telling me that asteroids are valuable all my life; but I’ve never before seen anyone explicitly connect that to the K-T boundary.)

I suppose that Niven and Pournelle might have taken that as evidence that I’m not worth talking to, and/or not bright. But I’m more inclined to take it as evidence that sometimes the things that we think everyone knows are in fact things that not everyone knows.

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