LET us be clear.

The thrust of my exegesis concerns neither gnats nor their eyebrows. I don't know where you got that idea. I should also make clear that I don't mean "Nat's eyebrows" in reference to the two caterpillars that rear up on the coupon of Mr Alex Salmond. Once, I bumped into him on the Royal Mile, and he left me in no doubt he was sensitive about the issue.

Doubtless I shouldn't have started the conversation by saying: "Good afternoon, First Minister. Drunk again, I see. What preposterous eyebrows you have. May I pluck a hair from them and send it to a laboratory?"

No, today's topic arises after I read in The Herald about something coming "to within a gnat's eyebrow" of something else. The expression was used by a top scientist an' all, and the somethings were pretty important. Professor Paul Renne, of the University of California, Americashire, was talking about yon cataclysmic meteor that did for the dinosaurs.

Boffins at the East Kilbride-based Scottish Universities Environmental Research Centre, working with researchers in Holland and the US, have dated the doing of the dinosaurs to 66,038,000 years ago. They were done "within a gnat's eyebrow" of the meteor bunging itself into the Earth's surface. Or as Prof Paul put it: "We have shown these events are synchronous to within a gnat's eyebrow." Synchronous: that's what I was going to say. Scientists say it probably wasn't just the meteor that blootered the dinosaurs. Dramatic climate fluctuations had already made the global ecosystem vulnerable.

Picture an agitated dinosaur using angry capital letters and generous punctuation: "CLIMATE CHANGE IS ALL POPPYCOCK!!!!!" Then he says: "What was that bang?" And then he was gone: two events separated by a gnat's eyebrow.