CLOSE CALLS: Billion-Ton Comet May Have Missed Earth by a Few Hundred Kilometers in 1883: A reanalysis of historical observations suggest Earth narrowly avoided an extinction event just over a hundred years ago. Shades of, well, you know.

UPDATE: Reader Chris DeBoe writes: “Shades of The Peshawar Lancers by SM Stirling, which posits a comet hitting North America and Europe during Victoria’s reign, and the British government relocating to India. And the Great Game still goes on.” Several readers made that connection, which I should have caught. I read that book and it was good — one of several that made my list of recommended alt-history reading.

ANOTHER UPDATE: Some skepticism on the comet claim.