Climbing Mount Rumsfeld

Somewhere in my house, quietly turning to coal under a pile of papers, is a ‘planetary calculator’ (astronomy stats on two sliding pieces of cardboard), a free gift with the second issue of Star Lord comic in May 1978. Shifting the display to Pluto confidently declares that world to be moonless – as well established a fact as nearly 50 years of observations with the world’s biggest telescopes could make it. Since then, the Hubble telescope as well as the New Horizons probe fly-by has produced terabytes of data on the size, composition, orbits, shape, appearance etc of Pluto’s five moons. A torrent of brand new information that nobody in that May of 1978 had any reason to expect even existed. In Donald Rumsfeld’s immortal words, Pluto’s moons were an unknown unknown. How much has yet to be discovered? What unknown unknowns lie before us? Just how high does Mount Rumsfeld go? It’s those unknown unknowns that trip us up. We are in the position of a mountain climber who can only look down....