There’s an explanation at the latest Abstruse Goose.
To recycle some of my own writing, from page 107 of NEW, the book:
When I was a graduate student at Princeton, one day I was leaving the library perhaps thirty feet or so behind Witten. The library was underneath a large plaza separating the mathematics and physics buildings, and he went up the stairs to the plaza ahead of me, disappearing from view. When I reached the plaza he was nowhere to be seen, and it is quite a bit more than thirty feet to the nearest building entrance. While presumably he was just moving a lot faster than me, it crossed my mind at the time that a consistent explanation for everything was that Witten was an extra-terrestrial being from a superior race who, since he thought no one was watching, had teleported back to his office.
And, before anyone takes this seriously, I certainly don’t believe this is the explanation for the “M” or that any actual teleportation occurred. To quote the next paragraph of the book:
More seriously, Witten’s accomplishments are very much a product of the combination of a huge talent and a lot of hard work. His papers are uniformly models of clarity and of deep thinking about a problem, of a sort that very few people can match. Anyone who has taken the time to try and understand even a fraction of his work finds it a humbling experience to see just how much he has been able to achieve.
Update: Clifford Johnson at Asymptotia points out a recent talk by Witten to a non-specialist audience about knots. It there is a Martian plot going on here, at least it has led to some wonderful insights about mathematics and quantum field theory that human beings might never have otherwise been able to figure out…