His mind is travelling at relativistic speeds, so he's actually only forty years old.

My dad died of MND in 2003 after a fairly short length of time, somewhere in the region of 3.5 years after diagnosis. I put Dr Hawking’s longevity at least partially to being happy to work completely in his brain. Conversely, my dad was a very phsyical person and always had some project to build on the go. When that was taken away from him he seemed diminished.

Incidentally, he did try to carry on coding using Dragon Dictate, but it was painful to watch. I wonder if speech recognition has come on any since then? Apple’s Siri seems fairly remarkable although I haven’t had a chance to use it yet. Is anyone on HN coding by speech?

I completed a large fraction of my thesis by speech, including coding and LaTeX. While there are tools to help with coding (there used to be many knowledgeable people at http://tech.groups.yahoo.com/group/VoiceCoder/, but I'm not up to date since my condition has improved) I wouldn't want to wish it on my worst enemy. I'm amazed that Hawking has te patience to function like that, he must be an extremely driven individual.

Conversely, I wonder if his extraordinary luck of being the only known long-term survivor of ALS has pushed him to accomplish more.