What will people think of our enormous steak dinners and obese portions of food? That's on the cusp of changing. What will they think of our profligate use of fossil fuels and other non-renewable resources? Our assumption that the American way of life will go on forever, just as it is, much as the British thought their empire would go on forever? What about our assumptions about unlimited technological progress? Will science fiction visions of star flight or "the Singularity" seem as quaint as "the White Man's Burden"?

Above all, what will they think of the appalling amount of waste in our culture? Have you ever walked through a tourist area - say Fisherman's Wharf in San Francisco - and seen entire stores devoted to schlock, made in developing countries by people who must scratch their heads in wonder at a people so wealthy that they can afford to spend money on things that are so utterly and obviously useless?