So another thing I'd be interested in looking at is a way of putting, say, chalk dust up into the atmosphere on a steady basis. It's actually a beautiful solution, because if you just stop, everything goes back to normal. So it's... and you don't have to put up that much. So I've been thinking, for instance, of launch systems for doing that, and I've got one that I really love, which I call a Surfatron. It's based on... there's an idea called a Slingatron, which is sort of a spiral centrifuge that accelerates stuff out. But what I'm interested in is sort of a linear version of this. It works more like a whip. So you know how a whip gets smaller and smaller and it ends up supersonic, which is why it cracks. So what I want to do is make a set of tracks, that the wave velocity increases. So the track just moves up and down, and it actually doesn't move up and down very quickly, but the wave propagation velocity accelerates over the length of the track, so there's something that sort of surfs the wave that's attached to the track. The technical problem is that bearing, which is presumably a magnetic bearing or something like that. And so you wave the track up and down with local motors, and you put this thing that rides the track and accelerates as the wave velocity accelerates, and gets fast enough to fling off and certainly get into the stratosphere. Maybe you could build one that was fast enough to get into orbit, get outside the Earth's orbit. So there's another thing that I would love to build, is this Surfatron.

[Q] And where does it have to be?

It depends on whether you just want to get stuff into the stratosphere or you want to get stuff into space. If you want to get stuff into space, you'd probably want to do it near the equator, and you want it to slant up, so maybe Mount Kilimanjaro, where it flings up that way. But if you're just getting stuff into the stratosphere, actually I think a very likely place for it to be is going to be the Tibetan plateau. And I think the Chinese are much more likely to do this than the Americans, because the Americans are... you know, have lost their sense of adventure about this sort of thing. So the Chinese could save the world from global warming. So part of me is tempted to try to convince them to and explain how to do it.