Hi REB

No emulation can predict THE future as it will actually happen. Heisenberg's Uncertainty and Chaos theory ensure that. Instead it will generate A future consistent with the current state of the atoms in our little neck of the woods - and if the cosmic-ray theory of lightning and weather is correct - you'd need to emulate a big chunk of the local universe to do so.

It's pretty amazing in my mind that cosmic-rays from across the cosmos trigger lightning and perhaps help clouds form. It means that we're influenced everyday by cosmic events, that some hypernova millions of parsecs away is ultimately responsible for some bush fire or plane-crash caused by lightning arcs. But that's what seems to be required by the current theories on what kickstarts the charge cascade that launches those bolts from the blue.

As for a time-viewer there are fancy quantum ways of viewing without actually absorbing the photons from what I've read and maybe the fuzz of uncertainty is enough to ensure that absorbing a few photons isn't going to alter the present anyway.

I like the idea of a time-viewer - certainly Arthur Clarke and Stephen Baxter's combined novel on the idea was very cool.

Adam