A handy guide to growing your own spaceship

Terran life-forms need not apply

Column If you were one of the SETI at home crowd - three million PC owners worldwide, all trying to scan radio signals from space to find alien transmissions - you may have missed the news that gives us (yes, I was one!) hope of really reaching the stars. I'm thinking of building a living starship.

The news came from a report on The Limits of Organic Life in Planetary Systems suggesting that we're daft to limit ourselves to searching for protoplasmic life with a taste for watching Big Brother TV signals.

OK, it doesn't say that. What it says is:

As the search for life in the solar system expands, it is important to know what exactly to search for. Previous life-detection experiments have been criticised for being too geocentric. This study aims to inform research programme managers, policymakers, and mission designers about the possibilities for life on other solar system bodies. Further, during planetary protection exercises at the National Aeronautics and Space Administration (NASA), questions concerning the possibility of non-terran life recur repeatedly. Remarkably little knowledge is organised that might shed light on the plausibility of bizarre life as a concern for planetary protection.

The heck with that. I'm interested in bizarre life as a way of reaching other planetary systems.

I'm entirely with Charlie Stross on this: the way we're thinking about it now is obviously nonsense.

"This is not to say that interstellar travel is impossible; quite the contrary. But to do so effectively you need either (a) outrageous amounts of cheap energy, or (b) highly efficient robot probes, or (c) a magic wand. And in the absence of (c) you're not going to get any news back from the other end in less than decades. Even if (a) is achievable, or by means of (b) we can send self-replicating factories and have them turn distant solar systems into hives of industry, and more speculatively find some way to transmit human beings there, they are going to have zero net economic impact on our circumstances (except insofar as sending them out costs us money)."

If you haven't read his analysis, you'll be wasting a lot of everybody's time commenting to this. I'm going to assume much of what he says is true, because it so obviously is. Actually, I think he is vastly over-optimistic.

It's one of the dreams of SF writers to produce a convincing interstellar space opera and, as Charlie says, most of them involve c - a magic wand - in some way or other. The main reason for saying that is that nothing the human race has ever done can prepare for the designing of starships.

Larry Niven was fond of saying that his Ringworld was "just" a very big suspension bridge. It's odd he should say that; this month we discovered that nearly all the UK's existing suspension bridges - from the Forth to the Severn and including the Humber - are coming apart. The individual wires are breaking, because it turns out that water can get into the cables, and you can actually hear the "ping" as they break. The Forth road bridge will be out of commission in less than a decade, unless someone can find a way of rebuilding it while using it.

It doesn't matter what materials you build out of - nothing we have ever used for making houses, pyramids, bridges, tunnels, or ships can be expected to last the sort of time-scales a starship will have to endure - and endure with a 100 per cent non-failure record. But suppose we could grow the thing?