You know SETI, the nice folks out in California who scan the stars for radio transmissions, hoping to find evidence of E.T. You are probably also aware that this strategy hasn't exactly panned out. (Quick clarification: The preceding does not mean I think SETI isn't productive—they're involved in a lot more work than simply scanning for alien life, and that work contributes to science and space exploration in important ways. They haven't found E.T. yet, but they still rock.) Now, some physicists are starting to pipe up, suggesting that SETI's problem maybe isn't so much a lack of aliens, but an over-dedication to searching for one, narrowly defined artifact of intelligent life. SETI is space archaeology, they say. And current practice is the equivalent of studying ancient Earth-bound civilizations using nothing but flint spear points—there's a lot of cultures you'd completely miss, because their technology was more advanced.

Paul Davies, a physicist at Arizona State University, points out that widespread radio communications may prove a short-lived historical phenomenon on Earth. Humans are, after all, increasingly using fibre optics to talk to each other. Moreover, many modern radio devices (such as mobile phones) rely on a technique called "spread spectrum" encoding. It uses signals that look like background noise, except to a receiver equipped with the right unscrambling code. Radio signals that are clearly artificial in origin may, then, be only a transient sign of civilisation.

What to look for, instead? Scientists interviewed by The Economist suggested everything from pollution (the fact that there are Earth-based telescopes capable of studying the atmospheric composition of planets outside our solar system is mind-blowing enough on its own), to evidence of intelligent tampering with the energy output or aging process of distant suns. The Centauri Dreams blog gets into those later, sci-fi inspired possibilities a bit more in-depth.

It seems like the key to this new approach is looking ahead in our own development, rather than behind or alongside, for searchable signals of intelligent life. And that's fascinating, not just for its possibility in the field of alien hunting, but for the questions it forces us to ask about Earth-bound technologies. Things like: Is there a better way we could be doing some of our basic techie activities, and how soon would it be able to supplant current methods? What might we be capable of in 1000 years, and what impact could that technology leave on our planet and our solar system? At the very least, I fully expect this line of inquiry to lead to some great, new literature—and maybe some usable tech ideas, too.

(Via Lee Billings)

Image courtesy Flickr user pasukaru76, via CC