Bracewell probes: part two

Assuming that aliens have dispatched Bracewell probes to distant planetary systems, it's reasonable to expect marvelously sophisticated devises. I'd be genuinely surprised, for instance, to discover a relatively nearby alien artifact "merely" eavesdropping on terrestrial transmissions and notifying its creators. Such a craft smacks of human engineering, not of the ancient galactic civilizations we may be forced to confront if SETI is to shed its cozy anthropomorphic chauvinism. Given speculative breakthroughs in fields as seemingly diverse as nanotechnology and artificial intelligence, I think it's more likely to expect Bracewell probes to exhibit behavior in keeping with the recently popularized "law of accelerating returns"; in other words, machines engineered by ETs should be truly intelligent, not simple telerobotic puppets limited to radio transmission.

Instead, Bracewell probes could very well outsmart their own makers and transform themselves into machines quite unlike the quaint transponders imagined in "The Galactic Club." Once the potential of nanotechnology and self-replication are accounted for, the potential for visiting ET craft appears nearly limitless. Not only could such emissaries engage an emerging technical civilization in an excruciatingly patient dialogue before alerting others, they could choose to remain chameleon-like, perhaps operating in the background like stealthy computer viruses. We might never even suspect they're here (neatly accounting for the so-called "Fermi Paradox"). Conversely, we could have been deliberately inoculated to their presence long ago, never seeing their machinations for what they are.

Supposing, for sake of argument, that a Bracewell device resides in our solar neighborhood, what might it be doing? More pertinently, why would it elect to remain hidden when we Earthlings have developed an unmistakably "intelligent" electromagnetic signature?

Both questions force us to reconsider Bracewell's legacy in ways I'll explore in my next post.

This piece originally appeared at aboutSETI.com.