Through the Glass, Darkly?

Last September I spent a week in Paris at the Searching for Life Signatures symposium. It’s a hopeful time for astrobiologists. The 2009 launch of Kepler gives new urgency to our search for life’s signatures (see page 28). And in California, the Allen Telescope Array will soon be by far the most powerful instrument ever devoted to listening for alien radio signals.

One evening, working late in my hotel room, I notice my father’s Skype online icon, so I ring him. We chat about my trip, and his weekend, and then turn to current events. My father is not optimistic about the future. In 80 years he has seen a lot, but these days he worries about overpopulation, environmental degradation, and the extinction of any number of species, including ours. 

In my 1960s youth the paragon of our hopeful expectations was 2001: A Space Odyssey. Alien contact was a part of the exciting future. We humans were on our way somewhere. But something went wrong. In 2009 we have no Moon base, and no human missions to the planets. 

My father’s mood is broken by laughing grandchildren. Yet he fears these kids may inhabit a world declining into ignorance, poverty, and conflict. I cannot refute his evidence, but I try to remind him that history is full of surprises. And I find that a week immersed in extraterrestrial life makes me worry a little less about the here and now. Is this escapism or an enlarged realism?

At the symposium the next day we focus on the globally conspicuous properties of life, its interaction with planetary evolution, and especially its torquing of our atmosphere into an unlikely mixture of gases. This pervasive global influence is the signature of our kind of life. Although we are planning to search for it on worlds orbiting distant stars, we have nearly given up on finding it in our own solar system.

This double standard is born of pragmatism. We can go to Mars and dig for isolated pockets of life. But on an exoplanet light-years away, we can’t look for organisms. We will only be able to see chemically obvious biospheres. So, we can only seek life as we know it, the kind of life that has completely taken over and transformed its planet.

Or, someone may be sending signals. For our search to have a decent chance of success, a civilization must be stable and committed to a global project — the broadcasting project — for thousands of years. So we seek something that has never existed on Earth, something unimaginably different from our own young, fragile civilization. This search is an act of faith that such an outcome is possible.

If inhabited planets or radio-friendly civilizations are out there in large numbers, we may soon be equipped to find them. Nobody knows what the effect of such a discovery would be. It might lead us toward a less-divided view of ourselves, and that could be a game changer.

When pondering life’s efforts at self-recognition, you can’t help but gain some increased identity with Earth’s 4-billion-year-old biosphere — a resilient beast that is going through an awkward transitional phase now but is not credibly threatened with extinction. And you can’t help but wonder what, if we survive the coming century, we might become. Or at least remembering that, as Nobel laureate Doris Lessing reports her father once told her, looking up at the stars, “If we blow ourselves up, there’s plenty more where we came from.”

This article originally appeared in print in the January 2009 issue of Sky & Telescope. Subscribe to Sky & Telescope.