The Stuff of Dreams

Natural History, Feb, 2000 by Freeman J. Dyson

With a little help, from technology, humankind should someday be able to generate biological systems on worlds with no life of their own.

Thirty years ago, people were walking on the moon. Back then, everyone assumed that Neil Armstrong's "one small step" was the first on a great journey that would soon take us to Mars and the satellites of Jupiter and Saturn. We had grand dreams of discovering other worlds, landing with our spaceships and tramping proudly over the ground. None of that happened. Instead, the emphasis shifted to unmanned vehicles, because they were able to go farther and see more than people could. And so we sat in front of our televisions watching Star Trek, while our marvelous instruments in space--the Hubble Space Telescope and the Voyager and Galileo spacecraft--did the job of exploring for us. In this manner, the dreams of the 1960s died and, with them, our vision of why we had wanted to explore space in the first place.

Human nature has often led us along this path of boom and bust. We dream great dreams, invest in great engineering projects--enormous dams and nuclear power stations--and then let them die. But each of these cycles leaves behind something of permanent value--a residue of knowledge, a new science or industry, a stepping-stone toward the dreams of the next generation.

Sooner or later, there will be new dreams of the exploration of the universe by humans. Fulfilling these dreams will require new and drastically cheaper technologies, based on biology rather than on massive engineering. We will need inexpensive ways of traveling to new worlds and staying alive once we are there. Bioengineering and biotechnology will allow us to grow new species of plants, microbes, and animals adapted to living in harsh environments. The trick will be to breed plants that generate their own greenhouses to sustain warmth, moisture, and air. This kind of ecosystem could be created on Mars, Saturn, and places even farther from the Sun.

Such dreams make sense only for worlds with no life of' their own. If we find life on Mars, for example, we should leave the planet alone and move on to some of the billions of lifeless worlds where, with a little help from humans, terrestrial life might flourish. Even as far away as Pluto, plants could be warm and cozy in greenhouses that had big mirrors around them to collect sunlight. (The same plants that make use of biotechnology to make the greenhouses could produce the mirrors as well.) Life, once it has made the big jump away from Earth, could adapt itself to take root almost anywhere, since its necessary ingredients--sunlight, a supply of common chemicals, and water--are found in abundance throughout the universe. We will have to tread lightly, though, just as we must do on Earth, if we are not to destroy the newly created ecosystems.

We are a restless species. After another century or two, when life and human settlements have spread widely in space, we will dream again of giant engineering projects. Technologies based on resources drawn from all over the Solar System will make interstellar trips affordable. The dream of spreading life as we know it throughout the Galaxy might come true--unless, as the poet Robinson Jeffers warned, the day comes "when the earth will scratch herself and smile and rub off humanity. "That future is also possible, if we behave foolishly. The choice is ours.

Freeman J. Dyson is professor emeritus in the School of Natural Sciences at the Institute for Advanced Study in Princeton, New Jersey. His latest book is The Sun, the Genome, and the Internet:Tools of Scientific Revolutions (Oxford University Press, 1999).