I have been reading a book called Lonely Planets and the other night as I looked up in the sky in the country where the stars are so numerous and bright, I wondered if another conscious being on another planet was wondering about me. I felt sorry that we would never meet the way we regret two lonely people looking out of the window at night in the same town may never get to know each other.
We once thought earth was the center of the universe, and although we now know we are just one planet circling a star in one of many galaxies, we still tend to think we are the only planet burdened with intelligent life, and that in spite of having to make a living and raise our kids and keep up with the holidays, it falls to us to ask how the universe began, how it will end and why it is here. Yet like a busy mother who dreams she has another forgotten child, we keep looking for signs of life elsewhere.
We ask what requirements life on another planet would have and guess, from our own experience, it would need water and be carbon-based since only carbon can form long chains called organic molecules. Intelligent life would need a long time to evolve as it took five billion years, half the expected life of our sun, for us to ask these questions.
We imagine life would need a planet about the same size as ours, just the right distance from its star, and with just the right organic chemicals. But perhaps life arises not so much from a chance encounter with a perfect planet as by an arranged marriage. What life may need is a good enough planet and then by a series of changes and interchanges, a biosphere that attains a stable disequilibrium. Scientists seeking signs of life look for a biosphere with variable weather and atmosphere, a planet that appears to breathe. By the time any intelligent life evolves it will have adapted to and created the world it lives on.
The earth’s atmosphere at first had very little oxygen which was fortunate because oxygen which rusts metal can very easily burn up carbon-based life. When over time one cell called algae, safely in the ocean, developed the trick of photosynthesis, of taking carbon from carbon dioxide and releasing oxygen into the air, the ozone level was formed and other cells began to respire, to use oxygen in small controlled fires, to burn carbon fuel, and create the caloric energy that distinguishes animals from planets as warmly alive.
But it may again be earth-centered to imagine life elsewhere similar to ours. It would probably replicate itself in a different chemical language. Adenine, quinine and thymine seem even less universal than earth, air and water. We sometimes picture people from other planets as green, suggesting, I suppose, that they photosynthesize like plants. Would they be cold to the touch? Arthur Clark, the science fiction writer, has said that any extremely advanced technology would appear to us to be magic as the people of King Arthur’s court thought the Connecticut yankee who could light a match was a magician.
In whatever form and however advanced, intelligent life is probably out there. Estimates range from one thousand to one billion possibly communicating civilizations in our galaxy alone. Whether any of these civilizations will communicate with each other depends on the average length of such civilizations. A communicating civilization would have to last thousands of years after the invented the technology to communicate, and the technology would have to last millions of years.
Why then, as the physicist Fermi asked, haven’t we heard from anyone when many stars and planets formed in our galaxy long before the earth and the sun? Is it that the most technological societies self-destruct? Photographer Sabastian Salgado, who has spent many years researching humans suffering in refugee camps, crowded cities and war zones, believes that life has broken the balance it once had with our planet. Is intelligence an evolutionary asset? As much as our hearts go out to Bach and Shakespeare and Galileo and Einstein, the question is debatable.
How hard is it to hold in our minds as we drive and shop and look at the news, that this is not science fiction, that we are the intelligent life of one planet, and the possibility of interstellar communication could rest on our ability to last here.