The universe is much emptier than we once thought it was. Not too long ago, in the era of Einstein and Picasso, it was possible for reputable astronomer to speculate about the canals of Mars (could they possibly be remnants of an ancient civilization?). The science fiction of the mid-twentieth century often postulated a very densely populated solar system: Venus with its steaming jungles, Mars with its red-rose dusty cities half as old as time (with perhaps some hidden survivors encamped like Bedouins among the ruins), perhaps even monstrous intelligent whales swimming in the oceans of Jupiter.
One by one, these speculations were transformed into fantasy. The more we learned about our solar system, the more desolate it became.
And not just the solar system. Given the size and age of the universe, scientists like Frank Drake and Carl Sagan entertained the possibility that the universe was teaming with life with millions of inhabited planets. Inspired by these hopes, the search for intelligent life in space (SETI as the enthusiasts call it) has been going on for several decades now. Perhaps it hasn’t been as wide-ranging as it could be but our ears are cocked to the stars and we are trying to pick up any faint signals of intelligence. So far, only silence.
Increasingly, we have to ask the question raised by physicist Enrico Fermi: “Where is everybody?” There are any number of answers: perhaps the extra- terrestrials just don’t want to talk to us. Perhaps it’s the nature of intelligent species to destroy themselves at the very point at which they can send messages into space. Perhaps the distances are too large to make communication possible (if that were so, then in effect it is the same as if there are no extra-terrestrials at all).
But consider this: It’s entirely possible that earth is the only planet in the universe that is filled with abundant life and self-conscience species. We could be a very tiny and fertile oasis in an unimaginably large desert.
The possibility that we’re all alone in the universe has real implications. If there are no ETs then the survival of earth becomes a matter of more than self-interest. Taking care of the earth becomes a cosmic responsibility. If we muff it here, then it’s game over for life.