Unlikely Alone—Part 2

If life is discovered on other worlds, it will have a profound impact on our psyches. Some of us will have the foundations of our beliefs dramatically shifted and will have to rethink our basic convictions. Earth and humans will no longer occupy the pinnacle; this precious little planet will no longer be the only vital place in the universe. Others will rejoice that the cosmos is as rich as we could ever have imagined. 

The discovery of extraterrestrial life—if it comes—will not come any time soon, however. Moreover, the forms of life we discover will quite probably be of a type that we as yet can't begin to guess. Our current expectations of what we might find are probably too restrictive. The various scenarios that TV and movies have portrayed (aliens who usually look and talk like us—especially using modern English) are far too limiting.

Scientists have frequently speculated on what kinds of life we might find out there—describing the conditions under which “life as we know it” may exist. We’re coming to see that that view is too narrow, as we've been taken aback by the new types of life we've found right here on Earth—the so-called “extremophiles” that I mentioned earlier. Clearly our understanding of types of beings that we can't currently conceive of will soon be expanded even more, as we continue to explore our planet. 

I also wonder if we could even recognize some other strange form of life elsewhere in the universe, were we to encounter it tomorrow. It took us a long time to “discover” some of those extremophiles right here on Earth. 

To date, we have only one example of life and only one vital planet that we know about. With just a single sample, there's no saying that life has evolved “out there” as it has here. Even if we could rewind history and replay evolution on Earth, there's no telling what creatures would roam our planet today—but it certainly would be dramatically different. So many random events occurred along the way that would never be repeated—events that changed the course of evolution and altered life. (Think of the improbable asteroid that blew away the dominant dinosaurs, 65 million years ago, removing them and opening up so many niches for mammals.)   

Furthermore, it's taken something on the order of 3-4 billion years for life on Earth to evolve from some unknown ancient seed to the complexity we see today—that’s several billion years for a technologically proficient form of life to evolve on our friendly little planet. The chances of our finding life on some distant planet that is anywhere near as advanced (or immature) as humans are has got to be incredibly remote—given that they may have begun billions of years before us or are just getting started. We might find ourselves unable to communicate with beings who are either primitive or much further advanced than we. 

And the distances involved! The universe may be teeming with life, but those beings could be so unimaginably far away that we may remain ignorant of them forever.

So, where are we, in being able to answer the question, Are we alone? We've no more a definitive answer than 100 years ago. It's still an unknown, even though the likelihood seems to be much greater than even a year ago. Expect to live with the mystery for a good while yet. Don't hold your breath—just open your mind a little more to the possibility.