No Phone Home—Part 1

One of humankind's enduring questions is whether or not Earth is alone in the universe in harboring life. Are we the only—and therefore exceedingly special—example of animation in the vast cosmos, or might there be others out there? This very question has evolved as our understanding of the universe has grown. The ancients may have wondered about life existing on the other shore of the sea, and people a couple of hundred years ago speculated on beings living on the Moon and Mars.

Today, however, we know much more about the vastness of the universe (even though we may not be able to wrap our heads around how truly vast it is), so now our imaginations extend way beyond our solar system, even our own galaxy, to the billions of galaxies out there. Yet the same question still poses itself, but the potential territory has gotten immensely greater, and thus the possible answers far more manifold.

We also now know much more about how life may have arisen on Earth and the extreme forms that it can assume here. We know that the presence of humans, along with all the other planet's creatures is the result of a long and torturous path that could have taken countless other directions. Some of those other alternatives could easily have resulted in the final termination of life on Earth (it could have come to a dead end and may still), or brought about life forms quite alien to what we know today.

So back to that perennial question: Is there life out there? What chance is there that it bears any resemblance to Earth's critters? Would we even recognize it as life, if we were to encounter it? More to the point, are the distances so vast that we'd ever encounter it? Movies like “ET” offer us fascinating and bizarre creatures who come to visit, and then “phone home,” to return to their world. But any kind of life out there may be simply too far away for us ever to come in contact with, or simply be unable to phone home, because of the tremendous distances.

And the distances are what matters. Humanity has for a few decades been engaged in space communication efforts, in which various researchers have scanned deep space, looking for electromagnetic (EM) signals that distant civilizations may have broadcast to the universe—signals that announce their existence. These projects are labeled Search for Extraterrestrial Intelligence (SETI). The premise is that distant technological civilizations (if they exist) would likely emit EM transmissions, in an attempt to notify other civilizations of their presence. 
 
But is this assumption justified? The SETI project surmises that distant technological species would choose to send out some kind of “I am here” signal, but is this true? Stephen Hawking wrote that this can be a risky process for Earthlings, if we engage in this game, because some life forms that may be far superior to us could thereby discover we are here and subsequently launch space ships to come and dominate Earth.

Another point to consider is that our SETI projects have evolved dramatically, in the last few decades. As our technology has advanced, we come up with progressively better methods of searching. But the civilizations we hope to contact may be centuries or millennia ahead or behind us. They may have developed communication schemes that we either once rejected or have yet to discover. We may be way out of temporal sync with these creatures and miss connecting, simply because our technologies do not match. It could be analogous to Europeans in the 19^th century looking for radio wave emissions from Tierra del Fuego, when the inhabitants there preferred smoke signals.

More on extraterrestrial life next time...