Interstellar Methods of Communication

Interstellar Methods of Communication

There may be many effective methods of communication that have substantial merit: interstellar spacecraft optical or infrared lasers; pulsed neutrinos; modulated gravity waves; or some other kind of transmission that we will not discover for a thousand years. Advanced civilizations may have graduated far beyond radio for their own communications. But radio is powerful, cheap, fast and simple. They will know that a backward civilization, like ours, wishing to receive messages from the skies, is likely to turn first to radio technology.

Perhaps they will have to wheel the radio telescopes out of the Museum of Ancient Technology. If we were to receive a radio message we would know that there would be at the very least one thing we could talk about: radio astronomy.

But is there anyone out there to talk to? With a third of half a trillion stars in our Milky Way Galaxy alone, could ours be the only one accompanied by an inhabited planet? How much more likely it is that technical civilizations are a cosmic commonplace, that the Galaxy is pulsing and humming with advanced societies, and, therefore, that the nearest such culture is not so very far away – perhaps transmitting from antennas established on a planet of naked-eye star just next door. Perhaps when we look up at the sky at night, near one of those faint pinpoints of light is a world on which someone quite different from us is then glancing idly at a star we call the Sun and entertaining, for just a moment, an outrageous speculation.

I’m quite sure someone quite different from me is glancing idly at a star we call the Sun and entertaining, for just a moment, an outrageous speculation: Is it possible that an intelligent species exist near that yellow star? Image: Magical World © Elena

In fact, it is very hard to be sure. There may be severe impediments to the evolution of a technical civilization. Planets may be rarer than we think. Perhaps, the origin of life is not so easy as our laboratory experiment suggest. Perhaps the evolution of advanced life forms is improbable. Or it may be that complex life forms evolve readily, but intelligence and technical societies require an unlikely set of coincidences, just as the evolution of the human species depended on the demise of the dinosaurs and the ice-age recession of the forest in whose trees our ancestors screeched and dimly wondered. Or perhaps the civilisations arise repeatedly, inexorably on innumerable planets in the Milky Way, but are generally unstable; so all but a tiny fraction are unable to survive their technology and succumb to greed and ignorance, pollution and nuclear war.

It is possible to explore the great issue further and make a crude estimate of N, the number of advanced technological civilizations in our galaxy, but let’s talk about this issue later.