Extraterrestrial Civilizations - Isaac Asimov [130]
It will take Pioneer 10 about 80,000 years to recede from us to a distance equal to that of Alpha Centauri. It will not be anywhere near Alpha Centauri at that time, however, for it is not going in that direction.
Pioneer 10 was not aimed with any star in mind, after all. It was aimed at Jupiter in such a way as to give us maximum information about that planet, and whatever direction it took up thereafter, on leaving the Solar system—that was it.
As it happens, Pioneer 10 will be following a path that will not come close enough to enter the planetary system of any star we can see for at least 10 billion years. Of course it may through sheer accident skim by a free-world some time in its long journey. The chances of even that must surely be exceedingly small, however, and no one seriously expects that Pioneer 10 will come within the purview of any intelligent species at any time in its long journey.
In that case, why should we have bothered?
In the first place, it was a very small bother. And in the second place, it just might be picked up at some time, and even if those who pick it up are much too far away from us to do anything about it, or if it is picked up at a time long after humanity is extinct, we would nevertheless have made some mark on the Universe.
We would have left behind evidence that once there was an intelligent species on our small world that could manage to put together enough expertise to hurl an object out of our Solar system. There is such a thing as pride!
Finally, we can multiply our chances by sending out more than one message. An identical plaque was placed on Pioneer 11, which will eventually leave the Solar system on a track different from that of Pioneer 10.
And in 1977, probes were launched on which were included numerous photographs showing widely mixed aspects of life on Earth, together with a recording containing enormously varied sounds produced on Earth.
RECEIVING
Obviously, it will be some time before we are in a position to send out messages that are more than passive cartoons, aimed virtually at random.
Furthermore, there is some opposition to the thought of sending out messages at all. The nub of that opposition rests with the question: “Why attract attention?”
Suppose we do announce our presence. Are we not simply inviting civilizations advanced beyond ours, which have hitherto not been aware of our presence, to make for us at full speed and to arrive with the intention of taking over our world, of reducing us to slavery, or of wiping us out?
The chances seem to me to be strongly against that. I have explained earlier in the book why I consider it very likely that civilizations that have advanced beyond our own level of technology will be peaceful. Even if not peaceful, civilizations are very likely confined to their own planetary systems. In the very unlikely case that a civilization is warlike and is also roaming freely through space, it has probably examined all stars and is aware of our presence. Finally, even if it has unaccountably missed us, we have already given ourselves away by our radio broadcasts.
For all these reasons, it makes no difference whether we signal or not, and yet it is hard to answer the unreasoning fears that assume the very worst combination of possibilities. Suppose there are civilizations out there as vicious and warlike as we ourselves are at our worst, who can move through space freely, who are looking for new prey, and who have until now been unaware of us. Shouldn’t we lie low and keep absolutely quiet?
Accepting that argument, should we not, for our own safety, find out as much as we can about these hypothetical monsters even while we are lying low? Shouldn’t we want to know where the danger is, how bad it might be, how best we might defend ourselves, or (if that is impossible) how best we might more effectively hide?
In other words, abandoning any attempt to send messages (at which we