What Stephen Hawking thinks about aliens made news this weekend, and Centauri Dreams readers will know from our past discussions more or less what Hawking has to say. Assuming we come into contact with an extraterrestrial civilization, it is widely assumed that one of two things will happen. Either an alien visit will be devastating, as has all too often happened when cultures with widely different technologies met, or a benign transfer of information will occur, in which case we benefit by our exposure to new science and revolutionary ideas.

A Threat to Humanity?

Hawking, who has been working on an upcoming program for the Discovery Channel, opts for the former, as this story in TimesOnline notes. Most life elsewhere in the universe, the physicist believes, will be relatively simple, microbial or primitive animals. But there will be exceptions:

…a few life forms could be intelligent and pose a threat. Hawking believes that contact with such a species could be devastating for humanity.

He suggests that aliens might simply raid Earth for its resources and then move on: “We only have to look at ourselves to see how intelligent life might develop into something we wouldn’t want to meet. I imagine they might exist in massive ships, having used up all the resources from their home planet. Such advanced aliens would perhaps become nomads, looking to conquer and colonise whatever planets they can reach.”

Historical analogies are inevitable:

[Hawking] concludes that trying to make contact with alien races is “a little too risky”. He said: “If aliens ever visit us, I think the outcome would be much as when Christopher Columbus first landed in America, which didn’t turn out very well for the Native Americans.”

Ambiguity and Recognition

We’ve argued this point of view and its opposite many times in these pages. My own belief is that contact with an advanced culture would be something different than either of the above alternatives. Assume a wide enough disparity in our capabilities and the problem will be knowing when an encounter has actually taken place. Indeed, just as a civilization a million years in advance of our own (and we should ponder exactly what ‘in advance’ means) might have no real interest in us, we for our part might not even be able to recognize them.

One of many possible examples: Suppose our inability to find magnetic monopoles is actually a marker for intelligent activity. The problem with magnets is that they’re always dipoles, north pole at one end and south at the other. A magnetic monopole is an isolated ‘north’ or an isolated ‘south,’ and there’s precedent for this in the fact that electric charges come as monopoles. There’s a rather robust literature about magnetic monopoles but the problem is that nobody can find them, despite a false alarm back in the early 1980s.

We believe that magnetic monopoles should have been created in the early universe, and one notion about where they’ve gone is that a period of cosmic inflation spaced an abundant population of monopoles so widely that finding even one would be all but impossible. But maybe that theory is wrong. A sufficient number of ‘north’ monopoles encountering their ‘south’ monopole counterparts would create vast amounts of energy. So what if, as Paul Davies speculates in The Eerie Silence, the lack of monopoles tells us something:

Theoretical physicists are masters at predicting things that might exist, but don’t seem to be there. Exotic subatomic particles with whimsical names such as neutralinos, shadow matter and axions grace the theorists’ lexicon, but haven’t yet shown up in the lab. At the other end of the mass range are mini-black holes, quark stars and cosmic texture, to name but a few. Did ET make off with them? Clearly, extreme caution is needed before considering alien culpability.

Extreme caution indeed, and no one is seriously suggesting this is the case. In fact, even as Davies goes through a set of scenarios for viewing possible extraterrestrial activity — his point being to ask whether we would know it when we found it — he’s quick to add this:

Remember Bayes’ rule: the hypothesis that aliens are the correct explanation for the anomalous absence of something is only as good as the prior probability of an alien super-civilization in the first place. That may be very low. By contrast, the prior probability that Professor A’s theory of the so-and-so particle, or Dr B’s prediction of such-and-such an astronomical object, is simply wrong could be a lot higher.

But if we’re willing to go to this speculative extreme, it seems worth saying that a civilization that evolved aeons after a Kardashev Type II-scale engineering project had depleted local resources might not be able to tell that it was living among the debris of a neighborhood that had been effectively ‘mined out’ of materials that would have proven of use to the former super-civilization.

The Real Encyclopedia Galactica

My guess is that if there are other civilizations in the galaxy at the present time and if we at some point do encounter them, we’ll have a lot of trouble figuring out what they’re after, where they’re going, or what their motives are. Let’s hope such an encounter would be benign enough for us to learn, ponder and muse about the unfathomability of intelligence that has evolved elsewhere. Maybe we would be able to communicate enough to acquire deep knowledge, but I suspect the idea that there is an Encyclopedia Galactica out there to be studied is a chimera. The real Encyclopedia Galactica is more likely to be the one we build with science, one whose entries we refine with new observation and experiment.

A 2002 Roper poll taken in the US found that most Americans are ‘comfortable with and even excited about’ the discovery of an extraterrestrial culture. If the poll is accurate, Hawking’s ideas will probably strike most of its respondents as alarmist in tone, and reminiscent of a particular kind of bad science fiction movie. The problem is that we have only one example to work with, our own. We can see what has happened in the history of our species to cultures that have met superior technologies, but when it comes to encounters with entirely different beings, we have no template to fall back upon.

That leaves us guessing, a pleasurable human activity that is a long way from science. I think alien nomads in massive starships are a lot less likely than alien bacteria, but we press on with the search for both kinds of life and anything that may exist in between. Meanwhile, I’ll watch Hawking’s program with pleasure. The man is a titan. He has paid his dues and continues to expand the way we look at the universe, and the last thing I would do is take his views lightly.