Just what effect would it have on us if we knew that there was intelligent life elsewhere in the universe? I ask the question because another new project, Breakthrough Listen, which will search the entire galactic plane of the . . . Milky Way and also to 100 of the galaxies closest to ours for detectable radio transmissions has recently been started. Apparently we now have the technology to detect transmissions of no more power than aircraft radar, so we should at least be able to detect transmissions from the regions around the 1,000 nearest stars if they advanced civilizations exist there.
My own view is that intelligent life besides ourselves on Earth certainly exists. The odds against life besides ourselves not existing seems infinitesimally small given the uncountable trillions of stars. However, if civilizations are advanced enough to send messages that were strong enough to reach us — apart from inadvertent ones for their own use — then they wouldn’t bother anyway because time lags of millions of years would outlast any civilization — sender or recipient. There’d simply be no point
If intelligent life exists elsewhere, and they were advanced enough, then almost certainly they’d set about colonising at least their own part of their galaxy in order to find other liveable habitats to maximise their own continued survival when their original sun expires (more correctly, explodes). In that case, I would say that the odds are higher that aliens are already observing us here and now rather than our finding signs of life elsewhere. If aliens were observing us, then they wouldn’t make contact because of culture shock, nor would they be interested in colonising Earth, because as advanced space travellers, they’d have plenty of other choices if they were, indeed, looking for another home — or to add to those they had already colonised.
It’s a nonsense to say that advanced life on other planets would have already transmogrified themselves into becoming computers — computers that are conscious that is. But this is only what electronic nerds like to tell us. We already know that anything that can regenerate needs moderate temperatures in which to do so, and all the evidence so far points to carbon as being the only fundamental element that enables by far the maximum number of possible chemical variations than any other. Besides, memory based on DNA (being self-reparable) is far more stable than anything made from silicon and copper. We know, for example, that carbon-based compounds have existed for millions of years inside meteorites. Electronic circuits or anything remotely resembling them could not have done so.
Indeed, there is a perfectly respectable theory of life (Panspermia) — once derided but now taken seriously — that life on earth was seeded by amino acids or other carbon compounds carried to earth by meteorites. If we are being observed by a living alien based on carbon chemistry or by an electronic sensor made by them on some distant planet — undetectable by us in both circumstances then we needn’t get too carried away with the possibility of finding life elsewhere. By all means let us look — it would be denying our curiosity instinct otherwise — but the chances are still very remote, all the same.
Meanwhile there are millions of different life-forms on earth of intense fascination — 95% of which we couldn’t survive without (bacteria) — we’ve yet to understand, and our own sensitively counter-balanced instincts also. That’s more than enough to be going on with. Perhaps one day when we know in much more detail how the Earth works, we’ll have a message from an ever-attendant invisible alien: “Welcome to the adult universe!”