Despite being blocked by Roger Pielke Jr yesterday for pointing out that his righteous indignation appeared to be based on information that was not true, I thought I might still comment on his recent Guardian article about the risks associated with discovering extra-terrestrial life. By and large, it appears to show a significant lack of understanding of this general topic.

The sub-heading is

The search for extraterrestrial life is seen as one of pure curiosity. But, as in other areas of science, we should worry about the consequences of success.

and it ends with

My answer is the same one I apply to other areas of investigation and invention. So long as we are searching, we should be discussing the consequences of success of that search. If we discover alien life we may not end up dead or captured, like the New York prison escapees, but we will better prepared for the possibility of success if we consider success possible.

Roger seems to be essentially confusing two related, but largely independent, issues:

what are the chances that we could be attacked by some alien civilisation, and

what are the risks associated with our search for extra-terrestrial life?

Personally, I think that the chance that some alien civilisation could attack us is vanishingly small, but there would be nothing wrong with considering this risk, and it’s quite possible that this has been done. However, this is largely unrelated to our search for extra-terrestrial life, which carries virtually no risk at all. Why? Because, with the exception of potential robotic searches in our own Solar System (which are almost certainly not going to uncover some advanced civilisation living on one of Jupiter’s moons and that will attack us once discovered) all extra-terrestrial searches for the foreseeable future will be passive. We’ll be listening with large radio telescopes, or observing with large optical/infra-red telescopes.

Given that detecting human-like extra-terrestrial intelligence will be difficult even with the largest radio telescope we’ll have in the next few decades, the most optimistic scenario is that we detect some spectral signature that might indicate the presence of life on a planet outside our Solar System. We will probably not even be able to confirm that it is indeed life on another planet, or – if it is – how complex such life forms may be. Even if it were some advanced, war-mongering civilisation with the ability to travel through inter-stellar space, it would certainly have no knowledge that we’d discovered its existence. Also, if it were advanced enough to travel through space, it would almost certainly know of our presence, before we knew of theirs. I guess it could work out that we now had the technology to detect their existence and should therefore be destroyed, but I can’t see us deciding to avoid technology development just in case some alien civilisation might attack us once we become too advanced.

The only possible realistic risk that I can envisage, is how we might respond to the knowledge that we aren’t alone in the universe. However, not only is this not the first time that humans have encountered unknown civilisations, I suspect that the societal response to climate change will give us some hints as to what might happen; those who find that this information challenges their world-view will simply deny it, while almost everyone else will simply carry on with their busy lives regardless. Remember that the best we will probably have in the next few decades will be some complicated spectrum that scientists will claim shows signatures of life; we’re not going to have photographs of little green men.

So, unless Roger was joking, I don’t think his article presents a particularly informed view of this issue. If you want to read something more informed, you could try this. I should, however, acknowledge a very strong conflict-of-interest, as I’ve worked closely with the author of this article for many years.