We are not alone

Yes, that was the title of Walter S Sullivan’s 1960s classic about extraterrestrial life and the human hunt for it. (Younger readers note: he was the canonical New York Times science correspondent, not the character in Silent Hill.)

Have things moved on in the 40+ years since he penned the book? In one massive way, yes. On many interesting topics (the origin of the universe, the formation of the Moon, the genetic predisposition to addiction), we now have solid data on matters that were pretty much speculation then. And for our purposes, one important one is that we now know that planets are common. There are billions of them in the galaxy, and presumably in every galaxy. So, ripple of applause for the US and European taxpayer (mainly).

Because existing methods find it easiest to detect big planets with orbits near a star, we know that our existing knowledge of exoplanets (planets of other stars) is statistically skewed. But we also know that a lot of what we used to think about planets, for example that it would be impossible for them to form in multiple star systems, was wrong. The proof? A planet in the Alpha Centauri system, our solar system’s nearest cosmic neighbour.

However, it is simply human to want to go beyond this knowledge, and to find out about life elsewhere in the universe. Here things get tricky at a rapid pace. First, our knowledge of what amounts to life, where it dwells and how it gets going is surprisingly patchy. Previous unfunded biologists have now got money to study “extremophiles,” things that live in places that are very hot, deep, dark, salty, acidic, alkaline (flamingoes) etc. But there is a big difference between something living there, on a well-populated and generally accommodating planet with lots of genetic diversity, and life getting started there, say in the Antarctic Dry Valleys.

At the same time, we are bound to be influenced by our own experience on Earth when we contemplate these issues. Back in the 1960s, this meant the the Drake Equation, a totally anthropomorphic attempt to find out how many Earth-like planets in the galaxy might have technological life, ie creatures like the role models of the 1960s United States. Nowadays, this Earth-centrism is seen in the concept of the Habitable Zone, an imaginary region of Earthlike conditions, especially liquid water, around a star. We have known for decades that Jupiter’s satellite Europa has a huge volume of liquid water, but it still isn’t in the zone.

The latest contribution to this trope is a pronouncement from the usually sensible folk at the SETI Institute and colleagues, alleging that there can be few advanced civilisations out there because they are not emitting detectable radio waves. Well, so what? The aliens may know things we don’t about communications. (They have probably been advanced longer than we have, so that’s likely.) They may have developed a different technological and social pathway. They may regard radio noise with the disdain we have for intrusive sound or (increasingly) for excessive light illumination. Loud radio noise in certain frequencies would probably indicate life as we know it, but its absence says literally nothing.

About Martin Ince

UK-based science and higher education journalist, big strengths in universities and university ranking, futures, media strategy and training, Earth and space sciences
This entry was posted in Uncategorized. Bookmark the permalink.