Just Finished Reading: The Possibility of Life – Searching for Kinship in the Cosmos by Jaime Green (FP: 2023) [276pp] 

As far as we know, life on Earth emerged practically the moment conditions allowed. As soon as the crust was cool enough for liquid water – BAMM Life! That being the case I have long thought it likely (actually very likely) that life is everywhere in the cosmos although, like Brian Cox, I like to restrict myself to our galaxy which is plenty big enough to be getting on with. 

Starting by looking at the origin of life on Earth (still very much open for debate and further study) the author considers exactly what conditions had to exist to facilitate the leap from lifeless to living matter and how this process could have been replicated on other worlds both similar to and different from our own. Interestingly (again as Brian Cox has stated) there are likely to be BILLIONS of Earth-like worlds in the galaxy so, unless the odds for life are vanishing low, we can expect life elsewhere just on the basis of statistics. Although the Earth does seem to have some ‘unusual’ characteristics – a significantly larger moon that we’d expect – personally I don’t think that we’re odd enough to be anywhere like unique. 

Once the foundations are laid, the author moves onwards looking at planet formation (most stars seem to have at least a few planets) and relates what we can glean about other planetary systems orbiting a variety of star types (note: Red Dwarves last a LONG-ass time!). Then its time for the meat... Multicellular life. Whilst its true that for most of Earth’s history we were a world dominated by single cell life personally I don’t think that such a state is the universal default. If cells bunching together happened here – no matter how ‘late’ - I don’t see why it can’t happen elsewhere and possibly a whole lot quicker. Of course, operating with a single example – US! - its difficult to draw any firm conclusions. Hopefully such a state of affairs won’t last forever. Again, personally I’m betting for simple life on Mars and more complex (fish?) under the ice of Jupiter’s moons. Here’s hoping! 

Once you have complex life the next natural question is going to be about intelligence – could we recognise alien creatures as people? I’m not sure about this one. We humans are late arrivals in the grand scheme of things and its possible that we’re an aberration. We might just be alone in that regard. Of course, the other thing – especially if we’re hoping for some kind of communication if not actual hand/tentacle shakes is technology. The ability to send and receive messages over stellar distances is VERY new for us, so we might be checking out planets that haven’t invented radio yet or even have been scanned in the past during the height of the Roman Empire – proving that there are no intelligent beings here! 

Its still (very) early days and there are still lots of questions to be answered (or even posed). From what we know about our planet and our galaxy life SHOULD be reasonably common. Finding it is, of course, a whole other ball game. We haven’t been looking very long and we’re still working out exactly what we need to look for – water worlds, radio waves, mega-structures? - so I’m not particularly let down by the results so far. Jupiter’s moons are our best bet for finding additional life in our Solar system. What would be really nice is if we could establish early on that it emerged and developed completely independently of life on Earth. If life could begin in two places in the same system, then that would indicate that life is EVERYWHERE (crosses fingers). 

The author is obviously enthusiastic about the subject which really comes across. She also uses a LOT of Sci-Fi references – an important source of speculation about alien life – which is why I’ve added the SF label to the list. Such references certainly didn’t hinder my enjoyment of this work. If you’ve ever wondered about the subject and wanted an idea where the latest research and ideas are leading us then this is the book for you. Definitely recommended.