Astronomers believe they may have discovered signs of life on the exoplanet K2-18b. The planet itself is only known to them because of the slight flicker that occurs each time it passes between its sun (K2-18) and us, and the indicators of life are the tiny changes in the colour composition of that light that occur at the same time, assumed to be the result of light passing through the planet’s atmosphere. Spectroscopy suggests that these changes indicate the presence of dimethyl sulphide and/or dimethyl disulphide, both of them gases which on Earth are produced by marine algae and bacteria. The planet is so far away that the light being analysed has been travelling towards us for 124 years.
There have been claims like this before which haven’t stood up to further examination -claims, for instance, that the imprints of bacteria had been found found in meteorites of Martian origin – so too much excitement is premature. Also, even supposing that the biological origin of these chemicals is somehow confirmed, this doesn’t mean that K2-18b is populated by organisms like our animals and plants. On Earth, as I understand it, these chemicals are produced by simple prokaryote organisms, and there is a really huge evolutionary leap involved in getting from prokaryotes to the much more complex eukaryotes that are the basis for all large multicellular organisms on Earth.
Nevertheless, even the discovery of something resembling bacteria or algae on another planet would represent an enormous change in our knowledge of the universe. As far as we’ve known up to now, life could be unique to our own planet -the result perhaps of a set of coincidences so unlikely as to literally never have occurred anywhere else. But if we know that life also exists on another planet only 124 lightyears away (‘only’ is an odd word to use for such an immense distance, but bear in mind that our galaxy, itself one of billions, is some 90,000 lightyears wide, and 1,000 lightyears deep), it becomes clear that life must be present all over the place. Like the Copernican revolution, proof that this was the case would represent a futher radical decentring of our place in the universe. Or at least it would do so, if it wasn’t for the fact that it doesn’t feel all that surprising. We have been familiar for a long time, after all, with the idea of life on other planets, which has been a staple of science fiction for a century and more.
This, for me, is a reminder that science fiction, dismissed by many as a rather lowly form of writing -escapist entertainment and no more- is a modern form of fantastical literature that burgeoned in the wake of the incredibly rapid scientific and technological changes of the past two centuries, and perhaps serves a rather important cultural function for such a constantly changing world. Interplanetary travel, robots, artificial intelligence… all were explored in fiction long before they actually existed. (Social media admittedly, not so much!) And, just as children’s play helps prepare them for adulthood, science fiction helps us deal with the fact that, unlike people in earlier ages, we live in a time where, within a single lifespan, things will be discovered that will turn upside-down the way we see and interact with the world.
And science fiction also provides a way of visiting, if only in our imaginations, the places in the universe which we know might well exist, but which we know we will never actually see. I mean, how could we bear knowing that there is, or may be, other life out there, without at least speculating about the forms that life might take? And isn’t it the function of all fiction, in fact, to take us to places where we couldn’t otherwise go?
