The search for aliens is growing in pace and importance. Some say that we are being readied for a ‘big reveal’. Others, and many of them, say that the whole thing is a bunch of ‘hooey’ and we should get on with our lives (although that is tricky at the moment).
We have always assumed that aliens live light years away and will arrive at warp speed, demanding to be taken to our leaders. We have also assumed that our search for aliens would end with green humanoids, possibly with bigger brains than ours, who will shake hands and show us how to get to the other side of the galaxy at impossibly high speeds, even through the roiling turmoil that lies outside our galaxy.
Now, though, our search for life is focused closer to home. We know that several planets in our neighbourhood have water in some form. The clouds of gas around Venus we now know have the building blocks for life and probes have detected what they believe are life forms. This prompted Russia to call Venus the Russian Planet (giving rise to a debate about who owns what).
There was also, scientists believe, some form of life on Mars.
Obviously, we are not expecting to find green humanoids on Mars or Venus (although some believe they are hiding there waiting for the moment the Earth becomes warm enough to sustain them, before they pounce) and anyway, the search for life close to home is about us surviving on other planets.
The problem with aliens is whether we would recognise them if we met them and if we did, then would that be useful to either party.
Thinking outside the box is the only way to think about aliens. One James Lovelock, who thought up the concept of Gaia – the earth is the being that is alive – believes, with others, that we should have a wider concept of life than just the human one. He calls it lyfe (pronounced loif).
He and his colleagues suggest four criteria for lyfe:
- It draws on energy sources in its environment that keep it from becoming uniform and unchanging.
- It grows exponentially (for example by replication).
- It can regulate itself to stay stable in a changing environment.
- It learns and remembers information about that environment. Darwinian evolution is an example of such learning over very long timescales: genes preserve useful adaptations to particular circumstances.
All of which is fine.
It may be that one day, we find creatures like ourselves and we all get along and set off to distant galaxies.
It may also be that in our search for aliens, what we actually encounter are creatures that are very different from ourselves, resembling spiders or weird sea creatures, in which case we will face a very different set of challenges.