We live our lives without much thought for the universe of which our planet is a part. We know that we live on a planet in a solar system in which, so far as we know, ours is the only planet with life, certainly intelligent life and we might occasionally consider the wider context: that the Sun and its planets are part of a Galaxy with many billions of stars and that it is only one of billions of galaxies that we can see. But that is beyond our comprehension and we just live for the moment, doing what we like or have to do here on this planet. Daily life takes precedence.
Sometimes we might consider that, since intelligent beings have evolved on this planet, there might be others on other planets. Some are certain that this is the case and have tried to send signals to likely stars or listened for signals that might be from other advanced technological civilisations. So far, neither has brought a positive result. Some believe that aliens have already visited Earth and see UFO reports as evidence of it.
This optimism is based on the fact that we exist. If intelligent beings have evolved here then it must be easy for intelligent life to evolve anywhere.
However, there is a flaw in this presumption. It overlooks the curious circumstances that have led to our evolution. When examined in detail, it emerges that we are an accident. Earth did not plan for our emergence; in fact it has largely been hostile to us and, several times, has threatened to extinguish us. But somehow we survived, being helped by a series of lucky accidents. For details of these lucky accidents, see my article ‘Are we alone?’ at: https://asedinburghjournal.wordpress.com/.
In an almost infinite (well very big) universe almost anything can happen. This means that even the unusual chapter of accidents that led to our emergence will inevitably occur somewhere. Well, they occurred here and we are the result. This probably means that they have occurred nowhere else, certainly not in our Galaxy and we are the only intelligent beings for a million light years. We may even be alone in the universe. What a responsibility that lays on us: to nurture our civilization and to see that it survives. Being lucky so far does not guarantee that we will always be lucky. There are several catastrophes that could overcome us, leading to our disappearance. We should take steps to see that somehow human life survives to take us out into the universe, to see that no single catastrophe can wipe us out. The universe has been kind enough to allow us to appear so let us make sure that it does not accidentally exterminate us.