What is it about space travel that is so alluring? Even a ‘short’ journey in space takes a long, long time. It’s cold up there, dangerous up there and, what’s worse, for long stretches there’s nothing up there. Alpha Centauri is the star system nearest to our own and even that is over four light years away – or to put it another way 25.6 trillion miles; and yet, when you get there, most of the universe is going to look much the same as it does from Earth, because as vast as the distance from here to there sounds, in relation to the size of the Universe it’s trivial.
Ever since i can remember i have longed to make that voyage. Alpha Centauri is my love, my other. It is all that is unattainable – the 99.999999% of the Universe which not only will i never visit, but to which a visit would be impossible.
For me but not for my descendants? Because it is conceivable that one day we – as in human beings – could make such a journey; whereas for most of the Universe no such possibility exists. We would have to become something other than human – and would therefore no longer be ‘us’ – to endure the centuries, millennia even, that even the fastest spacecraft would require for the trip to other galaxies.
Even measured in light years the distances to these can run into the billions; and at such a distance, there is no way of knowing if the galaxies are still there. After all if the picture we’re seeing is billions of years old, who knows what’s happened since? And their size! In what way is it meaningful to visit a galaxy? We live in a galaxy, but if we were to climb into a spaceship at birth and visit a planet – or even a star a day – we wouldn’t see them all before we died. 100 to 400 billion: that is how many stars our galaxy contains.
By contrast, a visit to another star system sounds positively manageable. And what an experience! Imagine seeing the Sun as a yellow pinprick in the darkness. For just as Alpha Centauri is visible from Earth, so the Sun would be visible from a planet orbiting either of the two stars* in that system. Just as astronauts, when they saw the Earth from the Moon, gained for the first time a sense of the Earth as an object separate from themselves; so from Alpha Centauri we would gain something like the same perspective on our Solar System.
Might Alpha Centauri contain an alternative Earth? Unlikely, given its twin suns, but it doesn’t stop people dreaming, especially those of us who have never felt fully at home on this Earth. The important thing is that it remains unknown and thus is the perfect playground for dreams and nightmares, much as was true of Mars or Venus before spacecraft revealed the more prosaic truth: that Mars is an empty red desert and Venus** an inferno. We may still wonder sometimes about the possibility of life on Mars, but for the most part our Martian fantasies are now not about what we might find there but what we might create there: terraforming. There’s another parallel too: just as Mars and (occasionally) Venus have been conceived as mirrors or twins to the Earth, so Alpha Centauri performs this function for the Solar System as a whole.
I think, having considered it, that all these factors play their part for me: the longing to attain the unattainable; the need to reduce the universe to something more intelligible; the desire to see the reality i live within from without; and an adult version of my childhood dreams of a passage to other worlds.
* Actually, there are three but the third, Proxima, is much smaller and dimmer.
** An atlas we had when i was a child included an ‘artist’s depiction of what Venus might look like’. It showed a lush, vaguely prehistoric looking jungle.