A flat earth implies edges, and beyond the edge lies the unknown and the abyss. We hold ourselves superior cartographers: our world is a safe, unending sphere. But we ignore the facts of geometry. The surface of a globe is all edge; naively we seek the abyss at our feet: it lies above us.
When we look up at the sky we do not see this yawning infinity. First our eyes rest on the comforting pillows of the clouds - but these are poor comfort. As insubstantial as air, they serve best as lowering backgrounds to Dutch landscapes, or as prompts to our histrionic imaginations - in a solitary cloud we may see a mighty whale, and in a blazing sunset we can feel the sadness of great aerial cities in final conflagration.
Beyond the clouds there are the aeroplanes, shining symbols of technology's prowess. Unlike the passive floating hazes which hang like veils before our eyes, the aeroplane determines its own course, and seems to have cut the earth's heavy leading strings. But they only skirt the world's new edge, staying in sight of land like timid galleons before the sextant.
At least from the plane our perspective begins to change. As we rise with it, through the great blue dome which seems to shield us, we find the sky turns black, the blackness of absence. We begin to realise that there is nothing there, that it is all literally a trick of the light.
Yet when, of a clear summer's evening, we contemplate the stars, we still wilfully misapprehend them. The recidivist poet within us says they are tiny sequins embroidered on a huge tent roof; they are a thousand glow worms on a great cave's ceiling.
We ignore the awesome generosity of the sky: we do not see the stars as billions of fiery spheres wheeling through space unimaginable distances away in an ungraspable structure. We ignore the message of their patterns: we do not see the waving speckled band of the Milky Way as the cross-section of the galaxy's spiral in which our sun forms such an insignificant part. We ignore the imperious laws of physics and the arduous journey the stars' light has made to reach us: we do not see the night sky as the cosmic Daguerreotype it is, an ancient image of other suns which died perhaps before the earth was born.
We ignore all these things because they put us in the ultimate context. They beg the terrible questions: how was the universe created? By what? What came before it? What comes after? - all the questions which have nothing to do with the world that was once flat and the centre of all creation, all the questions which seem to negate the point of every quotidian act or thought. Confronted by the reality of the stars we are confronted by the galactic irrelevance of our lives.
Which is why we turn the sky into a protective carapace, a hemisphere of Blue Wedgewood, cushioned by amiable clouds, the playground of the proud arching aeroplanes, and the stars into baubles. And who dares see more?