Someone said that there's a meteoroid somewhere in space, large enough to end life on earth as we know it, making its way towards us right now. It's only a matter of time before impact. It's preordained, they say, we just can't see it yet. One day, it will appear in our sky. It's out there now, in another sky, or in the same sky, since sky is everywhere at once, and no one owns it as far as we know. I don't know if the meteoroid is picking up speed, or slowing down, or if it has kept a steady pace throughout whatever it counts as a life. I don't understand how gravity works out there, or down here. I don't understand the laws of propulsion, nor do I really want to understand.

Instead, I have a vision of blue flies in a shallow bowl, all of them still and shiny, at peace. Only if the bowl moves do they move, with a faint rustling, like a thin layer of leaves glistening over another thin layer of leaves, a sound so gentle you might say, 'It's utterly quiet out here, wherever we are', although of course that's never quite true.

I don't know if any of this is true - the meteor, the end of all our lives. Perhaps, statistically speaking, if the universe is infinite, it all has to be true.

The infinity of space is a concept I've carried over from childhood. I have no desire to let the concept die, though I suspect my version of it holds very little resemblance to what astrophysicists of today believe in. I remember asking my mum - not an astrophysicist - what exists on the edge of space and her answer was 'More space'. I couldn't imagine this. I suppose that's the point. Instead, I imagined spaceships finally coming up against a semi-porous, concrete barrier, semi-porous because in my mind the concrete is struck through with tiny air bubbles. I have no idea where those air bubbles came from in my childish mind, or if I superimposed them at a later date. Perhaps they are only being created now. I'm also not sure if 'More space' was actually the answer my mum gave. She probably gave different answers depending on the day I asked the question. At some point she probably said, 'No one really knows'.

Children don't like this answer. Whether it's because it fails to light their imagination, or because they can't imagine an adult 'not knowing' something, this response usually isn't enough. I felt I was being lied to as a child when someone said 'No one really knows'. Now, I suspect I'm being lied to if someone says they know anything. We have to lie to ourselves every day about what we know, otherwise we would crash and burn and end everything. Still, unknown things become more interesting with age; untapped regions of our collective knowledge, the stuff that sits outside the sum of all experience on earth.

A man walks through the library, smiling to himself for no obvious reason. He has no headphones on. He isn't speaking to anyone else. Something in his mind is making him smile. He carries a see-through water bottle, almost empty. Perhaps he's going to refill it. Perhaps the knowledge that water - clean, cold, drinkable - is all around is causing him to smile. It's a perfectly good reason. The world is full of strange, huge, tiny blessings.

The other day, I thought of humans as meteors; bundles of unknown force, propulsion, pull and spin, heading in directions no one can ever see, even though people often say they can. Our destinations, always separate, are far from here, buried deep beyond us, far beneath the future. You can not go forward, or back, though we all have velocity, immeasurable, but undoubtedly there. We appear in each other's sky, briefly, often when no one is looking, and usually at a distance that is itself a wall. It may prove to be porous, but we haven't seen through it yet.