The density of space junk peaks around 620 miles up, in the middle of so-called low-Earth orbit. That's bad, because many weather, scientific, and reconnaissance satellites circle in various low-Earth orbits.

Some things, like the orbits of the planets, can be calculated far into the future. But that's atypical. In most contexts, there is a limit. Even the most fine-grained computation can only forecast British weather a few days ahead. There are limits to what can ever be learned about the future, however powerful computers become.

I am unable to believe in a God susceptible to prayer. I simply haven't the nerve to imagine a being, a force, a cause which keeps the planets revolving in their orbits, and then suddenly stops in order to give me a bicycle with three speeds.

And it came to me then. That we were wonderful traveling companions but in the end no more than lonely lumps of metal in their own separate orbits. From far off they look like beautiful shooting stars, but in reality they're nothing more than prisons, where each of us is locked up alone, going nowhere. When the orbits of these two satellites of ours happened to cross paths, we could be together. Maybe even open our hearts to each other. But that was only for the briefest moment. In the next instant we'd be in absolute solitude. Until we burned up and became nothing.