"Sweet Newton's ghost!" howls Ed from the basement. His voice is abject astonishment tinged with fear.

This is never a good thing.

Ed seems to have been stamped directly from the comic-book mad scientist mould - last week he raised an Amiga 500 to sentience (although it took us a while to notice; it thinks darned slowly). When Ed gets even slightly worried about anything, it's time to run for the next Earthlike planet.

"What's up, Ed?" I holler back, for I am busy fighting a boss and cannot be interrupted.

"You remember last year when I found a second layer of reality below this one?"

My mind races. I vaguely remember something like that. Ed had remotely hijacked control of the Relativistic Heavy Ion Collider, just out of curiosity. It's a long story. "Yeah... but you said it was completely featureless void, didn't you?"

"That's what I thought, but it's not. You should come and have a look at this."

Odolwa will have to wait. I pause the game and descend into the basement.

*

"So what did you find?"

"Messages," says Ed. "Messages, encoded into the very fabric of reality itself. Absolutely no question about it. It's like a pattern of vibrations in- well, the details aren't important. What's important is that the message is obviously in some kind of language; and there was enough of it for me to translate it.

"I've just finished reading the translation. Look at this: it reads like a piece of software documentation." Ed hands over a chunk of paper. I leaf through it.

The first page is a table of settings. The numbers I don't exactly recognise, but some of the names I do.

"Those settings," says Ed, anticipating my first question, "are fundamental physical constants. The speed of light. The Planck Constant. The gravitational constant. Some others that you won't have heard of. Some others that even I haven't heard of."

Next is a list of instructions for altering the settings. Short one-line commands followed by large tracts of incomprehensible vector equations. This goes on for about forty pages.

"The instructions are extremely detailed. In order to alter the constants, you basically need to access this second level of reality and adjust it in some special way. That involves using some seriously heavy hardware. And when I say 'heavy' I mean heavy - if I'm reading this right, I think we're looking at something like five white dwarfs in a Klemperer Rosette..."

"Sorry, white dwarf stars?"

"And that's just to get access. To actually change the settings, for instance if you wanted to increase the speed of light by a factor of a thousand; well, use your imagination. There's no way mankind will ever get that far, not in a million years. But think about what this means. Our universe is 1) open-source and 2) user-modifiable."

"Are you saying... that God uses Linux?"

"Keep reading."

I leaf through another few pages. "It says here that the settings have been changed. There are comments, too."

"Several times, and by several different people, yes. The comments you see there were written by the changers. There aren't any dates - after all, we measure our time according to the vibrations of a caesium atom, and theoretically, one could adjust the frequency of that vibration as much as you liked. But check out the very last comment. 'The next wave of changes that our race makes to these settings will hopefully result in the spontaneous creation of an entirely new universe from the ashes of our own dead one.' I'm willing to bet that the very last change occurred roughly one quadrillionth of a second before the Big Bang."

I am deeply thoughtful for a moment. "It is my considered suggestion that we don't attempt to mess with these settings."