So you've heard of a rattlesnake wormhole, right?

Josh watched the words appear in his chat window, and had absolutely no idea what AstralBoy was talking about.

You know what a rattlesnake is, yes?

Yes, of course.

You know what a wormhole is, I presume?

Josh rolled his eyes. Sometimes AstralBoy could be so patronizing. Josh had only put up with him for so long because, whoever he was, he had given him a lot of insight with his PhD thesis.

OK then, now we're getting somewhere ;)

Josh could almost hear the chuckle through the screen.

Imagine a regular wormhole connecting two points in space-time, which, for some reason, becomes detached at one end.

The idea was absurd, thought Josh. And how, exactly, would that happen?

Well, there are probably many ways, but one way is if you dump enough mass-energy in at one end. The sudden mass expansion of that end is so great that it transiently detaches itself from the rest of the wormhole.

He's having me on again, laughed Josh to himself. It'd happened several times before.

That free end of the wormhole then whips around like the tail of a rattlesnake throwing off lumps of very high — almost singularity-dense — matter.

So, what happens to these lumps of matter? asked Josh, humouring him.

AstralBoy paused. You're living in one of them. Where d'you think your Big Bang came from?

Josh rocked back in his chair. If what AstralBoy was saying was remotely possible, this would solve many problems in his thesis. You have the maths to show this?

Credit: JACEY

Yes.

Josh made some hasty notes. So, what happens to the free end of the wormhole?

It may reattach itself or attach to other free ends. This is happening all the time. So, in this way, your multiple universe theory is correct.

Despite his bravado, Josh was amazed and wondered for the umpteenth time who this guy was. He clicked on AstralBoy's icon again. The international symbol came up. No help there, or in his personal details either. Using a more direct tack, he typed: Where are you from?

The same place as you.

What do you mean by that?

Exactly what I said.

Then why can't I see you?

Think about it.

Josh sat back and thought for a while. You mean the multi-universe theory?

Not just a theory here — hey, everyone say Hi to Josh!

Josh's chat window was suddenly filled with a seemingly endless stream of messages, scrolling down rapidly, all saying something like Hi Josh! All the senders were named Josh. Josh was dumbfounded. So can everyone there talk to copies of themselves in these other parallel universes?

Yes, mostly.

So why can't I?

Not sure. For some reason, in your universe, your technology seems to have developed in a different direction from the rest of us.

So why have I been able to chat with you, online?

I've been enabling your computer. That much is possible from my side.

Josh thought for a while. So, you've been helping me with my thesis. Why?

The reply came from one of the other Joshs. Your thesis will be the key to your world developing a real awareness of parallel universes. Although some of your scientists have postulated this multi-universe idea before, they couldn't prove it, so it's just remained a hypothesis. By assisting you with your thesis, we can help you to prove this idea and therefore make contact with us.

Yes, but why now?

There was another pause, as though the other Joshs were conferring.

Perhaps this is related to the alternative technological advances there, but because of this you still have some elements in your world that we have depleted but still need here. For various reasons we cannot just enter your world and take them — we need a bridge built from both sides. This is why we need your help.

Josh considered this. But then, won't we end up like you? Is that why there are so many of you in the same situation? Each of you agreed to help each other in the past, having been contacted in the same way as you've contacted me?

Yes, AstralBoy replied. You are showing remarkable insight.

What if I decide not to cooperate?

Another of the Joshs interrupted. D'you think you're the only person we're contacting? There're others here chatting with the Andrews, Ethans et cetera, of your world. Someone there will respond. Of that, I'm sure.

Why are you doing this?

Survival, of course, answered another of the other Joshs. But you should see what we are trying to preserve here before you judge us too harshly. You may not necessarily end up like us. If you can give us what we need, we can promise to stop communicating with anyone else from your world. Our calculations suggest that the elements we need, such as sulphur and silicon, are very plentiful there because you don't have this technology yet. You can choose not to disseminate what we will teach you so that you do not end up like us.

Josh gave this some consideration then came to a decision. So, how do I cross over for a look-see?

Are you sure? asked AstralBoy. It may not be so easy to send you back.

Josh had no doubts. How could he give up an opportunity like this? Yes.

Press CTRL SHIFT ALT BACKSPACE together — I've already enabled your computer, typed AstralBoy.

Josh did as he was told and, with a brief flicker in his dorm room's fabric of reality, he was gone.