1000+ words of YA technobabble.

[matt_doyle]

Still vaguely working on Starstuff, the nebulous scifi YA novel I may someday write.  Its rough drafts are much, much rougher than my usual, which tells me that this narrator really isn't done cooking yet, but I wrote something today that might be of interest:  the tech used in this universe for long-distance spacetravel.  For sublight, there's a diametric drive, and for FTL, there's a wormhole-creating machine.

My grasp of astrophysics and theoretical physics is very weak.  So I am not at all sure that I am describing these concepts correctly, and I am certainly not sure if my attempt to give a practical, Bill-Nye-ish explanation to young readers is at all comprehensible.

So if you are an astronomy or physics nerd, and this sort of thing interests you, please, read what i've got here and

 

To me it looked like a sailing ship, more or less – a big ceramic bowl with a glass lid and dozens of long silver needles projecting from the rim, with butterfly-wing parachutes towing it through the sea of vacuum. I couldn't tell how fast it was going, but they told me later – three percent of the speed of light, pulling 45 Gs-- accelerating almost fifty times faster than things fall in earth-normal gravity. It was the sails that let it do that, they said, by messing with particles that weighed less than nothing, and something about the way they did it meant that we could walk around that ship like it was standing still, rather than feeling 45 times heavier than we should – which is good, since nobody on board would have been strong enough to move around three tons of weight with our muscles.

 

Now, the sails began to fold inward, making strange origami-shapes as their surfaces shifted, drawing in the energy they caught and pulled with. Nikhita is better with the science of it than I am, but even her eyes start to glaze over when Draconis started talking about gravitons, tachyonic exchanges, and manipulation of stable antisingularities. What it comes down to is that there's something like a black hole without any mass in the center of every ship with a stardrive, and it allows travel in two different ways. First is the diametric drive, which lets it catch and direct weird particles that move away from gravity rather than towards it. Since the ship itself has mass, and all mass has gravity, the particles move away from the ship. But since the sails can catch and hold the particles, if the sails are ahead of the ship, the energy drags the ship forward. It's kind of like you put a big fan on the deck of a regular sailboat, and used it to make the wind.

 

When they pull the sails in around the ship, the second drive comes into play. The entire ship becomes surrounded by those weird particles, and something called negative energy strings, which basically cut out a section of the universe – they remove a portion of the 'fabric' of space-time. Then they remove a second section, somewhere else in the universe, and match the edges of each hole up. They move the ship through the hole, and close it behind them... and in a single instant, we are somwhere completely different in the universe. The ship only has to travel the width of the hole, so it never technically goes faster than light... okay. Let me find a less confusing way to talk about this.

 

Take a piece of tagboard. Draw a little planet in the upper left corner, and another one in the lower right corner. Fold the sheet in half. Then use a scissors to cut a star-shaped hole in the middle. Just trust me, making it star-shaped will get important later in the discussion. Cut through both layers, so it goes all the way through. Now. If you use a tape measure to figure out the distance between the two planets you drew, you can do it two ways. Unfold the sheet of tagboard and put the tape measure across it... or keep it folded, and thread the tape measure through the hole. That's always going to be quicker.

 

I wondered, the first time it was explained to me, why we ever used the diametric drive at all. Why not just use wormholes all the time? But as it turns out, there are two good reasons for that. The first good reason is pretty simple – you are literally punching a hole in the universe. If you do that out in the middle of nowhere – deep space, where there's nothing but vacuum, dust, and weird particles... there's no problem. If you do it on or near a planet, though, there's a much bigger chance that you will be punching a hole through something someone cares about. Like a spaceship, or a person. And it it's moving while that happens – and everything in the universe is moving away from the Big Bang, really really fast – then when you close the hole, it won't match up right. And you're stuck with big, messy, physics-boggling holes in things. People can fall through them, or be cut in half by them when they open, or all kinds of nasty things can happen.

 

Of course, someone like Captain Eburneus doesn't care about that. But he does care about the second reason. Gravity. When you're cutting through space-time, you need to remember that gravity pulls at everything with mass, causing space itself to be curved. The more mass, the closer it is to you, the more it's curved. Take that tagboard, then, and press both sides between your fingers, so that the tagboard bends and curves, but doesn't fold.

 

It's hard to cut a hole that way. It's even harder to get the edges to match up. And it leaves space between the two pieces of tagboard, so you're not saving as much distance... if you're lucky, and come out where you want to go in the first place... or if you get out at all, rather than getting stuck somewhere outside the universe where the laws of physics may be different, or meaningless. The middle of a wormhole is a weird, scary place. Nobody wants to stay there. So everyone uses a diametric drive to get as far away from big, massive, space-bending things like stars and planets as they can. At least, they do usually.

 

The last thing you need to know about wormhole travel is you always use two jumps to get where you're going, rather than one. Why? I still don't really understand why it matters – Draconis uses words like 'chirality' and I have no idea what he means – but this is why your hole is shaped like a star. Unfold that tagboard. On one half of the tagboard, the star is right-side up. On the other half, it's upside-down. Everything that goes through a wormhole has every particle in its body flipped around. Directions are reversed. You won't notice this. But everything else will. Every right-handed person you know who didn't jump with you will be left-handed afterwards, as far as you can tell. The best way to stop that from happening is not to jump directly where you're going, but to jump out to the middle of nowhere, and then jump again to your destination, so that you get flipped twice – from heads to tails and back to heads.