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Monday, 14 November 2016

Answers for Authors: Where can I get antimatter from?

Before we start, I ought to check: You're not planning on building anything... bombish, are you?

Anyway... the short answer is: Saturn's rings.

There you go. Cup of tea?

Ah, you'd like details? Well:

Antimatter is often called normal matter's 'opposite', 'mirror image', or 'dark twin'. Which is very dramatic, and makes physicists feel cool saying it, but doesn't explain much. 

I'm a physicist, but I've made peace with my cool quotient being pretty damn low. I think of it like this: If a particle of matter can be defined by a set of numbers - it has an electric charge of 2 for example - then it's antimatter equivalent would have the same numbers but with a '-' in front*. So an electric charge of 2 for a matter particle becomes an electric charge of -2 for its antimatter equivalent, and so on. The interesting bit, from a spaceflight (or killing things) perspective, is that when the particle and antiparticle meet they disappear in a flash of energy.

And you can be sure that's true, because no sane person would make something like that up and expect you to believe it.

So, if you mix antimatter with regular matter you can make astounding amounts of energy: A gram of antimatter, if released into our environment, would explode with the force of a medium sized nuke.

Brilliant! Where do I get some**?

Come on,  you don't seriously think an incredible new energy source wouldn't be weaponised before breakfast

You won't be surprised to hear that a material that explodes on contact with anyything isn't just lying around. But it's not just rare: For reasons we genuinely don't understand, our universe is made of matter only - there just isn't any natural antimatter

We know antimatter can exist, because we can make tiny amounts of it with particle accelerators. Our best theories of the Universe's beginning predict that it should have begun wit equal quantities of each. But, somehow, everything has ended up made of matter -  which is a huge mystery,  and another reason scientists would love to get their hands on enough to investigate better. 

But how? It can only be found inside the most powerful particle smashers, in incredibly minute quantities? We could set up huge atom smashers, optimised for antimatter production, all over the place. But, at a cost of 65 trillion dollars a gram, mass production might be a bit impractical. 

This is $1 trillion - the speck on the lower left is a person. I can't recall if the stack is of twenties or fifties, but it's a lot to spend for a gram of something.

Is there another way?

Cosmic rays – fast moving particles hailing from who know’s-where-in-deep-space – form antimatter when they collide with planetary ring systems and atmospheres. The reaction is roughly analogous to reactions that produce antimatter in particle accelerators, but a planet's atmosphere or ring system is hugely bigger, and 'runs' non stop for billions of years. As the antiparticles produced are electrically charged they can get stuck in the planets magnetic field, whizzing around it until they hit some stray bit of matter and go bang

Even though the amounts produced are much better than current accelerators, they are still minute – there are 160 nanograms over Earth, and even Saturn’s mighty rings only produce a quarter of a milligram a year.

Sorry Scotty.

But, used cleverly, even that is enough to power a super fast spaceship. The trick is that antimatter doesn’t have to be used as a fuel in itself, it can be used as a catalyst to make engines using less powerful fuels work better - like giving a car nitrous

Although not much like, unless nitrous does vapourise the car and 'Fast and The Furious' just left that bit out.

Both nuclear fission and nuclear fusion reactions could be made much easier to start and keep running with a pinch of antimatter thrown into the mix - which makes building a nuclear powered engine a lot easier. And a spaceship powered by an antimatter catalysed engine could reach Mars in three months, for example. 

Antimatter doesn't just go bang - for example a teensy dose of antimatter delivered to the right spot could be used to kill cancer cells. And it could us why our universe is a safe place made of matter,  not an constantly exploding matter/antimatter cauldron. 

Since it might be so useful, there are plans to extract it: James Bickford put forward a plan for a constellation of satellites to collect antimatter from Earth’s upper atmosphere, and store it in strong magnetic fields. It could be collected, and returned to Earth as needed. 

If we could get those same satellites out to Saturn we could  collect enough antimatter to spark a dozen revolutions in particle physics, medicine, and space ship propulsion - although we’d need a revolution in spaceship propulsion first:
We'd need fleets of satellites needed to cover the massive acreage of satirn’s ring s and collect significant amounts. 

But, if you were rocking an antimatter catalysed fusion engine in the year 2223, you might well find yourself refuelling over Satirn’s rings. Which means that, unlike at most petrol station forecourts, you’d get one of the best views in the solar system as you filled you tank. 

* Not quite all - for example inertial mass and gravitational attraction are the same

** Like most physicists, I am 2% supervilian. It's part of the initiation... I've already said to much... 

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