Antimatter: how the world’s most expensive — and explosive — substance is made
It’s the most expensive substance on Earth, costing quadrillions of dollars for a single gram.
It’s also likely the most explosive substance on the planet.
Michael Doser — who works in the only factory making it — describes this reaction as “probably the most violent process you can think of because the full mass of the object disappears and transforms into energy”.
And based on what we know about this terrifying-sounding substance, the Universe probably shouldn’t exist at all.
So what is it?
It doesn’t sound like it should be real, but “it does exist”, says Professor Doser, a physicist who studies the properties of antimatter at CERN, the European Council for Nuclear Research.
This international scientific institution in Switzerland is home to the Large Hadron Collider, and it regularly exposes the hidden particles that make up our universe.
Lesser known is its role in studying the anti-particles of the Universe.
Professor Doser leads a team studying this strange, expensive, explosive stuff in the wonderfully named Antimatter Factory.
Here they create and capture this bizarre anti-stuff.
What is antimatter?
You can think of it as matter’s evil twin.
Professor Doser actually thinks matter might be the evil half of this equation, with antimatter being the “good guy”.
But the point is: antimatter is the opposite of matter.
It’s exactly the same as matter, except all the electrical charges of its component parts are reversed.
This is why it’s so explosive.
When a bit of matter comes into contact with its evil antimatter twin, they cancel each other out, releasing all the energy stored inside them.
“[When] a proton and antiproton annihilate each other, their mass completely disappears,” Professor Doser says.
“So this is by far the most energetic process that you can think of.”
By converting all their mass into energy, you’re getting more bang for your buck with an antimatter explosion.
“In the case of a chemical reaction, you’re transforming only about a millionth of the mass of the object of the molecule into energy,” Professor Doser says.
The violence of an antimatter reaction was clearly demonstrated when a tiny pinch of the stuff exploded over Vatican City … in the fictional Dan Brown epic, Angels and Demons.
Thankfully, outside the realms of science fiction, we won’t see antimatter destroying cities anytime soon.
“Even in that hypothesis you’d still need a gram of antimatter, which would take 10 billion years to accumulate,” Professor Doser says.
And for my Trekkie friends out there, that also means fusion-powered warp drives like those on Star Trek ships are unlikely to be a thing any time soon.
So how is antimatter made?
To create antimatter you just need to create matter.
Expensive? You bet.
The recipe they use at CERN’s Antimatter Factory to achieve this feat is:
1.Take a proton (a charged subatomic particle)
2.Speed it up enormously
3.Crash it into an iridium block.
One in every million collisions creates a proton-antiproton pair.
The basic principle is that so much energy is concentrated at a single point that it creates mass — the mass of matter.
And yes, bizarrely, energy can become the mass of matter — and vice versa.
This equivalency is most famously described in Einstein’s equation:
e (energy) = m (the mass of matter) x c (the speed of light) squared
But whenever this happens — when loads of energy gets concentrated and turned into the mass of matter — antimatter is born too.
“Antimatter appears every single time matter appears,” Professor Doser says.
The cost of creating antimatter like this makes it the world’s most expensive substance.
Professor Doser once estimated how much it would cost to make antimatter in large amounts.
“One 100th of a nanogram [of antimatter] costs as much as one kilogram of gold,” he says.
After a bit of number crunching that means a gram of antiproton antimatter would cost an absurd 5 quadrillion euros. That’s 5 thousand trillion euros.
There’s not really any point translating that to Australian dollars because it’s absurd either way.
Other sources of antimatter
And yet, a piece of fruit makes antimatter too. And so do we!
“Bananas are a perfect unit for antimatter production. It’s one antiparticle per hour, approximately,” Professor Doser says.
As radioisotopes in bananas decay, they release pairs of electrons and anti-electrons.
The same process happens in the human body too, so we’re all creating anti-electrons.
But to understand the properties of this mysterious anti-stuff, apparently anti-electrons won’t cut it.
Professor Doser and his colleagues need anti-protons.
“You need 2,000 times more energy to make [anti-protons],” he says.
“So we actually need infrastructure like at CERN, accelerators that will produce enough energy locally in a very small spot to produce pairs of an antiproton and a proton.”
But … why would we bother?
Ah yes, the multi-million dollar question.
There are a few answers.
The first is that the technology developed in CERN’s Antimatter Factory has been applied in medical imaging tools called PET scanners.
The second is that CERN is interested in fundamental research — understanding things without knowing how this knowledge could be applied.
And the final is that it might help us solve a fairly enormous cosmic conundrum: why the material universe exists.
The Universe probably shouldn’t exist
At the moment of the Big Bang, all the energy of the Universe was concentrated and exploded.
“We actually expect that the whole Universe — since there was lots of energy around at the moment of the Big Bang — should consist of equal amounts of matter and antimatter,” Professor Doser says.
“The big surprise is that it doesn’t.”
There is no antimatter left in the Universe from the Big Bang that we’re aware of, he says.
Which is fortunate.
If the Big Bang led to equal parts matter and antimatter forming, these probably would have then bumped into each other, obliterated one another, and then presumably exploded again.
“We want to study it to see why it’s not here anymore and why the Universe isn’t just empty.”
So, what’s their working theory as to why our evil antimatter twins didn’t just cancel everything out, long ago?
“The best explanation that we have found up to now is to say that there’s a slight difference in the properties of particles and antiparticles,” Professor Doser says.
This means that although equal amounts of matter and antimatter should have formed, they weren’t quite equal, he adds.
“One particle is left over out of a billion, and this one particle out of a billion is everything we see in the Universe. All the galaxies, the clusters of galaxies, the stars, the planets, us.
“We’re the leftovers in this model.”
It’s a pretty convenient explanation.
But it’s not the only one.
He says an alternative hypothesis is that we’re living in a part of the Universe filled with matter — but other parts might be full of antimatter.
In other words, antimatter planets, antimatter stars or antimatter galaxies could be a thing.
“If we don’t find a difference between matter and antimatter, then that’s going to be the only remaining explanation,” Professor Doser says.
Unravelling this cosmic conundrum is what the researchers at CERN’s Antimatter Factory are trying to do.
But so far, this mysterious anti-stuff remains elusive. The team hasn’t found any other meaningful differences between matter and antimatter.
And if you’re concerned that this work doesn’t warrant fooling around with such a violently explosive anti-substance, Professor Doser says there’s no need to worry.
“We make such minute quantities that even if you were to destroy all the antimatter that we’re making in the course of a year, it wouldn’t be even enough to boil a cup of tea.”
ABC News, 19 February 2023