When it’s not lending its name to the worst show on cable TV, the Big Bang Theory tells the origin story of our universe. According to the theory, a massive explosion created all the matter in the universe — and for every particle of matter that was created, a particle of antimatter was created too. In mass, shape, and size, antimatter should be exactly the same as its counterpart: The only defining differences between them are in their electrical charge and quantum numbers. If you smash a particle of matter into its corresponding particle of antimatter, the two should obliterate each other into nothingness — or so the theory goes.
It’s the best explanation we’ve got for the existence of the universe, but it leaves one all-important, gaping hole in our origin story: If there are equal parts matter and antimatter in the universe, then why hasn’t all of it canceled each other out?
As scientists at CERN pondered in a Nature study in mid-October, antimatter, as far as we can tell, exists in far smaller quantities than the matter that makes up everything in the universe, but nobody really knows why. Whatever the reason, it’s what’s responsible for the existence of everything we know.
The Big Bang Theory posits that all matter in the universe has corresponding antimatter.
Scientists grappling with this question — perhaps the most fundamental cosmological riddle of all time — figure that there must be some sort of asymmetry between matter and antimatter that allows things to exist. In their study, the team of scientists that make up CERN’s BASE group, which includes researchers from Japan and Germany, made extremely high-precision measurements on rare antiprotons — the counterparts to the positively charged protons at the heart of every atom in the universe — to find infinitesimal differences between the two particles that might account for their refusal to cancel each other out.
In a statement on October 19, Christian Smorra, Ph.D., the study’s first author, summed up the team’s conclusions in a single line:
”All of our observations find a complete symmetry between matter and antimatter, which is why the universe should not actually exist.”
The CERN antiproton decelerator in Geneva.
Attempts to find differences between protons and antiprotons have been made before, but CERN’s team, equipped with tools that allowed them to make parts-per-billion-scale measurements of the magnetic force of antiprotons, tried to make some of the most precise observations yet.
In their experiments, they used 16 antiprotons that had been generated at CERN in 2015 and carefully stored in a vacuum cooled to near-absolute zero, where they were isolated from matter that could annihilate them. The high-precision technique they used for measuring the antiproton’s g-force, which used devices called Penning traps, produced data that was then compared to known measurements of the proton g-force.
The Penning trap system was used to measure the magnetic movement of the antiproton.
They had hoped that the comparison would yield some insights into the differences between the two particles, but they were out of luck. There was no discernible difference between them.
“An asymmetry must exist here somewhere but we simply do not understand where the difference is,” continued Smorra in his statement. “What is the source of the symmetry break?”
If we don’t want the universe to continue contradicting our own existence, we should hope that the asymmetry exists in some even more minuscule property of antimatter that we haven’t been able to measure yet. Because if it doesn’t, then we might have to rethink the Big Bang Theory altogether, which would make this cruel cosmological riddle infinitely more perplexing.