Axions
Axions are one of the most intriguing ideas in modern physics. Originally proposed to solve a problem in the theory of particle interactions, they have since become a leading candidate for the mysterious dark matter that makes up most of the mass in our universe.
On this page, you can explore what axions are, why physicists are searching for them – and where in the universe we might find them.
What is the axion?
How we understand the world
All matter around us is made of elementary particles – building blocks like electrons, quarks, and photons. These particles interact through fundamental forces, described by the so-called Standard Model of particle physics. It’s one of the most successful scientific theories ever developed.
But the Standard Model is not complete. It leaves key questions unanswered – and that’s where the axion enters the picture.
Open questions – and how the axion could help
One mystery lies in the strong nuclear force: it behaves more symmetrically than expected. This is puzzling, and physicists call it the strong CP problem. The axion was originally proposed as a solution to this symmetry mystery.
But it turns out axions could do much more. If they exist, they could also be the particles that make up dark matter – the invisible substance that shapes galaxies and cosmic structure. Axions would be incredibly light, stable, and weakly interacting – the perfect ingredients for dark matter.
Physicists are now looking for axions in the cosmos and in the lab – to test if this elusive particle could solve more than one of nature’s greatest riddles.