Scientists have proposed a new theory that combines some of the most mysterious phenomena in the Universe – black holes, gravitational waves, and axions – to solve one of the most confounding problems in modern physics. And it’s got experts in the field very excited.
The theory, which imagines a Universe filled with colossal ‘gravitational atoms’ that are capable of producing vast clouds of dark matter, predicts that it could be possible to detect entirely new kinds of particles using a giant gravitational wave detector called LIGO.
But what are axions? Well, they’re a bit tricky, because unlike black holes and gravitational waves, we’re not even sure if axions exist – and we’ve been searching for them for the past four decades.
Axions are one of the many candidates that have been proposed for dark matter – a mysterious, invisible substance whose gravity appears to hold our galaxies together, and is predicted to make up 85 percent of all matter in the Universe. They are predicted to weigh around 1 quintillion (a billion billion) times less than an electron, and if we can prove their existence, these super-light particles could solve some major theoretical problems with the standard model of physics.
A team of physicists led by Asimina Arvanitaki and Masha Baryakhtar from the Perimeter Institute for Theoretical Physics in Canada have proposed that if axions exist and have the right mass, they could be produced in the form of vast clouds of particles by a spinning black hole. This process would be enough to produce gravitational waves like the ones that were detected recently, and if so, we can use gravitational wave detectors to finally observe the signature of dark matter, and close the gaps in the standard model.
You can think of this scenario like this: a black hole is like the nucleus at the centre of a giant, hypothetical gravitational atom. Axions get stuck in orbit around this nucleus, whizzing around like electrons do in regular atoms.
“[E]lectrons interact via electromagnetism, so they let out electromagnetic waves, or light waves. Axions interact via gravity, so they let out gravitational waves,” Mandelbaum explains. (1)
Here you go!
After coming at a dead-end for searching for smaller particles, now we search for large particles. Harmonia Philosophica has said that a long long time ago. When all you think is particles, then all you will find is particles.
It is a simple truth evident to a small child.
But evidently, not to evident to modern physicists.
Imagine the world as a giant whatever!
Then discover that whatever!
Here you go!