Thanks to a supernova, the search for dark matter would be completed in 10 seconds!

In 1963, the American astronomer Vera Rubin begins his observations of galaxies and their stars. There she discovers a mystery that is still unsolved today: the stars far from the center rotate almost as quickly as the others.

This may not seem dramatic at first glance, but it is nevertheless one of the most frightening puzzles facing contemporary physics. We know well how gravity works, firstly through Isaac Newton who laid such solid foundations that we were able to go to the Moon, then thanks to Albert Einstein whose ultrafine understanding of the curvature of space astounds. still, more than a century after the publication of the general relativity. And yet…

Despite all the machines and experiments, dark matter remains elusive, but…

It clearly appears that when we study the mass responsible for movements in galaxies and between galaxies – and even during their collisions – we miss matter, and not just a little! Around 85% of the matter in the Universe is invisible to us, but it is very active according to observations. This is why the theory of dark matteran elusive “thing” whose influence is nevertheless very palpable. We have built machines to detect it, underground tanks cooled to -100°C filled with liquid xenon, but with certainties, nadaNothing, niente…

In 1987, a star suddenly became billions of times brighter. It had just exploded in the Large Magellanic Cloud, a small galaxy very close to ours. The explosion was even visible to the naked eye in the sky. The report? Well, if it happens again in the Milky Way soon, the authors of the study discussed here believe we would solve this incredible and fundamental mystery of dark matter. We'll see why.

Here is the difference in brightness of an exploding star in type 2 supernova and before its explosion.

And here is the magnificent remnant of this explosion, as it is visible today.

Note that thanks to the James-Webb Space Telescope (JWST), a neutron star was discovered in this remnant. However, neutron stars would precisely be a possible “laboratory” for the detection of a type of dark matter.

Here is the photo taken by JWST of the supernova remnant sn1987a.

Silence, engine, it’s running… Axion!

Today, the search for dark matter is mainly focused on the detection ofaxiona hypothetical particle capable of decaying into light, that is, into a photon. In certain cases, we should then observe an excess of light, which would betray the presence of this particle. And the best cosmic mechanism for this is the collapse of the core of a massive star called a type 2 supernova. Yes, like sn1987a in 1987. Technological progress would help if we had enough telescopes capable of detecting gamma photons (very high energy) from this explosion in the Milky Way, then the case could be heard!

There is always a “but”…

But between the explosion and the transformation of this axion particle (“axion QCD” to be precise) into gamma photons, astrophysicists and astronomers would only have 10 seconds to react. Unfortunately, today we only have one satellite suitable for this type of observation: NASA's Fermi Gamma Ray Space Telescope. In other words, if a type 2 supernova occurred tomorrow in our galaxy, we would only have a one in 10 chance of putting an end to one of the greatest quests in physics! The authors of the study therefore believe that we should place a few more of these satellites in orbit.

The Milky Way owes us supernovae!

Statistically, a supernova occurs every 50 to 100 years in a galaxy the size of the Milky Way, but the last one we detected was in 1604, the so-called “star of Kepler”. Moreover, this observed supernova opened the way to astrophysics, because it proved at the time that the heavens were not immutable contrary to beliefs. It would therefore be a fitting return for a new supernova to allow us to make a giant leap in our understanding of the nature of the Universe.

Here is the famous sn1604 from Kepler.

And finally, a little dive into the famous sn1987a.