When giant stars die in impressive supernova explosions, around 99% of the energy released goes into creating a flood of neutrinos. These tiny, ghostly particles slide through tons of matter like it's not even there. But a new generation of detectors will be able to catch them and tell us about the inner machinations of the death of stars.
In 1987, the world of astronomy saw the next supernova explosion in centuries, an explosion triggered from the large Magellanic Cloud just 168,000 light years away. One of the biggest surprises and joys of this explosion was the clear evidence of neutrinos from the event.
Neutrinos are subatomic particles that hardly recognize the rest of the particles in the universe. They're created in all kinds of nuclear reactions (from nuclear power plants to exploding giant stars), and trillions of them are flying through your body right now. However, since they barely interact with normal matter, you won't even notice them.
The detection of neutrinos in 1987 was a big deal as it taught us that supernovae can produce an enormous amount of neutrinos. In fact, less than 1% of the total energy of a supernova explosion goes into the light. Given that a single supernova can outshine entire galaxies, it's amazing how many neutrinos are produced with the other 99% of the available energy.
Unfortunately, a combination of extreme distance and the ninja-like stealth of neutrinos means our terrestrial detectors only captured a handful of neutrinos from the 1987 event.
But this time it will be different.
A collaboration of scientists from all over the world is currently building DUNE, the Deep Underground Neutrino Experiment. This experiment mainly detects neutrinos produced in Fermilab using a giant tank of liquid argon at the Sanford Underground Research Facility in South Dakota. The facility is also capable of detecting neutrinos from cosmic sources, and Betelgeuse is a lead candidate.
Betelgeuse is a red giant star in the constellation Orion, about 548 light years away from us. This star is almost at the end of its life and will become a supernova every day. In astronomical terms, of course, “every day now” means “within the next 100,000 years or so”.
But it could also mean … literally every day. When Betelgeuse becomes a supernova, it is visible during the day and creates enough light to cast shadows at night. And it will also produce a tremendous flood of neutrinos, giving DUNE astronomers an unprecedented front-end view of the heart of a giant star in the final moments of their lives.