This article was originally published on The conversation. The publication contributed the article to Space.com Expert Voices: Op-Ed & Insights.
Pablo Martinez Mirave is a postdoctoral fellow in theoretical particle astrophysics at the Niels Bohr Institute, University of Copenhagen.
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But what we can see with our eyes, or even with powerful telescopes, when these stars die is only a small fraction of the story. Because most of the energy from a supernova is carried away by neutrinosthese are almost invisible particles often called “ghost particles” because they pass through almost everything in their path.
Scientists are now finally on the verge of seeing these ghostly messengers. Using an extremely powerful telescope buried deep underground in Japan, astronomers may catch a glimpse of these stellar ghosts—and with them the remnants of explosions from stars that died as long as 10 billion years ago.
Particles from before time
And there is a very good chance that scientists may be able to finally see these ghost particles this year. This is largely due to Japan’s Super-Kamiokande Telescope receives an upgrade, significantly improving its ability to detect supernova neutrinos.
For me, as a particle astrophysicist, this would probably be one of the most exciting scientific achievements of my life. It would actually mean that we could see particles that were produced even before the Earth itself existed, as the telescope is now sensitive enough to pick up the faint “glow” of all the exploding stars in the universe.
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This is all possible because neutrinos almost never interact with anything. They have no electrical charge. So they can travel through space – and even through entire planets – without being absorbed or scattered, so almost nothing can stop them.
In fact, there are billions of these ghostly particles passes through the body every second – and you don’t even notice – and some of them have traveled more than 10 billion years to get here.
When a star dies
Big ideas lead to big questions, and one such question astrophysicists are trying to figure out is what remains after the explosion of such a star.
Does the collapsing core become a black hole? Or it forms another type of star known as a neutron star, that cools so slowly over time? A neutron star is an incredibly dense object, only about 20 kilometers across, about the size of a large city or about the length of Manhattan.
If scientists are able to detect the combined signal from all the supernovae that have ever occurred, it will bring us closer to being able to answer these questions. It would also allow us to study the deaths of stars throughout the history of the universe, using particles that have been traveling towards us for billions of years without ever stopping.
Supernovae are rare in our galaxy, occurring only once every few decades. But across the universe, a massive star explodes in a supernova about once every second. When they explode, they release enormous energy: only approx. 1% is visible lightwhile 99% escape as neutrinos.
Although these neutrinos are almost invisible, they carry the story of every star that has ever exploded—and now, for the first time, we may be able to catch them.
So if 2026 yields the first clear detection, it will mark a new era in astronomy. For the first time, we will observe not just the brilliant explosions of nearby stars, but the collective history of all the massive stars that have ever lived and died.
And it all starts with a telescope buried deep underground in Japan, patiently watching for the faint, ghostly glow of the universe’s oldest explosions.
