Belgian scientist who studies invisible particles in Antarctica wins Nobel Prize in Physics

Neutrinos are among the most abundant particles in the universe. Our Sun itself sends a vast amount here, all the time. Every second, 1 billion neutrinos pass through the palm of your hand and you don't feel or see anything. The neutrino has no electrical charge, has almost zero mass and passes through the entire planet as if it were a void. Therefore, it is called a ghost particle.

Until Halzen had an idea that many people didn't believe would work. He suspected that the rare collision of a neutrino with an ice atom would generate some reaction that would be possible to observe. To prove the hypothesis, the scientist went to the South Pole and turned ice into a detector. It was ideal because the ice is clear and dark. The team buried 86 cables with more than 5,000 light sensors in a gigantic block of ice. It worked out. It was possible to observe the blue light trails from neutrino collisions with ice, and Halzen created a new science, neutrino astronomy.

But why is observing a neutrino important? Because the particle can reveal many secrets about the universe. To do this, scientists want to identify high-energy neutrinos, which come from further away, from deep outer space. As the neutrino hardly interacts with anything, it travels through the universe in a straight line, it points, like a compass, to the place it came from, like black holes or very distant galaxies.

"This light leaves a trail. And this trail allows us to reconstruct the direction from which the neutrino came. And this allows us to begin to compose a scenario about the regions of the universe that produce these types of particles. They always, therefore, carry information about extreme processes in the cosmos. For example, what happens around black holes? Or what happens when a star explodes? It can bring information from regions that light cannot access, such as, for example, the core of stars themselves, when there is a process of collapse and explosion This was truly revolutionary because it opened a new window in astrophysics”, says Ulisses Barres, researcher at CBPF/Instituto Serrapilheira.

Although Halzen is the first scientist in more than three decades to receive the award alone, he gave credit to the team. More than 400 scientists from around the world are part of the IceCube project in Antarctica. He said the challenges were overcome by a combination of perseverance, talent and luck.