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Nobel Prize in Physics for the discovery of high-energy neutrinos of astrophysical origin

Francis Halzen will be awarded the Nobel Prize in Physics in 2026.

Francis Halzen discovered that ice from the South Pole could be used to detect particles called neutrinos. Following this idea and with the help of other researchers, they created the IceCube Neutrino Observatory in Antarctica, a cubic kilometer equipped with ice light sensors. This observatory has made it possible to detect high-energy neutrinos coming from remote space.

“Francis Halzen has led an international team of researchers and engineers who have created an excellent tool. Its firmness and scientific approach have paved the way for a new astronomy,” said Mark Pearce, Chairman of the Nobel Committee for Physics.

“We still don’t know which process gives so much energy to neutrinos.”

Ghosts called neutrinos

It is known that in the cosmos there are neutrinos with high energy levels, but it is not yet known which process gives so much energy to neutrinos. These processes are known as cosmic accelerators and are believed to be astronomical phenomena unknown today.

Neutrinos are everywhere, but unlike other particles, they have no electric charge or almost no mass, so they pass through matter. Neutrinos arriving on Earth arrive directly from the origin, with virtually no energy loss along the way, and can provide information that is otherwise inaccessible. But for the same reason, a neutrino can only be detected when it collides with the nucleus of an atom, which is very unusual.

Why the ice

in 1980, Francis Halzen discovered that Soviet researchers were planning to detect neutrinos in Antarctica using radio wave detectors. This idea attracted Halzen, but instead of radio waves, it occurred to him to detect blue rays of light.

When a neutrino collides with an atomic nucleus, an electrically charged particle is formed. This particle travels in the same direction as the neutrino traveled and produces a blue ray of light. Therefore, with all the necessary tools, it is possible to determine the direction of light and the origin of the neutrino.

To detect this blue ray of light, ice offers two main advantages: it is transparent and, in a thick layer of ice, there is always darkness in the interior.

Why at the South Pole

Francis Halzen specifically chose the ice of the South Pole... In fact, there it is free of various types of interference and there is no risk of earthquakes. Halzen and his idea soon gained the support of other researchers and, in a few years, preliminary tests were carried out on the Antarctic ice.

They created the IceCube Neutrino Observatory

Neutrinos reach the Earth continuously, but most of them have lower energy levels and reach the Earth from nearby stars. High-energy neutrinos, however, are very rare. Therefore, an enormous volume of ice is required to observe the appropriate number of high-energy neutrino collisions, which is why the IceCube Neutrino Observatory takes one cubic kilometer of ice.

it was launched in 2011 and soon the first high-energy neutrino collision was detected. Years later, it was shown that these neutrinos originate away from the solar system. In view of these promising results, it is expected that the observatory will help clarify the origin of high-energy neutrinos and even reveal cosmic phenomena that are currently unknown.