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When scientists beginning started asking to build neutrino detectors, the big question was: why bother? Neutrinos were incredibly difficult to find, they interact only weakly with regular matter, and they didn't even seem to have any mass. These neutrino detectors were incredibly expensive and finicky rigs that had to be built deep secret, merely for a hope of capturing the presence — allow alone management — of a neutrino bombarding the Earth from infinite. Nevertheless now, researchers working in Japan and Canada take been awarded the 2022 Nobel Prize in Physics for their piece of work on the neutrino. What did they find, and why was information technology so impressive?

First off, neutrinos are incredibly numerous. Though they don't interact with the matter that makes upward our bodies, there are many billions of neutrinos bombarding our bodies at any given second. Some originated during the Big Bang, while others arise from the bear on of cosmic rays with the upper atmosphere and even radioactive decay of elements in the Earth's crust. They come in three "flavors" referred to as tau, electron, and muon. Earlier experiments investigating the muon neutrino earned the Nobel Prize in Physics in 1988.

neutrino nobel 2Yet, abundant as they are, physicists idea that they should be far more abundant than mankind's new-fangled neutrino detectors observed them to be. Additionally, they were non ever of the flavor that they ought to be — and, in 1998, a Japanese squad under the leadership of Dr. Kajita plant that muons can actually flip flavors on their ain. Shortly after, a Canadian team proved that neutrinos from the Sun are undergoing a similar flavour-switch on their way to Earth.

Proving that this "oscillation" betwixt flavors really does occur solved two problems at once: information technology showed that the roughly ii thirds of neutrinos that were "missing" had in fact just switched away from their expected season, and it showed that neutrinos must take mass. The only problem was that both theory and observation said that the neutrino did not have mass.

For their work proving the neutrino cannot be massless, leading adequately quickly to separate observations of that mass, the 2 teams were awarded the 2022 Nobel Prize in Physics. The ii recipients were Arthur McDonald of Canada'due south Queens University, and Takaaki Fajita of Japan'south Academy of Tokyo.

Thanks to their work, we at present know that the neutrino does in fact take some incredibly small amount of mass, probably about a millionth of the mass of an electron, a particle which was itself once believed to be massless. Yet, given the incredible number of neutrinos in the universe, these tiny masses could sum to weight more than than all the stars in the universe.

McDonald and Kajita.

McDonald and Kajita.

Neutrinos could potentially exist a very powerful way of looking into the universe, since they tin can penetrate matter with so petty trouble. A similar class of lepton called muons also penetrate deeply into dumbo matter and have been used to expect inside the Fukushima Daichi reactor and the Great Pyramid of Giza — merely muons can only bury a few kilometers into the Earth. Neutrinos, on the other mitt, easily pass all the style through and come out the other side. They'll demand to be affected past cadre of the World in some style to exist useful for deriving data, merely it'due south non inconceivable than neutrino detectors could i solar day permit scientists look deep into the core of the Earth itself.

Or, crucially, inside stars. As mentioned, ane major source of neutrinos are stars, and scientists have already used the neutrino emissions from the Sun to learn about the fusion reaction going on inside. With a better and ameliorate ability to read the language of neutrinos, in that location's no telling what new insight astronomers might be able to gain about the universe and its components.

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