Answers to some of the most commonly asked questions about neutrinos and neutrino science are provided below:

What are neutrinos, and how do they work?

Neutrinos are elementary particles, which means they are one of the many sorts of small particles that make up the universe. Neutrinos are the most prevalent mass-carrying particles in the universe. In the time it took you to blink while holding out your thumb, about 100 billion neutrinos traveled through your thumbnail. Neutrinos, on the other hand, have another crucial property: they don’t like to interact much. Even though millions of neutrinos pass through your body every second, just a few will interact with you over your lifetime.

Neutrinos are extremely light particles that come in three flavors (named for the particles they make when they collide). Neutrinos include electrons, muons, and taus. Neutrinos are unique among fundamental particles in that their flavors change as they move, which is one of the reasons physicists are fascinated by them.

Are neutrinos considered to be safe?

Yes! Neutrinos are extremely harmless. The vast majority of neutrinos pass through stuff without ever colliding. Because they are so little and neutral (they don’t have a charge), they don’t come into touch with other particles very often. Neutrinos do not produce radiation or cause damage to the items they pass through.

Why are neutrinos being studied?

Neutrinos are the universe’s most prevalent massive particle, but we know very little about them. We don’t know how much they weigh—or why they have mass at all—despite the fact that they are one of the universe’s essential building blocks. They wouldn’t, according to our models. Neutrinos are a harbinger of new physics, or methods of explaining the world that we don’t yet understand. They may also possess special features that explain why the universe is made up of matter rather than antimatter. We won’t know some of the secrets of our universe—or how to harness them for more practical purposes—until we learn more about these mystery particles. See the FAQ “What are the Benefits of Neutrino Research?” for more information.

What are some of the advantages of neutrino research?

Because neutrinos are still poorly understood, basic research is currently the top priority. This gives us more information about the particles and how they fit into our understanding of the universe. They can also help us better comprehend and test our theories about how things work by assisting us with broader fundamental physics concerns. We don’t always know where basic research will lead us, as we don’t always know where basic research will lead us. Consider the electron: Early researchers could not have predicted that the discovery of the electron would change the world forever, bringing us electronics, computing, and a more linked globe. No one could have imagined how the World Wide Web, which was created to share physics data, would revolutionize the way we interact, shop, travel, and do a thousand other things.

The same can be said of neutrino studies. We don’t know where the technology—sensitive detectors, powerful particle accelerators, data processors, and other components that allow experiments to run—will be valuable in the future. Neutrinos and neutrino studies have already spawned a slew of intriguing uses. Because neutrinos are so small, deceptive, and difficult to detect, there are numerous practical challenges between where we are now and where we want to go. The use of neutrino detectors to monitor nuclear proliferation for national security is maybe the closest to reality. It might also be used to look for mineral riches in the Earth’s crust or give a new form of communication. We’re still at the start of our neutrino trip; what we do with this technology and information will be left to future scientists to figure out.

Where do neutrinos originate?

Everywhere! When one particle converts into another, neutrinos are produced as a natural byproduct. Neutrinos can originate from the Earth’s core, our sun, far-off star explosions, the Big Bang, particle interactions in our atmosphere, or even reactions within your own body. Neutrinos are produced by even bananas. Scientists can also make them using accelerator beams or nuclear reactors, resulting in a more regulated and studyable source.

How did neutrinos come to be discovered?

In 1930, neutrinos were proposed as a possible explanation for the radioactive process known as beta decay. Clyde Cowan and Frederick Reines, armed with hypotheses, found the neutrino in a reactor experiment in 1956. Different flavors of neutrinos and additional features were discovered in subsequent investigations. In the timeline, you may learn more about these experiments.

Do neutrinos travel at the speed of light?

They don’t, in fact. Neutrinos are strange, but not that strange.

The source of this misunderstanding is a 2011 result. The findings from the OPERA experiment revealed that neutrinos arrived at the detector remarkably swiftly, reportedly faster than the speed of light. Other tests in the same neutrino beam (and elsewhere) were unable to reproduce the anomaly. The OPERA team eventually discovered that the timing mismatch was caused by a malfunctioning piece of equipment (a cable). After being restored, OPERA measured neutrinos to be very close to, but not exceeding, the speed of light.

What method do we use to detect neutrinos?

To detect neutrinos, scientists can utilize a variety of materials, ranging from mineral oil and dry cleaning fluid to Antarctic ice and water. It is unable to detect neutrinos directly due to their neutrality and small size. Instead, depending on the substance, all systems rely on detecting the heavier, charged particles produced when a neutrino interacts, which provide a distinctive track, flash of light, line of bubbles, change in temperature, or other signal. Because neutrinos interact so seldom, detectors must be large and experiments must operate for lengthy periods of time to collect enough data. They’ll also need technologies to filter out interactions from other particles that could contaminate neutrino data.

What is a neutrino beam, and how does it work?

Physicists can examine neutrinos using a neutrino beam. Particle accelerators are used by scientists to create energetic particles that collide with a target and produce additional particles that decay into neutrinos. This results in a concentrated group of neutrinos with a distinct taste and energy level. It’s easier for researchers to perform tests and analyze neutrinos when they have a lot of knowledge on the types of neutrinos that are produced.

Why are neutrinos being sent such a vast distance?

Neutrinos change flavor as they travel, and the amount of change is proportional to the distance traveled. We can learn more about neutrino properties by placing detectors at varied distances from the source. Researchers can learn more about how neutrinos and antineutrinos differ when they travel large distances by comparing how they alter. This can help them understand how neutrinos and antineutrinos have shaped our cosmos.

What are neutrino oscillations, and how do they work?

The way neutrinos change flavor as they travel is referred to as oscillations. A neutrino that starts off as one flavor (electron, muon, or tau neutrino) will eventually morph into the other flavors, with the likelihood of it appearing as a different flavor varying depending on how far it has traveled. Quantum physics, or the strange way things behave at very small sizes, causes oscillations. The discovery of neutrino oscillations was particularly intriguing because it proved that neutrinos have mass, something the current model could not account for. It’s the first and only proof that particle physics’ current model isn’t complete. That means there will be more fascinating physics to explain this big puzzle.