8 Interesting Facts About Neutrinos

Neutrinos, generally referred to as nature's ghost particles, are fermions which were first postulated in 1930 by Wolfgang Pauli to explain the conservation of energy, momentum and spin in Beta decay. From the day of its discovery itself, they have baffled everyone due to their unique properties. Though they make most of the universe, still they are the least understood subatomic particles till date. Here in this article, we have compiled a list of 8 astonishing facts about this ghost particle, that will blow away your mind for sure!

Also Read: Basics of Astrophysics Series

8. Abundance

Neutrinos are the second most abundant particles in the universe after photons. The sun sends 65 billion neutrinos per second per square centimeter to earth. So about 100 trillion of them pass through the human body every second.

7. Mass of Neutrinos

According to certain estimates and approximations, neutrinos are about a million time less massive than electrons. Yet, despite being so light weight, their total mass can account up to 20% of the total mass of the universe.

6. The Force of Interactions

There are four fundamental forces in nature: Strong, Week, Electromagnetic and Gravitational. Neutrinos are the only particles found to solely interact through the weak force. Hence, they play a vital role in digging into the details of the weak force.

Also Read: The Quantum Week Series

5. The Flavor of Neutrinos

Neutrinos
The electron, muon and tau neutrinos changing their flavor.

Neutrinos have three flavors (types), electrons, muon and tau. As a neutrino travels along, it can switch in between these flavors, acting like a chameleon changing colors. This is known as the neutrino flavor oscillation: a phenomenon that solved the long standing solar neutrino puzzle.

Also Read: Neutrino oscillations and solar neutrino puzzle.

4. Extent of Interaction

Both photons and neutrinos are created inside the core of stars. But while photons take tens of thousands of years to reach the edge of sun, neutrinos make this trip in just 3.2 seconds. This is because the latter interact quite feebly with the matter.

3. Detecting The Neutrinos

Neutrinos are hard to detect. On an average, only one neutrino from sun will interact with a person's body during his or her life time. The largest neutrino detector in operation today is Super Kamiokande-III in Japan, which houses 50,000 tones of water to interact with neutrinos.

Neutrinos
Kamiokonde Detector

2. Role In Supernovae

These particles dissipate about 99% of the total supernova's energy. If Betelgeuse goes supernova today, Super Kamiokande-III would detect an estimated 13 million neutrinos. So the supernovae are very important astrophysical events to study the properties of these ghostly particles.

1. Dark Matter

These high velocity particles are also proposed candidate for hot dark matter, as they do not emit or absorb light, making them appear dark.

Also Read: What is dark matter and what are its types

Neutrinos are one of the most important particles. What makes them interesting is their speed and interaction with matter. Earlier scientists hypothesized that they travel at the speed of light. According to special relativity, anything that travels at the speed of light would not experience time i.e. it would freeze in time. But neutrino oscillations suggest otherwise. There is a fixed frequency of these oscillations. Now if neutrinos are changing their flavor, it means there is an intrinsic clock in the neutrino's rest frame which further implies that they have a finite mass. Anything with finite mass cannot travel at the speed of light, again according to special relativity. Neutrino mass is a hot topic of research these days.

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