ClassX Video Lessons Youtube Channel Domain of Science What’s The Probability You Have Seen A Neutrino?
Today, let’s dive into the fascinating world of neutrinos. These are fundamental particles that play a crucial role in the standard model of particle physics. Neutrinos are produced in massive quantities during the fusion reactions in the Sun, with an astounding 1038 neutrinos being generated every second. Out of these, about 1029 pass through the Earth each second, and approximately 300 trillion pass through your body every second. This is why they are often called “ghost particles” in popular media.
Given the sheer number of neutrinos passing through us, it’s no surprise that we don’t notice them. However, there’s a minuscule chance that one might collide with an atom in your eye, causing a faint flash of light. Although the probability of this happening to any individual is extremely low, with billions of people on Earth, it’s estimated that about 10 people per hour might experience such a neutrino collision. This would result in a faint blue flash, but it’s harmless.
Neutrinos are among the most intriguing particles in the standard model, and there are several reasons for this. Firstly, they interact with other particles only through the weak nuclear force. Among the four fundamental forces—gravity, electromagnetism, and the strong and weak nuclear forces—the weak force has a very short range, affecting particles only when they are extremely close, about 10-18 meters apart. This allows neutrinos to pass through matter, including our bodies, as if it were empty space.
Technically, neutrinos are also influenced by gravity, but their masses are so tiny that the gravitational effect is negligible. This brings us to the second peculiar aspect: we don’t know where neutrinos get their mass. Unlike other particles that acquire mass from the Higgs field, neutrinos seem to derive their mass from an unknown source.
Additionally, neutrinos can change from one type to another as they travel through space, a phenomenon unique among particles in the standard model. Lastly, we’ve only observed left-handed neutrinos and right-handed anti-neutrinos, whereas other particles exist in both left-handed and right-handed forms.
Despite being the most abundant particles in the universe, neutrinos are challenging to study due to their weak interactions. Scientists have built large underground detectors to capture the rare events when neutrinos collide with matter. One such detector is Super-Kamiokande, a massive tank filled with ultrapure water and surrounded by photomultipliers, which are sensitive cameras that detect light.
These detectors work by capturing Cherenkov radiation, a type of light emitted when a neutrino collides with an electron in the liquid. This phenomenon is similar to a sonic boom but for light, occurring when electrons travel faster than light does in the liquid. It’s important to note that this doesn’t violate the speed of light in a vacuum; it only appears so because light slows down in the liquid.
Interestingly, these large detectors can be compared to human eyes, which are also filled with liquid and sensitive to light. If a neutrino were to hit an electron in your eye, it could potentially produce Cherenkov radiation. However, the probability of this happening is extremely low, averaging once every 89,000 years for an individual. Yet, with billions of people on Earth, about ten people per hour might experience this phenomenon.
Our eyes are quite sensitive to light, capable of detecting flashes as faint as 10 photons in a dark room. Cherenkov radiation from a neutrino impact generates around 200 visible photons per centimeter in the eye, which is significantly more than the minimum needed for detection. However, this would only be visible in the dark, as daylight would overwhelm it. Factors like the angle of impact and the alignment of the Cherenkov light with the retina also play a role.
Astronauts have reported seeing light flashes in their eyes when outside Earth’s magnetosphere, likely caused by cosmic rays. On Earth, our magnetosphere and atmosphere protect us from most cosmic rays, but some do penetrate, potentially causing flashes of light in our eyes. If you ever see a random flash of blue light, it might be a glimpse of a neutrino, although it’s more likely to be something else, like a detached retina. If it happens frequently, it’s best to consult an ophthalmologist.
If you’ve ever seen a faint blue flash in one eye, I’d love to hear about it. With enough people, there’s a chance someone has experienced this in the past year. Please share your experiences in the comments.
If you’re interested in developing your physics problem-solving skills, consider exploring Brilliant, a platform that offers interactive courses in science and mathematics. They provide a range of topics, from quantum mechanics to relativity, with engaging elements to help you learn. Visit brilliant.org/DOS for more information, and if you’re among the first 200 to sign up, you’ll receive a 20% discount on a premium subscription.
Thank you for reading, and I hope you found this exploration of neutrinos enlightening!
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Engage in a virtual simulation where you can observe how neutrinos interact with matter. Use this tool to visualize the paths of neutrinos and their rare interactions with atoms. Reflect on the challenges of detecting neutrinos and discuss your findings with peers.
Research different types of neutrino detectors, such as Super-Kamiokande or IceCube. Prepare a presentation that explains how these detectors work and their significance in neutrino research. Share your presentation with the class and facilitate a discussion on the technological advancements in this field.
Calculate the probability of a neutrino interacting with an atom in your eye. Use statistical methods to understand the likelihood of such events. Collaborate with classmates to compare results and discuss the implications of these probabilities in real-world scenarios.
Participate in a debate about the mystery of neutrino mass. Research current theories and present arguments for different hypotheses. Engage with opposing views and explore the potential impact of discovering the source of neutrino mass on the standard model of particle physics.
Write a creative story from the perspective of a neutrino traveling through space and matter. Incorporate scientific facts about neutrinos and their interactions. Share your story with classmates and discuss how creative writing can enhance understanding of complex scientific concepts.
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Today, I want to talk about neutrinos. They’re fundamental particles, and they are represented in the standard model of particle physics. Neutrinos are created in the fusion reactions in the Sun, which produces an astonishing 10^38 neutrinos every second. A massive 10^29 of these neutrinos pass right through the Earth every second, and around 300 trillion pass through your body every second. This is why they are often referred to in mainstream media as “ghost particles.”
Because so many neutrinos pass through our bodies without us noticing, we definitely shouldn’t be able to see them with our eyes. However, there is a very slight chance that one of them could hit an atom in your eyeball and cause a visible flash of light. The chance of this happening to you is very small, but because there are so many human eyeballs on the planet, roughly 10 people per hour on Earth will experience a neutrino collision with one of their eyes. Nothing harmful would happen; you’d just see a very faint flash of blue light. I’ve never heard anyone discuss this before, even though my calculations suggest it’s true!
Neutrinos are among the most peculiar particles in the standard model, and they are the ones we understand the least. There are four main reasons why they are considered strange.
First, they are the only particles that interact with others solely via the weak force. There are four fundamental forces in nature: gravity, electromagnetism, and the strong and weak nuclear forces. The weak force is termed “weak” because it has a very short range, only affecting particles that are extremely close together—about 10^-18 meters apart, which is a thousand times smaller than the nucleus of an atom. This is why neutrinos can pass through your body as if it isn’t there; to them, we appear as empty space.
Technically, neutrinos also experience gravity, but they have such tiny masses that gravity’s effect on them is negligible. This leads to the second peculiar aspect of neutrinos: we have no idea where they obtain their mass. All other particles with mass acquire it from the Higgs field, but neutrinos seem to derive their mass from an unknown source.
Additionally, neutrinos can change from one type to another as they travel through space. This is unique among particles in the standard model, as they spontaneously transform into different particles.
Finally, we have only observed left-handed neutrinos and right-handed anti-neutrinos. All other particles exist in both left-handed and right-handed forms, but neutrinos do not. For more information about this, check out my video and poster on the standard model of particle physics. If you’re looking for gifts, I have a variety of educational posters available in my store, dosmaps.com, along with a range of children’s books covering topics like space, physics, the human body, and the oceans. The link is in the description below.
As I mentioned, neutrinos are strange, and our understanding of them is limited because they rarely interact with anything. Despite being the most abundant particles in the universe—possibly even more numerous than photons—neutrinos have incredibly small masses, less than 10^-37 kg. However, the combined mass of all the neutrinos is roughly equivalent to that of all the stars in the universe.
To study neutrinos, scientists have constructed large detectors underground to capture the rare instances when they collide with matter. One such detector is called Super-Kamiokande, located deep underground to prevent interference from other particles. It is a massive vat with a volume of 50,000 cubic meters, filled with ultrapure water and surrounded by photomultipliers, which are highly sensitive cameras.
Other neutrino detectors operate on similar principles but use different types of liquids that absorb various energies of neutrinos. When a neutrino collides with an electron in the liquid, the electron absorbs energy and moves through the liquid, emitting a special type of light known as Cherenkov radiation.
Cherenkov radiation is akin to a sonic boom but for light, as electrons can travel faster than light does in the liquid. This may sound confusing, but it’s important to note that electrons do not exceed the speed of light in a vacuum; they only appear to do so because light slows down in a liquid. In this scenario, Cherenkov radiation is emitted.
With these large liquid vats, scientists are detecting sporadic neutrino impacts, collecting data to better understand how neutrinos function. Interestingly, these detectors can be likened to large eyes. Our eyes are also filled with liquid, and the retinas are sensitive to light, similar to the photomultipliers. So, if a neutrino were to hit an electron in your eye, could it also produce Cherenkov radiation?
While our eyes are much smaller than these giant detectors, we have many eyes. I calculated this possibility and consulted with a professor, and indeed, there is a very small chance that a neutrino will collide with the fluid in your eye and create a flash of light! However, this would only occur on average once every 89,000 years. So, while you may never see one, the sheer number of human eyes on Earth means that if we average this out over 7.7 billion people, we can expect around ten people per hour to experience a neutrino collision with their eyeballs.
You might wonder how visible this flash would be. Our eyes are quite sensitive to light; in a dark room, we can detect flashes of as few as 10 photons. Cherenkov radiation from a neutrino impact generates around 200 visible photons per centimeter in the eye, which is significantly more than the 10 photons needed for detection. However, this would only be visible in the dark, as it would be overwhelmed by daylight. There are also factors like the angle at which the neutrino hits your eye and whether the cone of Cherenkov light overlaps with your retina. I’m not an expert on eyes, so I can’t say how this would affect the statistics, but even if the chances are reduced by tenfold, that would still mean one person per hour on Earth might experience this!
Astronauts have reported seeing light flashes in their eyes when they travel outside the Earth’s magnetosphere, which are believed to be caused by cosmic rays. We don’t experience this on Earth due to the protection of our magnetosphere and atmosphere, but some cosmic rays do penetrate, potentially causing flashes of light in our eyes from cosmic rays or background radiation. It’s fascinating to think that if you see a random flash of blue light in your eye, it could be a glimpse of the most mysterious particle in the universe. However, I should note that statistically, it’s much more likely to be a detached retina, so if it happens frequently, it’s best to consult an ophthalmologist.
I’m genuinely curious if any of you have seen a faint blue flash in one eye. If we get 90,000 people to watch this video, there’s a good chance that one of you has experienced this in the past year. Please let me know in the comments below if that has happened to you.
If you want to learn the skills to tackle physics-based problem-solving yourself, a great place to start is Brilliant, who are sponsoring this part of the video. They offer a website and app where you can learn science and mathematics by actively solving problems. I love having learned physics because it equips you with the tools to creatively address any intriguing question, like whether it’s possible to see a neutrino. To excel at this, you need plenty of practice solving puzzles, and Brilliant is an excellent platform for doing so while learning fundamental physics concepts. They offer a wide range of courses, from quantum mechanics to relativity, along with many other subjects in mathematics and computer science, featuring interactive elements to explore. If you’re interested, visit brilliant.org/DOS, and if you’re among the first 200 people to sign up through that link, you’ll receive a 20% discount on your premium subscription, which grants access to all their content.
Thank you for watching, and I’ll see you in the next video!
Neutrinos – Subatomic particles with a very small mass and no electric charge, which interact only via the weak nuclear force and gravity. – Neutrinos are notoriously difficult to detect because they rarely interact with matter, making them elusive particles in physics experiments.
Particles – Small localized objects to which can be ascribed several physical or chemical properties such as volume, density, or mass. – In particle physics, researchers study the fundamental particles that make up the universe, such as quarks and leptons.
Gravity – A natural phenomenon by which all things with mass or energy are brought toward one another, including planets, stars, galaxies, and even light. – Einstein’s theory of general relativity describes gravity as the curvature of spacetime caused by mass.
Mass – A measure of the amount of matter in an object, which is not affected by the object’s location in the universe. – The Higgs boson is a particle that gives other particles mass through the Higgs field.
Collisions – Events in which two or more particles come into contact with each other, often resulting in the exchange or transformation of energy and momentum. – High-energy collisions in particle accelerators allow physicists to study the fundamental forces of nature.
Detectors – Devices used to measure and record physical phenomena, often used in experiments to observe particles and radiation. – The Large Hadron Collider uses sophisticated detectors to track the paths of particles resulting from high-energy collisions.
Light – Electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. – The study of light and its properties is a fundamental aspect of optics, a branch of physics.
Radiation – The emission or transmission of energy in the form of waves or particles through space or a material medium. – Cosmic radiation is a significant area of study in astrophysics, as it provides insights into the origins of the universe.
Cosmic – Relating to the universe or cosmos, especially as distinct from the Earth. – Cosmic microwave background radiation is a remnant from the early universe, providing evidence for the Big Bang theory.
Physics – The natural science that studies matter, its motion and behavior through space and time, and the related entities of energy and force. – Quantum physics explores the behavior of matter and energy at the smallest scales, where classical physics no longer applies.
