Neutrinos: ghost particles that fly through the Earth
About this app
About 65 billion solar neutrinos pass through every square centimetre each second: light stops in a thumb, neutrinos fly through, and even the whole Earth stops only about one in a hundred billion. Plus the sky map of neutrino sources: diffuse flux 2013, blazar TXS 0506+056, NGC 1068 and the Milky Way.
With explain mode: an AI tutor walks you through the app, points out what matters in the scene and answers your questions.
What it is about
Neutrinos are electrically neutral, almost massless elementary particles that only feel the weak interaction. The Sun makes them in huge numbers in nuclear fusion: about 65 billion per square centimetre per second arrive at the Earth, from above by day and through the Earth at night. Because they react so rarely with matter, they cross bodies, buildings and the whole planet almost unhindered. That makes them ideal messengers from space, but also extremely hard to detect.
What the app shows
In the passing-through scenario, light and neutrinos stream from the Sun onto a thumb or onto the whole Earth. The light stops at the surface, the neutrinos fly on. A logarithmic counter counts, for a column of one square centimetre, how many pass through and how many get stuck: for the Earth about one in a hundred billion. The sky map in galactic coordinates shows the discoveries of the IceCube detector: the diffuse cosmic flux in 2013, the blazar TXS 0506+056 (2017/18), the galaxy NGC 1068 (2022) and the Milky Way (2023).
Try it yourself
Switch between thumb and Earth and let time run in time lapse: the left bar grows into the trillions, the right one hardly at all. Hide the light to see only the neutrinos. On the sky map, drag the slider from 2010 to 2024 and watch the sources appear one after another. Tapping a source shows its year, distance and how it was found. The numbers are orders of magnitude from a simple model.
Frequently asked questions
- How many neutrinos pass through my body?
- About 65 billion solar neutrinos per square centimetre per second arrive at the Earth. Through a thumbnail that is about 65 billion per second, through the whole body many trillions. Almost all of them fly on unhindered, by day and by night.
- Why can neutrinos fly through the Earth?
- Neutrinos carry no electric charge and only feel the weak interaction, whose range is tiny. A solar neutrino crossing the whole Earth gets stuck with a probability of only about one in a hundred billion.
- Where do cosmic neutrinos come from?
- IceCube found the first high-energy neutrinos from space in 2013. Single sources are the blazar TXS 0506+056 (2017/18), the active galaxy NGC 1068 (2022) and the plane of the Milky Way (2023). Most of the flux cannot yet be traced to a source.
- What can I try in the neutrino app?
- You let solar neutrinos fly through a thumb or the Earth, compare them with light, read off the counter how many get stuck, and play the discoveries from 2013 to 2023 on the sky map.
Subject: Physics
More from Physics
- Cavendish-Experiment: die Erde wiegen (3D)
- Der eingefrorene Wasserstrahl (3D)
- Double slit — observer on, pattern gone (3D)
- The double-slit experiment
- Real collisions from the LHC (3D)
- Handpan — physics, mechanics and construction (3D)
- IceCube: a telescope made of ice (3D)
- Navier-Stokes
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