All of it was driven by a flood of experimental results that were not compatible with classical physics.
See "Ultra Violet Catastrophe" in black body radiation, photo effect.
Planck famously performed curve fitting on the black body spectrum and only afterwards found the theoretical foundation for the function that fit the data.
I'm actually not sure exactly what "they" is in this sentence.
I know about the Ultraviolet catastrophe, but that's cherry-picking.
Dirac predicted the Positron before it was discovered.
Quantum entanglement was predicted by Einstein, Podolsky and Rosen before it was shown ("Spooky action at a distance")
Black Holes and Gravitational waves were both predicted before they were detected.
Einstein predicted time dilation before it was detected.
Szilard predicted chain reactions in Nuclear fission before they were demonstrated.
And probably most pertinent to this discussion, Pauli predicted Neutrinos before they were detected.
Half of the list above are critical for GPS, energy, semiconductor research and many other fundamental technologies of the modern age. They were researched and predicted without any thought of a "monetisable" product.
- In the beginning, for the first couple of events, only because they have way higher energies than anything in the solar system could produce
- By now, with enough data collected, their origin correlates very well with the milky way
- we are close to identifying several far away galaxies as well
This is the significance. Contrary to some statements published today, IceCube was not primarily built to study Neutrinos, it was built to study the universe using Neutrinos.
That's why we care where they are coming from, we want to learn about the astrophysical objects that produce them.
" in February 2023, [KM3NeT] detected the most energetic neutrino ever observed. It's called KM3-230213A, and its estimated energy was 220 PeV (220 x 10^15 electron volts or 220 million billion electron volts) "
That's an insane amount of energy. If your are knowledgeable about this do you know why some neutrinos have more energy than others? surely it is just a relationship with it's speed. I thought all neutrinos moved close to the speed of light.
If my quick math is correct that is equivalent to dropping 3.59g one meter in a vacuum in earths gravity. insane that a subatomic particle can have that much energy.
It says "typically, energetic neutrinos from active galactic centers are thought to originate from interactions between protons and photons, producing gamma rays of comparable intensity." and suggests other theorized sources.
Another good source on this new branch of astronomy:
Particle physics processes in the sources we suspect accelerate particles in a way that results in a power law distribution of energies. So you can get extremely high energy particles, but the higher the energy the rarer.
And sources have a maximum energy they can accelerate particles to.
Very shortly summarized, only if the particle is faster than the local speed of light, you get constructive interference between many atoms that were polarized by the moving particle.
For a slower than light particle, you also get emission, but it is completely random and thus does not give the well defined emission in a cone of Cherenkov radiation.
For a faster than light particle, the spherical suddenly line up to form a cone:
Neutrinos are neutral particles, they do not carry an electromagnetic charge. They thus do not cause any Cherenkov light themselves.
What Neutrino detector measure is the Cherenkov light emitted by secondary particles that are created when a Neutrino interacts with the matter inside the detector.
E.g. a muon Neutrino reacts with a water molecule producing a muon, which is a charged particle and thus emits Cherenkov light.
The article has a section about what it can be used for, but only mentions the uses of the IAEA.
Of course I am biased because I work in the field, but the by far most wide reaching application of Cherenkov radiation is in the detection of high energy particles, particularly in astrophysics.
- Imaging Atmospheric Cherenkov telescopes detect the Cherenkov radiation emmited in the atmosphere when a high energy cosmic ray or gamma ray creates an air shower
- Water Cherenkov Detectors detect Cherenkov light when the secondary particles of these air showers reach water tanks on the ground
- Neutrino telescopes like kamiokande, Icecube and km3net detect Cherenkov radiation in water or ice produced by secondary particles produced by the rare interactions of Neutrinos in their detector volumes
Modern, high energy astrophysics is all about detecting different kinds of Cherenkov radiation and then reconstructing the original particle properties.
As an aside, open core research reactors that glow are a very cool marketing tool for STEM. I went to a college with an open-core TRIGA run by undergraduates that loved to pulse it. It never failed to awe high school students.
All of it was driven by a flood of experimental results that were not compatible with classical physics.
See "Ultra Violet Catastrophe" in black body radiation, photo effect.
Planck famously performed curve fitting on the black body spectrum and only afterwards found the theoretical foundation for the function that fit the data.
https://en.wikipedia.org/wiki/Ultraviolet_catastrophe