The most probable candidate for HDM is the neutrino that moves at \(0.999 \%\) the speed of light and nearly massless (about 1 eV) and are found everywhere in the Universe. Neutrinos are made through nuclear reactions within stars, from supernovae, and from any other energetic reaction. There are three flavors of neutrinos, the tau neutrino, the electron neutrino, and the muon neutrino and, the neutrino can change flavors as it ages. They are extremely hard to detect because they only interact weakly with normal matter. Because they move so fast and are basically massless, it took physicists decades to detect the neutrino. Now, there are many large-scale experiments looking for neutrinos such as IceCube, ANTARES, and AMANDA II. They are no longer considered a good candidate for dark matter because their velocity is much too high to produce small-scale formation. (7)