sterile neutrino dark matter theory

Sterile neutrino dark matter theory suggests there exists a type of neutrino—called sterile neutrinos—that doesn't interact via the usual forces like regular neutrinos do, except through gravity. These particles could have formed shortly after the Big Bang and are stable enough to still exist today. Because they don't emit light or much interaction, they are "dark" and make up part of the universe’s unseen matter. Their properties might explain some cosmic observations, and researchers are studying possible ways to detect or confirm their existence as a form of dark matter.