These nearly massless particles decoupled from matter seconds after the Big Bang. They barely interact with anything, making them hard to detect. Despite their ghostly nature, they outnumber all other particles in the universe. Detecting cosmic neutrinos can reveal conditions of the universe’s earliest moments. Neutrino observatories like IceCube aim to capture these ancient messengers. They carry unique information that photons cannot.
It matters because primordial neutrinos provide clues to the Big Bang’s first seconds.
It also opens a window into particle physics at unprecedented energies.
Cosmic neutrinos have been traveling for 13.8 billion years, largely unnoticed.
National Science Foundation [nsf.gov]