You’ve surely heard of the Big Bang, the theory that our current universe grew from a single point of extreme heat and density and has been spreading and cooling ever since. Scientists are eager to understand more about the origins of life. Looking at the oldest type of light, the cosmic microwave background, is one way. However, this light does not appear until 400,000 years after the Big Bang. It took a long time for the boiling stew of stuff to mix enough for light to move outward instead of being imprisoned in an opaque mass.
However, because neutrinos interact so infrequently, they should have been able to escape the sea of matter long before light—possibly within a second of the Big Bang. These Big Bang neutrinos may hold the key to understanding our origins.
These Big Bang neutrinos are found throughout the universe, with one theory claiming that around 300 Big Bang neutrinos are present in every cubic centimeter (about the size of your thumbnail). The Big Bang neutrinos, on the other hand, are nearly impossible to locate due to their low energy. The cosmic neutrino background is thought to be significantly colder than the cosmic microwave background, with a temperature of roughly minus 271 degrees Celsius, according to scientists. These neutrinos would have a fraction of the energy of other types of neutrinos, which are already miniscule.
Data acquired by telescopes like Planck and BICEP shows some of the consequences of the Big Bang neutrinos. Other experiments, such as PTOLEMY at Princeton University, aim to discover and estimate the mass of Big Bang neutrinos.