Scientists in the UK have used data relating to the structure of the entire universe to limit the mass of the lightest member of the neutrino family, one of the smallest and most difficult parts of the universe to study: no more than 0.086 electron volts, or about six millionths of the mass of a single electron.
Neutrinos are everywhere, but because they barely interact with ordinary matter, they are called 'ghost particles' and are hard to detect.Despite more than 50 years of searching, scientists still know little about them, or even their quality.
But scientists know that neutrinos' behavior changes the behavior of entire galaxies and other massive bodies.In a paper to be published in the journal physical review letters, the researchers used this to work out the mass of the lightest neutrinos (there are three) from precise measurements of the large-scale structure of the universe.
They took data on the motions of about 1.1 million galaxies from the baryon oscillation spectrum survey, combined with other cosmological information and neutrino experiments on earth, and fed it all into a supercomputer.'With supercomputers taking more than half a million hours to process data, this project pushes the limits of big data analysis in cosmology,' said co-author andrei cucho, a doctoral candidate in astrophysics at university college London.
The study does not provide a fixed number for the lightest neutrino's mass, but it does narrow it down: no more than 0.086 electron volts, about six millionths of the mass of a single electron.
Previous experiments have shown that at least two of the three neutrinos have masses, and that there is a relationship between their masses.The latest study also puts an upper limit on the mixing mass of the three neutrinos: 0.26 electron volts.
The study suggests that physicists may never be able to pinpoint the masses of the three neutrinos, but they can get closer and closer.As experiments on earth and measurements in space improve, the range of neutrinos' masses will shrink to better explain how the universe fits together.