A new work uses data about the structure of the entire universe to measure the mass of one of its smallest, most difficult to examine components. We are full of neutrinos the whole time. They are everywhere, almost undetectable, and whiz through normal matter. We hardly know anything about them – not even how heavy they are. However, we know that neutrinos can change the shape of the entire universe.
And because they have this power, we can use the shape of the Universe to weigh them, just as a team of physicists has done now. Due to physics, the behavior of the smallest particles alters the behavior of entire galaxies and other giant celestial structures. And if you want to describe the behavior of the universe, you must consider the properties of the smallest components.
In a new article published in the upcoming issue of the journal Physical Review Letters, researchers used this fact to calculate the mass of the lightest neutrino (there are three neutrino masses) from precise measurements of the large-scale structure to be calculated universe. They took data on the motions of about 1.1 million galaxies from the Baryon Oscillation Spectroscopic Survey, scaled it up with other cosmological information and results from smaller-scale neutrino experiments, and fed that information into a supercomputer. We spent more than half a million computing hours processing the data, “said co-author of the study, Andrei Cuceu, a doctoral student in astrophysics at University College London.”This is equivalent to almost 60 years on a single processor.
This project has exceeded the limits of big data analysis in cosmology. The result did not provide a fixed number for the mass of the lightest neutrino type, but it constrained it: this neutrino species has a mass of not more than 0.086 electron volts (eV) or about six million times less than the mass of a single electron.
This number sets an upper limit but no lower limit for the mass of the lightest neutrino species. It is possible that it has no mass at all, the authors wrote in the newspaper. What physicists know is that at least two of the three types of neutrinos must have a mass and that there is a relationship between their masses (this article also sets an upper limit on the total mass of all three flavors: 0.26 eV).
Confusingly, Neutrino’s three mass types do not match the three tastes of neutrinos: electron, muon, and tau. According to Fermilab, every taste of neutrino consists of a quantum mixture of the three mass types. So a certain Tau Neutrino contains a bit of Earth Species 1, a bit of Species 2 and a bit of Species 3.
These different mass species allow the neutrinos to jump back and forth between flavors, as revealed by a 1998 discovery (which won the Nobel Prize in Physics).
While physicists can never pinpoint the masses of the three neutrino species, they can get closer and closer. The masses will become ever narrower as Earth experiments and measurements in space improve, the authors wrote. And the better physicists can measure these tiny, omnipresent parts of our universe, the better physics can explain how the whole thing fits together.