The primordial helium amount in the first minutes of the universe was measured with record precision

An international scientific team, including researchers from the University of Minnesota, measured the amount of primordial helium formed in the first five minutes of the universe as approximately 24.6 percent by mass, with an uncertainty of 0.5 percent, based on observations made with the Large Binocular Telescope. This measurement, carried out about 13.8 billion years after the Big Bang, provides important data on processes in the early universe.

An international team, including the University of Minnesota, conducted a total of 130 hours of observations using the Large Binocular Telescope (LBT). These findings, discussed in five separate scientific papers, were published in The Astrophysical Journal. Within the scope of the research, 15 distant galaxies that have undergone less chemical evolution and have low heavy element abundances were examined. The light coming from the galaxies was analyzed through MODS spectrometers developed at Ohio State University; more than 10 spectral lines belonging to helium and 15 belonging to hydrogen were handled simultaneously. By eliminating small systematic errors, measurement precision was brought below 1 percent, achieving a precision approximately three times higher compared to previous studies.

According to the obtained results, the primordial helium abundance was calculated to be approximately 24.6 percent by mass. This ratio shows compatibility with the standard model of Big Bang nucleosynthesis. The findings contribute to testing calculations of the number of neutrino families in the early universe and the Standard Model of particle physics. Although the study does not put forward a new physics theory, it significantly reduces the uncertainty of a critical measurement in understanding the conditions of the early universe.