According to astronomers from the University of California, Irvine and Baltimore’s Space Telescope Science Institute, they have generated the most exact statistical description of faint, early galaxies so far. These galaxies used to exist in universe 500 million years after the Big Bang.

The team, in a research paper published in Nature Communications, has described a new statistical method for analyzing Hubble Space Telescope data captured during lengthy sky surveys. The deep-sky survey belongs to a bigger Hubble-based study project known as the Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey.

With the help of the method, the scientists were able to parse out signals from the noise in Hubble’s deep-sky images and came up with the first ever estimation of the number of small, primordial galaxies in the early universe. As per the researchers, there are nearly 10 times more of these galaxies than were detected earlier in deep Hubble surveys.

Lead author on the paper Ketron Mitchell-Wynne, UCI Ph.D. student, said the time span they are investigating is called the ‘epoch of reionization’. When talking about Big Bang cosmology, reionization is the phenomenon that reionized the matter in the universe after the ‘dark age’. It is the second of two main phase transitions of gas in the universe.

The epoch of reionization was set apart by a phase transition of hydrogen gas which took place because of the accelerated process of star and galaxy formation. It came after the Big Bang and a few hundred million years wherein photon-absorbing neutral hydrogen dominated a dark universe.