Study suggests faint galaxies illuminated early universe

A new study has found that the light from tiny galaxies more than 13 billion years ago played a larger role than previously thought in creating the conditions in the universe as we know it today.

According to a new study by researchers at the Georgia Institute of Technology and the San Diego Supercomputer Center (SDSC) at the University of California, ultraviolet light from stars in these faint dwarf galaxies helped strip interstellar hydrogen of electrons in a process called reionization.

The researchers have found that the epoch of reionization began about 200 million years after the Big Bang, and astrophysicists agree that it took about 800 million more years for the entire universe to become reionized.

According to the study, this marks the last major phase transition of gas in the universe as it remains ionized today, and tiny galaxies, despite being 1,000 times smaller in mass and 30 times smaller in size than the Milky Way, contributed nearly 30 percent of the UV light during this process.

The study was published in the journal Monthly Notices of the Royal Astronomical Society.