An international research team has determined that newly formed dwarf galaxies are a likely reason that the universe heated up around 13 billion years ago, potentially creating a new way of understanding the 14 billion year history of the universe.
According to Phys, after the Big Bang the universe became massively hot and dense in a relatively quick hundred thousand years or so. In fact, the universe was so hot and dense that the matter was ionized instead of being in a neutral form.
A question still being debated by physicists is how, after the ionization of the universe, things cooled down enough to the extent that its matter reverted to a neutral form before ionizing again in a process called “cosmic re-ionization.”
One hypothesis involves galaxies which emit mass amounts of ions contributing to the reionization of the universe, though before recently there hadn’t been any data to support this hypothesis.
A nearby compact dwarf galaxy — which appears to be ejecting and emitting a large number of ionizing photons into the space between galaxies — was examined by the team using data from the Hubble Space Telescope. What the researchers found might be the key to figuring out how cosmic re-ionization occurred the way that it did.
“This galaxy appears to be an excellent local analog of the numerous dwarf galaxies thought to be responsible for the reionization of the early universe,” said University of Virginia Astronomer Tin Thuan.
Data from other such ion rejecting galaxies was examined for the study. These types of galaxies became known as “green pea” galaxies due to their apparent green color and compactness.
After discovering that “green pea” galaxies can eject and emit photons at level that had been previously unseen, astronomers might now have what they need in order to confirm their hypothesis.