Astronomers found that a galaxy as old as the Universe might be containing extraterrestrial oxygen. The galaxy is named SXDF-NB1006-2 and is located 13.1 billion light-years away from Earth.
Early Star Formation
The classical theory says that after the Big Bang, the heat of the Universe split the atoms into nuclei with positive charges and electrons with negative charges. The light could not travel free because of the electrically charged ions.
380,000 years after the Big Bang, the Universe already started to cool down. The particles combined into atoms, and light managed to find its way across the Universe. The only light that existed was the one coming from the Big Bang, as the stars were not formed yet.
Millions of years after, the universe started to go through a period of reionization which lasted half a billion years. During this time, gas collapsed and formed stars and galaxies.
The intense ultraviolet light destroyed the hydrogen, which split into protons and electrons.
The reionization area remains mysterious to scientists because there is little information on what happened millions of years ago.
Scientists look at very distant objects in the universe as the further away they are from Earth, the longer it would take the light to reach our planet. Thus, the information we receive is counted as being from the past.
Concerning the reionization, scientists believe that it was either the first massive stars or the black holes that created the event.
SXDF-NB1006-2 was discovered in 2012 and at that time, it was the most distant galaxy known to science.
Researchers used data from the Atacama Large Millimeter/submillimeter Array to reconstruct the image of the galaxy as it probably appeared to be 700 million years after the Big Bang.
Astronomers were looking for heavy elements that existed in the early universe, which might help them to have a clear image of what happened millions of years ago.
Extraterrestrial Oxygen on SXDF-NB1006-2
The oxygen found on SXDF-NB1006-2 was ionized, and scientists believe that means the galaxy used to possess young giant stars that would have emitted intense ultraviolet light.
However, there is ten times less oxygen in the galaxy than it was in the sun.
Scientists believe that light elements like helium, lithium and hydrogen existed ever since the universe was created. Heavier elements, such as oxygen, were created later after the stars appeared.
Researchers found that the dust from the galaxy was three times less abundant than predicted. One explanation may be that the space dust was destroyed by supernova explosions.
As the galaxy does not have any black holes, but only massive stars, scientists look into the possibility that the source of reionization may be the massive stars.
Image Source: Wikipedia