Just recently, scientists have detected oxygen in a galaxy from a very long time ago, and very far away.
Well I suppose to be more precise, the SXDF-NB1006- 2 galaxy which is 13.1 billion light-years away. This is the oldest findings of oxygen that has ever been discovered. Why is this so important? Well, to make along story short, after the Big Bang, only the lightest elements (Helium, Lithium, and Hydrogen) existed. The heavier ones, like oxygen and carbon, were needed for the creation of all the life that surrounds us.
What this means for us now is that it gets scientists one step closer of discovering the origin of the life-providing molecules. It can be used to fill in the gap from cool down period after the Big Bang to the slow creation of the universe, which is also known as the dark age. The oxygen found in SXDF-NB1006- 2could only have been supported by the existence of many stars that are much larger than our sun.
So, by studying old galaxies like SXDF-NB1006- 2, the yellow brick road to learning the dark age of our universe has become a little more illuminated.