One of the first places that happened was in galaxy A2744_YD4. Also, the light of this particular galaxy took 13.2 billion years to reach Earth, which is 96 percent of the total age of the universe. This detection, coupled with the age of A2744_YD4, helps astronomers to better pin down the life cycle - including the formation - of the universe's first stars, called Population III stars. This galaxy was observed shortly after its formation and is the most distant galaxy in which dust has been detected. The presence of oxygen in this distant galaxy gives us a hint to when and how the first galaxies formed and what caused the cosmic "reionization".
The detection of A2744_YD4 and its properties, which was made by an global team of astronomers led by Nicolas Laporte of University College London, is remarkable for several reasons.
An worldwide astronomy team has made the earliest known discovery of oxygen in the universe - more than 13 billion years, or just 600 million years after the Big Bang. Findings indicate stars started to form when just 400 million years after the dawn of the universe.
ALMA observations have uncovered an extremely young, dusty galaxy already polluted with the products of supernovae, as pictured in this artist's impression.
ALMA (ESO/NAOJ/NRAO), NASA, ESA, ESO and D. Coe (STScI)/J. The chemical elements are said to have been forged inside stars and are scattered across the cosmos as they die in spectacular supernova explosions. Using the gravity of a group of galaxies known as Pandora's Cluster, the researchers magnified the light of the more distant A2744_YD4.
Next, the scientists will look at the composition of the dust clouds and the early stars, to understand how the stars came to produce other elements in the universe.
Further to this, the team also detected ionised oxygen coming from the galaxy - making it the earliest oxygen ever detected.
The galaxy is estimated to contain an amount of dust equivalent to six million times the mass of our sun.
The astronomers also measured the rate of star formation in A2744_YD4 and found that stars are forming at a rate of 20 solar masses per year - compared to just one solar mass per year in the Milky Way. Far beyond this cluster is the faint, young galaxy A2744_YD4.
This means that significant star formation began approximately 200 million years before the epoch at which A2744_YD4 is being observed. In the earliest days of the universe, when the first generations of stars had not yet exploded, there wasn't much stardust around yet. You, the screen you are now reading these words on, the chair you are sitting on and the planet you live on are all the end result of 13.8 billion years of cosmic evolution - a process that began with the birth and death of the first stars.