Published: Sun, March 12, 2017
Research | By Jennifer Evans

Young Galaxy's Old Stardust Sheds Light on the First Stars

Young Galaxy's Old Stardust Sheds Light on the First Stars

The galaxy is 13 billion lightyears away, and with the universe being 13.7 billion years old, light has been travelling the majority of the universe's life and has only just reached the ALMA telescope.

Now, researchers have observed this process taking place during the universe's extreme infancy, in a galaxy called A2744_YD4, using the Atacama Large Millimeter Array (ALMA) and the Very Large Telescope (VLT), both in northern Chile.

The universe burst into existence almost 13.8 billion years ago in an event we now know as the Big Bang. It sits at a redshift of 8.38, which is associated with a time when the universe was just 600 million years old.

The ancient galaxy was found by astronomers via the gravitational lensing technique. This was possible by looking at a galaxy called A2744_YD4 which appeared to us as if the universe was in extreme infancy.

Researchers were able to witness a unique view of how the universe looked like during the formation of the first stars and galaxies. This represents the most distant galaxy in which cosmic dust has ever been found - giving scientists a new insight into how and when the very first stars were born and died. Located about 13 billion light-years away, it's filled with dust from exploded stars - and according to scientists, the dust could be the remnants of the first stars in the Universe.

The scientists determined that the dust scattered in A2744_YD4 added up to about six million times the mass of the Sun, while the mass of all its stars amounted to two billion times the mass of the Sun. In the press release accompanying the announcement, Laporte explained that "the detection of so much dust indicates early supernovae must have already polluted this galaxy". She studied journalism at Douglass College, Rutgers University, and earned a Graduate Certificate of Science in astronomy from Swinburne University's Astronomy Online program.

Further to this, the team also detected ionised oxygen coming from the galaxy - making it the earliest oxygen ever detected.

The stars from which the dust were created began forming 200 million years before the light from A2744_YD4 reached Earth, which means these are some of the vestiges of the earliest stars in the Universe. 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. One way this can be done is by studying distant galaxies, through which we get a glimpse of what the early universe was like. This is despite the fact that the earliest universe has the least probability of having its first-generation stars die out to leave behind stardust in such high quantities. "Further measurements of this kind offer the exciting prospect of tracing early star formation and the creation of the heavier chemical elements even further back into the early Universe", Laporte said.

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