Astronomy 13-billion-year-old galaxy a glimpse into the universe’s ancient past

13-billion-year-old galaxy a glimpse into the universe’s ancient past

Imagine being able to see all the way back to the Big Bang and the early days of our universe.

Well now we can.

An international team of astronomers from The University of Melbourne, United States, and Europe have confirmed the existence of one of the most distant galaxies in the universe.

The ancient galaxy, with the catchy name of MACS1423-z7p64, is 13.1 billion years old and provides an eye-catching glimpse into the universe when it was a mere 700 million-years-old.

Normally galaxies at this distance and of this size would be too faint to detect.

“There have been a few other discoveries of galaxies whose light has travelled for more than 13 billion years before reaching us, but they were all extremely luminous objects, brighter than our own galaxy,” said Michele Trenti from the University of Melbourne.

“In contrast, we estimate that this galaxy contains just 300 million stars.”

Faint galaxies are thought to be much more common than bright ones in the young universe, but until now have not been confirmed.

To find such faint, distant objects, the research team used gravitational lensing.

As light from the distant object passes by a massive object such as a galaxy cluster in the foreground, it gets bent by gravity, just as light gets bent passing through a lens.

When the foreground object is massive enough, it magnifies the object behind it.

The newly-discovered galaxy just happened to fall into the “sweet spot” behind a giant galaxy cluster that magnified its brightness tenfold and made it first visible to the team using the Hubble Space Telescope.

They were then able to confirm the galaxy’s distance by analysing its spectrum — the combined colour and light coming from its stars.

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