Astronomers have made an amazing discovery – an early-universe galaxy located around 13 billion light years away from our planet.

Using gravitational lensing on the W. M. Keck Observatory telescope in Hawaii, the international team of scientists found the faint and far-off galaxy which is believed to be born just after the Big Bang occurred and was located behind the galaxy cluster MACS2129.4-0741. It was because of this location that the astronomers were able to create three different images of the object showing the same galaxy due to similar spectra in each image.

It all couldn’t be possible without the gravitational lensing – a phenomenon predicted by Einstein where gravity can bend the path of light and enables the magnification of distant objects in space.

“Currently, the most likely suspect is stars within faint galaxies that are too faint to see with our telescopes without gravitational lensing magnification,” said Tommaso Treu, a professor of physics and astronomy in the UCLA College and a co-author of the research. “This study exploits gravitational lensing to demonstrate that such galaxies exist, and is thus an important step toward solving this mystery.”

This discovery is exciting because it could help towards understanding the process of cosmic reionization which was a stage in the universe’s “dark period” when hydrogen gas between galaxies transitioned from being mainly neutral to being mostly ionized and the stars were created. So far little is understood about this process according to Marc Kassis, staff astronomer at the Keck Observatory.

“It’s a very, very small galaxy and at such a great distance, it’s a clue in answering one of the fundamental questions astronomy is trying to understand: What is causing the hydrogen gas at the very beginning of the universe to go from neutral to ionised about 13 billion years ago? That’s when stars turned on and matter became more complex.”

The research was published in the Astrophysical Journal Letters.