The Oldest Known Spiral Galaxy Was Just Detected, And It Has Some Surprises For Us


Scientists have captured a picture of the oldest known spiral galaxy, which was formed 12.4 billion years ago.

The galaxy, officially named BRI 1335-0417, was snapped by the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile. 

It shows that spiral galaxies were formed as early as 1.4 billion years after the Big Bang.

The photo was taken as part of a study published in the peer-reviewed Science journal on Thursday.

"It puts us back the time when we knew that galaxies started to look like modern-day galaxies by roughly 1 billion years," Dr. Kai Noeske, communications officer for the European Space Agency and distant galaxy researcher told Insider. 

Spiral galaxies are more mature forms of galaxies. 

In the early phases of formations, dark matter brings hot gas together in small clumps that create stars. These merge together to create larger galaxies, which are clumpy and misshapen.

Eventually, these galaxies can start rotating, creating galaxies that are disk-like, Noeske said. 

This computer simulation shows what it would look like:

Spiral galaxies happen when that disk starts being disturbed, Noeske said.

"The interesting thing about this, aside from of course looking really pretty, is that in these spiral arms, the gas is being compressed. So they are actually a catalyst to trigger new star formation," Noeske said.

"You cannot form a star and or a planet somewhere out in space," Noeske said. "Without the galaxies, there wouldn't be any humans. It's part of our story."  

The currently accepted paradigm is that galaxy formation peaked about 3.3 billion years after the Big Bang, when most of the stars in the universe were formed. 

"It is surprising that our results show that BRI 1335-0417 already have structures (compact structure like a bulge, disk, spiral) similar to nearby galaxies, long before the active phase of the galaxy formation," Takafumi Tsukui, graduate student at SOKENDAI University in Japan and lead author of the Science study, told Insider in an email.

The oldest known spiral galaxy observed before Thursday's study was seen in by the ALMA telescope in 2019. 

It was formed 2.5 billion years after the Big Bang, about a billion years later than BRI 1335-0417.

"Our result will update our knowledge of how and when the galaxies form and evolve to matured galaxy observed today, including the Milky Way Galaxy," Tsukui said.

Though this is the oldest known spiral galaxy, it is not the oldest-ever observed galaxy. That title is held by GNz11, which was spotted in December last year. It was formed 13.4 billion years ago, 400 million years after the Big Bang.

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