Another unique aspect of the merger is the apparent lack of new stars being formed, Rines added.
Typically when galaxies converge, the intervening gas clouds compress and begin to form stars, he explained. But scientists have not detected gas clouds in the four galaxies, which means no new stars will be born from the merger.
Rines' team will publish the discovery in an upcoming issue of Astrophysical Journal Letters.
Benefit of Happenstance
Rines said the megacollision will help scientists learn more about how large galaxies are formed.
"This merger tells us that you can make a clear distinction between when a star in a galaxy forms and when the galaxy itself assembles," he said.
In this case, all of the stars had formed before the merger.
"But if you had just looked at the star age [once the new galaxy is fully formed], you would have assumed the galaxy is much older than it really is," he noted.
Rines hopes to see more of these megamergers, but he admits it was happenstance that his team spotted the new one during a survey of distant galaxy clusters.
He's also not holding out hope that he'll see the monster galaxy fully formed in his lifetime—it will take about a hundred million years for these four galaxies to finally become one.
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