The earliest known galaxy merger occurred 13 billion years ago, but it's only now that scientists are able to see it unfold.

The galaxy merger, dubbed as B14-65666, is a peek at the early universe, occurring within the first billion years of its lifetime.

These galaxies are likely to be among the earliest that sprung from the Big Bang. From their epic collision, a new generation of stars burst into life, and their light traveled through the cosmos for billions and billions of years until it reached Earth, specifically the Atacama Large Millimeter/submillimeter Array of telescopes in Chile.

Watching An Ancient Collision

In a new study published in the journal Publications of the Astronomical Society of Japan, researchers explained how their use of ALMA allowed them to capture radio emissions of oxygen, carbon, and dust from 13 billion years ago in the cosmic object B14-65666.

It's not the first time that scientists have observed B14-65666, which is located in the constellation Sextans 13 billion light-years away. The Hubble Space Telescope have previously identified two star clusters within the object, but ALMA's detection of the three signals revealed much more information than astronomers previously had.

Analysis of the radio emissions revealed that while the two clusters are part of a single system, they move at different speeds, indicating that they're two separate galaxies in the process of merging. It's the earliest example that scientists have ever found of merging galaxies.

"With rich data from ALMA and HST, combined with advanced data analysis, we could put the pieces together to show that B14-65666 is a pair of merging galaxies in the earliest era of the Universe," study author Takuya Hashimoto, who is a postdoctoral researcher at the Japan Society for the Promotion of Science and Waseda University, explained in a statement.

More About B14-65666

The galaxy merger B14-65666 is estimated to have 10 percent less stellar mass than the Milky Way, which suggests that it's in the earliest stages of evolution. However, it's also giving birth to stars at 100 times the rate of Milky Way's production, which is another feature of galaxy mergers.

Study author Akio Inoue, a professor at Waseda University, said that the team plans follow up their research by looking for the molecules of other major chemical elements, such as nitrogen and carbon monoxide.

"Ultimately, we hope to observationally understand the circulation and accumulation of elements and material in the context of galaxy formation and evolution," Inoue concluded.