Scientists discover universe’s largest gas cloud 20 times larger than Milky Way

November 5, 2022  16:42

An international group of scientists have discovered a huge cloud of atomic gas which is about 20 times larger than the Milky Way galaxy. As reported by Space.com, this is stated in their study published in Nature magazine.

Using the Five-hundred-meter Aperture Spherical Telescope (FAST), scientists based in China have found that five closely packed galaxies—known as Stephan's Quintet—in the Pegasus constellation are surrounded by a huge cloud of atomic gas that is 2 million light-years across.

Each galaxy in Stephan's Quintet is made up of millions of star clusters; four of them actually interact with each other, whereas one is quite close to Earth.

"This is the largest atomic gas structure ever found around a galaxy group," said Xu Kong, an astronomer at the National Astronomical Observatories of the Chinese Academy of Sciences and lead author on the new research.

The mystery of the gas cloud has raised new questions

According to the scientists, the discovery is a mystery and will require astronomers to rethink how gas behaves at the edges of galaxy clusters.

The scientists note that because atomic hydrogen moves more freely through galaxies than other components of the atomic gas cloud, it is easily dispersed when objects in the galaxy interact with each other. According to the researchers, the hydrogen scattered in Stephan's Quintet is a time capsule that can tell scientists about such events that happened about a billion years ago.

This gas cloud is a particularly interesting find because astronomers expected that ultraviolet light would change the nature of the hydrogen in the cloud. UV light ionizes the atoms in the atomic gas cloud—meaning they will gain or lose electrons and become charged as a result. But the gas observed in Stephan's Quintet is not ionized.

In the study, the scientists explain that the lack of ionization suggests that the gas may be a remnant of galactic formations. Dispersed clouds of atomic hydrogen far from stars exist on their own, which may indicate that they are a byproduct of galaxy-forming interactions. It is also possible that the cloud surrounding Stephan's Quintet was released by a long-ago collision between two galaxies. The answer to this question could change humanity's understanding of how galaxies are born and continue to evolve.


 
 
 
 
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