How do galaxies form? For decades, that’s been a mystery, but it may have finally been solved by a group of astronomers using the world’s largest radio telescope.
While spiral galaxies like our Milky Way are flat, the most ancient galaxies in the early universe seen by astronomers are all kinds of shapes, including blobs and “bulging footballs.”
Collision Course
According to a paper published today in Nature, the reason is intense episodes of star formation in the cores of galaxies caused by large flows of cold gas and collisions between galaxies. “Two disk galaxies smashing together caused gas — the fuel from which stars are formed — to sink towards their center, generating trillions of new stars,” said Dr Annagrazia Puglisi from the University of Southampton, who co-authored the research.
Earliest Galaxies
A team of researchers worldwide looked at some of the earliest galaxies in the universe. Using the ALMA array in Chile’s Atacama desert, they looked back 12 billion years, when galaxies were first being formed, where they saw spheroid-shaped galaxies. The scientists made the discovery using a new technique, which looked at the distribution of light emitted by over 100 star-forming and highly-luminous galaxies.
Bursts Of Stars
“This is the first real evidence that spheroids form directly through intense episodes of star formation located in the cores of distant galaxies,” said Puglisi. “These galaxies form quickly — gas is sucked inwards to feed black holes and triggers bursts of stars, which are created at rates ten to 100 times faster than our Milky Way.”
Future Discoveries
The next task is to combine these findings with data from the James Webb Space Telescope, the Euclid satellites and the Chinese Space Station, to map the stars within the ancient galaxies. “Astrophysicists have sought to understand this process for decades,” said Puglisi. “This will give us a more complete picture of early galaxy formation and deepen our understanding of how the universe has evolved since the beginning of time.”
Wishing you clear skies and wide eyes.
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