Among all space mysteries, the creation of the universe’s grandest galaxies is among the most mystifying, but new research has brought astronomers one step closer to deciphering this phenomenon. A study published in Nature details the process that spawned immense galaxies, which could help unravel the evolution of the universe since the beginning of time.
Exploring the Origins of Elliptical Galaxies
The study — a collaboration between the University of Southampton, China’s Purple Mountain Observatory, the Chinese Academy of Science, and several other institutions — observed the birth sites of elliptical galaxies, finding that galactic collisions were key to their formation.
These galaxies often appear to have a round or oval shape and are less structured than the brighter, disk-shaped spiral galaxies, known for their “arms” that are abundant in gas and young stars. Elliptical galaxies, with less gas and dust, generally contain older stars.
Despite their more unassuming appearance compared to spiral galaxies like the Milky Way and the Andromeda, the ambiguity behind elliptical galaxies’ origins has interested researchers for decades. Now, they may have figured out how these galaxies — some of the largest in the entire universe — first formed.
Read More: 10 Facts You May Not Know About the Milky Way
Evolution of the Universe
Experts involved in the study analyzed more than 100 star-forming galaxies with ALMA, the largest radio telescope in the world residing in Chile’s Atacama Desert. They concluded that flows of cold gas and collisions between galaxies early in the universe’s history likely created the vast systems.
“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 Annagrazia Puglisi, a research fellow at University of Southampton who co-authored the research, in a statement.
Puglisi added that these collisions occurred around 8 billion to 12 billion years ago during a period when the universe was undergoing active evolution.
“Our findings take us closer to solving a long-standing mystery in astronomy that will redefine our understanding of how galaxies were created in the early universe,” Puglisi said.
A New Research Technique
The discovery was possible due to a new technique that looked at the distribution of light emitted by distant and highly-luminous galaxies. The study also took advantage of open-source archives — known as A3COSMOS and A3GOODSS — to collect observations of distant galaxies.
Ultimately, they concluded that the spherical shape of these systems developed from starbursts billions of years ago.
“These galaxies form quickly — gas is sucked inwards to feed black holes and triggers bursts of stars, which are created at rates 10 to 100 times faster than our Milky Way,” said study lead Qing-Hua Tan of the Purple Mountain Observatory, in a statement.
Read More: The Merging of Two Galaxy Clusters May Be the Largest Astronomical Event in the Universe
Mapping Galaxy Evolution
Researchers hope this insight on elliptical galaxy formation will help them piece together the evolutionary path of the universe. Beyond the process described by the new study, other galaxy-forming events have been examined in the past.
Along with collisions, astrophysicists have elucidated the idea of merging galaxies; this occurs when two galaxies interact with each other and meld together due to gravitational forces. As another important manner of cosmic evolution, merging galaxies may create an irregular galaxy — resulting in an amorphous shape full of gas and dust — or a ring galaxy — where material is pushed outwards, surrounding a dense core of older stars.
The progress on elliptical galaxy studies, however, will push forward as researchers plan to combine their findings with data gathered from the James Webb Space Telescope, Euclid telescope, and the Chinese Space Station to advance their knowledge of galactic evolution.
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Jack Knudson is an assistant editor at Discover with a strong interest in environmental science and history. Before joining Discover in 2023, he studied journalism at the Scripps College of Communication at Ohio University and previously interned at Recycling Today magazine.
