Something’s strange about this ‘normal’ looking ancient galaxy
The galaxy SPT0418–47, formed in the ancient Universe, looks entirely normal — and that’s what’s so strange about it.
The impetuousness of youth
Theories of the earlyUniversesuggest that the first galaxies should have been chaotic, their structures untamed like those seen in the modern age.
“This is because the strong effects associated with galaxy mergers and supernova explosions would lead to most young star-forming galaxies being dynamically hot, chaotic and strongly unstable,” researchers write inNature.
Galaxies as distant as SPT0418–47 appear too small and distant for astronomers to directly image. Too make this finding, researchers at theAtacama Large Millimeter/submillimeter Array (ALMA)took advantage of gravitational lensing. This effect, possible in rare cases when a large mass like a galaxy lines up nearly directly between the Earth and a distant target. As light passes the intermediate galaxy, it bends just as if it were traveling through a lens, magnifying the distant image.
One ring to calm them all
Light from the distant galaxy was stretched into a near-perfect ring as it traveled towardEarth, due to the precise alignment of the galaxy and the gravitational lens.
“When I first saw the reconstructed image of SPT0418–47 I could not believe it: a treasure chest was opening,”Rizzo states.
This new finding from the European Southern Observatory (ESO) reveals the early Universe as less chaotic than once believed.
“What we found was quite puzzling; despite forming stars at a high rate, and therefore being the site of highly energetic processes, SPT0418–47 is the most well-ordered galaxy disc ever observed in the early Universe. This result is quite unexpected and has important implications for how we think galaxies evolve,” saidSimona Vegettiof the Max Planck Institute for Astrophysics.
Although SPT0418–47 possesses a disk ofstarssurrounding a central bulge, astronomers believe this ancient galaxy was destined to develop into an elliptical galaxy, not a spiral galaxy like the Milky Way.
In May 2020, ALMA scientists released a finding of a differentdisk galaxyat a similar distance to SPT0418–47, but these new images show their target in far greater detail than the earlier release, due to the fortuitous effects of gravitational lensing.
Future studies utilizing instruments such as the Extremely Large Telescope (ELT) will help determine how common galaxies like this one were present in the earlyUniverse, providing astronomers new insights into the evolution of the Cosmos.
This article was originally published onThe Cosmic CompanionbyJames Maynard, founder and publisher of The Cosmic Companion. He is a New England native turned desert rat in Tucson, where he lives with his lovely wife, Nicole, and Max the Cat. You can read this original piecehere.
Astronomy News with The Cosmic Companionis also available as a weekly podcast, carried on all major podcast providers. Tune in every Tuesday for updates on the latest astronomy news, and interviews with astronomers and other researchers working to uncover the nature of the Universe.
Story byThe Cosmic Companion
Exploring the wonders of the Cosmos, one mystery at a time.Exploring the wonders of the Cosmos, one mystery at a time.
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