Astronomers just found a galaxy way too advanced for its time

Cosmologists might have to go back to the drawing board.

By Elisha Sauers on October 8, 2024



Cosmologists may have to rethink galaxy evolution theories as more mature and orderly galaxies are found in the early universe. Credit: NASA / ESA / CSA / Joseph Olmsted (STScI) illustration

Imagine archaeologists excavating an old cave where they believed they'd see primitive ape-like ancestors and instead found a fossil almost indistinguishable from a modern human.

That might be what astronomers felt when they discovered an evolved galaxy similar to the Milky Way, but lighting up space when the universe was merely 700 million years old. Given that most scientists believe the universe is 13.8 billion today, that period could still be considered the universe's toddler era, shortly after the Big Bang.

Using the Atacama Large Millimeter/submillimeter Array, or ALMA, an observatory in Chile’s Atacama Desert, researchers discovered a galaxy that appears to be as orderly as contemporary galaxies. The team named the cosmic wunderkind REBELS-25 and believe it to be the most distant rotating disk galaxy found so far. The findings were published in the Monthly Notices of the Royal Astronomical Society on Monday.

"According to our understanding of galaxy formation, we expect most early galaxies to be small and messy looking," said Jacqueline Hodge, a co-author of the paper at Leiden University in the Netherlands, in a statement.

The discovery is not only a record-breaker but another piece of mounting evidence, thanks to the James Webb Space Telescope, that suggests cosmologists need to revise their previous notions about galaxy evolution. Up until recently, theorists have believed a galaxy as elegant as the Milky Way — having a rotating disk and spiral arms, for example — would require billions of years of evolution.

More:
https://mashable.com/article/oldest-evolved-galaxy-rebels-25