James Webb reveals Milky Way-like galaxies existed much earlier than previously thought

Barred spiral galaxies have long been thought to have evolved over billions of years. Now, however, a team of scientists from The University of Texas Austin has published a new study detailing the discovery and observation of 11-billion-year-old barred spiral galaxies — meaning they are almost as old as the universe itself.

"Bars solve the supply chain problem in galaxies," said Shardha Jogee, one of the study authors. "Just like we need to bring raw material from the harbor to inland factories that make new products, a bar powerfully transports gas into the central region where the gas is rapidly converted into new stars at a rate typically 10 to 100 times faster than in the rest of the galaxy."

These bars have typically been believed to form long into a large galaxy's evolution and their discovery in 11-billion-year-old galaxies was a surprise for astronomers. "This discovery of early bars means galaxy evolution models now have a new pathway via bars to accelerate the production of new stars at early epochs," Jogee explained.

The existence of these bars, therefore, challenges existing theoretical models pertaining to the number of barred Milky Way-like galaxies in the universe. For their study, the scientists trained Webb on a series of distant galaxies that had previously been observed by the Hubble Space Telescope. Webb's higher-resolution observations revealed the bar structures for the first time.

"I took one look at these data, and I said, ‘We are dropping everything else!’" said Jogee. "The bars hardly visible in Hubble data just popped out in the JWST image, showing the tremendous power of JWST to see the underlying structure in galaxies."

James Webb has peered further back in time than any observatory in history

It's not the first time James Webb has called existing theories about the early universe into question. Early on in its scientific operations, the space observatory observed the earliest galaxies ever witnessed by humanity, some of which were more evolved than expected.

The telescope's large mirror allows it to peer further into the universe — and further back in time — than any previous observatory. It also makes observations at long infrared wavelengths, meaning it can peer through enormous dust clouds and reveal the otherwise hidden details underneath.

Webb's science mission is expected to last for approximately a decade, during which time it will surely continue to change our understanding of the cosmos. In the process, it will likely continue to throw a whole host of long-held theories about galaxy formation into question.