James Webb unveils hidden baby galaxies in Spiderweb protocluster

By observing the protocluster as it appeared just 4 billion years after the Big Bang, astronomers identified previously hidden galaxies in this early-stage galaxy cluster by using the NASA/ESA/CSA James Webb Space Telescope.

"We are observing the build-up of one of the largest structures in the universe, a city of galaxies in construction," said Jose M. Perez-Martinez of the Institute of Astrophysics of the Canary Islands, according to a science release published by ESA.

"We know that most galaxies in local galaxy clusters, the biggest metropolises of the universe, are old and not very active, whereas in this work, we are looking at these objects during their adolescence," he added.

The JWST's advanced infrared capabilities allowed scientists to penetrate cosmic gas and dust that previously concealed these galaxies.

This marks a significant leap in studying how massive structures in the universe evolve.

Team member Rhythm Shimakawa of Waseda University noted that they discovered more galaxies than anticipated.

"We found that previously known galaxy members, similar to typical star-forming galaxies like our Milky Way, are not as obscured or dust-filled as previously expected, which also came as a surprise," Shimakawa said.

Contrary to earlier theories, Helmut Dannerbauer, also of the Institute of Astrophysics of the Canary Islands, suggested that the growth of these galaxies might not be driven by mergers but rather by gas accumulation across their large-scale structure.

The findings demonstrate the JWST's power, with the team achieving these results in just 3.5 hours of observation.