An international team of 48 astronomers led by the University of Massachusetts Amherst has identified galaxies formed just one billion years after the Big Bang, potentially rewriting our understanding of cosmic history. The research, published in The Astrophysical Journal Letters on February 17, 2026, reveals a population of previously unknown, dusty star-forming galaxies dating back almost 13 billion years. These galaxies appear to bridge the gap between the earliest bright galaxies and older, “quiescent” galaxies, offering a crucial “snapshot” in galactic evolution. “It’s as if we now have snapshots of the lifecycle of these rare galaxies,” says Jorge Zavala, assistant professor of astronomy at UMass Amherst and the paper’s lead author, suggesting star formation occurred earlier in the universe than current models predict.
ALMA and JWST Identify 13-Billion-Year-Old Dusty Galaxies
Subsequent near-infrared observations from NASA’s James Webb Space Telescope then allowed them to pinpoint approximately 70 faint candidates at the universe’s edge, many unseen until now. By revisiting the ALMA data and “stacking” observations, the team definitively confirmed these galaxies formed almost 13 billion years ago. These discoveries are challenging existing cosmological models, suggesting star formation began earlier in the universe than previously understood. The dust itself, which absorbs ultraviolet and visible light, previously obscured these galaxies from traditional telescopes, but submillimeter telescopes reveal the infrared energy emitted as the dust heats up.
Dust Obscuration Resolved with Submillimeter Telescopes
The ability to observe the universe’s earliest galaxies has undergone a revolution, thanks to advancements in submillimeter telescope technology. For decades, understanding galaxy formation in the immediate aftermath of the Big Bang—which occurred 13.7 billion years ago—was hampered by pervasive cosmic dust. This dust absorbs ultraviolet and visible light, rendering many galaxies invisible to traditional telescopes. However, the development of instruments capable of detecting longer wavelengths has pierced this veil, revealing previously hidden populations of galaxies.
Galaxies Link Ultrabright Sources to Early “Quiescent” Systems
“My research involves trying to identify and understand a population of rare, dusty star-forming galaxies that were only discovered at the end of the 1990s,” Zavala explains. The team initially identified approximately 400 bright, dusty galaxies using the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile, then pinpointed around 70 faint candidates with NASA’s James Webb Space Telescope. These galaxies appear to connect the recently discovered ultrabright galaxies, formed 13.3 billion years ago, with the early “quiescent” galaxies that ceased star formation roughly 2 billion years after the Big Bang.
Dusty galaxies are massive galaxies with large amounts of metals and cosmic dust.
