Astronomers have uncovered a mysterious group of distant galaxies that may fill an important gap in our understanding of how galaxies grow and change over time.
These newly identified galaxies formed only about one billion years after the Big Bang, making them some of the earliest massive galaxies ever observed.
The discovery, led by researchers at the University of Massachusetts Amherst and involving scientists from around the world, could reshape current ideas about the early universe.
The galaxies are unusual because they are packed with dust and actively forming stars. Cosmic dust blocks visible and ultraviolet light, which means traditional telescopes cannot easily detect them.
For decades, this made such galaxies nearly invisible, hiding an important chapter of cosmic history.
Only with newer technology that can detect longer wavelengths of light have astronomers begun to reveal these hidden objects.
To find them, researchers first used the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, a powerful telescope designed to observe the faint glow of cold dust in distant space. ALMA identified hundreds of bright, dusty galaxies.
The team then used the James Webb Space Telescope to look deeper into the same regions in near-infrared light, which can pass through dust more easily.
This allowed them to pinpoint about 70 faint galaxy candidates at extreme distances, most of which had never been seen before.
By combining and analyzing the data carefully, scientists confirmed that these galaxies existed nearly 13 billion years ago, when the universe was still very young. What makes them especially important is their role in a possible cosmic timeline.
Astronomers have recently discovered extremely bright galaxies that formed just a few hundred million years after the Big Bang, as well as older “dead” galaxies that stopped forming stars relatively early. The newly found dusty galaxies appear to sit between these two stages, representing a middle phase in galaxy evolution.
Researchers compare this to seeing different snapshots of a life cycle. The ultrabright galaxies are like infants, bursting with new stars.
The quiescent galaxies are elderly, no longer forming stars. The newly discovered group may represent the “young adult” stage, when galaxies are still growing but beginning to mature.
The discovery challenges existing models of how quickly galaxies formed in the early universe. The presence of large amounts of dust and heavy elements suggests that star formation began earlier and progressed faster than scientists previously believed. This means our current understanding of cosmic history may need to be revised.
Although more observations are needed to confirm the details, the findings provide a new piece of the puzzle of galaxy evolution. By revealing these hidden galaxies, astronomers are getting closer to understanding how the vast variety of galaxies we see today came to exist.
As technology continues to improve, scientists expect to uncover even more surprises in the distant universe. Each new discovery brings us closer to answering one of the biggest questions in astronomy: how did the cosmos grow from a simple beginning into the complex universe we observe today?
Source: University of Massachusetts Amherst.
