Dinosaur in the space: Astronomers discover ancient galaxy untouched for 7 billion years

Astronomers have confirmed the discovery of a rare, ancient galaxy that has remained virtually unchanged for over 7 billion years, offering a rare glimpse into the early universe.

The galaxy, known as KiDS J0842+0059, is being hailed as a “cosmic fossil” due to its pristine and undisturbed state. Researchers say it has experienced little to no interaction with other galaxies since its formation, allowing it to retain its original structure.

Cosmic fossil

A cosmic fossil is a galaxy that has managed to remain unchanged by collisions and interactions with other galaxies. That means they can act as pristine time capsules to help astronomers study earlier galaxies.

“We have discovered a galaxy that has been 'perfectly preserved' for billions of years, a true archaeological find that tells us how the first galaxies were born and helps us understand how the universe has evolved to this day,” said Crescenzo Tortora, co-leader of the research team from Italy’s National Institute for Astrophysics (INAF).

The findings were made using observations from several leading instruments, including the Large Binocular Telescope (LBT) and the Very Large Telescope (VLT), which allowed astronomers to confirm the galaxy’s compact size and stellar mass, approximately 100 billion times that of the Sun.

KiDS J0842+0059 was first identified in 2018 during the Kilo-Degree Survey (KiDS). More recent high-resolution imaging from LBT provided a clearer picture of the galaxy’s structure, ruling out prior uncertainties.

“This is the first time that we have been able to do this with such high-resolution data for a galaxy relic so far away,” said Chiara Spiniello, a researcher at the University of Oxford and a member of the research team.

The galaxy, located 3 billion light-years from Earth, has shown almost no signs of star formation over billions of years, which is unusual for galaxies of its size. Most galaxies continue to evolve through collisions and mergers, which trigger bursts of new star formation. In contrast, KiDS J0842+0059 appears to have remained dormant and isolated.

“Fossil galaxies are like the dinosaurs of the universe,” Tortora said. “Studying them allows us to understand in which environmental conditions they formed and how the most massive galaxies we see today evolved.”

The team compared KiDS J0842+0059 to NGC 1277, another well-known relic galaxy located much closer to Earth in the Perseus Cluster. Both share compact structures and similar characteristics, but KiDS J0842+0059 is far more distant, making it a rare observational target.

The researchers hope that future observations, particularly with the upcoming Euclid space telescope, will help identify more fossil galaxies and further refine models of galaxy formation and cosmic evolution.