Discovery of a “Fossil Galaxy” 3 billion light-years away: An unchanging cosmic witness for 7 billion years

Scientists have observed a galaxy 3 billion light-years away that has undergone almost no evolutionary change for 7 billion years. This galaxy, designated KiDS J0842+0059, is classified as a "fossil galaxy" and offers unique insights into the universe's earliest star formation periods.

Italian astronomers who conducted the research stated that 99.5% of the galaxy's stars formed when the universe was still very young. Therefore, KiDS J0842+0059 is thought to be one of the giant galaxies that has not merged and remains isolated.

An exception to the two-stage galaxy evolution

According to astronomical models, large galaxies generally form in two stages. In the first stage, dense stars form rapidly, and in the second stage, the galaxy grows by merging with its surroundings. However, fossil galaxies survive to the present day without experiencing this second stage.

In this respect, KiDS J0842+0059 preserves a frozen memory of the first few billion years of the universe.

A star-studded yet silent structure

Despite the galaxy containing billions of Sun-like stars, new star formation has almost completely ceased, rendering the galaxy "quiet." Scientists say that finding planetary systems in such dense and isolated structures would be extremely difficult.

Exploration started in 2018, verification just arrived

The first traces of the galaxy were discovered with the VLT (Very Large Telescope) in Chile in 2018. However, the identification of KiDS J0842+0059 as a fossil galaxy was made possible thanks to high-resolution observations made with the Large Binocular Telescope (LBT) in Arizona.

Dr. Chiara Spiniello, one of the lead authors of the study, emphasized that such galaxies exist at a rate of one in a million in the universe, saying, "These are galaxies where time has stopped."

New telescopes will reveal fossils

Scientists believe the Euclid telescope, launched by the European Space Agency in 2023, will play a key role in discovering more such fossil galaxies. Euclid will also collect data on dark matter and energy.

Prof. Michele Cappellari from Oxford University said, “Fossil galaxies are invaluable natural archives for our understanding of the early universe.”