Scientists have made a groundbreaking discovery using the James Webb Space Telescope (JWST), uncovering the oldest “dead” galaxy ever observed. This cosmic corpse has left astronomers perplexed as it challenges our current understanding of the early universe. The galaxy, named JADES-GS-z7-01-QU, ceased star formation when the universe was just 700 million years old, defying expectations given the abundance of pristine gas and dust available for star birth at that time.
The findings, published in the journal Nature, provide astronomers with a glimpse into the mysterious mechanisms behind galaxy evolution in the primordial universe. It raises questions about why galaxies stop forming new stars and whether the forces driving their starbursts change over time.
Lead author Tobias Looser, from the University of Cambridge’s Kavli Institute for Cosmology, explains that galaxies require a rich supply of gas to form new stars, and the early universe was like an “all-you-can-eat buffet.” However, current models fail to explain how JADES-GS-z7-01-QU not only formed in less than a billion years after the Big Bang but also abruptly halted star formation.
Typically, galaxies stop forming stars much later in the universe’s history. Francesco D’Eugenio, another researcher at KICC, highlights that other “dead” galaxies discovered elsewhere paused star formation when the universe was approximately 3 billion years old. This suggests that everything occurred more rapidly and dramatically in the early universe, including galaxies transitioning from a star-forming phase to a dormant state.
To locate JADES-GS-z7-01-QU, Looser and his team utilized the JWST’s infrared vision to penetrate the thick veil of dust obscuring early objects in the universe. In addition to being the oldest “dead” galaxy found thus far, this newfound galaxy is significantly lighter than other similarly quiescent galaxies from the early universe.
The JWST’s data indicates that JADES-GS-z7-01-QU experienced an intense period of star formation lasting between 30 million to 90 million years before abruptly ceasing. However, the exact cause of this cessation remains unknown. Astronomers propose several factors that could slow down or extinguish star formation, such as turbulence within the galaxy or a supermassive black hole emitting radiation that pushes gas out of the galaxy. Another possibility is that the galaxy’s surroundings failed to replenish the gas reservoir necessary for star formation.
However, study co-author Roberto Maiolino suggests that none of these scenarios can fully explain the observations made with the JWST. Current models based on the modern universe are inadequate in explaining the properties of JADES-GS-z7-01-QU, indicating that they may require revision.
Another intriguing hypothesis is that galaxies in the early universe may “die” and then experience a resurgence in star formation. However, previous research on “dead” galaxies from around 3 billion years after the Big Bang contradicts this idea. These galaxies were unable to rejuvenate even through mergers with nearby galaxies, which only served to expand their size.
Further observations are necessary to unravel the mysteries surrounding JADES-GS-z7-01-QU and determine whether galaxies in the early universe can indeed experience a rebirth. The discovery of this ancient “dead” galaxy challenges our current understanding of the early cosmos and highlights the need for continued exploration and research in the field of astronomy.