In this vast universe, the James Webb Space Telescope (JWST) has captured a stunning astronomical phenomenon – it has discovered the oldest known "dead" galaxy to date. The discovery of this galaxy not only challenges our understanding of the early universe, but also reveals new mysteries of cosmology.
When the universe was young, only 700 million years old, the galaxy was named jades-gs-z7-01-qu (jades for short), and its star-forming activity suddenly stopped. This phenomenon is in stark contrast to the bustling scenes of star-forming elsewhere in the universe. There, thanks to the abundance of primordial gas and dust, the birth of stars is as brilliant as fireworks.
A recent article published in the journal Nature detailed the description of this galaxy, providing us with a unique perspective on the mystery of the evolution of galaxies in the primordial universe. The article examines the possible reasons why galaxies stop forming new stars, and whether the forces that drive their star explosions will change over time.
Life in galaxies needs abundant gas to give birth to new stars, and the early universe is full of such resources, as if it were an endless source. Tobias Luthor, a researcher at the Kavly Institute for Cosmology (KIC) at the University of Cambridge. However, the current model of the universe cannot fully explain the phenomena of the Jades galaxies. Not only was it born shortly after the formation of the universe, but it quickly ended the operation of its starfactory in less than a billion years.
We usually only see galaxies stop forming stars in the late stages of the universe. Francesco de Euginho, another researcher at KIC, added. At the same time, researchers have found that some other "dead" galaxies appear to have stopped the formation of new stars during the period when the universe was about 3 billion years old.
In the early universe, everything happened faster and more dramatically. "This includes the transition of galaxies from the flourishing star-forming phase to dormant or extinguished." ”
To unravel the mystery of the Jades, Luthor and his team used JWST's powerful infrared vision to penetrate the thick curtain of dust and observe the earliest objects in the universe. Not only is this newly discovered galaxy the oldest known "dead" galaxy, but it is also far less massive than other similar stationary galaxies discovered in the early universe. JWST data shows that the galaxy experienced a period of intense star formation of about 30 million to 90 million years before it stopped star formation, but what exactly caused its "death" remains a mystery.
Astronomers already know that there are a variety of factors that can cause star formation to slow down or stop. For example, turbulence inside galaxies, or radiation from supermassive black holes, can push gas out of galaxies, depriving them of the gas reserves needed to form new stars. Another possibility is that the environment around the galaxy has not been replenished with enough gas to support the continued birth of stars, leading to the depletion of star-forming materials.
We are not yet sure if any of these scenarios can explain the phenomena we observed through the Webb telescope. Said Roberto Meolino, an astrophysicist at KICC. This means that current models based on the modern universe may need to be revisited.
Another possibility that new galaxies are dormant is that galaxies in the early universe experienced a "death" and then "resurrected". De Juuginho put forward such an assumption. However, studies of "dead" galaxies in the universe about 3 billion years ago – and the period when stars were most frequently born – have shown that even by merging with nearby galaxies, these galaxies do not rejuvenate, but only cause them to "expand" further.
We need more observations to help us figure it all out. De Juginho said.