Unlocking of a "Dead" Galaxy from the Dawn of Time

Peering into the depths of our solar system, astronomers confront the daunting reality: we barely scratch the surface of understanding the boundless void that surrounds us.

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Peering into the depths of our solar system, astronomers confront the daunting reality: we have barely scratched the surface of understanding the boundless void that surrounds us. In a recent groundbreaking discovery, astronomers announced the mysteries of a seemingly ‘dead’ galaxy from the earliest echelons of the universe. This galaxy, formed just 700 million years after the Big Bang, provides a glimpse into the cosmic beginning and challenges existing theories about galaxy formation and evolution. 

This galaxy, named JADES-GS-s7-01-QU, was discovered by an internal team of astronomers led by the University of Cambridge using the James Webb Space Telescope (JWST). The JWST is one of the most technologically advanced telescopes ever constructed. Unlike optical telescopes like the Hubble Space Telescope, the JWST is equipped explicitly with infrared electromagnetic spectrum technology. This allows radiation to pass through dust without getting scattered, so astronomers can get clear images of space from areas that are not visible at optical wavelengths. This sensitivity allows the JWST to detect emissions from distant objects like the "dead" galaxy. 

What made this galaxy incredibly unique was its puzzling discovery and appearance. The JWST sensors caught faint emissions from ionized oxygen within the galaxy, and researchers classified it as a “dead” galaxy because it lacked the telltale signs of active star formation and appeared dormant. The galaxy wasn't actively ionizing oxygen, which was present in the first place, indicating that massive stars once thrived within the galaxy, emitting intense ultraviolet radiation that ionized the surrounding gas. However, the galaxy's star-forming activity unexplainably ceased, leaving many older stars and remnants of ionized oxygen.

Since the galaxy existed near the universe's beginning, rapid star forming andstar  stopping was unexpected. According to  Kavli Institute for Cosmology astrologist Tobias Looser, the first few hundred million years of the universe were active phases. Many gas clouds collapsed to form new stars. During this time, galaxies needed a rich gas supply to continuously form new stars. The process of forming new stars involves collapsing gas and dust clouds, where dense cores form and evolve into protostars—stars whose cores are not yet hot enough for fusion. Then, protostars become stars through nuclear fusion. Nuclear fusion is the process where hydrogen nuclei fuse to form helium nuclei by combining two protons and converting one of them into a neutron to form the heavy isotope of hydrogen known as deuterium, which releases tremendous amounts of energy. This energy is used to ignite the protostars, leading to star birth. Throughout their lives, stars emit radiation, stellar winds, and streams of charged particles, influencing their surroundings and regulating the star formation process within galaxies. The great mystery was that the “dead” galaxy stopped producing stars that early since previous galaxies were only seen to stop forming stars later in the universe. Astronomers had previously theorized that various factors could hinder star formation within galaxies by depriving them of the necessary gasses for new star birth. For example, internal forces such as internal black holes or external lack of replenishment, such as a lack of hydrogen gas, can deprive stars of such gasses. Still, even such scenarios couldn’t explain the situation of the “dead” planet as the process of creating stars abruptly stops. 

While the oldest, the dead galaxy is also the smallest mass of the known galaxies. Such statistics continue to confuse astronomers as other quenched galaxies at the time were of high mass. Thus, astronomers continue to hypothesize explanations for such a phenomenon—some theorize that it appears dead at the current observation time, but it’s possible that instead of permanently not being able to create stars, the galaxy goes through phases of activity and inactivity. Scientists additionally theorize that in roughly 13 billion years, this galaxy may return to life and start forming new stars again. Ultimately, this discovery prompts astronomers to reconsider existing models of galactic evolution such as the idea of galaxies continuously creating stars at the beginning of their journeys. Further observations of similar galaxies would provide valuable insights into the cosmos' mechanisms driving star formation and quenching.