What Is The Farthest Galaxy?

The James Webb Space Telescope (JWST) has been operating for less than a year, yet it may have already discovered the farthest known galaxy in the universe. The study, which was led by Rohan Naidu at Harvard University, used recent data and images from Webb to find a candidate for the farthest, and oldest, known galaxy in the universe. The fact that Webb has been in operation for less than a year and has potentially broken the record for farthest galaxy goes to show just how powerful this telescope truly is. 

Observing The Early Universe

Webb Deep Field
This image from the JWST contains some of the furthest, and oldest, known galaxies. Image credit: NASA/ESA

The candidate galaxy is designated as GLASS-z13. The galaxy itself is located a staggering 13.5 billion light years away. The universe is 13.8 billion years old, so this galaxy formed within 300-million years after the Big Bang. If the numbers are confirmed by later studies, GLASS-z13 would be both the farthest and oldest galaxy ever discovered. By observing this galaxy, Webb is able to study the universe as it was a mere 300-million years after the Big Bang, allowing the telescope to further our understanding of how the first galaxies came to be. Observations of GLASS-z13 and other distant galaxies are already changing assumptions of early galaxies. Many of the most distant galaxies observed by Webb are more massive than earlier models predicted for the early universe. For example, GLASS-z13 is over one billion times the mass of the sun. Although galaxies this large have been discovered in the early universe, astronomers believed them to be quite rare. However, recent observations from Webb are revealing that early galaxies may have been more massive than originally thought. The reason why early galaxies are generally believed to have low masses is because not enough time has passed since the Big Bang for enough stars to form. If it turns out that early galaxies are indeed more massive than originally predicted, it will also suggest that star formation happened a lot faster and more often than astronomers believed. The researchers note, however, that this study has not yet been confirmed, and they caution against any factual claims that GLASS-z13 is indeed the farthest galaxy ever discovered. Future observations from Webb are needed to confirm these findings, yet they still go to show just how powerful Webb is compared to other telescopes.