Webb discovers oldest galaxies in this image of Abell 2744 galaxy cluster

This Webb Space Telescope image of the outer parts of the enormous galaxy cluster Abell 2744 shows two of the furthest galaxies seen so far.

Credits: SCIENCE: NASA, ESA, CSA, Tommaso Treu (UCLA), IMAGE PROCESSING: Zolt G. Levay (STScI)

November 17, 2022

The state of the art James Webb Space Telescope, operated by NASA, has uncovered a hitherto mostly unexplored "undiscovered territory" of early galaxies that is surprisingly abundant. The universe being revealed by Webb is incredibly rich, and the first galaxies that formed seem very different from the mature galaxies we see around us now. Two extremely brilliant galaxies were discovered by researchers between 350 and 450 million years after the big bang. Astronomers find their great brightness perplexing. Young galaxies are converting gas into stars at a very fast rate. They are much smaller than Milky Way galaxy in size, but are compressed into spherical or disk shapes. Just 100 million years after the big bang, which occurred 13.8 billion years ago, stellar birth may have begun.

The distances to these far-off galaxies should be confirmed by additional spectroscopic measurements made with the Webb space telescope, which will also provide information on the rate of star formation and the elemental abundances in the early stars.

After only a few days of official science operations, NASA's James Webb Space Telescope allowed scientists to observe early galaxies that had previously eluded all previous telescopes. Researchers discovered two extraordinarily brilliant galaxies in the GLASS-JWST photos after only four days of processing. Future spectroscopic observations with Webb will help corroborate that these galaxies existed between 450 and 350 million years after the big bang (with a redshift of roughly 10.5 and 12.5, respectively).

These two galaxies' current Webb distance estimates are based on analyzing their infrared hues. These cosmic yardstick readings will eventually be independently verified by subsequent spectroscopy measurements that demonstrate how light has been stretched in the expanding universe.

Source - NASA