James Webb Space Telescope Finds Tiny Galaxy From Early Universe That Produced Stars At High Power

The galaxy observed by James Webb Space Telescope existed around 500 million years after the Big Bang, and is one of the smallest ever discovered from the distant universe. 

James Webb Space Telescope's observations have helped researchers find a tiny galaxy from the early universe that produced stars at an extremely high rate for its size. The galaxy existed around 500 million years after the Big Bang, and is one of the smallest ever discovered from the distant universe. 

Researchers from the University of Minnesota Twin-Cities discovered the galaxy by looking back more than 13 billion years into the past. The study describing the findings was recently published in the journal Science. 

Why is it difficult to observe early galaxies?

According to the study, ultraviolet light from early galaxies is thought to have ionised gas in the intergalactic medium. However, the faintness of galaxies from the early universe, and the redshift of their optical light, or the stretching of the wavelength of light such that it appears 'shifted' towards the red part of the spectrum, result in observational constraints on the distant universe. The optical light is redshifted to infrared, which has a greater wavelength range. 

How did Webb obtain a detailed image of the tiny galaxy?

Galaxies from the early universe can provide clues to how the universe became re-ionised. James Webb Space Telescope has captured a detailed image of the galaxy by leveraging a phenomenon called gravitational lensing. This is a process in which a huge mass, such as that in a galaxy or galaxy cluster, bends and magnifies light. The small background galaxy with high star power appeared 20 times brighter than it would if there were no gravitational lensing because a galaxy cluster in the foreground magnified the light from the miniscule galaxy. 

In order to measure how far away the galaxy was, and determine some of its physical and chemical properties, the researchers used spectroscopy, which is the study of the absorption and emission of light and other radiation by matter. 

Significance of the discovery

Since the James Webb Space Telescope is capable of collecting about 10 times as much light as the Hubble Space Telescope, and is much more sensitive at redder, longer wavelengths in the infrared spectrum, scientists are able to access an entirely new window of data.

In a statement released by University of Minnesota Twin-Cities, Patrick Kelly, senior author on the paper, said the galaxy is far beyond the reach of all telescopes except the James Webb Space Telescope, and these "first-of-its-kind observations" of the distant galaxy are spectacular. He also explained that through this galaxy, the researchers have been able to see most of the way back to the Big Bang, and scientists have never looked at galaxies when the universe was this young in this level of detail. The volume of the galaxy is about a millionth of the volume of the Milky Way, but it formed the same numbers of stars each year.

Hayley Williams, first author on the paper, said the galaxies that existed when the universe was in its infancy are very different from the galaxies seen in the nearby universe. Therefore, the discovery helps researchers learn more about the characteristics of those first galaxies, how they differ from nearby galaxies, and how the earlier galaxies formed.