from NASA James Webb Space Telescope revealed the most distant galaxies ever discovered, some dating back just 300 million years after the creation of the universe during the Big Bang – a time when the cosmos was only 2% of its current age.
The primordial galaxies were discovered by an international team of scientists responsible for the design of two of the JWST’s state-of-the-art instruments. The first instrument, known as the Near Infrared Camera (NIRCam), was tasked with observing a small portion of the night sky in the constellation Fornax.
For 10 days, NIRCam observed the light emitted by a population of nearly 100,000 galaxies over a range of nine infrared wavelengths. From this dataset, astronomers isolated 250 of the faintest, reddest galaxies and targeted them with another of JWST’s instruments, the Near Infrared Spectrograph (NIRSpec).
Incredible images from the James Webb Space Telescope
NIRSpec is designed to collect light emitted by celestial bodies and break it down into its constituent colors. This process creates rainbow graphics called spectra. Astronomers can analyze a galaxy’s spectra to find out everything from its elemental composition to the number of stars in it, and even its distance from Earth.
The latter is achieved by measuring a phenomenon known as redshift. It may take billions of years for light emitted by very distant galaxies to reach our planet. During this time, the wavelengths of this light stretch and lengthen, slowly moving into the “redder” part of the light spectrum.
As light travels towards Earth from its source, it will inevitably pass through vast clouds of interstellar dust and gas. These clouds are known to absorb certain wavelengths of light, while allowing others to pass relatively unhindered. This interference creates a distinct pattern in the rainbow spectra.
Scientists were able to determine the age and distance of distant galaxies by observing how much the patterns in the spectra had shifted from their expected positions due to the redshift.
Using this technique, scientists have discovered four phenomenally old galaxies hidden in the JWST data, believed to have formed just 300 million years after the creation of the universe during the Big Bang. This makes them 100 million years younger than the oldest galaxy discovered by the The Hubble Space Telescope.
This means that the light detected by the JWST left its source about 13.4 billion years ago, at a time when the universe was only 2% of its current age. The record age of galaxies will make them invaluable to scientists trying to unlock the evolutionary secrets of the early cosmos.
“It is difficult to understand galaxies without understanding the initial periods of their development,” explained astronomer Sandro Tacchella of the University of Cambridge, co-author of a study describing the results (via the University of Arizona). “Just like with humans, much of what happens later depends on the impact of those early generations of stars.”
“So many questions about galaxies have been waiting for Webb’s transformative opportunity, and we’re thrilled to be able to play a part in telling this story.”
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Image credit: Northrop Grumman.
Anthony is a freelance contributor covering science and gaming news for IGN. He has over eight years of experience covering groundbreaking developments in multiple scientific fields and has absolutely no time for your shenanigans. Follow him on Twitter @BeardConGamer