NASA’s James Webb Space Telescope has revealed the most distant galaxies ever discovered, some of which date back 300 million years to the creation of the universe in the Big Bang.
The primordial galaxies were discovered by an international team of scientists who were responsible for designing two of the JWST’s flagship instruments. The first instrument, known as the Near Infrared Camera (NIRCam), was developed to observe the smallest patch of night sky in the constellation Fornax.
Over the course of 10 days, NIRCam observed light emitted from a population of nearly 100,000 galaxies over a total of nine infrared wavelengths. From this dataset, astronomers selected 250 faint and red-shifted galaxies, and targeted them with another JWST instrument—the Near Infrared Spectrograph (NIRSspec).
NIRspec is designed to collect the light emitted by celestial bodies and break it down into its colors. This process creates iridescent graphs called spectra. Astronomers can analyze the spectrum of a galaxy to find out everything from its elemental composition, to the number of stars it contains, and even its distance from Earth.
This is done by measuring a phenomenon known as redshift. It can take billions of years for light emitted from very distant galaxies to reach our planet. During this time, the wavelengths of that light are stretched and become longer, gradually moving into the red part of the light spectrum.
When light travels from its source to Earth, it must pass through vast clouds of interstellar dust and vapor. These clouds are known to be good at absorbing certain wavelengths of light, while allowing others to pass through a relative barrier. This interference creates a distinct pattern in the rainbow spectrum.
Local galaxies and their redundancies (Credit: SCIENCE: NASA, ESA, CSA, Rolf A. Jansen (ASU), Jake Summers (ASU), Rosalia O’Brien (ASU), Rogier Windhorst (ASU); Aaron Robotham (UWA), Anton M. Koekemoer (STScI), Christopher Willmer (University of Arizona), JWST MARGARITA Team. IMAGE COURTESY: Rolf A. Jansen (ASU), Alyssa Pagana (STScI))
Knowing the age and distance of distant galaxies, they could infer how far the patterns in the spectra shifted from their expected redshift positions.
Using this technique, scientists have discovered four phenomenally old galaxies hidden in the JWST data, which are thought to have formed only 300 million years after the creation of the universe in the Big Bang. That makes them 100 million years younger than the oldest galaxy found by the Hubble Space Telescope.
This means that the light detected by JWST left its source about 13.4 billion years ago, at which time the universe was just 2% of its current age. The fractional age record of galaxies will prove valuable to scientists trying to unlock the mysteries of the early cosmos’ evolution.
“It is difficult to understand galaxies without an understanding of the first period of their development,” explained the astronomer Sandro Tacchella from the University of Cambridge, who co-opted the study to describe the results (through the University of Arizona). “As with humans, so much of what happens later depends on the impact of these stars at an early age.”
“We’ve been waiting for Webb’s transformative opportunity for so many questions about galaxies, and we’re thrilled to be able to play a part in this unfolding story.”
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Image Credit: Northrop Grumman.
Anthony is a freelance clothing science contributor and video game reporter for IGN. He has over eight years of experience in covering developments in multiple scientific fields and has absolutely no time for your shenanigans. Follow him on Twitter @BeardConGamer
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