Webb telescope captures the most distant galaxies ever seen
NASAs James Webb Space Telescope has revealed the most distant galaxies ever discovered, some of which date back just 300 million years after the creation of the universe in the Big Bang — a time when the cosmos was only two percent of its current age.
The original galaxies were found by an international team of scientists responsible for designing two of the JWST’s most advanced instruments. The first instrument, known as the Near Infrared Camera (NIRCam), was tasked with observing a small slice of the night sky in the constellation Fornax.
Over the course of 10 days, NIRCam observed the light emitted from a population of nearly 100,000 galaxies across a range of nine infrared wavelengths. From this dataset, the astronomers isolated 250 of the dimmest and reddest galaxies and focused them on another instrument of the JWST: the Near Infrared Spectrograph (NIRSpec).
Incredible images from the James Webb Space Telescope
NIRSpec is designed to capture the light emitted by celestial bodies and split it into its component colors. This process creates rainbow-like graphs called spectra. Astronomers can analyze the spectra of a galaxy to discover everything from the composition of the elements to the number of stars present and even its distance from Earth.
The latter is done by measuring a phenomenon known as redshift. It can take billions of years for light from very distant galaxies to reach our planet. During this time, the wavelengths of that light stretch and lengthen, slowly moving toward the “redder” part of the light spectrum.
As light travels to Earth from its source, it will inevitably pass through huge clouds of interstellar dust and gas. These clouds are known to be good at absorbing certain wavelengths of light while allowing others to pass relatively unimpeded. This interference creates a clear pattern in the rainbow spectra.
Scientists were able to figure out the age and remoteness of the distant galaxies by observing how much the patterns in the spectra had shifted from their expected positions due to redshift.
Using this technique, the scientists discovered four phenomenally ancient galaxies lurking in the JWST data, believed to have formed just 300 million years after the universe was created in the Big Bang. That makes them 100 million years younger than the oldest galaxy known by 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-breaking age of the galaxies will make them invaluable to scientists trying to unravel the evolutionary secrets of the early cosmos.
“It’s hard to understand galaxies without understanding the early stages of their development,” explains University of Cambridge astronomer Sandro Tacchella, who co-authored a study describing the results (via the University of Arizona). “As with humans, so much of what happens later depends on the impact of these early generations of stars.”
“So many questions about galaxies have been waiting for Webb’s transformative opportunity, and we’re thrilled to play a part in revealing this story.”
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Image credit: Northrop Grumman.
Anthony is a freelance contributor covering science and video game news for IGN. He has more than eight years of experience in cutting-edge developments in multiple scientific fields and has absolutely no time for your jokes. Follow him on Twitter @BeardConGamer
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