(ORDO NEWS) — Spectroscopic observations by the James Webb Space Telescope have confirmed the existence of four ancient galaxies that formed less than 400 million years after the Big Bang.
Three of them became the most distant galaxies from Earth known today.
Using data from the James Webb Space Telescope (JWST), an international team of astronomers has discovered the earliest and most distant galaxies known today.
The telescope captured the light that these galaxies emitted more than 13.4 billion years ago.
This means that they formed less than 400 million years after the Big Bang, when the universe was only 2% of its current age.
Initial observations by the JWST and the Hubble Space Telescope have provided scientists with data on several candidate galaxies located at extreme distances.
Scientists can determine the distance to a galaxy by measuring its “redshift”.
Due to the constant expansion of the universe, distant space objects are moving away from us, which is why the light they emit is stretched to longer red waves.
Now, long-term spectroscopic measurements have confirmed the existence of four of them. At the same time, three turned out to be the most distant galaxies from the Earth.
This study was the result of a collaboration between scientists who developed two instruments aboard the JWST: the Near Infrared Camera (NIRCam) and the Near Infrared Spectrograph (NIRSpec).
Astronomers first used NIRCam to observe for 10 days the so-called Hubble Ultra-Deep Field, a region of the sky that contains the most distant known objects in the universe.
The team observed the field in nine different infrared wavelengths, taking images that showed nearly 100,000 galaxies, each billions of light-years away.
The scientists then used NIRSpec to capture the emission from 250 dim galaxies. This made it possible to accurately measure the redshift and determine some properties of the gas and stars in these galaxies.
According to the authors of the work, star formation in these early galaxies should have begun about 100 million years earlier than the age at which they are observed now.
This fact shifts the estimated time of formation of the earliest stars by about 225 million years after the Big Bang.
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