NASA's Webb telescope detects galaxies formed right after Big Bang
NASA's James Webb Space Telescope (JWST) has spotted four of the oldest galaxies seen to date. These galaxies formed just 400 million years, or even earlier, after the Big Bang, which took place 13.8 billion years ago. A paper on them, which is yet to be peer-reviewed, was presented at the Space Telescope Science Institute in Baltimore on December 12.
Why does this story matter?
JWST, which took to space on Christmas last year, is the world's largest and most powerful space telescope. Before its arrival, the oldest galaxy ever seen in the universe was GN-z11. It is 25 times smaller than our Milky Way and is located in the Ursa Major constellation. It was discovered by the Hubble Space Telescope in 2016.
James Webb pictures galaxies as they were after Big Bang
"This is the way the galaxies would have appeared 13.4 billion years ago," said Brant Robertson, lead author of the paper and professor at the University of California, Santa Cruz. "With Webb, you can rewind the clock and see them as they were back then. That's what we're trying to do by taking these observations: we're looking back in time," he added.
The faintness of the galaxies suggested that they were old
What led to this discovery was a study conducted by the JWST Advanced Deep Extragalactic Survey (JADES). The research team, which consists of more than 80 astronomers from 10 countries, investigated a deep field that consisted of 100,000 galaxies, which was first captured by Hubble in 2010. The size, luminosity, and distance of several of these galaxies suggested that they were old.
Infrared radiation can pass through dust in interstellar space
Hubble could not provide a clear picture or determine the age of these galaxies, chiefly because it operates in visible light, which cannot penetrate the intervening dust of interstellar space. Webb, on the other hand, functions in the infrared spectrum, which can pierce through dusty layers and that's how it captured galaxies that lie as far as 13.6 billion light-years away.
The more distant an object is, the redder it appears
The concept of 'red shift' was used to study the four galaxies. To elucidate, the redder a cosmic object appears, the more distant it is. As reported by the study, the galaxies had red shifts of 10.38, 11.58, 12.63, and 13.2. "For most galaxies, the highest red shifts [or the oldest galaxies] we had spectra for were at six, seven, or eight," said Robertson.
