James Webb is ten times more effective at capturing lights than the Hubble

Ultra Deep Field completed in 20 hours instead of 11 days 05.Jun.23 7:28 AM By Abigail Richards Photo NASA    354

Whereas the Hubble Space Telescope needed an exposure time of more than 11 days to create its masterpiece 'Ultra Deep Field', the James Webb telescope needs only a small day to paint the same galaxies on the black canvas. On 11 October 2022, the James Webb telescope was tasked with observing for 20 hours a patch of sky in the Taurus constellation that had been photographed by Hubble 16 years earlier. The result is astonishing. The space telescope took less than 10% of Hubble's exposure time to get the same result. Webb's own 'Ultra Deep Field' shows distant galaxies that existed when the universe was only 800 million years old. By the way, these galaxies are barely visible: they are faint red dots on the inky black background. The larger galaxies in the foreground are relatively close, when the universe was about a billion years younger than today. "We even see hot, ionised gas in galaxies. These are places where stars are born," says Professor Michael Maseda of the University of Wisconsin-Madison. "This information is very important because we still don't know exactly how galaxies became what they are today. Less than 24 hours of exposure time is not long, but in this relatively short time we have gained a better picture of how galaxies grow during this particular phase [reionisation, ed.] of the universe." When the universe was tiny, only neutral hydrogen gas existed. But the process of reionisation changed that. A few hundred million years after the Big Bang, the first stars, galaxies and supermassive black holes were born. To this day, astronomers still don't quite understand where the incredible amount of energy required for this came from.

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