Since it started delivering its first results in July 2022, the James Webb Space Telescope (JWST) has been supplying stunning images of the universe that include observations of the most distant and early galaxies we've ever seen. But how do we know that they really are so old?
Recently, it was confirmed that the JWST had indeed observed four of the most distant and thus earliest galaxies known to date, which existed when the 13.8 billion-year-old universe was no more than around 350 million years old.
