The James Webb Space Telescope has discovered two of the oldest galaxies ever seen in space, and they’re much brighter than expected, meaning astronomers are rethinking their beliefs about how the first stars formed.
The two galaxies are believed to be billions of years old, just 100 million years after the Big Bang. Webb can glimpse some of the oldest galaxies because he operates in the infrared, which means he can see redshift galaxies, Digitartland reports.
A redshift occurs when light from a distant galaxy shifts towards the red end of the spectrum due to the expansion of the universe. Webb can see it.
Previous research estimated that some of Webb’s galaxies could have redshifts of up to 14, but recent results are more accurate thanks to better instrument calibrations and indicate redshifts for the two galaxies of 10.5 and 12.5, respectively.
The web also takes advantage of a phenomenon called gravitational lensing, in which a massive object such as a galaxy or group of galaxies has such a large mass that it curves in space and acts like a magnifying glass, allowing researchers to see more distant galaxies behind of them.
