Currently, the oldest galaxy is JADES-GS-z13-0.
Before the discovery of JADES-GS-z13-0 by the James Webb Space Telescope (JWST) in 2022, GN-z11 was considered the oldest and most distant galaxy known. While GN-z11 remains a significant discovery, JADES-GS-z13-0's redshift indicates it's observed at an even earlier point in the universe's history.
It's important to note that the term "oldest" refers to how far back in time we are observing the galaxy, based on its redshift. Redshift is a measure of how much the light from an object has been stretched due to the expansion of the universe; a higher redshift corresponds to a greater distance and an earlier time. Therefore, the galaxy with the highest confirmed redshift is considered the oldest observed galaxy. Discoveries are ongoing and future observations could lead to the identification of even older galaxies.
