Small galaxy Jades-GS-Z7-01-QU was at rest 13.8 billion years ago. It is the earliest quiet galaxy in the cosmos to date - also called a dead galaxy.
Previous record was 1.2 billion years after the Big Bang. Astronomers don't know why star formation in the galaxy abruptly stopped, but they have a few theories. All of the quiet galaxies known to date in the young cosmos are significantly larger, with over ten billion solar masses.