Just 1.2 billion years after the Big Bang, galaxies were already shaped by where they lived

A large protocluster of galaxies that existed 12.6 billion years ago, first discovered with the Subaru Telescope, has been examined in detail using the James Webb Space Telescope (JWST). The study found that galaxies in crowded regions are more extended than similar galaxies in less dense environments. The results, published in The Astrophysical Journal Letters , show that even when the universe was only 1.2 billion years old, environment was already influencing how galaxies grow.