🌅 Galaxies Form Families

SOURCE

Toni et al. (2025)

WHAT TO KNOW

• Astronomers used the James Webb Space Telescope to observe nearly 1,700 galaxy groups some 12 billion light-years away in the constellation Sextans, capturing the largest and deepest sample of galaxy groups ever observed. The universe is believed to be 13.8 billion years old, so the galaxies captured by the team offer “unprecedented insights” into the early universe and how galaxies form and evolve over time.

WHY IT MATTERS

• Like humans, galaxies come together and form “families” (called galaxy “clusters” or “groups,” depending on the size), which are important as they allow astronomers to observe the galaxies as they interact and merge together, transforming their structures and appearances over billions of years of cosmic time (galaxies born in the early universe tended to have irregular shapes and formed a lot of stars, while galaxies that formed later on appear more symmetrical and structured, like our Milky Way). Galaxy clusters also allow astronomers to study other mysterious phenomena, like dark matter, supermassive black holes, and the hot gas that fills the space between galaxies.

CONNECT THE DOTS

• The observation captured in the present study is known as a “deep field observation,” which astronomers use to reveal faint space objects by collecting their light for an appropriately long period of time. NASA’s first such observation was the Hubble Deep Field in 1995, which captured 3,000 distant galaxies at various stages of evolution. NASA followed that up with two more deep field observations using Hubble, culminating with the Hubble eXtreme Deep Field released in 2012, which captured some 5,500 galaxies up to 13.2 billion light-years away.