Black holes in Webb data protect cosmology’s standard model.

• Astronomers have been exploring how galaxies grew in the early universe since NASA launched JWST three years ago.

• The universe began with a Big Bang about 13.8 billion years ago as a hot, dense mixture of gases and subatomic particles.

• Over time, the universe expanded and cooled, creating larger structures such as stars, galaxies, and galaxy clusters.

• The standard model of cosmology suggests the first stars formed around 100-200 million years after the Big Bang and the first galaxies within the first billion years.

• JWST revealed massive, fully-developed galaxies around 400-650 million years after the Big Bang, a mismatch with the standard model.

• The study, led by Katherine Chworowsky and Steven Finkelstein at the University of Texas at Austin, suggests that the early universe produced stars more efficiently than the current galaxies.

• The study also examined the black holes at the centers of these ancient galaxies, also known as “little red dots,” which rapidly consume the galaxies’ gas, causing them to emit heat and light.

• The researchers found that the star mass of galaxies may have been overstated in previous studies due to the additional light emitted by their black holes.

• The standard model could explain more efficient star formation in the early universe in the form of extreme physical conditions and abundant gas.

• Previous JWST observations of massive, well-developed galaxies in the early universe have questioned the standard model, including the universe’s age, the timeline for the formation of the first galaxies, and galaxy formation theories.

• The team is working on including more data from JWST in addition to CEERS to push the analysis to higher redshifts and higher masses.