09/01/2026
Have you tried baking cookies without flour, sugar, or butter?
It requires some inventiveness. Webb revealed rare dust created in a primitive cosmic kitchen that shows that the early universe shared bakers’ resilience. Sextans A is an early dwarf galaxy with very low metallicity (meaning low amount of elements heavier than hydrogen or and helium), so astronomers didn’t expect to find dust.
Planets are built from dust created by stars. Creating dust in Sextans A is like baking cookies without flour, butter, or sugar. The elements just aren't there. However, astronomers not only found dust, Webb showed that one of these stars used an entirely different recipe than usual to make that dust.
Webb also revealed polycyclic aromatic hydrocarbons (PAHs), which are complex, carbon-based molecules integrated in the smallest dust grains, that glow in infrared light. The discovery means Sextans A is now the lowest-metallicity galaxy ever found to contain PAHs.
Together, the results show that the early universe had more diverse dust production pathways than the more established and proven methods, like supernova explosions. Additionally, researchers now know there’s more dust than predicted at extremely low metallicities.
Because it is relatively close, Sextans A gives astronomers a rare chance to study individual stars and interstellar clouds under conditions similar to those shortly after the Big Bang.
Read more: https://go.nasa.gov/49o60LL
