Webb detects universe's earliest complex organic molecules 12 billion light-years from Earth

The gravitational lensing technique in JWST enabled the study. “This magnification happens when two galaxies are almost perfectly aligned from the Earth’s point of view, and light from the background galaxy is warped and magnified by the foreground galaxy into a ring-like shape, known as an Einstein ring,” Vieira explained. 

The complex organic molecules are associated with cosmic dust grains

This research sheds light on the "complex chemical interactions" that occurred during the universe's early years. JWST gathered spectroscopic data that revealed that the galaxy is rich in heavy elements. 

The team discovered the presence of a type of molecule known as polycyclic aromatic hydrocarbon, or PAH, in the data. These molecules are found in our planet's oil and coal deposits. Interestingly, these molecules, which are composed of carbon chains, are considered to be the basic building blocks for the earliest forms of life.

Authors highlighted that these complex organic molecules are noted to be common in space and are generally associated with cosmic dust grains. The study of these molecules may shed light on the activity within galaxies, such as the rate at which cosmic gas cools.

Additionally, these organic molecules can help astronomers understand galaxy formation, its lifecycle, and evolution. 

“Detecting these complex organic molecules at such a vast distance is game-changing regarding future observations. This work is just the first step, and we’re just now learning how to use it and learn its capabilities. We are very excited to see how this plays out,” concluded Vieira. 

The results have been reported in the journal Nature.

Study Abstract:

Dust grains absorb half of the radiation emitted by stars throughout the history of the universe, re-emitting this energy at infrared wavelengths. Polycyclic aromatic hydrocarbons (PAHs) are large organic molecules that trace millimeter-size dust grains and regulate the cooling of interstellar gas within galaxiesObservations of PAH features in very distant galaxies have been difficult owing to the limited sensitivity and wavelength coverage of previous infrared telescopes. Here we present James Webb Space Telescope observations that detect the 3.3 μm PAH feature in a galaxy observed less than 1.5 billion years after the Big Bang. The high equivalent width of the PAH feature indicates that star formation, rather than black hole accretion, dominates infrared emission throughout the galaxy. The light from PAH molecules, hot dust and large dust grains and stars are spatially distinct from one another, leading to order-of-magnitude variations in PAH equivalent width and ratio of PAH to total infrared luminosity across the galaxy. The spatial variations we observe suggest either a physical offset between PAHs and large dust grains or wide variations in the local ultraviolet radiation field. Our observations demonstrate that differences in emission from PAH molecules and large dust grains are a complex result of localized processes within early galaxies.