A far-off chemical signal, detected by the infrared capabilities of the James Webb Space Telescope, has recently provided a fresh perspective on the molecular universe. For the first time, an international group has discovered intricate organic molecules within the ices encircling a young star situated well outside our Milky Way galaxy.
This groundbreaking discovery, achieved under intense cosmic circumstances, provides fresh insight into the chemical reactions that can lead to the fundamental components of life.
This significant breakthrough was achieved by a scientific team headed by Marta Sewiło from the University of Maryland and NASA. By utilizing the MIRI instrument aboard the James Webb Telescope, scientists examined the makeup of the ices around the young star ST6, which is found in the Large Magellanic Cloud, a companion galaxy to our own. The high quality of the spectra collected allowed for the identification of five different organic molecules, some of which had not been seen in this type of setting before.
A real-world environment featuring harsh conditions
The Large Magellanic Cloud presents a challenging setting for complex chemical processes. This galaxy contains only one-third to one-half the range of heavy elements found in our Solar System, and it is exposed to strong ultraviolet radiation. These features make it an important example of the early galaxies that existed in the universe’s infancy, when elements heavier than helium were far less common than they are now.
The identification of organic molecules in this scarce setting highlights the resilience of chemical reactions occurring in space. Scientists think these molecules mainly develop on the surface of cosmic dust particles, where atoms and basic molecules slowly come together due to the effect of surrounding radiation. This theory, which has been backed by previous theoretical models and lab tests, now receives clear observational support.
The existence of these organic compounds in such an extreme environment implies that prebiotic chemistry might be a common occurrence across the universe, including in the earliest galaxies. This possible universality supports the notion that the fundamental components required for life’s origin could be present in many different galaxies, extending well beyond our Milky Way.
Impacts on the beginning of life
Among the molecules discovered are methanol, ethanol, methyl formate, acetaldehyde, and acetic acid, with the last one not having been definitively found in interstellar ices prior. These carbon-based substances, familiar on Earth where certain ones like ethanol and acetic acid have everyday uses, serve as chemical building blocks that can contribute to the creation of more complex biological molecules.
The group also identified spectral signs indicating the existence of glycolaldehyde, a compound linked to sugars and seen as a possible building block for RNA elements. While this finding needs additional verification, it raises possibilities about the chance that molecules essential for life might develop in interstellar space prior to the formation of planets.
The persistence of these organic molecules throughout the process of planetary formation poses a significant challenge in comprehending how the building blocks of life can be integrated into newly forming planets. Scientists believe that these substances might survive the early stages of planetary growth and be transported undamaged to the surfaces of protoplanets, where they could take part in chemical reactions that contribute to the emergence of life.
Article author: Cédric DEPOND
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