Life's building blocks may have formed near newborn stars and planets

A study from the American Chemical Society has shed new light on the origins of life’s essential building blocks. The researchers have discovered that carbamic acid, a simple amino acid, may have formed in the icy environments near newborn stars or planets. 

This finding challenges the traditional belief that life’s building blocks originated solely on early Earth, suggesting a cosmic genesis.

Prebiotic molecules 

Life on Earth is a relatively recent phenomenon in geological terms, but the components that led to its formation could be significantly older. 

The study proposes that prebiotic molecules, instead of originating in the oceans of early Earth, might have been birthed in the extreme cold of interstellar ices. These ices, composed of water and various gases, are found in the frigid realms of space.

Origins of amino acids

Previously, it was believed that amino acids, crucial for life, were products of reactions on prebiotic Earth or were brought to our planet by meteorites. 

The meteorite theory suggests that these molecules were collected by space rocks from interstellar ices or cosmic dust. However, the origins and formation period of these building blocks remained a mystery.

Model ices

To investigate, a research team led by Ralf Kaiser and Agnes Chang conducted experiments simulating conditions in interstellar ices. They created model ices with ammonia and carbon dioxide and observed their chemical reactions as they were gradually warmed on a silver substrate. 

Using Fourier transform infrared (FTIR) spectroscopy, the researchers detected the formation of carbamic acid and ammonium carbamate at extremely low temperatures of -348 and -389 degrees Fahrenheit (62 and 39 Kelvin). This indicates that these molecules, precursors to complex amino acids, could have formed during the earliest and coldest phases of star development.

“Ices observed spectroscopically in molecular clouds are predominantly water, unlike model ices employed here; however, the reaction products observed have also been identified with FTIR in model ices composed primarily of water,” noted the study authors. 

Key insights

The team discovered that at higher temperatures comparable to those near a new star, two carbamic acid molecules could combine to form a stable gas. The molecules could have been part of the raw materials of solar systems, including ours, and later delivered to early Earth by comets or meteorites.

The research opens new possibilities for deep space exploration. Instruments like the James Webb Space Telescope could be trained to search for these prebiotic molecules in distant, star-forming regions, potentially unraveling more secrets about the origins of life. 

The study was supported by the Division for Astronomy of the U.S. National Science Foundation, the W.M. Keck Foundation, and the University of Hawaii at Manoa.

The study is published in the journal ACS Central Science.

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